In the bleak mid winter

My monthly update is late as I wanted to see how the weather situation resolved, particularly with respect to the effect of snow on the panels. First is a graph of the past 34 days.


Notice how ten days are at zero. No appreciable power was generated because of the shading effect of snow on the panels, even when the Sun shone. If there is no more snow, then perhaps the recent fortnight might be the lowest point. What was remarkable was that a large portion of the panels could be clear but it took only a few percent coverage to completely short out the panels. A steeper roof would have cleared them more quickly. It has been an unusually snowy winter so far - and earlier than we are used to. Now on to the bigger picture:

This graph shows all generation since the beginning. The red line is the panels' 30-day average and the recent paucity of power has brought that figure down to only 1.54 units per day. The yellow line is the average daily power since installation. With ten days to the solstice, this figure is at 8.43 and continues to drop as expected. My hope is that by 18 May, it will be above 6.85. That would mean I had beaten the prediction of 2,480 units annually. I must say, it's starting to look like a close-run thing.

Hitting the bottom

Five days ago, winter came early to the UK and I learned what effect the snow has on a solar PV array. Basically, for me at least, it means zero power - even in bright sunlight. In the relative warmth of the day, the blanket of snow on the panels melts slightly and moves down the incline to expose up to 50% of their area. Yet apparently just having a portion of a panel shaded shorts out the whole panel and dramatically reduces its effectiveness. A trickle of power is generated but even after four days, it has not been enough to make my generation meter tick over one tenth of a unit.

Perhaps if the inclination of the panels had been greater, they would have shed the snow easier. As it is, I will just have to wait it out.

Having just got the payment for September's FiTs readings, EDF sent me an email for December's. We'll see if they pay this one faster. Only £130 is due this time.

Zero point one!

This is October's report though it's now 5th November - Fireworks are going off all around. In the summer, I tried to predict what my lowest figure for a day's generation would be. I seem to remember guessing it would be one or two units. Yesterday came in at a paltry 0.1 kWh! Wow. It can hardly get any less. There have also been other days with 0.2 and 0.3 units and sunny days have peaked around seven units. Amazing how a heavy Atlantic front cuts out the light. Here is the graph of production thus far:

The profound reduction as we head into late autumn is very apparent. My 30-day average to today is 3.68 units while the average since I started has just gone below ten at 9.84 units. Still hoping it stays above 6.85 units come 18 May. Overall, I think the panels are performing to expectations or better. It will be interesting to see how much the deepening winter will cut the power further.

One other thing. I sent a meter reading to EDF on 13 September which should yield over £550. This has still to appear in my account. I phoned them after six weeks and it was nicely pointed out that payments can take up to 90 days. I hadn't expected that. At this rate, my summer peak will arrive in time for Christmas.

September's report

This month's graph shows that a combination of shortening days and autumnal weather has heavily cut into the amount of power my solar panels can generate.

There is a very noticeable dip on the right side that began on the 13th September when a weather system cut my power to less than one unit (0.9) of electricity. This was repeated two weeks later and the 30-day average (orange line) has made a strong dip to 7.22 units. The overall average (yellow) is sliding more gently, as would be expected, and is now at 11.19 units a day since the panels were installed.

I'm still waiting for EDF to send my first payment after I sent my meter reading. It is now three weeks. I'll need to chase them up.

Where'd the light go?

Two interesting things happened coincidentally today. There was an email waiting for me when I got the computer on. It was from EDF and it was asking me for my FiTs meter reading. FiTs meter readings are supposed to be taken every three months but the timing of my start in the system means there is an extra sunny few weeks tagged onto the front of this set. Therefore, from 26 May to 12 September, I generated 1,306 units and this should realise £539.38. Additionally, half of these units should attract the £0.03 export tariff which adds another £19.59.

Amazingly, on the same day, a huge weather front passed over the UK today depositing a lot of rain. It also blocked the Sun rather well. Before today, my worst daily generation had been 3.4 units about 3 weeks ago. Today's return was a measly 0.9 units; astonishingly low and an indication of how poor a wet December or January day will be.

Improving weather and free power

It is a measure of our poor summer that even as the days shorten dramatically, my averages are improving. Of course, this is helped by the end of August being blessed by a true indian summer that looks to continue into the first few days of September. As the graph shows, even my annual average, which had been declining steadily (yellow trace), is showing a distinct upturn.

At the end of August, my total average as measured from installation was 12.3 units daily, well clear of the 6.85 figure that the predictions gave for my installation over the course of one full year. In fact, Given that the prediction was for 2,480 units annually, I reached the halfway mark of 1,240 units on 26 August. That's just over 3 months since installation.

The total earned from the Feed-in Tariff was £493 from 1,200 units since the scheme began. That excludes any addition made for the 3 pence export tariff. Since half of those units will be deemed to have been exported, that should add 600 x 0.03 which is an added £18. What happens next is that during September, I expect a letter from my energy company requesting a reading from my generation meter. My actual payment for the summer will be based on that.

I'm very happy with the performance of the installation thus far. In fact, I view it as a small part of my pension. Like a pension, I make an investment while I'm earning which realises a return when I'm not. There was an item on the BBC which shows that I'm not the only person who views it as a long-term investment. A company in England has seen a very clever opportunity to make a profit.

What they do is lease space on a homeowner's roof to install an set of panels. The owner gets access to the electricity and will therefore save money on their bill if they use the power when it is available. The company gets the Feed-in Tariff, which is the really profitable part. I guess it's a good system for those who are not able to access the cash to install panels themselves. It gives them the benefit of free electricity when the Sun shines. Yet I feel that what's good for that company will be good for me and my family. I am much happier having made that investment now.

Gloomy summer

In late June, the Sun shone well and my array of panels were reaping over 20 units of power daily. Since then, the Scottish summer has broken and wave after wave of Atlantic maritime fronts have washed over us. We get a front every two to three days and the associated cloud has kept a lid on power generation.

On 20 June, my 30-day average peaked at 15.7 units. Now at the start of August, the 30-day average is down to 10.4, helped in large part by poor Glasgow weather for the two weeks we were away in the Western Isles, when daily power averaged only 9.4 units.

Another interesting figure is that my daily average since the panels were installed is at 12.57 unit and gently falling as the days begin to shorten and the Sun gets lower. A good heatwave would help but there's no sign of it. Still, I'm well clear of the 6.85 average that the government estimated. Here's a chart of daily usage since I started. The two smoother displays represent the 30-day average (orange) and the overall average (yellow). The straight line towards the right is the generation over the 14 days we were on holiday. Since I wasn't there to take a daily reading, I've had to take the total generation over the two weeks and divide it by the number of days. Its low value indicates how poor the weather was at home while we enjoyed the sunshine in Lewis.

There's not really any other news at the moment. The next reading to go the FiTs people will be in September and I expect it will yield £450.

No more bureaucracy

In the last few days, I've finally dotted the final 'i' and crossed the last 't' when it comes to the bureaucracy that can surround the acquisition of solar panels in the current regulatory framework. 

The first item was my application for payment of the feed-in tariff (FiT) from my current energy supplier, EDF. I got a mailing from them that included two copies of their 'Statement of Terms', one of which I had to sign and send back. I note they didn't call this a contract and, worryingly, there was a clause on the accompanying letter that stated that the Statement of Terms was subject to change.

Given the fiscal tendencies of the current government, it is easy to imagine that the terms might be changed without warning. It seems that FiTs can no longer be thought of as being guaranteed for 25 years despite the claims of the website of the Energy Saving Trust. Now that I'm on the scheme, all I can do is watch it over its lifetime. 

Along with the Statement of Terms was a form for me to fill in my meter reading. This bothered me at first because I initially feared that they wanted my FiT payments to start from this new reading. That would render the electricity I had generated so far worthless and cost me £200. I had already lost £40 because I had applied for FiT payment a week after the panels were installed.

A phonecall to the Green Team at EDF calmed my fears. The reading stated on the Statement of Terms at the end of May was the starting point for my payments. The form was merely being sent because June is one of the four months annually that I have to send them a reading, along with September, December and March. Had I received that form earlier in the month, I would have probably received my first FiT payment now. As it is, the payment up to June will be lumped in with the payment between June and September.

The second bureaucratic box I had to tick was to send Installation Company's receipted invoice to the people at the Energy Saving Trust. This was along with photocopies of bank statements that show both the money coming in from EST and the payments out to Installation Company.

Meanwhile, the panels have settled into their routine. Since the last of my weekly updates, I had a week across the summer solstice where generation was into the 20s four days in a row, 133 units in total or £55. The weather then broke with fronts coming through interspersed with sunshine and showers. for two weeks, generation has been around 83 units or £34. Quite a variation. Here's a graph of daily generation:

My average is sitting at 14 units per day and I still reckon I'll beat the official figures, despite the poor weather recently.

Week four update

It's kinda good that the panels were installed just before midsummer. It means I have the joy of quickly seeing how much they can make when the Sun is at its highest in the year. Come the week after next, the days start to get shorter as we head towards winter. Cheery, aren't I?

So to this final weekly report on the system's output. I'll change to monthly updates after this. Here's the results:

Day 22: 5.2

Day 23: 15.0

Day 24: 21.3

Day 25: 16.5

Day 26: 17.2

Day 27: 11.2

Day 28: 14.7

The highlight is day 24. Being so near to the summer solstice, 21.3 units might represent the very highest the panels can reach - unless we get a belter of a day in the next week or two. Also, there was one fully overcast day. It's interesting to note that the week includes what appear to be a minimum and a maximum day, and that one appears to be a quarter of the other. Overall, the week's performance was pretty good with 101.1 units generated, yielding £41.75.

Once again, the average daily generation has risen; it's now 13.76 units a day since I started. My hope is that by 18 May 2011, and having gone through winter, it will be above 6.85. 11 months to go. In six months, I'll be finding out what the generation is like over the winter solstice.

Let's look at the total generation each week. This will smooth out some of the daily variations:

Week 1: 92 kWh

Week 2: 93.6 kWh

Week 3: 98.5 kWh

Week 4: 101.1 kWh

So that's a gentle rise as we head towards the solstice, and indeed, one wonders whether 100 units are about as much as the system will be able to produce in a week.

I phoned EDF to check on the progress of my contract for the payment of the Feed-in Tariff. They say it's all progressing well and I ought to hear from them in about 2 weeks. Also, now that I have a receipted invoice from Installation Company, that has to be sent to Energy Saving Scotland as proof of purchase. Meantime, I'm well chuffed with my system and it's ticking along well. Unless there is anything else to report, I'll be back in a month.

Week three update

The third week of solar production had a much more even look to it which reflected the more changeable weather we've seen. However, there was a consistent run of four days with above average sun. Here are the units of electricity produced each day:

Day 15: 7.7

Day 16: 17.4

Day 17: 17.1

Day 18: 17.8

Day 19: 18.5

Day 20: 8.5

Day 21: 11.5

This was a total of 98.5 units and a FiT income (eventually) of £40.68. That's a pretty good week. The relatively sunny days meant that my average rose slightly to 13.53 units a day, well clear of my 6.85 target for the year.

So to the highlights this week. The main event was a letter from Energy Saving Scotland (ESS). My loan funds were released. I visited Installation Company to pay the balance of the funds owed to them. They will post me out a receipted invoice which I have to send to ESS as proof of purchase. Repayments will be spread over 8 years. It was a chance to chat to them and one of the bosses asked me to explain the operation of the spreadsheet I had given him to monitor generation. I also mentioned to them that the panels had outperformed their rated capacity. Robert, their installer, suggested maybe that was a good batch of panels - a little more efficient than normal. Maybe.

I did manage to catch the system reading 3,609 watts output at one point myself, so good to confirm my son's similar reading last week.

There has been no word back from EDF Energy about my FiT arrangement. I'm assuming that reading I took two weeks ago when I filled out their form is the relevant one to base their payments on. When I get a day off, I might phone them to chase this up.

Meanwhile, I'll make one more weekly update of the generation figures before going to monthly updates.

Week two update

It's a little later writing this than I intended as pesky brother-in-law (   ;-)   ) decided to phone and tell me how his system was operating. He was also asking if my large spreadsheet for entering power data into could be passed onto another person who generates solar power. No problem. One of the points we discussed was that it would be a good idea for Installation Company to ease their customers into the Feed-in Tariff by providing at least a checklist of the hoops they have to jump through to claim the tariff. It's an onerous business and it wasn't clear to me. In particular, installers would be doing their customers a favour by getting them to claim as early as possible. A good few sunny days can go by before the FiTs are applied for and serious money can be lost, as happened to me last week.

So, onto the readings for this week. There wasn't as much Sun with a lot more Atlantic air passing over, so no maximum days:

Day 8: 17.5

Day 9: 16.1

Day 10: 13.7

Day 11: 15.5

Day 12: 5.5

Day 13: 11.3

Day 14: 14.0

That's a total of 93.6 units. However, day 8 was still prior to my FiTs claim so the financial return is less than it would otherwise be at £31.43. The running average since I started is 13.26 units a day which is excellent and well ahead of the 6.85 annual target. It's also becoming clear that when it comes to buying power, I'm using about 10 units a day less than before which represents about £1 a day financial saving on top.

One interesting fact during the week is that my son caught the inverter stating a momentary power output of over 3,600 watts. That's ever greater than the array's rated peak output. How can that be? Here's my theory:

A bright overcast sky can easily generate getting on for 1,000 watts, whereas a blue sky before the Sun gets to the panels generates only about 200 watts. I suspect it would be true to say that blue sky is relatively poor for solar power. So compare two situations. The first is where a bright Sun is in the middle of a clear blue sky. Presumably all but 200 watts of the power is coming from a direct Sun - say 2,800 watts. Now suppose we have a lot of broken cloud and a strong Sun shining through a gap. Could we then have 2,800 watts from the direct Sun and a further 800 watts of reflected light from the clouds - 3,600 watts in total? These numbers are just illustrative, but you get the gist?

FiT bureaucracy

At last I got around to registering my solar installation for payment of the Feed-in Tariff (FiT). Soon after my solar panels were installed, I was sent a certificate that I would use to claim for these payments because it certifies that my system is eligible. Then I got busy and the days ticked by. The panels generously provided valuable power but it has taken me a week to finally get around to making that claim. I did so today and it proved to be interesting. First, a recap of the FiT system.

Feed-in Tariffs are an arrangement whereby microgenerators (like me) get paid for every unit of electricity they generate, even if they use it themselves. If they don't use it and put it on the grid instead, they gain an additional small amount called an export tariff. All the major electricity companies support the FiT scheme and the money comes from a levy on all other electricity users.

To claim my FiT payments, I contacted the Green Energy department of EDF Energy, my supplier. They said I could apply by email but I would need to include a scan of some form of ID (my passport), a proof of address (utility bill), the invoice from Installation Company and a copy of the MCS certificate. I asked whether the initial meter reading from the panels (00001) would be used as the starting point for the payments. I was told that a meter reading would be asked for when I filled in the form and it wasn't to be backdated. As it was now at 00110, it means a loss of £45, the payment that would have been due for the first 7 days generation, had I got off my backside as I should.

EDF sent me an application form in the form of a PDF. I was at work and had hoped I could register from there, but having discovered I would have to scan documents, I would have to wait until I get home. When I did get in front of my computer, I saved the PDF to a folder and opened it to fill it out. It then told me that I wouldn't be able to save the completed form but that I could print it out for my records. I couldn't work out how I was to use this to apply by email.  I did check with EDF and the lady said they were getting many applications by email. Maybe I'm missing something. Anyway, I filled it in electronically and printed out two copies - one to send and one for my records.

All the forms and requsite scans were put into an envelope and posted to EDF. The PDF is a bit naff as it drops all the leading zeros, some of which are important in the likes of meter serial numbers and bank codes. I added them by hand. I guess had I been able to send it electronically, those zeros would have been included.

It's good to learn from EDF exactly how the FiT payment will work. At the start of every third month, I will send them a reading from my generation meter. They should then lodge the appropriate payments to my bank account within that month. I should therefore expect quarterly payments. For now, there is no way to determine what proportion of the solar power is fed to the grid and what is used here at home. Therefore, it is assumed that the ratio is 50%. This means that for half of the units I generate, I will get the basic FiT of 41.3 pence and for the other half, I will get an additional 3 pence.

One week update

At last, I have figures for a full week of generation by my solar array and it's been very heartening. The first two days were overcast so only five or six units were generated each day. For the rest of the week, however, we had glorious May sunshine and the daily haul jumped to a high of nearly 21 units. Here are the results:

Day 1: 4.9

Day 2: 6.6

Day 3: 18.2

Day 4: 20.8

Day 5: 17.1

Day 6: 20.2

Day 7: 17.5

If I add on the 4.2 units generated on the first evening it was switched on, this gives a total of 110.3 units for the week. The average generation per day was 13.7 units which is exactly double the 6.85 units I want for across the whole year. With the peak of the summer still to come, I'm hoping this keeps up. Once these units are converted to cash under the FiT scheme, the proceeds should be £45. An excellent result.

As the week progressed, the family began to take almost as much interest in the system's performance as me. My wife even phoned me at work to let me know how it was progressing. My son recorded the highest output power of the week at 3,398 watts. I'm very pleasantly surprised by this since the array is rated at 3,500 watts and it shows the necessity of installing an inverter that can handle all the power the panels can deliver. 

For most of these sunny days, the house runs entirely off solar electricity. Therefore, the number of units I have to buy daily have reduced from a typical 25 units daily to only 15, saving me a further £1 a day.

Meanwhile, Installation Company has sent me a certificate as part of the Microgeneration Certification Scheme which I will pass onto EDF to register for FiT payments. 

Two-day update

I thought I'd update followers on the performance of the panels after two days. I'll give a full week's update at the appropriate time. 

For the time between switch-on and sunset on Tuesday, a matter of roughly three hours or less, strong sunshine produced 4.2 units. Since then, the following two full days have been completely overcast and it's been interesting to see how the panels have performed. On Tuesday night, the inverter shut itself down once it sensed insufficient power was being delivered. I awoke at 5:30 am Wednesday morning and toddled downstairs to see how it was doing. Conditions appeared to be daylight outside but I was just in time to see the inverter power itself back up and tell me it was producing all of 4 watts.

Mid morning, we headed for the West End of town, but before we left, I noted a reading of about 250 watts. By the time we returned home, it still appeared overcast but there was now 750 watts being injected into the house. However, as I watched, it cranked itself up to 1,200 watts. It was obviously brightening outside yet it still appeared overcast. Happily, the retail meter had stopped ticking. The house was running on overcast! On Wednesday, we generated a total of 4.9 units.

Today, Thursday, was also overcast and I was at work all day. The folks at home couldn't remember the Sun having come out all day. However, the meter has clocked up another 6.6 units. Since the average daily figure I need for my target is 6.85, to nearly achieve that on a cloudy day is very pleasing. Given that a cloudy January day will be only half as long roughly, I expect those days will yield barely 2 units. 

So far, I should have clocked up £6.50 in FiT payments. Now all I need is a really sunny day to calibrate the top end of the range. My next blog will be when I have 7 full days of operation.

Installation - Day 2 - Power

It was the early evening when I got home from work but the Sun was shining and its photons were already pushing electrons around the house. It had been doing so since about 5 pm and had already generated its first unit. I was delighted. My WSW roof now carries 20 panels, each capable of generating 175 watts when the Sun shines directly on them; a total of 3.5 kW.

The installer showed me his handiwork. The 20 panels sit about 10 cm off the roof and have been connected as two 'strings' of ten panels each. The panels are connected in series so that the voltage from each panel is added with the others so the 44 V max that each is capable of becomes 440 volts DC total. A more typical voltage for each is about 35 V. In the attic, each string goes through its own isolator switch before running down the cavity in the wall to the cupboard under the stairs.

This cupboard is now lined with equipment. The two DC strings go into a large red unit, the inverter, which converts their power to AC, and does so at the same phase as the incoming mains power. Its output goes to a meter certified by Ofgen that measures the power being delivered by the system. Its reading is the basis of the payment of the Feed-in Tariff. Finally the power is fed through another isolator switch and a circuit breaker for high current protection before being merged with the house's main electricity supply.

At 5:40 pm, this system was pumping out 2,300 watts. The little red flashing light on our retail meter was flashing no longer and instead glowed a steady red. Amazingly, the entire house; all the computers, monitors, lights, TV and internet systems, fridge; absolutely everything was running off the Sun. Whatever excess power was left over was being fed to the grid. The middle of the day was obviously the time to run those power-hungry appliances such as vacuum cleaners, irons, dish washers and tumble dryers.

In this blog I've avoided identifying Installation Company. This is because they have a family connection and so I cannot make any unbiased recommendation. However, on this occasion, I'll make an exception to this anonymity. I'd like to thank the folk at Absolute Solar and Wind for their service, particularly Robert and Chris. The system looks great and it's working well.

So now the fun starts - and I'm delighted that tomorrow is a day off for me. The weather is supposed to be cloudy but I'll regularly monitor the instantaneous power output from the inverter to get an idea of its profile during the day. Tonight, I'll begin filling in a spreadsheet that I've already formatted and I'll start to carefully observe how the system performs over the coming year. My intention is to post weekly performance figures on this blog that will keep followers up to date with daily and cumulative performance.

My expectation is that I will generate 2,500 units annually which is an average of 6.85 per day. Anything over that will be considered a bonus. It has to be kept in mind that the first few months of this will across the longest and brightest days of the year. Generation will appear very good at first. However, the short days of winter will be a strong counter to the optimism of summer. Wish me luck!

Installation - Day 1

My prediction of yesterday didn't quite come off. There aren't yet any panels on the roof but there is a stack of them in the house and all the supporting rails are installed. I'm a very happy bunny.

One of the interesting aspects of this project has been the way its details have changed. This isn't a problem as I'm pretty flexible as long as my overall desire for the project comes off. To recap, Installation Company had originally intended to use Topsola 175 watt panels with a Sunny Boy inverter. Then it was going to take a while to get these items so we went for Sharp panels and a Diehl inverter. However, as it has transpired, by the time the installation came around, Installation Company had stocks of the original panels and the original type of inverter will be delivered tomorrow.

Today, the installers concentrated on the supports for the panels on the roof. They reported that they found the tiles quite tight and difficult to lift. They overcame this while the Sun beat down and, as seen in the photo, a set of four rails are in place to accept the panels tomorrow.

Another change was in the placement of the inverter. We started with the idea of having it under the stairs. Then it was going into the loft with some way of remotely metering it. This was to keep the cable run short - something the installers often do to reduce power losses. Then it was going into a cupboard in an upstairs bedroom for ease of access. Today, it returned to the cupboard under that stairs. Part of the rationale for this was due to the wall there. It used to be an outside wall and thus has a cavity. It was easy for the installers to make a relatively straight run of cable down that cavity. Since I take all my other meter readings in that cupboard, I might as well take the solar reading from there too.

If the inverter arrives tomorrow, the system should be running by day's end. Spreadsheet is primed and ready to roll!

Panels day

It's a beautiful, sunny May Monday morning. Solar photons are flooding in the east-facing windows of the house, and by the end of the day, they'll be striking a huge array of photovoltaic panels on my west-facing roof. 

The installers should arrive in an hour to begin installing 20 panels. I'm hoping that when they do, they manage to leave room for a future thermal panel. Normally a system of this size would take two days to get going. However, I believe the inverter won't arrive until later in the week so I have to wait a few more days before I can generate valuable power.

I'll be at work all day so I won't get to watch progress. I'm looking forward to seeing the results however.

Installation imminent

Got a phone call from Installation Company to let me know that they intend to begin installing my panels on Monday. I didn't take the call myself and the message that was passed on said that apparently they are having problems acquiring an inverter. As a result, it will be installed later in the week. That surprised me as I had thought we had agreed to change from one brand of inverter to another specifically because they were easier to get hold off.

Meanwhile, and unintentionally whetting my appetite, my brother-in-law happily informed me that his south-facing array had produced just over a hundred units in its first week of operation. That is an average of over 14 units a day. The extremes were as many as 20 and as few as 5. Another way to look at it is that he's earned over £40. Nice earner.

Unfortunately, I'm working most of next week so will miss the work being carried out.

Starting gun

An important step forward was taken today when I paid the deposit for the solar array. I am impatient for things to get going.

To slake my thirst a little, I visited my brother-in-law's home where he is in the process of having a system identical to mine installed. It looked great and it ought to be pushing electrons by the end of the day. Perhaps the installer saw how I was salivating at the idea of having mine up and running, but he mentioned, perhaps in jest, that he might have to work over a weekend to get mine going asap.

Watching the inverter getting taken up to the attic made us think more carefully about where we ought to place ours. The original intention was to place it under the stairs. However, it was pointed out that there was significant power loss if the cable run from the panels to the meter was very long. Also, it's a big brute. At 70 x 30 x 25 cm, it is twice the size of the one we were originally to have and would barely squeeze into that little space. The preference was to have the inverter in the attic, with the meter next to it. But I want to read the meter nightly. There were thoughts of having a wireless webcam installed to allow me to see it from my computer but issues of providing lights were making this less than ideal.

After seeing the installation today, we thought a better place might be one of two cupboards we have in the upstairs bedrooms. The cupboard in our spare room seems the best place. It's not far from the roof and is directly above where the power enters the house. It's accessible and won't require a webcam or remote meter.

There was one other small step in this project that occurred today. EDF Energy wrote to let me know that our energy supply moves over to them on 7 May. As part of that, they asked for an electricity meter reading which I supplied by phone by speaking to a computer. It all worked successfully. They say I'll get another letter soon, asking for a gas meter reading. Ignoring for the moment the solar panel installation, I expect my £2,000 annual energy bill to drop to at least £1,500. The panels and the Feed-in Tariff (FiT) payments should make a huge dent in the remainder.

From dreams to reality

This solar project is nearing fruition and I'm back to waiting; waiting for Installation Company to acquire all the equipment needed, and then come and install it on my roof. It occurred to me that maybe I should compare my initial hopes for this project with the reality I have since become aware of as I have studied its details.

The major difference between late February and now is the change in the government's system of grants and loans. Then I had expected that nearly the full cost would be covered by a £10,000 interest-free loan and a £4,000 grant. This has since been descoped to a mere £4,000 interest-free loan. I had just missed a window late last year where these schemes would have been available and so most of the finance must come from our own resources.

A more subtle difference comes in the amount of power I can expect to generate. When a lady from Energy Saving Scotland visited, she pulled out tables that said a south-facing array of the size I was planning ought to generate 3,100 kWh annually. I had seen a table on the web that suggested an east or west-facing array ought to generate 90% of that figure. That gives 2,790. However, I was thinking of a 4-kWp array and it transpired that a smaller array, 3.5 kWp, was a better plan to avoid the power company having to do a feasibility study. Looked at now, that ought to generate 2,440 kWh, but maybe I would get a little more as my roof is 20 degrees south of facing west. Yet somehow, I was going through this whole process with 2,900 annual units in my head.

Part of this was because when Installation Company quoted for my system, they suggested it ought to generate just over 2,900 kWh. That seemed about right - it appeared to be around 10% lower than the figure I had heard originally and I had assumed that whatever figures they were using, they had taken the orientation of my roof into account. However, on speaking to them last Friday, I discovered this orientation was new to them. They thought I had a south-facing roof. Their revised quote that I got later that day was appropriately adjusted. Their calculations, based on government tables, and assuming an east-west roof, is now 2,480 kWh annually or 6.8 units a day average. That matches my own new calculations.

So a new reality is setting in, but I can accept this gradually declining expectation of my roof's generating abilities as the figures still look good in the spreadsheet. What does it say? Using the new figure for annual generation, the difference between installing and not installing the panels is now £25,300 in my favour over 25 years, down from about £32,300 before. I am looking forward with glee to the 365 days that will come after the installation is complete when I will see how accurately this final prediction compares to reality.

When I visited a house with a panel array already in place, it was cold but sunny. Being February, the days were still short. Yet this array, the same size as mine but south-facing, had generated 15 units of power that day. Its current performance is 9 units a day average over the months of February, March and April which translates to 3,285 annually. Given that this period is biased towards shorter days, this system seems to be outperforming its expectations by a significant margin and it has made me think that the government tables are somewhat pessimistic. Time will tell.

Revised plans

This eventful day ended with a small change of plan, and hopefully a shorter wait before I get the Sun to push electrons around my house. The chap from Installation Company phoned after I had emailed him to let him know of my roof measurements. We reckon we can get 20 Sharp ND-175E1 panels onto the roof, probably arranged as a 9 by 2 array with two extra panels below. To convert DC to AC, we'll use a Diehl Platinum 3100S inverter. It's a big brute but as it will be going into the loft, there will be plenty of room for it. Installation Company find it easier to source these components which hopefully means the system should be installed sooner rather than later.

An interesting sideline is that the inverter has a comprehensive display on its front panel which includes a smart little graph of power production over a day. It also appears to be backlit. I like the idea of pointing a wireless webcam at it so I can see it downstairs, but it leaves me with a problem. I'd also like to see the generation meter. Can I arrange things to have a single camera see both displays? Is having two cameras a silly idea?

Installation Company emailed me a revised quote (same price) late afternoon. I'll get the acceptance form and a deposit off to them real quick. Movement... at last!

Loan at last

It only took twice as long as they said it would, but Energy Saving Scotland (ESS) finally approved my loan. It made for an interesting morning. I phoned ESS first thing and enquired about my application that had thus far taken twice as long as it should have. The lady at the other end informed me that a letter had been sent out yesterday and that approval had been given. Yay!

I then phoned Installation Company and decided to go down to their premises and chat directly. During this visit, various things were learned and a few issues came up. One was the availability of the Topsola panels that we had been quoted for. End of May was their earliest date. An alternative panel they can supply is made by Sharp but they have a different aspect ratio - short and fat instead of long and thin. There was doubt whether they would fit on the roof. A chap is coming out at teatime to check the roof's dimensions. In the meantime, I did a bit of measuring myself.

I reckon the roof pitch is 9.6 by 4.6 metres. If an 8 by 2 array of Sharp panels was set up in portrait orientation, with a further 4 panels arranged in landscape orientation along the bottom, that would give an array of 8 by 3.6 metres - well within the roof's edges and it allows for the 200 mm of roof space that has to be left all around. The question is whether the cabling of this layout would be acceptable. I'll ask the chap when he gets here. Another issue with layout is to leave enough room for a solar thermal array in the future.

Next is the availability of inverters. The Sunny Boy 3300 model I was quoted for is currently difficult to get hold of. They can supply a much larger inverter from another manufacturer. Now originally, I had thought it best to have the inverter and meter under the stairs. However, it was pointed out that it might be better to have it in the loft. The shorter cable run to the meter means fewer power losses before it gets metered for payment of the Feed-in Tariff (FiT). If so, I could maybe accommodate the large inverter.

If the generation meter goes up in the loft, there is the issue of gathering readings from it. For the purposes of metering for the FiTs payments, access to the meter only needs to be gained every few months. However, I'm a technophile who loves his spreadsheets and I'd want a reading every evening. There are various options.

1. Sunny Beam. This expensive kit (over £350) is only available for the Sunny Boy inverters and I may end up not getting one of those.

2. Wireless energy monitor. For between £30 and £45, these will send readings to a desktop unit based on their own measurements of power flow from the inverter. Their chief disadvantage in my head is they are likely to give a different reading from the meter that will be used for the payment of the Feed-in Tariff (FiT). I'd prefer to know the readings that reflect the money.

3. Wireless webcam. This is a daft, but wonderfully workable idea that came to me. Wireless webcams like this one link into the house WiFi system. They have their own webserver software built in. If one could be set up peering permanently at the FiT meter, I can gather a reading from it when I like. Appropriate LED lighting would have to be set up, as would a mains power feed.

By the time we got home, the postie had delivered the ESS letter about the loan. Happy days.

Wireless energy monitor

Had a chat with Installation Company about when inverters will become available and the latter half of May looks likely. Apparently, component supply problems with the manufacturer are at the root of the issue. They did suggest I get back onto the people at Energy Saving Scotland to chase up the progress of my loan.

They also pointed out that at over £300, the Sunny Beam monitoring system I was looking at is a very expensive way to go about keeping an eye on the output of the panels. Instead, they suggested I search for 'wireless energy monitor'. I did. For somewhere between £30 and £45, I could get a system that will do a decent job for me. Two systems come to light in the search. The Owl is very common. Tesco sell them. Another is by Efergy. Some of these will even connect to a computer and display their results as graphs though apparently their data structure is rather proprietary. You can't load the files into, say, Excel.

These units are meant to monitor energy usage in the home. They easy to use and install. They include a sensor that is simply clipped around the live cable to your electricity meter. This sensor is connected to a transmitter unit that sends the measurements to a receiver which displays the results. The suggestion from Installation Company is to use one of these to monitor the AC electrical output from the inverter.

On the Amazon UK page for the Owl unit, some reviewers have pointed out that the system lacks sensitivity. It will give you a reasonable idea of the bulk power flowing though the cable but it struggles to accurately respond to the change caused by, say, a 60-watt bulb being switched on. However, it looks like a fun gadget that I had not seen before and I might get one just to play with.

One thing to point out is that I don't actually need any of these toys to monitor the daily operation of the panels. The inverter will have a display, and there will be an approved meter on its output for the purpose of working out the Feed-in Tariff I am to be paid. I can gather these numbers each evening for the spreadsheet as I do now.

Long delays-2

Our extraordinary spring continues with long, sunny April days burning away raw memories of a cold, harsh winter. With each day, I ponder at the wasted photons striking my roof and the pennies that could have been gathered from them. Now I will have to wait a while longer.

When I received my quote from Installation Company, they specified a SMA SB3000 inverter, and like many would, I immediately hit the web to find out more. It turned out that the number in that designation, 3000, referred to its power rating and this one was rated at 3 kW. This seemed strange because the array of panels I was ordering are to have a peak capacity of 3.5 kW. I wondered whether this underspecification was intended as a way of keeping costs down. 

Solar photovoltaic systems generate direct current (DC). Like a battery, they have a positive and a negative terminal and the electricity from them flows in only one direction. However, the power systems within our homes and factories work using alternating current (AC). Here the electricity flows first in one direction and then in the other, swapping polarities and back again fifty times a second. It is the job of the inverter to convert the DC power from the panels into AC that can work with the domestic supply, and it will do so in sympathy with it - making sure that positive and negative are the right way round at the right time. As it does so, it has to be able to handle the amount of power being generated by the panels.

For most of the time, a 3 kW inverter would be absolutely fine. Given cloud, seasonal sun or times of the day when the illumination is not optimum, there is almost no time in the year when my system will generate power at its peak capacity. That can only occur when the Sun is shining through a clear sky at an exactly perpendicular angle to clean panels. My first guess was that Installation Company had figured there was no need to supply an inverter rated to match the array for this very reason. I brought it up with my contact within the firm and he took the opposite view. The 3 kW inverter was wrong and it should be a more muscular version, the SB3300. In fact, there may be a time of year, in the early afternoon on a sunny June day, that the illumination on the panels might just stretch the ability of a 3 kW inverter to do the job.

Today, I decided to see if Installation Company had a firm date for my panels to be installed. The lady's answer was that their supplier was having difficulty sourcing the correct inverter and the signals were that the units wouldn't arrive until the latter half of May. That seems to put the installation back about 4 weeks from when I had hoped. The good news is that I can afford to wait longer for the bureaucracy behind my loan application to do its stuff. The bad news is mild frustration and the thought of a zillion more springtime photons landing uselessly on my roof.

One interesting sidenote is that while the SB3000 is rated for a peak of 3 kW, the SB3300 will handle a peak of 3.6 kW, more than enough for my system. Another fascinating nugget for this gadgetboy is that the inverter can have a Bluetooth interface which allows it to be monitored remotely, and to a very high extent; heaven for someone like myself who loves monitoring systems. A little remote display called the Sunny Beam will keep daily reports of the power from the panels and will pass that information into my computer via USB. Oh, heaven! It will even draw little histogram graphs to show how the generation of power was distributed over a day. I'll investigate this more later.

Loan delays

I finally got through to the Energy Saving Trust in Edinburgh. The lady I spoke to said there were quite a few applications in before mine so news about my loan for installing solar panels is not imminent. I did mention to her that I was in a queue with Installation Company with 2 to 3 weeks remaining. Her suggestion was that I hold off postponing the job until a week or so before it happens and if I haven't heard anything by then, give them a phone.

In truth, I don't have a definite date for the installation. My only clue came from a conversation with an employee of Installation Company who I spoke to on Easter Sunday and who said about 4 weeks. That put it at the beginning of May.

Two steps forward, one back

We're having a fabulously sunny mid-April and it frustrates me a little thinking about all those photons landing on my roof, their energy only to be absorbed and dissipated by the tiles. I am having to wait; wait for the Energy Saving Trust to decide whether they are going to give me a loan, and wait for the date to arrive when Installation Company will come and install my solar panels. I think that will be about two to three weeks away.

The problem is that if I want to take advantage of the loan, the installation work cannot begin until the loan has been agreed. EST are supposed to have made a decision within 15 working days and that has time has long passed, so I decided I ought to chase them up. It did not work out well. I started with their freefone number and a lady gave me another number in Edinburgh to phone. Every time I phone that, I get an automated message telling me that they are not available. I'll console myself with the idea that if the installation date arrives and they still haven't agreed the loan, I'll go ahead on my own finances.

Meanwhile I took a couple of steps forward. First, I changed my energy supplier from Scottish Power to EDF Energy. Depending on whether you believe EDF's figures or mine, I'll save between 26% and 30% on my gas and electricity bill in the long term. Interestingly, my estimate is the more optimistic of the two. The tariff I'm on only lasts until June 2011, but even then, their standard tariff is cheaper than what I'm paying Scottish Power.

Of course, this really has little to do with solar power and anyone can change to a cheaper supplier. However, EDF Energy are a registered supplier for the payment of Feed-in Tariffs. This means that when the solar panels are installed, EDF will look after the payments due to me for units generated. Here's how it is supposed to work. Installation Company, who are MCS registered (and they must be for the FiTs scheme) will register my installation on a national database. They will also give me a certificate. I'll apply to EDF for FiT payment. They'll cross-check me on the database and arrange how often payments will get sent to me.

My second little step was to send a letter to the local planning authority along with a simple plan, requesting a letter from them that confirms I don't need to apply for planning permission for this.

Right, I'll go and sit out in the sunshine and ponder my lost photons.

Loan bureaucracy

The Energy Saving Trust sent me a letter on 1 April to let me know of the changes to the grants and loans schemes that have taken place with the introduction of the FiTs. Whereas their letter of 22 March merely informed me of the reduction in the loan amount, at least this one informed me of the fact that the grant for which I had applied was being discontinued - as well as restating the position on loans. The letter doesn't actually say that I'm not getting the grant. Rather, it states that I will hear from them shortly. However, I'll assume I won't get a penny. I wish they'd just get on with it.

Meanwhile, I've heard that my panel installation ought to occur in about 4 weeks. The funding is in place and I'm ready to go ahead, loan or no loan. With relatives over to visit for Easter Sunday, I found myself telling one of them about the financial implications of microgeneration. I think he was intrigued.

Media coverage of FiTs

My ears pricked up while sipping my morning tea when the Today programme gave a mention of Feed-in Tariffs (FiTs) on the day that they are introduced. Later in the day, I managed to catch coverage on The World at One and on Reporting Scotland.

It was interesting to see the range of spin given to the story. The earlier bulletins focussed on the fact that the payments to microgenerators (like me soon, hopefully) would come out of the pockets of all the other power consumers. A figure of £11 per year was quoted as being the amount non-generating households would have to stump up for this scheme.

The regional news programme took a completely different, and much more positive slant. It looked at a little village where residents intended to erect wind turbines for the benefit of the village. I'll come back to this in a moment. All of the coverage failed to project what I believe is the most important aspect of this move. Feed-in tariffs are going to revolutionise our attitudes towards solar power. PV panels will become the must-have accessory to have on your home. I'll predict a very bright future for businesses that install them.

For those who wonder how a Feed-in Tariff works, here's my quick explanation.

Just now, electricity costs about 12 pence per unit (or kilowatt-hour, kWh). If you generate your own electricity, you will get an amount of money for every unit you make. For a 20-panel system that I have in mind, this is 41.3 pence. This tariff is guaranteed for 25 years and is linked to the RPI. There is a small additional tariff if you export your power onto the grid rather then use it yourself. The upshot for a homeowner like me is that for an outlay of less than £15,000, I will earn enough to pay off the panels and have essentially free electricity.

Back to the wind turbines. If ever there was a part of the world that was rich in untapped wind energy, it has to be the Outer Hebrides off Scotland's northwest coast. A few years ago, a company came in and laid out plans to cover Barvas Moor with hundreds of giant turbines. The people of Lewis were not happy on the whole and a large campaign was successful in stopping the development. 

A few hundred miles away, another company presented plans to the village of Fintry in Stirlingshire for 12 turbines on the nearby hills. A few thousands of pounds were offered to the village as a device to smooth the acceptance. With great wisdom, the village rejected the offer. With their next move, they played a blinder. They convinced the company to erect a thirteenth turbine, the proceeds of which would pay for its cost and the remainder would go to the village.

According to this Scotsman article, the villagers will get £100,000 a year for ten years while the cost of the turbine is paid off, then an additional £4 million in the succeeding 15 years. Already, this has allowed the villagers to carry out a programme to insulate all the homes in Fintry, thereby reducing the heating bills of everyone. With that completed, they have begun to replace old, inefficient boilers throughout the village. They have many plans to further improve the energy efficiency of the village and upgrade its facilities. 

I hugely applaud this way of bringing generation to the community. How sad then that the communities of Lewis could not use Fintry's example and take control of the plentiful wind energy available to them.

League of suppliers

Here is a table of suppliers' apparent charges for a quarter's worth of electricity based on the best information I was able to glean from their sites. The list is neither exhaustive nor guaranteed accurate.

£208.30 - EDF online saver 6 (until June 2011)

£240.09 - Atlantic, no standing charge

£266.08 - EON Fixonline 7

£271.91 - British Gas

£277.50 - EDF Standard tariff

£296.88 - Scottish Power Premium Plus

£302.54 - Atlantic Online

£307.13 - Scottish Hydro

£307.30 - Scottish Hydro, no standing charge

£325.58 - Green Energy

£334.18 - npower

An extraordinary range of prices. In general, the tariffs that have no daily standing charge tend to be the cheapest.

Now that I have a spreadsheet set up for the various types of tariffs, it will be easy to plug in the appropriate numbers and see how my sample quarter usage would be charged.

Suppliers surprise

In a spare hour of time, I played around with the records I now hold of my house's consumption of power over the last year and a half. The plan was to use it as a basis for comparing the cost of buying electricity from different suppliers. It was spreadsheet heaven and the results were surprising. Previous spreadsheets had shown me that the second most important factor in making the PV array pay was by paying as little as possible for for the electricity I would have to buy.

I waded through the morass of tables and systems for charging for electricity and standardised on a typical three-month period to which I could apply each company's tariff. This is becaue many tariff rules apply to the quarter of a year.

It is saddening to see how complex the market is and how opaque it must be for the vast majority of consumers. There are two main charging systems; some have a daily standing charge, others don't but they have you pay a higher unit cost for an initial quantity of power which drops to a low tariff once you have used a set number of units within a certain time. In negotiating this mess, the spreadsheet is invaluable.

My current supplier, Scottish Power, is run-of-the-mill. It matched a slew of companies by being around £300 for the sample quarter. Suppliers of so-called green energy were the most expensive, going well above the £300 mark. This is to be expected as you're paying a premium for buying energy from wholly renewable sources.

The shocker was EDF energy. At £208 for the quarter, it was well below its nearest rival and nearly two-thirds of what I pay now. The catch is that this is a promotional rate which will only last until summer 2011, but even their standard rate is competitive. I believe that part of the reason for the low price is an aggressive push into Scottish Power's home market. Like most of the other large suppliers, there were further discounts for direct debit payment.

If I weren't about to install a solar PV system, I'd likely jump on this wagon, or at least investigate further. However, once the generating system is built, I'll be placing EDF at the top of the list of suppliers to investigate though I wonder what their reaction will be to me wanting to sell them power through the FiTs scheme. [Note from 10 May: I did change to EDF, with 7 May being my official changeover date.]

Whither green?

Readers of this blog (if there are any) might assume that I am an environmentalist, that I vote for the Greens and that the description 'tree hugger' would sit well on me. In fact I don't see myself as a 'Green', at least not in the conventional sense.

I do see myself as a technophile who believes in the ability of technology, if applied intelligently, to make our lives on this planet much more fulfilling and comfortable; and there's the important bit - intelligently. Not that I see myself as much of an intellectual heavyweight. Quite the opposite. My qualifications mark me as an also-ran lightweight and I marvel at the ability of true intellectuals to quickly marshall thoughts, memories and knowledge into coherent analyses of situations. I have to mull over things for ages.

However, I do seem to have a sense for the direction things ought to go to promote maximum happiness (How American is that?) and I am often surprised when my antennae are proved to have been right, even when I'm horribly outvoted or out-shouted on an issue. This is how I feel about the issues surrounding solar-generated electricity.

Environmentalism first. I think a clean, fresh environment is a good thing and I don't believe businessess have a right to dirty our planet in pursuit of short-term profit. But the rantings of many environmentalists bother me. Specifically, they seem to say that anything human is unnatural, almost as if we don't have a right to live on this planet. I believe we have a right to grow, multiply and consume as much as the bacteria that regularly manage to colonise my damp dishcloth. But like them, our growth will be limited by the resources available. The difference between us and the bugs is our intellect.

I think it is fundamentally stupid of us as a civilisation to treat coal and oil as energy sources. It is short-sighted, dirty and is essentially us burning our capital. It is a huge mistake for our governments and big business to have conspired to deplete these resources when unimaginable vast amounts of energy are all around. Just because burning this stuff was an easy path to take, does not make it the right thing to have done and I don't say this as someone who has swallowed the CO2 and the global warming case; hook, line and sinker. Coal and oil should be a capital resource, not a consumable. As a civilisation, we ought to take it out of our energy portfolio and invest in the rest.

Green politics next. I worry that political structures constructed around single issues will always tend towards extreme viewpoints as their proponents bicker and argue themselves to a purer interpretation of their ideal. I also don't like the Westminster version of democracy - winner takes all. Advocates point out that it leads to strong government and my face falls. The last thing we need is a strong government hammering home its policies on pathetic mandates. We ought to force these folk to share their power to dilute it so that little legislation gets passed until there really is a strong groundwell in its favour. I prefer the Liberal Democrats over the Greens as I believe their wider political viewpoint, less tainted by issues of left and right, is a safer bet. But as soon as they get too big, I'll have no problem with ditching them.

Tree huggers. Actually I do have some sympathies here. The term 'tree hugger' is often used as a perjorative term for people who take their environmentalism to silly extremes but it equally applies to people, like me, with a scientific outlook who understand that both organisms, us and trees, share the chemical miracle that is DNA and life on Earth. It was planetary scientist and science populariser Carl Sagan who pointed out in his TV series 'Cosmos' that, at the cores of our cells, we and trees are made of the same stuff. That's important to remember.

So I approach renewable energy as a practical technological solution to our need for energy. I think the FiT scheme to encourage renewable electricity generation is the best sign that I've seen that UK politicians are beginning to come around to smarter ways of doing things.

The spending begins

I sent a small deposit to Installation Company to get on their queue for dates to come and erect my solar PV array. I feel I ought to start my first spreadsheet to start accounting for every penny that goes out of or into this project. That's quite exciting. I've also arranged the finance for it and I have high expectations for the loan application.

One other thing I did was to mention it to a friend who might be the sort of guy who'd be interested in this.

Discussing timescales

I spoke with Installation Company yesterday on the phone to find out how quickly they thought they could start if given the go-ahead. Six weeks was the answer. I decided that if it is going to take that long to get started, I might as well keep applying for the small (£4,000) government loan that is still available. It would save some money, though hardly a substantial amount, and so I've written to the EST to keep the application process going.

Meanwhile, boss of Installation Company has suggested that I lodge a small deposit to get myself into the queue while I wait for the bureaucratic wheels to turn. We discussed his own generation figures which, at 7.1 units per day in the late winter/early spring, appear to be heading to be better than figures from the government which average 8 units per day. I mentioned that according to my spreadsheet, any improvement on government figures was highly significant to the project's finances. I could almost hear hear the boss's ears prick up. "Could I have a copy of that spreadsheet, please?"

My problem in life is that I'm a geek. I recently read that a characteristic of many geeks is that they often fail to realise the monetary value of what they do, Bill Gates being an obvious exception to the rule. Therefore I've sent Installation Company boss a copy of my 25-year projections with no more than a weak plea that if he finds the sheet useful in his business, he shows that in some way beneficial to me. I may be an intrinsically happy, settled person, but I'll never be a businessman.

Loan letter

We got mail today from Energy Saving Scotland to tell us that the maximum loan available for generating electricity from renewable sources is now £4,000. It is a shame that the loan and the grant departments at this quango are not a single unit, as it would have been nice to have been officially informed that we were not going to get a grant either.

My wonderful partner is more cautious about this whole process. She simply sees that we are going to have to find over £14,000 quickly and then have to pay it back, increasing our monthly outgoings. This is a very understandable position and it is true to say that as I plough deeper into this (and as I model it ever more carefully with my beloved spreadsheets), it has become less attractive than it was. However, it is still very attractive.

Based on my most recent models, we will have to find more money, initially at least. But it is only on the order of £20 a month. This is because the FiT payments are generous enough to cover our total electricity costs and cover most of the loan. Once the loan is paid, it's all very positive.

I see things over the long term. Seen over 25 years, worst case and assuming 3% inflation, we have two options: Do nothing and spend £38,000 on electricity; or spend £14,300 now and never have to pay for electricity for that 25 year period - maybe even make some money. A no-brainer if ever I saw one.

Commentators have described it as a gilt-edged investment with a guaranteed 8% return, or as a way of buying 25 years electricity up-front. The most interesting comment came from George Monbiot when he was bitterly questioning the validity of solar PV andthe FiT scheme in the Guardian: "If you own a house and can afford the investment, you'd be crazy not to cash in."

Coming to a conclusion

As the loss of government finance for the panels sinks in, we are coming to the conclusion that we should just go ahead with our installation using our own resources. It's going to take another month or more for Energy Saving Scotland to get their bureaucracy moving and maybe offer us a £4,000 loan that, while interest free, would not save us much compared to dipping into our own savings.

I went daft with a spreadsheet this evening. I laid out the incomes and outgoings of the project on a year-by-year basis, but this time I factored in inflation and the deterioration of the panels as predicted in their specification. It still looks good. Some thinking still to be done.

Finance changes

It was all looking too good to be true. And it is.

When I began this solar quest, it appeared that essentially the total cost of my system would be met, either by a grant or an interest-free loan from Energy Saving Scotland. I got my report as required and I sent off my forms about a week ago.

I've just had a look at the Energy Saving Trust's (EST) website where it turns out that in preparation for the arrival of the Feed-in Tariff (FiT) they have amended their policy regarding grants and loans for electricity microgeneration - it is not good news.

For a start, the grants have been stopped. That's £4,000 we won't get. Also, the limit for loans has been reduced from £10,000 to £4,000. Therefore, if we go ahead on the basis of our existing quote, we'll at best get a £4,000 loan and have to find the rest.

In my opinion, it is still worth going ahead, given the long-term finances. Furthermore, rather than wait another month for a relatively paltry loan and lose a month of generation, it may be worth simply going ahead on our own finances and eschew the government's attempts to incentivise this. Perhaps what I'm saying is that the FiTs scheme from the government is incentive enough and both they and I know it

Suppliers

I've started looking around for a company to whom I'll sell my microgenerated units. I still have to determine whether the company I sell to has to be the same as the company I buy from. In fact, I still have to determine the exact nature of the finances involved.

From the various solar power sites I've read, I'm getting the impression that exported electricity not only gains a 3p (or is it 5p?) per unit payment above the 41.3p FiT payment, but that some companies might choose to give more to attract people like me. Certainly it seems that if they don't, my decision would surely be based on who sells the cheapest leccy. That would likely be the big boys. I do hope the smaller operators have something up their sleeve to tempt me to go to them.

Funny thing is that with the FiT arrangements just 10 days away, few companies seem to be rushing to gain my business. I trawled through some of the websites of large and small energy suppliers. The small companies sometimes mentioned FiTs but didn't have a policy towards them. The big boys just didn't seem to care. I'll keep an eye on this.

Spreadsheet Heaven

Ever since my Dad demonstrated a computer spreadsheet to me, I've been in love with them. They are so damn useful, though I'm sure they frighten a lot of folks. Their more advanced abilities frighten me but with my basic knowledge of how they work, I've generated many spreadsheets for a huge range of tasks. I have one for work that I enter my start and finish hours into and it calculates total hours, overtime, pay, tax and a lot of other cool stuff. At home, we use spreadsheets to keep track of our family finances. I religiously note my book's Amazon sales rank (and the rank of some of my friends' books) to watch the trends and I keep a close eye on the sales of my photography on a plethora of microstock websites; all using spreadsheets.

It therefore should not come as a surprise that I have a sheet where I keep a note of the meter readings for my gas and electricity supply. I have this spreadsheet calculate the daily cost for both and I watch how the spend rises and falls with the seasons. One interesting aspect of this is to note how this year's consumption of gas compares to last year's. We had our walls and loft insulated during the summer and I'm happy to say that, despite us having one of the coldest winters in decades, we used 100 cubic metres less gas than we did last winter.

I just know that the arrival of a solar PV system is going to be spreadsheet heaven. Not only will I be able to count the units of electricity we use, I'll eventually be able to count what we generate, how much of our own power we use and how much is exported to the grid. I'll then be able to apply monetary values to the results and see if the system is costing more or less than expected, and even if it has started to turn a profit of any sort.

And just because I haven't got my beloved panels installed on the roof yet, don't think I haven't already created a solar PV spreadsheet because I have. I was real keen to try to model the overall costings of the system. I had accurate figures for how much power our house used in a year and at what cost. I had been told how much power my PV system was expected to generate and I knew how much it was going to cost to install. I put all this into a simple sheet and had it work out the costs and benefits over 25 years, the expected lifetime of the panels and the term of the FiT arrangement. So did it teach me anything? Well...

It seems the most crucial aspect is how much the panels will generate annually, followed by what proportion of that is exported and how efficient we can become. The matter of export is clouded by something I read today. It seems that until the introduction of smart meters, the powers-that-be are going to deem that I will use 50% of my generated power and export the rest. OK, so I can plug that into the sheet. Only smart meters are going to be able to tell when I use power and whether there was power available from the panels at that time. Assuming all goes well with the grant and the loan, the cost to me to install the system will be £10,300. Well it turns out (given that this model will include some relatively simplistic assumptions) that over 25 years, the panels will pay for all my electricity and net me £10,273 - the same as what they cost me! There's a coincidence.

OK, so what improves things? The government tables say that I will generate on average 8 units a day. What if it's 9? It's for questions like this that I almost dribble with excitement at the thought of the spreadsheet I'm going to create to find out for real. Meanwhile, my predictive model has its own answer. Now my 25-year income jumps to £14,817, a clear profit of £4,500 and my electricity paid for quarter of a century.

Now instead, let's imagine that I'm only getting my 8 per day, but that we're managing to use the vast majority of it. I suspect this will be the case. This house's electricity consumption is heavier than most. So instead of 50% exported, let's assume 10%. The income rises to £12,317, mainly because we're having to pay for less electricity from the grid. This yields a £2,000 profit over 25 years and the leccy bills covered.

I'll do one last illustration with the starting point restored to 50% exported and 8 units per day generated on average. This time, we'll see the effect of cutting our annual consumption by 2 units a day, something that ought to be easily realised, mostly by simply replacing our fridge. (Old, noisy, power hungry beast whose efficiency I've been watching with a power meter to prove my suspicions about it.) The income figure is now £12,463, a £2,100 return after 25 years for the sake of a better fridge.

I can't control how much my panels will generate though I suspect they might deliver somewhat more than the government says. But I do have some control over how much power we consume and when we consume it. The lesson is that it will pay to use less power, and that, once the smart meter is installed, we should try to use power when the Sun is out. Whether or not reality follows these predictions will only be learned when I get to grow a nice, shiny, new spreadsheet.

Trading power

It's now a waiting game as the bureaucrats deal with my application for funds for the solar installation. In the meantime, I can start to think about how I'll go about buying and selling electricity.

There seems to be an arrangement that current generators have whereby some companies will buy green power at very good rates because they can sell that power at a premium to people who want use only green power. The owner of the system I've seen buys and sells with a company called Green Energy who give him 28 pence for every unit he exports. I don't know what he buys his power for. However, on 1 April, everything changes when the Feed in Tariff (FiT) system begins.

FiT is a government system where microgenerators are guaranteed a fixed payment from the power company not just for every unit of power they export, but for every unit they generate. In my case, it will be 41.3 pence. It is the concept that makes a solar PV installation worthwhile. However, if I understand it correctly, it has interesting consequences. It no longer matters which company I go with because I will get 41.3 pence with all of them. However, I will still have to buy a large portion of my power and it is obviously in my favour to find a supplier who is as cheap as possible. This might be to the detriment of the smaller companies as I can imagine that Scottish Power, my current supplier, or Scottish Hydro will clean up this market. 

Perhaps, as the FiT system beds in, we'll find that companies will try to offer an extra few pennies per unit over the 41.3 p offered for power from the microgenerators. So far, it's not been easy to see what companies' policies are on FiT.

Time to start looking again.

Application time

A substantial part of today was spent filling out forms because in the middle of the afternoon, I got an email from the Energy Saving Trust. Attached to it were three PDFs; a list of accredited installers, a pack for applying for a grant and a report on my home's energy efficiency measures including recommendations for renewable energy systems that might be installed. This latter PDF is the important one. It allows me to make my applications for a grant and a loan for my solar power system.

[Later note: The grants were discontinued and the loans were reduced to a max on £4,000 - all before I could get to take advantage of them.]

There's a tiny bit of silliness in these applications. Both forms are going to two different departments in the same building. However, the grant application only requires me to include a reference number to their report. The loan application wants a copy of it, and it's 27 pages long. So where one form goes in a small envelope with a printout of my quote, the other has had to go in a large A4 envelope and we'll need to go to the post office to get the appropriate postage. So much for saving carbon.

I have to wait for up to 15 working days - call it three weeks - to hear whether I'm going to be awarded either the grant or the loan. As soon as I know, I can give the installer the go-ahead.

One other thing I looked into today was planning permission. I phoned the local planning department in the afternoon but it seems the appropriate person was not there. I'll phone them again tomorrow morning. I am pretty sure I won't need permission (or so I'm told) because I'm not in a conservation area and my panels won't go more than 200 mm from my roof. I'll know more tomorrow.

Crude calculations

We are told that our hoped-for panel array is expected to generate 2,900 units of electricity per year. Under the FiT scheme that would mean £1,200 income annually. If we manage to export 10% of them, then at 5p per unit extra, that would only add £15. Pretty small, so we'll disregard it for now.

I'm assuming we'll use 90% of these units (based on our relatively high usage - too many computers in this house). Therefore, we won't have to pay for 2,600 units. Given that we used 8,700 units last year, we'll still have to pay for 6,100 of them. At eleven pence each, that's £670 to find but we've saved £290 off our previous bill. This is good. It seems we can pay for our electricity from our FiT income and still have £530 left over, an average of £44 per month. But I haven't dealt with the cost of the system. 

If we get an interest-free loan for £10k, then each monthly payment should be £104 over the maximum 8-year term of the loan. With the £44 going on that, we'll have to find about £60 per month. However, that's £23 less than the £83-per-month we are spending on electricity now. Therefore, while the panels are being paid for, we'd be just on the positive side of this deal. All this assumes we get the power predicted by the government tables. Hmm. I wonder.

I asked how much power my contact had produced in the 40 days since he had installed his system. He said 286 units. So across 40 days from late January to early March, he had averaged 7.1 units per day. Hardly the sunniest time of year, or the longest days. But the 2,900 units predicted for my system (the same size as his) represents only 8 units a day. Time will tell, but I suspect that the government tables are being a little pessimistic. 

Solar subtleties

Let's keep going with this blog while I have the interest.

I knew that the 41.3p FiT would only apply to systems below 4 kWp. I asked why I had been quoted for a 3.5 kWp system when another panel would increase its output further and still be under 4. Turns out that for systems rated over around 3.7 kWp, the electricity company have to carry out a feasibility study to check the cabling can carry the load. This may seriously delay the project and possibly cost heavily. OK. I'll stick with a 3.5 kWp system.

A note on terminology regarding panel ratings. A solar panel will produce electricity when light lands on it. More light, more power. The most power a typical panel can in reality generate will be when it is directly facing a very high Sun through a clear sky. The power then being generated will be its peak power and this is stated as Watts-peak. I've been quoted for twenty panels each of which are rated at 175 Watts-peak, or 175 Wp. Put 20 of these together and the rating of the entire system is 3,500 Wp or 3.5 kWp.

Of course, my system will almost never generate its peak power. It might approach it on the odd fortuitous late-June day. We get a lot of cloud in Scotland. That will be a big drop. Our roof pitch at the back of the house faces 20 degrees south of due west so will generate most electricity in the afternoon and will miss much of the morning sunshine. That's another drop. According to what I've read or heard, our location will cost 10% compared to the UK average. Our house's orientation will cost another 10%. Therefore, from government tables, we can expect to generate 2,900 units of power annually. It will be very interesting to see if reality matches the predictions. I can't wait to start taking daily measurements.

The starting point

It's been on my mind for decades that I would like to use the power of the Sun to generate electricity and now the opportunity has arrived. I'm going to blog my progress and see how it goes.

When I looked into it seriously in 2000, I was put off by the payback time. I remember electricity was about 7 pence per unit. When I worked it out, it seemed like it would take 120 years; 60 years when I took the then available 50% government grant into account. Now the situation has changed markedly. There are still grants available and politicians are falling over themselves to offer interest-free loans. Best of all, from 1 April 2010, a new system of reward for the microgeneration of electricity will come into operation - the Feed-in Tariff, or FiT.

As I understand it, FiT works like this. For every unit of electricity I generate, I will get 41.3 pence of tax-free income. This will be guaranteed for 25 years and will be linked to the RPI. If I use that electricity, then that is power I won't have to buy from the grid, saving me 11 pence per unit. Finally, if the system is generating power and I can't use it, I'll get a further 3 to 5 pence (depending on who you listen to) for exporting it. This completely changes the economics.

On a cold but sunny winter's day in late February, I visited a house where they have a large system. The owner proudly informed me he had generated over 15 units that day as the Sun was setting. That house had a 3.5 kWp solar photovoltaic array on its roof. I was getting interested in this.

There are a large number of hoops you have to jump through to take advantage of the grants and loans available for microgeneration and I'll try to relate here how I pick through them. First of all, there are grants of 30% up to a max of £4,000 available here in Scotland. [Later note: These grants were discontinued before I got to take advantage of them.] There are interest-free loans of up to £10,000 available but apparently the funds for these are nearly exhausted. [Later note: Maximum loans have been reduced to £4,000.] All this government largesse is only given if the powers-that-be are satisfied that you have implemented appropriate energy saving measures in your home. After all, the point of this intervention and incentive is to reduce the UK's emission of carbon. I think a discussion of that will be for a future blog entry.

The 41.3-pence FiT is only available on solar PV systems that have been retro-fitted onto existing houses and only up to a maximum of 4 kWp. Other rates apply for other sizes and other technologies for the microgeneration of power. OK. I would get a system that was slightly smaller than that. The 3.5-kWp system I had seen cost £14,000. It seemed I could get a grant of £4,000 and a loan for essentially the rest. OK. So what's first? I have to get a report from Energy Saving Scotland to check that I have mostly low-energy lightbulbs, have insulated my walls and attic and that my radiators are fitted with thermostatic valves. I do, I have and they do. I'm now awaiting a report arriving in the post that will clear the way for an application for a grant and a loan.

Meantime, I have got a quote for the system. 20 panels, each capable of 175 W peak and it's a shade over £14k. I've even used photoshop to simulate what they would look like on my rear roof. This is cool!