It's the Big Day!

My solar installation team have arrived and now they are getting stuff ready.

(I should have posted this just after 09:00 yesterday, but events sort of conspired against me.)

Anyway, all was up and running by 16:00; and the last couple of hours of daylight produced 0.45 kWh of electricity.

I have also learned that the human eye is utterly lousy for measuring light intensity. But I guess that's why cameras have exposure meters .....

Solar Payback Calculator

The "important solar calculation" below has been turned into a handy online calculator.  You can access it here.

Once you have had your site survey, you will receive a quotation for the installation and an estimated annual generation figure.  The brochures for your panels will include figures for degradation in performance due to ageing.  With these figures, you can determine the system output over its lifetime; and thence the equivalent cost per kWh treating the purchase of the generating system as a single bulk purchase of electricity.

Latest Developments on Solar Project

I now have my Energy Performance Certificate.  Montoya Mansions has earned a "D", 59 points.  Things like "energy saving light bulbs throughout"  (since 1996, for the record -- Ed.)  and "biomass secondary heating"  (my gorgeous log burner in the living room)  helped.  Solid walls, and only 100 mm. of loft insulation under the boards, did not.  Also, not having a room thermostat  (which I could leave cranked up to 30 all the time anyway)  on the  (non-condensing, but pilotless)  combi boiler counts against me, despite there being no suitable location for a room thermostat and all radiators having thermostatic valves -- but this is what happens when you prioritise box-ticking above thinking.

I also have my application forms for the feed-in tariff  (which I will need to send off as soon as I have the installation certificate),  a confirmed installation date for the solar panels, and a mini-statement from the cash machine shows that the cheque with which I paid the deposit has been cashed.  Things are moving forward .....

Solar Power: The Important Calculations

When deciding whether installing solar panels is worth it financially, you need to consider the system as a bulk purchase of electricity:  for the up-front price of the system, you are effectively getting all the electricity that it will generate over its lifetime.

The panels are reckoned to last for 25 years; after which time they will still be producing 0.8 of their rated capacity.  The inverter has no moving parts, so that should also last the 25 years.  Meaning, I will have paid just £5049 for all the electricity I am going to be producing over those 25 years.

Is that going to be worth it, compared to the price of electricity from my supplier?

My installer's  (pessimistic)  estimate is for 1400 kWh per year -- it probably will be more than that, in real life.  So over 25 years, that is a total of 35 000 kWh.  For £5049.  That works out at £0.144257143 = 14.43 p per kWh, which is less than I'm paying right now.  (I could do the calculation accounting for reduction in output, but I know that the installers' estimates are on the low side anyway.  Oh, all right.  At 25 years, the output will be 0.8 of what it is now; 1120 kWh/year.  £5049/25 for 1120 units is £0.180321429 = 18.03 p per kWh.  Due to the way this is decreasing, the most accurate average is the geometric mean -- the square root of the product.  So 16.12p.)

Even if the price of electricity doesn't go up, I am still going to come off better out of this deal :)

Montoya Mansions is going Solar Powered

Montoya Mansions is to become solar-powered!

I've had a very reasonable quotation to install solar panels on my roof.  They will be able to fit a 2kW system  (eight 250W panels)  in the clear space available  (the space immediately next to the chimney is unusable, as it would be in shadow in the afternoon; and the chimney is very much in use, for disposal of combustion products from my wood-burning stove).

Although the amount I am going to be able to generate is  (I hate to admit)  rather less than the amount I use, it is still worth it.  Electricity isn't getting any cheaper.  Even if the price per kilowatt-hour stays the same, the system should have paid for itself within 11 years.  And sooner if it goes up; since I'm effectively paying in advance for as much electricity as can I generate.  Whatever I generate and use, I won't have to pay for.

And if I can somehow reduce my consumption to the level of what I can generate, then I'm going to be up on the deal, since the rebate is paid on the assumption that you use half yourself and export the rest.

Anyway, having paid my deposit, there is now a statutory cooling-off period of 7 working days before they are allowed to begin the installation work; during which time, I am free to change my mind and ask for my money back.  The clock is already beginning to seem to take a long time between ticks .....

Watch this space for news.

Yes, actually: *Do* sweat the small stuff

There's an idea going around that we shouldn't be bothered about small things because there are bigger things going on elsewhere in the world that should be of greater concern.  Why should someone care about a nightclub refusing entry to someone wearing the wrong sort of shoes, when there is institutionalised racism, sexism, homophobia, you name it?  Why should someone care about Britain reducing its CO₂ emissions, when China is bringing so many coal-fired plants online?


Unfortunately, that is exactly the wrong way to think.

Because the thing is:  well, actually, it's twofold.

Firstly, the "small stuff" is precisely what keeps the "big stuff" going.  It gives your enemies a convenient excuse to carry on with what they are doing, knowing that somebody else in the world is getting away with a less-serious version of the same thing.  After all, what is a flood, other than a lot of little drops of water?  Hell, in China, they probably are using the excuse that London is ten centimetres deep in discarded sweet wrappers as justification for continuing to build more coal-fired power stations.

And secondly, the "small stuff" is by definition, exactly what we are most likely to be in a position actually to be able to do something about right now.  I can also tell you that having successfully convinced even a desperate and failing nightclub to change their door policy will make you feel like .....  well, just pick your favourite character from the history of the struggle against inequality, I wouldn't want to annoy anybody with inappropriate comparisons involving their hero(ine)?.  You will be stoked up with your success, and feel ready and able to take on all the institutionalised discrimination in the world.

If we don't start doing something right now, we'll end up simply accepting "small stuff" as normal.  And all that will achieve will be to make the "big stuff" look proportionately smaller.