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solar photovoltaic panels in Eynsham


Several people in Eynsham are making their own electricity by installing photovoltaic panels on their roofs. This page explains why they are doing it, how, and what the results are. A future page will do the same for solar thermal panels - using the sun to provide hot water

GreenTea

If you're interested in reducing Climate change, have a look at GreenTea, Eynsham's own Climate Change group

Elms Cottages - before
Elms Cottages - after

what

Photovoltaic panels use radiated light (not necessarily sunlight) to make Direct Current (DC) electricity. You may think there isn't enough sunshine in Eynsham to make electricity, but the panels can absorb light through the clouds (not as much as from direct sunshine of course). Ideally you need a south-facing roof, but south-west or south-east facing roofs are OK - they are just not as effective as south-facing roofs.'

The chart below shows the amount of electricity you would generate during an average year (the dark red is the usable electricity). Sunshine records in England are (slightly surprisingly) quite stable and reliable - so you should get what the chart shows.

Worldwide, production of electricity by photovoltaic panels has increased by 48% a year since 2002; it is the world's fastest growing energy technology.

It currently costs about £10,000 to £12,000 to install panels to produce 2,000 Kwh/yr.

You need a south-facing roof.

Why

There are two good reasons for making your own electricity - climate change and money.

Climate change
The Climate is changing - and it's changing because human beings are causing greenhouse gases which overall are making the world gradually warmer (though not always in Eynsham). There's a bit of disagreement about the exact figures and forecasts, though not about the general trend. In one sense the exact details don't really matter; if you're walking towards a cliff in the dark, it doesn't matter exactly where it is - you need to take action to avoid it.

Every Watt of electricity you make from sun-power reduces the need for it to be made at a power station such as the gas and coal-fired Didcot power station. Coal-fired power stations produce a lot of greenhouse gas, so producing your own electricity means that Didcot produces less greenhouse gas.

Also, your example may encourage others to do likewise, reducing Climate Change even more.

Indeed, your example may be more important than the actual 'dirty' electricity you save; by putting your money where your mouth is, you give governments - in Britain and around the world - more push to slow climate change globally.

money
There's a subsidy for generating your own electricity - you get 41.3p for each Kwh you produce - no matter who uses it. The Government announced the rate in Feb 2010. Click here for details. This income is tax-free. The subsidy, or Feed-in Tariff (FiT) is guaranteed for 25 years - though probably not at this high starting rate. Over 60 other countries already have FiTs.

What's the point of this subsidy ? The Government wants to increase the amount of 'clean' energy produced - partly to slow Climate Change, and partly to meet its targets. And this is a relatively cheap way of doing so - compared to building more power stations. The Government aims to have 1.5 million homes generating their own electricity by 2020. If they each make 2,000KWh/yr that would total 3bn KW/h/yr.

In money terms, photovoltaic panels to make your own electricity offer a pretty good return. It currently costs about £12,500 net to install panels to produce 2,000 Kwh per year - and you get back 2,000Kwh x 41.3p = £826 plus the cost of any electricity that you generate instead of buying. The cost of electricity you buy depends on the deal you have with your electricity supplier - 12p/Kwh is typical. So if you generate 2,000 Kwh/yr, you save 2,000 x 12p = £240. So your total return is £1,066 on an outlay of £10,000 - over 10%. Not bad these days. And if the price of electricity goes up, you save even more (though the FiT rate may go down). For all this in much more detail, click here. And for a useful Guardian article, click here.

how

It's all surprisingly easy. It's a good idea to have a chat with someone who has had it done already; click here for a list of people in Eynsham who have photovoltaic panels and who are happy to talk to you about them.

First check that you don't need planning permission; in Eynsham, Listed Buildings

Elms Cottages - the installation in progress
do, Conservation Area buildings don't (photovoltaic panels are "permitted development") - but it's worth getting a letter from West Oxfordshire District Council saying so. You then contact an accredited installer (be careful - there are bound to be cowboys about in an expanding field like this) - if you Google 'accredited photovoltaic installers', you'll get a good selection, They will give you a detailed estimate, as well as advice about how to apply for any grant, etc. Then choose your installer. Then go ahead with installation. Which takes three very painless days.
Elms Cottages - the installation in progress
Tell your insurance company (they are unlikely to increase or decrease your premium), and your electricity supplier (they pay your Feed in Tariff). You should also get an OK from the Building Regulations Inspector.

The installation process consists of putting up scaffolding, fitting the panels on the roof - and connecting them up to your house and the Grid. This needs an 'inverter' - see right - a box screwed to the wall in your loft or garage.

It converts the DC current generated by the panels into AC for your house and the Grid. It arranges that you always use your own electricity first; you only use the Grid's electricity when you are not generating enough of your own.

Elms Cottages - the inverter in the loft
There is also a connection system to you own supply, and displays to tell you how much electricity your are making and have made. You may also have an Export/Import meter installed by your electricity supplier.

There's a useful diagram which shows how all this works at the Energy Saving Trust's website - click See how solar electricity systems work in practice

the result

The result is that most or all of your electricity is both carbon-free and cost-free. The downsides are that you can't get your money back once you've installed the panels (unlike a car, which you could sell if you needed the money), and you or others may think your roof is not so attractive as it was without the panels.

more information

This is a really good time to install PV (because of the new FiTs - see above) - click here for more on how to do it - as a business or as a private individual.

There's also lots more information on the web - a good start is Energy Saving Trust's website.

The PV panels shed the snow very well. This photo was taken the day after 7" fell overnight