Installation of Photovoltaic (PV) solar electric and wind generator – the essential knowledge.
I am going to try and keep this really short and sweet because I could write about it for ever. Three years of misery have gone by before we have a reasonable working system. We live in Spain. There is a grant for installation of off-grid power which means battery-backed electrical systems. The type of solar panels that heat your water are quite different and we can consider those on another day.
There is quite a lot of help on the web for those seeking “normal” electric power when they live, as we do, miles away from any mains electric transmission line. But that help tends to be specific to, say, windmills or PV panels, so let’s look at the overall structure first and I will write new articles about the specifics. Firstly, relevant only to Spain, there is a grant “subvencíon” from Prosol, in Andalucía, a government sponsored agency. The grant was, in 2007, for 40% of your solar panel (PV) cost, it has dopped in 2009 to around 30% and you now need two sources of “green” energy for instance solar panels and a wind turbine.
These things matter, our total expenditure on stand-alone electricity has been around €24,000 of which €8,000 has come back by way of government subsidy grant. So, if you live in Spain (or anywhere where there is a government subsidy) number one on you priority list is to be absolutely 100% sure that your supplier qualifies for the grant. Although we eventually got ours, it took three years of legal battles. Our neighbours (our nearest but they are 3km away) were much smarter, they only paid the (same) installer 60% of the installation price and said they would pay the difference when their government grant came through (it hasn´t).
OK, so you are smarter than us and you have tied your supplier down to a really tight contract which gives you your power but throws the burden of reclaiming the government grants onto them. What are you going to order in the way of off-grid electric power? Obviously, this depends on where you live. If you don´t live somewhere with a resonable sunshine record, forget PV. Here in the sunniest part of Southern Spain (and we´ve had a horrid winter) we get around 12 kilowatt hours per sunny day from our 2kw array of solar panels. What does this mean? This means that we have 12 panels on our roof which generate (in perfect conditions) just over 2kw of power which goes into our batteries. The actual power that they produce depends on the amount of sunlight, the heat of the panels (they produce less electricity when they heat up, which they naturally do in the sunshine), and the length of the day. So, in winter the panels are cold, the day is short and the sun can be dazzling. In summer the panels are hot, the sun is out for ages and the quality of light is often less good – hazy.
We alter the angle of the panels in the Spring and Autumn because this gives us an extra 7% or 150 watts of power by pointing the panels towards the sun. In the winter, the sun is low on the horizon, in the summer it goes almost right overhead. Amazingly, the amount of power produced in a day in the summer or the winter is about the same.
The difference is that in the winter we don´t use much power, only for light and the normal household machines. In Summer the swimming pool pump is on for four to six hours a day and this really strains the system. I will come onto batteries, inverters, charge controlers etc. later but I want a reader to understand what they can achieve with a €20,000 spend on solar PV and wind electric.
When we first looked into this whole matter, there were numerous blogs and websites that told us that we had to save every ounce of energy or we would not be able to live a normal life. The reality is that we run the washing machine (but not tumble dryer), the dish washer, the steam iron, the fridge-freezer, the electric toaster, the Magimix, the breadmaker, the microwave, the de-humidifyer, the water pressure pump and (the worst culprit) the swimming pool pump. So we live a normal life and we have no electricity from the grid.
When we looked into the concept to begin with, websites told us that we couldn´t have fridges or freezers or any form of electric-guzzler. Just not true, you can use your hair dryer because it´s only on for 10 minutes and the big baddie is the swimming pool pump which consumes the same amount but is on for hours. To sum up, for an outlay of €16k, you can have an electric system better than the mains (at least in Spain where it is forever failing and “browning out”). Here in Andalucia, the average electric bill is €250 every two months to include Winter Heating and Summer Cooling. €1,500 a year, none of which is payable for a PV system. This seems a realistic payback timescale to me.
There are other costs which I shall go into in detail and the way that you plan and install your PV / wind generation is really important but I just want you to know that it is possible and that I will be letting you know the horrendous hurdles we had to overcome in order to be the happy owners of a stand-alone electrical system. Before you buy, just be certain of all your costs and I will show you in another report how some items are so much cheaper from the UK that, grant or not, you have to buy them there and get them couriered to Spain.
Read part two here http://courier-spain.co.uk/blog/alternative_green_energy/