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Here at Solarfeedintariff we like everybody to share their feelings on solar energy. One of our readers has been kind enough to give his thoughts on his new solar system and the report is below. Please feel free to submit any articles you feel would help educate the world on solar energy.

We have an unshaded South West facing roof at about 45^o angle.  We had scaffolding for some quite substantial roof work, so decided to use the opportunity to have PV panels installed.  Because of a dormer, we had little space and could accommodate only four panels, mounted horizontally, giving us a maximum of just less than 1kw. The supplier was a JHS, a small company in Banbury.

The inverter gives a reading of the current power and total units each day – this gives lots of opportunities for taking readings and doing all sorts of nerdy analysis. Over the first four weeks (July) we are averaging 3.5 units per day.  On about the 15 August the sun will actually hit the panels square on at one point in the day – will this be the best day overall?   Facing SW, the panels do not see the sun at all until after 11 am (BST), until that time we generate more power from bright clouds than blue sky.  Hence it is ideally white cloud until mid morning and then sun – although we do get several hundred watts from bright white clouds.

Getting ourselves registered through our utility company (SSE) took a bit of effort.  The web-site was uninformative, emails were not replied to and I did not have the patience to wait for them to answer telephones.  Writing a letter worked, we were put in touch with the ‘microgeneration’ department and now have a feed-in contract.  There does not yet seem to be a formal scheme for submitting readings of our solar generation, we are asked just to write or email the reading every three months.

There are four ways you save money, three of them legal.  (i) The feed-in tariff, 41.3p per unit generated is very generous.  (ii) For the power you actually use while being generated, you obviously save on your electricity bill – around 11p per unit.  (iii) They also assume (they cannot measure, without extra equipment) that 50% of your power goes back into the grid, effectively this gives you get an extra 1.5p per unit generated.  (iv) If you have an old fashioned meter, the little wheel goes backwards  when you are not using all the power, and this drives the meter backwards – the effect of this is that you are saving 11p per unit on all the power you generate, not just that you use.  I suppose the utility company knows this – the meter does belong to them!

Our installation cost around £6000.  Will we get out money back?  Well at my age (67) maybe not, but we should see a substantial saving each year – and  it’s all been very interesting.

C J Pavelin July 2010

A big issue for solar and wind energy is that the power they deliver is not constant. Unlike coal or nuclear power stations which produce a steady stream of power whatever the weather, wind and solar suffer from extreme fluctuations. For wind energy, a drop in wind speed can mean a 90% power loss over a large area in just a few seconds.

For solar energy, there are many different types of fluctuations. In the UK for instance, winter months produce only a quarter of the amount of energy as summer months. Obviously solar energy production takes place only between dawn and dusk, and even during the day, clouds can cause major fluctuations in solar energy output. These fluctuations make it hard for electricity grid operators to really use renewable energy since they need to guarantee power is delivered 100% of the time.

At the moment, because renewable energy makes up such a small component of our electricity generation in the UK these fluctuations are irrelevant. However as the proportion of renewables connected to the grid increases these effects will eventually become more significant. In southern Germany, where solar energy makes up over 4% of the electricity generated and at times represents 30% of the electricity on the grid, energy companies are starting to think carefully about how to use this resource most effectively.

Several can be done to decrease the impact from these fluctuations in renewable energy:

The first thing is to have a strong and efficient electricity grid. This is the case in Germany where energy can be efficiently and almost instantaneously moved from one part of the grid to another. This means that when there is a surplus of energy in one part of the country, energy can be transported at very short notice to where there is an energy deficit. Interestingly, as the amount of solar energy in a country increases, short term fluctuations caused by clouds are “ironed out” as shaded solar panels in one region are compensated for by unshaded solar panels in another.

In addition, as some of you may have heard, there is something called a ‘smart grid’ in development. This term is used to refer to lots of different things but on its most basic level it implies that energy demand can be controlled in some way. This could be very helpful for renewable energy since energy demand can be matched to when there is an abundance of solar energy in the middle of the day.

Another tool that can be used is prediction mechanisms. Using weather forecasting and remote monitoring, the amount of solar energy expected can be predicted. Providing this information to energy companies allows them to use various forms of reserve energy such as gas turbines or hydroelectricity which can be turned on and off in a matter of minutes.

The ultimate solution though, is to find a cheap means of storing energy. This would make all the fluctuations from renewable energy irrelevant. Researchers around the world are busy working on a wide range of different energy storage technologies. One of the most familiar ways of storing energy is to use a battery. Regular alkaline batteries are far too expensive and not durable enough to be used on a large scale, but there is huge number of new types of battery being worked on that could soon bring the cost down dramatically.

Besides batteries, there is a wide range of other technologies in development that could all be used to store renewable energy. Examples of these include; compressed-air energy storage, pumped hydro-electricity, molten-salt, fly-wheels and hydrogen, to name a few. Of course each technology has advantages and disadvantages, but it remains that we have a number of potential solutions for storing renewable energy. So the fact that the sun doesn’t always shine is certainly not a reason not to support solar energy.