Announcements on earlier this month that the Spanish government was to reduce spending in another sector of the Spanish economy would hardly have made for happy reading on the pages of El Pais and El Mundo. Nevertheless the news was that huge spending cut backs would be made on solar energy with tariffs designed to attract uptake with reductions of up to 45 per cent.

Draft proposals from the Ministry of Industry announced that spending cuts would reflect those seen on feed-in tariffs in Germany and Italy where the tightening of purse strings has necessitated the removal of what are seen as non-essential expenses.

Indeed, Spain will be reducing tariff payments for roof-based systems by up to 25 per cent but for large ground based solar installations a much more eye watering 45 per cent, news not likely to impress installers or investors.

Feed-in tariffs work by offering producers of renewable energy fixed, premium rates for the energy they both use and feed back into the grid. The energy firms are obliged by legislation to purchase the renewable energy at the premium rates the costs of which are spread across Spanish energy consumers. The Spanish government has therefore been able to justify cut backs explaining that they are a means of controlling rising Spanish Energy Bills.

The problems of course is that while consumers may make some savings on their monthly electricity bills, cut backs at this period could cause serious long term harm to an area of the Spanish economy which has been booming over the last decade.

With news this week that growth of the UK solar market has finally over taken that of Spain, it highlights once again the essentiality of tariff mechanisms as a way of creating long term attractiveness for investors in the face of struggling economies.

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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

Understanding how to design a PV system is not rocket science, but it is more complex than many people consider. Here’s a very quick overview of the important points.

Solar panels produce direct current (DC). This means you need an inverter to turn that electricity into mains frequency alternating current (AC).  Inverters come in a range of power ratings. The more solar panels you have, the more power the inverter has to deal with, so the size and cost increases. It’s very important to match the size of the inverter to the number of solar panels.

If the inverter is too small, you will lose out on some of the energy that your system produces. If it is too large, the inverter may not perform at its optimum efficiency, and you will have paid for more than is necessary. In the UK, the optimum situation is to have an inverter that is rated at 80% of the power rating of your PV system, since it is rare you will be producing at 100% power.

More critically than getting the power right, you need to ensure the voltage and current of your solar panel system remains within the input range of the chosen inverter. To re-cap, solar panels on your roof are generally connected together in series, in a ‘string’. This increases the system voltage, but does not increase the current. Once a certain number of solar panels have been connected in series, the voltage will become too high and the system needs to be arranged in two strings, each of the same number of panels, connected in parallel. This generally occurs after a string exceeds 8 – 11 solar panels. When strings are connected in parallel, the currents add-up, but the voltage remains constant.

By adding more and more strings in parallel, the current and voltage can be controlled to remain in the inverter limits. For large solar installations, inverters can used that that have a very high power capacity, or alternatively it is possible to use many small inverters connected in parallel.

It is important to remember certain constraints. Inverters come in several sizes, but there may be some numbers of solar panels for which no inverter is ideal. For instance, because it is necessary for all stings to be equal in size, you can only use an even number of solar panels when using multiple strings. In addition, all solar panels must receive the same amount of sunlight when connected to the same inverter. It is no good to have some solar panels facing different directions on different parts of the roof. New technologies, soon to become widely avaialable that will make this process much easier. Namely micro-inverters, which convert DC to AC at every solar panel, will mean that solar panels can face different directions, however these are not yet widely available.

If you have a sales visit from a solar company, make sure the salesman understands these points as he’s designing your system.

As usual, it seemed that the UK was falling behind competitors from abroad from a reluctance to look to the future and fully back green energy through strong legislation. Solar markets in Spain, Germany and Italy to name but a few in Europe, attracted investment through incentive schemes in the form of feed-in tariffs. With the UK government finally introducing the Clean Energy Cash Back scheme in April 2010, it now appears that the financial mechanism is in place to help UK solar investment catch up with more mature markets overseas.

According to many within the industry, the UK now has everything in place to become a player in the global solar market.

“The UK market for solar PV is growing explosively. This is because the FITs [feed-in tariffs] bring a huge new raft of players – the energy users – into the market; broadening it way beyond the traditional energy industry. All renewable power sources are benefitting, but solar is doing best because it is so easy to apply,”

Commented Philip Wolfe, Director of Ownenergy and leading exponent of feed-in tariffs.

With the tariffs working as a means of incentivisation for investors who were once reluctant to invest in what was once an extremely expensive field, the tariffs offset costs and greatly improve the attractiveness of green energy investments. In all countries where tariffs have been introduced there has been a massive uptake in investment with individuals keen to take advantage of legislation-protected investments with healthy ROIs.

With regards to potential for the solar PV industry, Edwin Koot CEO of Solarplaza stated that,

“Having experienced the benefits that FITs have to offer, European countries are now looking to capitalise on the emerging UK market. We can already see signs of this happening for our upcoming UK PV Conference: where 67% of delegate registrations are from international companies, compared to just 33% from the UK.”

However, warning that in the current climate the UK solar PV industry is unlikely to achieve overnight success, Clive Collison of South Facing said,

“It will take time to develop the UK market. Currently there is a lack of knowledge so education of potential customers and businesses is needed. Right now, very few people understand the feed-in tariff system and the opportunities to their full extent.

It took Germany, Spain and Italy three years after the start of their feed-in tariff to reach a substantial market scale. No doubt a similar market development will occur in the UK. That is why conferences like the UK PV Conference are important, to educate the business community and customers and build the business infrastructure. There will be plenty of business for everybody.”