Solar Feed In Tariff Website

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.”