Posts tagged with: PV

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.

If you want to buy a solar panel in the UK and use it to generate green electricity under the UK feed-in tariff, you will have a much smaller range of solar panels to choose from than customers anywhere else in the world. The reason for this is because of a scheme invented by the UK government called the Micro-generation Certification Scheme (or MCS). This benefits and drawbacks of this scheme were discussed in a previous article on this site and now that we are two months into the feed-in tariff it is a good time for a review of the situation.

There are more solar panels to choose from now than there were two months ago, however there is still a very restricted choice with some major solar panel manufacturers missing from the list. This can only hurt the UK industry. At a time such as now, when the industry is going through an unprecedented boom, customers need as much competition in the market place as possible. Such restrictions are dangerous as they can lead to inflated or irregular pricing. Europe as a whole is experiencing high volumes of demand at present (largely driven by Germany) which is causing equipment shortages and long lead times. We have seen evidence that the MCS restrictions are exacerbating these problems as there is a much smaller number of available suppliers to choose from.

Some of the stated aims of the MCS process are valid. I am very much in favour of protecting consumers from low quality, inferior products. The question remains is how much does MCS add on top of the existing international accreditation bodies for solar panels such as IEC and UL. These bodies are represented by committees with decades of experience in solar panel reliability testing who spend a huge amount of time developing new ways to prove reliability.

MCS accreditation requires visits from MCS inspectors who ‘inspect’ a manufacturer’s facility before their solar panels can be given the green light. Nowhere is it written who these inspectors are and what their qualifications might be to do this above and beyond IEC or UL testing.

Looking at the current list of MCS accredited solar panels it is difficult to see on what criteria certification is being given. Some large very high quality manufacturers are missing, whilst some small, unheard of manufacturers are already there.

I have heard from colleagues in the industry that administrative and beaurocratic issues are currentls holding up a large number of MCS applications and that a raft of new solar panels will join the list soon. I hope this is the case, and I would encourage anyone with more information on the issue to contact this site. My message to the organizers of the MCS process however, is to put more effort into not damaging the industry that it is designed to support.

After the official commencement of the UK feed-in tariff on April 1st we were surprised by the relatively mute response that it received in the UK media. The event did get some press coverage, but the general impression given was that this was just another green initiative, rather than the introduction of a program that has caused a major renewable energy boom in every other economy where it has been introduced.

Since then however, signs have been emerging that there is an ever increasing wave of companies entering this market, and that solar energy in the UK is getting interest from international investors.

As you may well be aware, qualifying for the feed-in tariff requires an MCS accredited installation company. Newly qualified installers have been added to the MCS list every day since April now and the range of companies now offering MCS solar installations is very broad. Some companies are one man, local electricians whilst at the other end of the spectrum are large energy companies such as E.On with thousands of installers, there is a large choice for those wishing to have solar panels installed.

One trend to look out for is the increasing number of professional investors who see an opportunity to make money from the feed-in tariff. By paying for a solar installation on a rented roof or field, investors can have access to the feed-in tariff revenue. Owning the PV system can provide up to 10% annual returns over a 25 year period with a high level of security.

Quite how these arrangements will work is not yet clear. There are a number of ways the contracts between the investor and property owner can be written, and great care to needs to be taken to ensure that all liabilities are covered in the case of a property sale or an accident. Despite this, a number of companies are exploring this type of agreement for the UK, which is already very common in the rest of Europe.

For land owners or property owners with suitable roofs, leasing space for solar panels can be a very attractive option. It requires no upfront investment, generates significant revenues, carries little risk, and improves the environmental credentials of the building. A property owner might earn more money if they own the solar system themselves, but that would require significant initial capital expenditure, something which many companies may not be able to afford.

The feed-in tariff is obviously very attractive to investors as there is little risk. Once you are in the scheme, the payments are guaranteed for 25 years. Photovoltaic systems are generally reliable, so long as you use good quality products. Solar panels are guaranteed for 25 years (to 80% of their power production) and inverters usually for 10 years (you should expect to replace an inverter at least once in the lifetime of the installation). Other than this, the only risk is that the sun will stop rising each day, and if it did, you’d have something a bit more serious to worry about than your profits…

If you would like to invest in a photovoltaic system, or have a suitable roof that you would like to rent, you can contact us for more information.

We have teamed up with one of the UK’s leading Photo Voltaic installer and Distributor to enable us to offer you this amazing Solar Investment.

This company is enabling UK investors to take advantage of a new opportunity unlike anything previously accessible, which will appeal to individual investors, savers, businesses and financial institutions alike

You can now purchase an investment-grade, high-yield Solar Power System (SPS) along with the UK Government-guaranteed right to income from the energy it produces.

How much does it cost?

A single payment of £16000 (plus VAT at 5%) gives you ownership and the rights to any income generated by the SPS for up to 25 years. If you choose to retain ownership for the full term, the payments you receive would repay your capital outlay and produce an additional average return of 7%.

What Is The Return?

Through the SPS, investors and savers can gain a guaranteed income for 25 years which is index-linked and will provide an average return of 7% per annum, by taking advantage of the government’s Feed-in Tariff Scheme (FITS) scheme, also known as the Clean Energy Cash Back scheme, which came into effect on 1st April 2010.

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