Solar Feed In Tariff Website

The whole idea of this feed-in-tariff business is that you earn money by selling units of energy produced by your solar panels. So much so that after 25 years of operation you’ve made your money back and have even turned a tidy profit. This means that in order to know whether putting up some solar panels makes any sense, you need to know exactly how much energy they’re going to produce over the 25-year guarantee period.

Easy, you might say – the calculation is pretty straightforward. You find out the average annual irradiation (sunnyness level) from your local weather station, and multiply by the efficiency of your solar panels and the number of square metres you have. This will give you a nice number and away we go. The only problem is you might be more than 50% wrong because we’ve missed out a couple of variables. Variables such as temperature coefficient, tilt angle, diffuse-light fraction, solar cell type, shading losses, inverter losses, cable losses, degradation, module de-rate factor, mismatch losses, anti-reflective coatings, snow and lightning strikes, to name a few.

Of course there are an infinite number of effects that can influence the output of your photovoltaic system (solar eclipse, anyone?). The question is whether you have considered the important ones or not.

Knowledgeable installers use one of a number computer programs designed specifically to take these factors into account. You type in what type of solar panel you’re using, how many, where they are, what angle they’re tilted at, what direction they’re facing and then press ‘go’. It then calculates the amount of energy you’ll produce each month and even the return on investment if you want it to. Behind these models is actually some physics that describes the behaviour of solar cells under different light intensities and correctly.

The most commonly used model in Europe is called PVSyst, developed at the University of Geneva. This software package contains information on a large number of different solar panel types and is capable of taking into account many of the above listed factors. Installers across Europe use this software package to predict the energy yield of residential solar systems, as do many banks pondering whether to provide multi-million euro loans to super-large PV power projects. Even with this advanced software package however, some of these factors are very complex, and improving these models is an active area of research.

Here, I’ll deal with a couple of these complications as examples. When you buy a solar panel, it invariably comes with a power rating. Full size modules are generally around 200W. What does this mean though? In principle, the power rating indicates what you get when the panel is illuminated by full-sunlight. ‘Full sunlight’ is not very specific, so the international community has defined what is known as Standard Test Conditions (STC), which corresponds to an irradiation of 1000 W/m2 and a cell temperature of 25oC, when the light has a specific spectrum (or colour) known as Air Mass Index 1.5. So the power of your solar panel comes from its performance under exactly these conditions. In general this is measured using special type of lamp called a ‘solar simulator’ that tries to reproduce the AM1.5 spectrum as closely as possible. Calibrating these lamps precisely is notoriously difficult and there are very few testing centers around the world that are truly trusted. The National Renewable Energy Laboratory (NREL) in Colorado, USA uses at least two different lamps and one outdoor measurement to record STC performance, after a long period of calibration.

Because measuring the STC performance is so tricky, the power rating you get has a plus or minus 5 percent error margin. This is hard to include in your simulation. In addition, manufacturers will often deliberately under-rate the power of their solar panels to be sure they don’t fall below the warranty. This means you may well get considerably more power than you expect.

Another factor that adds to uncertainty is the degradation factor. When you buy solar panels they are normally guaranteed for 20 years, but only to 80% of the initial power output. This means the manufacturer expects them to degrade 1% per year on average. When calculating performance in the models, people also tend to use a 1% degradation rate per year. This is only a rough estimate however. During the certification process, solar panels are given all sports of nasty treatment to test their reliability to breaking point. This doesn’t tell you much about the rate of degradation when the solar panels are outside under normal operation though. The only reliable way to test degradation over 20 years is to wait 20 years, but this is complicated by the fact that technology improves reliability much faster than that. So the degradation of solar panels made in 2008 has only been tested since, well, 2008.

What these issues highlight is that understanding the energy yield output of your solar panels is not as straightforward as it may at first seem. When having your system designed, make sure who-ever you’re dealing with has some experience, and if possible, get a second opinion.

The other critical piece of information for understanding the financial viability of a solar installation is how much you will get paid per kWh under the feed-in-tariff. Unfortunately, the UK government has not released the final figures yet, which means no-one in the UK can make a reliable financial plan for getting solar panels, even when the launch date for the feed-in-tariff is just 4 months away.

Hopefully I will be able to update you on this in the near future. For now though, it’s better to be more conservative with your numbers than too ambitious….

With the UK government’s announcement of the introduction of the Clean Energy Cash Back system, essentially a feed-in tariff designed to attract investment in the British renewable industry, controversy has raged with solar industry insiders believing tariff rates to be too low.

It therefore comes as no surprise that the Federation of Master Builders (FMB) has also announced that they believe the tariff rate which has been set (5p/unit with a subsidy of 36.5p for units of energy generated by small scale solar and wind installations) will be too low to make the UK market competitive and have suggested a rate increase of 10p.

Speaking under the banner of the widely publicised ‘We support solar’ campaign the FMB’s announcement comes in the light of a number of criticisms aimed recently at the Department of Energy and Climate Change (DECC) legislation to be introduced in the April of next year. The FMB is being given the full backing of the National Federation of Roofing Contractors (NFRC), and Electrical Contractors’ Association (ECA) with around 16,000 building firms adding their weight to the ‘We support solar’ demands.

Feed-in tariffs are designed to offer premium, guaranteed rates to small scale producers for renewable energy which is fed in to the national grid and bought by the utility companies. In markets where they have been introduced elsewhere they have proved successful at attracting investment in new solar markets. In Germany and Spain, solar sectors have experienced booms thanks to the attractiveness of solar stocks in those countries with high returns on investment made possible by the feed-in tariff mechanism.

It is certainly considered that while the UK does not enjoy Iberian sunshine levels a strong tariff would enable the sector in the UK to take off and of course attempt to catch up with other mature markets. Some critics have argued that a strong anti-solar lobby in Westminster led by the utility companies has influenced the government’s decision to go forward with legislation which is generally accepted to be insufficient. With this in mind Liberal Democrat MP Simon Hughes stated,

“The proposed “cash back” payments are designed to dampen solar PV demand over the next three years rather than to encourage it. This mindset needs to change. Solar power can play a significant role in the “greening” of our towns and cities, while providing tens of thousands of new construction sector jobs.”

Indeed, with support among certain power brokers and pro-solar lobbies acting to add 10p to the current tariff it may well be possible to tweak the legislation, making it workable in the long term. If not, the ‘We support solar’ campaign may fail to see the fledgling UK PV sector take off.

The role of the inverter is often overlooked in a photovoltaic system. Kept inside in the attic or in a closet, it is not the most visible part of a system but it performs a critical role and makes up large component of the equipment costs. The inverter is the hub that converts the direct current produced by the solar panels into alternating current suitable for the UK grid.

In a typical residential photovoltaic system, solar panels are connected in a ‘string,’ which means they are connected together in series so that the voltage of each module adds up. The positive and negative ends of the string are connected to the inverter which then does two main things:

Firstly, the inverter applies the optimum voltage across all the solar panels in the string. In order to extract the maximum energy from a solar panel you need to apply to certain voltage across it. The easy way to understand this is by remembering that power equals current times voltage. Current will still flow out of the solar panel if there is no voltage across it, but it won’t be able to provide energy. If too much voltage is applied to the solar panel then you lose current coming out of the solar panel, so the optimum voltage is somewhere in between. It is the inverter’s job to keep the solar panels at this optimum voltage. This is quite tricky since the optimum voltage changes with the temperature of the solar panels. To cope with this there is a special algorithm built into the inverter called ‘maximum power point tracking’, which makes continual adjustments to the voltage to ensure the most energy is got out of the system.

The second important job of the inverter is to convert the direct current produced by the solar panels into alternating current suitable for the mains electricity grid. In the UK, the mains frequency is 50Hz so the inverter must make sure that the electricity it supplies is matched to this frequency so that it can be used by other appliances in your house or be sold to your energy supplier.

Inverters are very common, for example your laptop charger uses an inverter to convert mains 50Hz electricity into direct current for your computer (this partly explains why laptop chargers are so expensive though I still think it’s a rip-off), and there are some very good solar inverters already out there. The largest manufacturer of solar inverters is called SMA, which enjoys a +30% market share worldwide (their line of residential solar inverters is called the ‘SunnyBoy’). Other big manufacturers are Kaco, Xantrex, Danfoss and Mastervolt to name a few. These inverters work well, so what are the developments on the horizon that make inverters interesting?

One issue is efficiency. Most commercial inverters are around 97% efficient, which is pretty good, but it still means that you lose 3% of all the energy you produce converting it from DC to AC. Increasing efficiency to 99% would increase the return on investment of your solar system and give a real competitive advantage. Several manufacturers claim to be close to offering new, super-high efficiency products.
The next issue is reliability. Most inverters are guaranteed for 10 years, which although is not bad, its only half the guaranteed lifetime of solar panels. This means consumers must allow for replacing the inverter at least once when financing a solar project. If inverters could be guaranteed for 20 years, it would mean consumers could feel comfortable knowing that the system will operate under guarantee for its entire lifetime until the whole thing needs replacing. Inverter manufacturers have been striving to improve reliability of their systems and products guaranteed for 20 years should be on the market soon. As a side point; proving 20 year reliability is very hard to do without actually waiting 20 years, and there is an entire field of study devoted to ‘accelerated stress testing’ of these products.

Another set of new features is how information is displayed. Many inverters come with an optional WebBox that allows you to view the performance of your solar system online. Some inverters now even come with iPhone apps so you can watch your solar energy production on-the-go, importantly show your friends in the pub. These types of innovations will keep coming so keep an eye out if this is something that interests you.

Perhaps the most radical development for inverters is the ‘micro-inverter’. Basically this means having not one big inverter but lots of smaller ones attached to each solar panel. This has several advantages. Firstly, it can improve the performance of the system significantly. Going back to the maximum power point tracking feature mentioned above, a normal inverter has trouble if not all the solar panels are performing the same. Solar panels could be at different temperatures to each other or just have different performance from factory errors. By using micro-inverters you can ensure that each solar panel is being operated at its own optimum voltage. Another issue is to do with shading. If one solar panel in a string is shaded or performing badly, it acts like a big resistor and dramatically reduces the performance of the whole system. Using micro-inverters isolates the performance of each solar panel so that power loss from shading is minimized. Enphase Energy, a leading manufacturer of micro-inverters in California claims that these features can lead to an improvement of up to 25% better energy output.

Other benefits of micro-inverters include the elimination of dangerous high voltage DC cabling on the roof, which can reduce fire and electrocution risks. (Another side point; some micro-inverter products are not actually micro-inverters, but they perform maximum power point tracking at each solar panel and then the AC:DC conversion at a central point.)

Currently, there is not a single micro-inverter product available in the UK. This is because it is still a new technology and the UK is such an insignificant market that it is not of interest to manufacturers rushing to bring their products to commercialization. That being said, the success of companies like Enphase in California, and the spate of companies following in their footsteps, means that it won’t be long before they become a real option, even in the UK.

The head of the newly formed New and Renewable Energy Centre (Narec), Tim Bruton, has made the claim that if every south facing home in the United Kingdom fitted solar panels, they would generate enough electricity to meet the country’s energy needs.

Speaking ahead of Solar Flair 2009, a conference to be held in Northumberland designed to highlight key issues regarding the take up of photovoltaic (PV) energy, Bruton gave his full backing to solar energy as a way of combating climate change.

With the north-east trying to put itself forward as a future leading light in solar PV expertise, Bruton is one of many academics from the region hoping to put the north of England on the PV map. As a fellow of the Institute of Physics and a reputation for insightful publications of articles relevant to the field of solar PV, Bruton asserted that the UK is on the ‘verge of something exciting’, commenting,

“The University of Northumbria carried out a study for the Department of Trade and Industry looking at the existing south-facing buildings in the UK”, adding,

“All we have to do is take the things we have already built and put solar panels on them and we can generate all the electricity we need.”

The claims made by Bruton have been made all the more possible with the announcement by the government that 2010 will see the introduction of the Clean Energy Cash Back Scheme, essentially a solar feed-in tariff (FIT) designed to attract investment in the new industry. The scheme would work by offering small scale solar energy producers guaranteed, premium rates for energy fed back in to the national grid.

The mechanism is designed as a way of off-setting the obvious initial costs of solar panel installation and where such FITs have been introduced elsewhere, they have proved to be very effective ways of nurturing fledgling renewable sectors offering returns on investments to investors which would otherwise have been impossible. Regarding a UK solar FIT, Bruton stated.

“If you look at what has happened in Germany, Spain and California where you have the right subsidy structure from the government, the market has taken off.”

Certainly, all involved in the UK solar industry will be hopeful that the government’s controversial tariff will be sufficient to see the fulfillment of Bruton’s prophecy in the coming years.

The government has recently introduced a new certification program for sustainable energy products. Called the ‘Micro-generation Certification Scheme’ (or MCS), the program is designed to protect customers by ensuring good quality in both products and installation. The scheme works by putting manufacturers and installers through an inspection process in which the applicant has to demonstrate a certain level of competency in the technology they offer, provide a documented, quality management process and show an example of a finished product or installation. In order to incentivize the industry to sign up to the certification scheme, the government has declared that customers may only apply for grants or feed-in-tariffs if their system is entirely covered by MCS which means there is little point in buying an installation without MCS accreditation.

Preventing cowboys from entering green-industry and exploiting customers trying to do their bit for the environment is essential. However, concerns have been raised regarding the real impact of the scheme on customers and regarding the credibility of the certification process itself.

Since this is solarfeedintariff.co.uk, let’s look at the certification requirements for solar energy as an example. In order to claim the UK solar feed-in-tariff arriving next April, you have to install solar panels that have been through the MCS process. At this stage however, few manufacturers have obtained MCS accreditation for their products. In many cases it is simply because they haven’t heard of the UK’s MCS program yet. In other cases, manufacturers who have been told about the scheme may not immediately decide to go for it. To get accredited, you have to pay a private certification center (that in turn has been ‘accredited’ by the MCS administrators) to inspect its product and facilities. This is a costly and time-consuming process. In many cases, someone from the accreditation center has to be flown (at the expense of the manufacturer) to a factory in Europe or Asia so that it can be ‘inspected’ often by someone with little or no experience of the photovoltaic industry. Once you have MCS, the rewards for manufacturers are not clear. In the world of solar energy the UK barely even registers. I am often met with surprise (or worse still, laughter) when I say I’m from the UK at solar conferences. The German market will be over 200 times greater than the UK market this year. There is not a single ground mounted PV power plant in the UK. This means there is no guarantee that investment in MCS will be worthwhile.

The second issue is that certification processes for solar modules already exist. The most prominent is the IEC certification process that can be administered only by a handful or institutions worldwide. This is a rigorous performance and reliability procedure that tests the energy output of a solar panel under controlled conditions, and puts it through a large number of stress tests. These include the damp-heat test (thermal cycling in a humid chamber) and the hail-test (bombarding the module with pellets of ice fired from a canon). IEC tests are designed and continually improved by a committee of international solar energy experts. Wisely, the MCS recognizes IEC accreditation and requires it as part of its inspection. This does lead to the amusing situation where a UK inspector will visit mulit-billion dollar factory that has been supplying solar panels to the rest of the world under the IEC has ‘approve’ that everything in order.

In a photovoltaic system, there are many different components besides the solar panel, however MCS applies only to the solar panel. This is hard to explain. The other expensive part of a PV system is the inverter, which converts the direct current produced by the solar panels into mains 50Hz alternating current so it can be used by most appliances in a building or sold to the grid. The inverter is therefore critical to the good functioning of a system and is known to be significantly less reliable than solar panels which are normally guaranteed for 20 years compared to just 10 for the inverter. Why then is the inverter not covered by MCS?

The MCS for installers in the UK has a clearer role. Many people are familiar with cowboy builders or decorators providing shoddy service, and MCS could be an excellent way to reduce this. Questions remain about the implications for accessibility of micro-generation however. Does MCS mean that a competent DIYer interested in building their own micro-generation system is denied access to government support because they haven’t forked out for an MCS installer?

The main concern is that MCS reduces the amount of competition in the UK, limiting the choice consumers have when it comes to products and installers. Prices of Solar PV systems in the UK are already shockingly high compared to Germany (up to twice the price) and MCS risks being a barrier to entry so that certain manufacturers can now charge even higher prices to UK customers. The MCS could be hurting those it is designed to protect, to the benefit of the manufacturers and installers already within its program.

Certainly the intentions of the MCS are good and with time it could play a key role. The MCS needs to be very careful however not to stunt the growth of the UK solar industry from its current insignificant size. The biggest barrier to that growth is cost, so any measures that may increase costs to the end customer must be rigorously justified.

Labour MP and advisor to the Department of Energy and Climate Change (DECC) Alan Simpson has warned of the presence of an cartel acting against the interests of renewable energy in the UK. At an event organised by Solar Century to promote the government’s proposal of a feed-in tariff system, Simpson announced that there is currently a lobby opposing the renewable campaign headed by the big utility companies keen to protect their own commercial interests at the expense of the development of green energy in the UK.

With the government’s announcement regarding the introduction of the Clean Energy Cash Back system (essentially a feed-in tariff system) in April 2010 much debate has raged regarding the tariff rate which will be required in order to optimise investment in the fledgling UK renewable energy industry.

The feed-in tariff works on the principle that small, renewable energy producers are guaranteed a fixed, premium rate for all units of energy they feed back into the national grid. The renewable energy units are purchased by the utility companies, something which they are obliged to do by the tariff legislation. In actual fact, the government has set a rate of 5p/unit with a subsidy of 36.5p for units of energy generated by small scale solar and wind installations, something which Simpson has controversially asserted will not be sufficient to spark the must needed investment in the industry.

Simpson claims that with the current rate set at 5p, the ROI for solar investors will only be around 5-7 per cent, yields which would possibly not be generous enough to turn the heads of investors who would potentially be attracted by more generous tariff rates elsewhere in the world. With a tariff rate of 10p, Simpson believes that returns could be a more healthy 10 per cent, rendering the UK as a highly competitive market in the world for attracting renewable investment in the long term.

For the UK to finally become one of the major players in the world of solar drastic changes will need to occur within the coming years to catch up with established markets such as Spain and Germany who are currently generating 2,511 MW and 1,500 MW of renewable energy annually respectively compared to the UK’s peak 6MW. Simpson certainly believes that this shortfall can only be remedied with the introduction of comprehensive tariff systems. Speaking at the Solar Century event, Simpson announced,

“Current energy policy in the UK is dominated by the vested interests of “Big Power”. The national grid is monumentally inefficient as an energy system. It was a half-decent idea for the middle of the last century, but 70%-80% of energy put into the grid disappears before you or I even switch the light on. We need not an energy, but a power revolution that takes control from the centre and literally puts power back into the hands of the people”.

Those within the industry back the words of Alan Simpson and are well aware that the future of the UK renewable energy industry is completely reliant on a strong tariff rate. Come April, it will be there to be seen if the government’s rhetoric on tackling climate change can be matched by a determination to take on the big utility companies and drive through a system which will see the UK become a leading light in the green energy revolution.

If you’ve ever carried a solar panel you’ll know that they’re pretty heavy (about 25kg for a 1.5sqm panel), and if you add on the racking that’s required it makes things even heavier. This is a bit of a problem for roofs that can’t support large weights, and for the installers who have to get the stuff up there.

As with many things in life however, technology has a solution on the way. In this case the solution comes in the form of flexible solar panels. This new type of solar panel doesn’t use glass as the supporting material; it uses transparent, flexible plastic sheets. They can be rolled up like carpets and unfurled across a low-sloping roof. This process is much quicker and easier than normal solar panel installation. The solar panels just need to be tacked down at the edges, rather than have heavy metal racking bolted into the frame of the roof. The material is also light enough so that any roof can support its weight.

This technology is spreading quickly but has yet to win dominance in the market. This is for several reasons. Firstly – only one company in the world is making flexible solar panels in large volumes. That company is UniSolar, based in Michigan, USA. UniSolar have developed their own proprietary process for depositing thin-film solar cells (see discussion “REF TO previous article”) on flexible plastic sheets.

In order to increase efficiency of the panels, their design in fact uses three solar cells stacked one on top of the other. Each solar cell responds to a different part of the sun’s spectrum so it maximizes the amount of energy converted to electricity. Despite this compmexity, these solar panels are significantly less efficient than traditional, crystalline silicon solar panels. They are made from ‘amorphous’ silicon and are currently around 6-8 percent efficient, compared to 16 percent for crystalline silicon panels. This means you have to cover a larger area of the roof.

A number of companies claim to have more efficient versions of the technology on the way. Companies such as US based Advent Solar, claim to have flexible solar panels that will soon reach over 10 percent efficiency while other companies, such as G24 Innovations in Wales claim to have lower manufacturing costs for this technology.

Given the success of UniSolar with their low efficiency and complex design, any company that can make an improvement is likely to have success with flexible solar panels. Let’s wait and see…

Environmental campaigners Greenpeace has released a ranking of the world’s leaders with regards to their respective commitments to tackling climate change. With the Copenhagen summit around the corner there is a massive media focus on the world’s leading economies to make real commitments to the environmental cause and Greenpeace are making an effort to look beyond the political spin.

Surprisingly Barack Obama is found wanting in the list with Greenpeace not impressed by the actions of the new American President. In the report, Greenpeace state that

“President Obama’s election hasn’t brought the breath of fresh air to climate talks that many had hoped for. Instead, it’s seen as a perpetuation of Bush-era efforts to disrupt and water down attempts to agree to a strong treaty as Obama tries to bring the whole world down to his own level of ambition”.

Certainly, with a rating of 8/100 Greenpeace have made clear that while the world’s most powerfulnation does little to address the issue of climate change, anything that occurs at Copenhagen will be futile.

Other powerful economies fared better with India’s Prime Minister Singh being lauded for his recent efforts to take on polluters. In the ranking table Singh was given a fairly good 53/100. The report stated,

“Singh has recently announced massive solar projects to accompany strong energy efficiency targets.”

However it also went on to criticise his policies regarding deforestation on the Indian sub-continent. The UK prime minister, Gordon Brown also benefited from the support his government ministers, and in particular the DECC has so far given to the solar industry in the UK with his recent announcement of the introduction of the Clean Energy Cash Back System, a feed-in tariff designed to incentivise investment in the solar industry. However, the report commented that Brown,

“Has failed to embrace renewable energy and an inability to quit coal has put the UK Prime Minister at odds with his own advisers on climate change. The EU’s wrangling over finance has left the UK unable to offer more than words to developing nations”.
The Copenhagen summit will highlight key deficiencies in global policy and will once again bring to th fore the debate in the UK regarding the feed-in tariff rate which will certainly need to be increased if Gordon Brown is to be taken seriously as a man with a real commitment to thwart the on set of global warming.

Conservative Party Leader David Cameron and probable next British prime minister come 2010, has reaffirmed his commitment to green issues by issuing a statement declaring his support for feed-in tariffs as a mechanism for encouraging the growth of renewable industries.

In a document released from the Conservative Party, authored by Cameron and titled The Green Consumer Revolution, the leader of the opposition outlined a 5 point approach to tackling climate change. Key to these points is the adoption of a series of incentives designed to spark investment in solar energy uptake by off-setting the obvious costs involved in the purchasing and installation of solar technology.

Feed-in tariffs operate on the basis that small scale renewable energy producers are offered fixed, premium rates for the energy fed back in to the national grid. The legislation obliges utility companies to purchase the energy from the small scale suppliers over a period of years, therefore offering investors returns on their initial investments on solar plant.

David Cameron used the German solar feed-in tariff example to demonstrate the effectiveness of tariffs as a means of provoking investment and installation, stating,

“Take the issue of people generating their own energy. The reason why Germany is so far ahead of us is because they have a system of what they call feed-in tariffs. That means people who generate their own energy sell it back into the national grid. That way, they can earn money as well as reducing their bills.

In addition he commented,

“We should be equally bold here. Two years ago we announced that a future Conservative Government would introduce a similar system of feed-in tariffs to Britain. And to make sure the system works, we will also give every house a smart meter so the amount of energy they are selling back to the grid can be calculated and they know how much electricity they are generating themselves”.

In the document, Cameron followed in the footsteps of Barack Obama and political rival, Gordon Brown by asserting the potential of green energy as a means of revitalizing the current stagnant economy. Both Brown and Obama used the term ‘Green New Deal’ drawing parallels with the initiatives introduced by Roosevelt as remedies to the Great Depression with Cameron asserting,

“It’s a triple win. It will create a new competitive market in energy efficiency worth at least £2.5 billion a year. It will create over 70,000 skilled jobs. And it will save an estimated 9.4 million tonnes of carbon”.