| 14 March 2011
When Peter Stephens, the Managing Director of British builders merchants John A. Stephens Ltd., asked solar installers EvoEnergy to hook up a small number of solar panels on the roof of his modest house in the East Midlands, little did he know that it would spark a process that would eventually lead to one of the largest commercial PV installations in the country.
“I had a small installation of 21 panels at home and was so impressed with the efficiency and explanation of the system that I asked the [installers] to look at our depot building,” says Stephens.
The installation will significantly help the company reduce carbon emissions, protect it from increasing fuel costs and secure a guaranteed return on investment for the next 25 years.
That project, completed in around four weeks at the John A. Stephens depot in Nottinghamshire earlier this year, ultimately ended up as one of the country’s largest commercial PV installations since the introduction of the UK government feed in tariff (FiT).
“The system generates 74,666 kWh/yr - enough energy to power about seventeen family homes,” says Kevin Hard, Managing Director of EvoEnergy.
Hard explained that the installation will significantly help the company reduce carbon emissions, protect it from increasing fuel costs and secure a guaranteed return on investment for the next 25 years.
In particular, it is anticipated that the electricity produced by the system will earn John A. Stephens a healthy 10% annual return on its initial investment - an estimated £23,445 ($38,138) per year, based on the UK government FiT rate of 31.4p/kWp for electricity used and 34.4p/kWh for electricity exported. It is also predicted that the installation will result in an impressive annual CO2 saving of 39,498 kilograms.
Technical specifications
The system is made up of 441 x 220W Sharp ND Series Polycrystalline Silicon Panels with a module efficiency of up to 12.4%(PDF) – fixed to the roof structure with a Conergy rail system, resulting in a total PV system size of 97kWp.
In choosing the panels, Stephens decided to go with Sharp because he had already had experience of using them on his own house and claimed that they were a high quality and trustworthy brand that had proven to be very reliable.
In terms of inverter technology, Hard explains that EvoEnergy always seeks to work with industry leading inverter manufacturers to find the most efficient inverter solution.
“The solution for this installation was an Eltek Valere THEIA TX central inverter, the first inverter of its kind in the UK with an efficiency of 97.4%,” he said.
Norway-based Eltek claims that these 3-phase, galvanically isolated inverters, combine Maximum Power Point Tracking (MPPT) and high efficiency to provide long term and reliable energy harvesting – crucially even under the kinds of adverse weather conditions often experienced in the UK. For more on MPPT, see “Understanding Inverter Strategies".
Weather challenge
During the installation, the EvoEnergy team ran into some difficulties as a result of a very British problem – the weather. When forced to battle against excessive amounts of snow in December 2010, the company struggled to meet its targeted completion date.
“The team of installers worked tirelessly to get all the equipment on to the roof, clearing snow in the process. And then the snow came again to challenge our team,” says Hard.
When snow was covering the panels, it was impossible for the team to take a proper output reading and test the equipment, but a few days later the panels were clear of snow and they completed the commission.
“We feel very proud to have completed such a large install[ation] for a local client, suffering only a few days’ delay when the rest of the UK was at a standstill,” says Hard.
The UK tariff – FiT for purpose?
Hard also contends that more certain but regular reviews of the FiT would be ‘healthy’ for the industry.
So, would the installation have been financially viable before the establishment of the UK government's FiT? For Stephens, who had been considering a solar project for five years, the answer is a definite no.
“[I]t was a large investment without any guarantee on how long it would take to get the outlay back,” he says.
As far as Hard is concerned, regardless of funding, the installation significantly reduces the Builders Merchants’ demand for electricity, while also holding electricity prices steady. “However, the return on the investment would have taken considerably longer,” he says.
Reflecting on the UK FiT system more generally, Stephens explains that he has been reasonably encouraged by his experience so far, but plans to reserve final judgement until satisfied that the subsequent payment system is administered to his liking.
“Not knowing what it costs to generate a kilowatt by a coal fired power station, it is difficult to say whether it is efficient or not, but it must be good ecologically,” he says.
“We are hoping that the payment system will work well, as I have had difficulties at home with Npower,” he adds.
From a commercial perspective, Hard says that the FiT scheme is the first he’s seen that will really help to drive the solar PV market and make green technology viable and accessible to everyone.
“Homeowners and businesses are seeing returns of 8-10%, index linked and guaranteed for 25 years. This has allowed us to scale our company fast to over 100 employees now and create employment in a time that is difficult in the construction sector,” he says.
Whilst the market for domestic solar is strong, Hard also explains that there is currently a lot of uncertainty in the medium scale (>50kWp) and larger (>1MWp) markets.
“This is slowing down the market, but it’s important that we have clear messages from the government of how they want the industry to grow so that the industry can provide job security and scale,” he argues – adding that “Ultimately, solar PV is a fast deploying and reliable technology. It is one of only a few inland electricity generating technologies that can help us diversify our fuel supply and offset our carbon emissions with speed.”
Hard also contends that more certain but regular reviews of the FiT would be “healthy” for the industry, and would help it to keep in line with the Department of Energy and Climate Change’s (DECC) and the government’s target ROI of 8-9% from a PV system.
“The larger scale systems allow us to deploy solar faster into the UK and increases the technical capability of the UK industry,” he said.
For more information about the UK Feed in Tariff, see the Solar Novus Today article "UK Feed in Tariff: What it means for solar".
About the Author
Andrew Williams is a freelance writer based in the UK. He has an M.Sc. in Sustainability and Environmental Policy and writes about green technology and renewable energy for a variety of publications including The Guardian and CSP Today.
