East-West orientation of commercial rooftop systems can be a good fit for the UK market, according to two mounting systems manufacturers.
Solar Power Portal spoke to representatives of USA-owned German company Renusol and Birmingham-based Solarcube at the Solar Energy UK show in Birmingham this week. Both companies are now offering East-West rooftop mounting products in the UK.
With the end of the ROC support scheme for large-scale solar imminent at the end of March, the UK government appears to be more enthusiastic on the prospects for commercial rooftops. Recently appointed energy and climate change minister Amber Rudd appeared at the event where she spoke of a concerted push to remove barriers to deployment.
Jason McCabe, technical support adviser for Renusol said the UK was a very important market for the company, both for domestic and commercial systems but described commercial rooftops in particular as the company's “specialty”. He described the market as “buoyant”, while his colleague Marko Balen, a product manager, talked up the benefits of the East-West concept as well as the product his team are offering.
“East West rooftop products have developed due to falling module prices and changing FiT models. They have become more attractive due to this and also because they don't produce as high a peak at noon. They distribute the yield of the PV system more evenly throughout the day. This reduces the risk for the grid to collapse, especially when there's a lot of PV connected. Also it gives the customer more possibility to use the electricity for self-consumption.”
Renusol also said that as of the last couple of years, UK installers and the market in general are becoming better educated and aware of technical issues in PV. Jason McCabe, who was himself an installer before joining Renusol said the quality and depth of knowledge is definitely increasing, in his opinion.
“If we go back three years ago or four years ago, I'd get a phone call simply asking me for advice about a roof-hook or a particular type of tile whereas now a typical phone call could be a deep question on thermal expansion” he said.
“It's completely changed within the last couple of years. We have some really good quality companies doing installs now, and the products have to be just as good and simple to use.”
McCabe said that as PV markets move away from subsidies, in the commercial rooftop market in particular, the East-West facing array could “make perfect sense” in terms of allowing companies to self-consume electricity and offset their businesses running costs.
“A lot of people focus on FiTs, and that's fantastic. However, there are a lot of businesses out there that have really high running costs, machinery etc. due to electricity, and that's really a plus for the East West system. You have a steady yield and a steady pattern, you don't have big peaks running up and down, the amount of current that could be produced from that – for example instead of doing a series connection we could look at parallel connections. For me it makes perfect sense. Rather than looking at what we can get back from the FiT, let's look at what we can generate to offset the running cost.”
Panos Bitarchas of SolarCube agreed with Renusol's assessment. He said while it was unlikely East-West orientation would take the place of South-facing installations in popularity, there is definitely a case to be argued for it.
“It's a solution for the UK. The roof is never going to be exactly what we want: south, the angle that we need etc. In the old days we were very strict about picking roofs for the right solar array, more and more you start becoming less picky about where you put solar. You start taking some information, for instance like – I put a solar panel on a flat roof and I just put it flat. For years I would tell you, ok you will get zero back for that but now it's about 40%, 30% back. It starts putting things in your mind that solar is not as sensitive as we think. Of course you cannot always take 100% but in some cases you don't want to take 100% so using East West systems you start working with the sun on it's everyday route.
“In an every day route you can see that you really generate a lot and more hours of the day. In many cases, we have products that can do that more and more we are really RandnD'ing products that can do 'tracking but not tracking' – so we are not fans of trackers. We didn't believe it before when they were successful but now that they're out of the market, we are looking for systems that try to follow the East-West daily, with small movements of the panel, not tracking. It's in RnD right now and we're getting very enthusiastic because micro-moving of the panel through the day is giving us a lot. On the other hand when you put in East West and start seeing the numbers that are generated you can see really, we can do that because we can use places, reclaim roofs that we didn't want to use before. Solar is very hard and can generate electricity on rooftops that we wouldn't use. In India, we put East West products in open fields and that's working very well.”