One Solution Fits Many Roofs in UK Social Housing
Once Weaver Vale Housing Trust specified microinverters for a large-scale deployment of rooftop solar systems, it wasn’t hard to find an Enphase partner that was also experienced at handling a hefty project pipeline: Rothwell Plumbing.
The Learning Curve
Weaver Vale Housing Trust’s journey to 1,600 solar roofs began with a single step. Actually, it was a single rooftop system at the head office in Cheshire, England. In that building, directors of the trust got together and devised a plan to reduce energy costs for tenants, part of its affordable warmth strategy. The trust resolved to learn a little more about solar energy and then roll out residential systems across almost a quarter of its 6,200 properties.
Simple to Scale
Each system at Weaver Vale Housing Trust is designed for six to 14 solar panels. Across hundreds of rooftops, Rothwell Plumbing’s team have to contend with a variety of tilt angles and orientation to the sun. This would have complicated the system design process if they had specified string inverters. With microinverters, the scale of the project adds no complexity to the design. Every panel gets a microinverter. It’s that simple.
“The Enphase Microinverter is a pretty fit-and-forget piece of equipment,” says Joe Cooney, Rothwell Plumbing’s estimator. “You couldn’t make a mistake installing the microinverter unit, to be honest with you. It’s not a complicated installation process.”
The ability to ramp up from dozens to hundreds of installations at a time is nothing new for the installer: That was how it made a name for itself three years ago, before teaming up with Enphase. Rothwell Plumbing had just started work on a contract to install five systems a week when the UK government announced that, in short order, the price for solar electricity supplied to the grid would be cut in half. The client wanted to know how many systems could be installed in three weeks. Graham Rothwell, the managing director, said his company could do 300. “We ended up installing 400,” he says. Next on the list: hundreds of Enphase Systems at Weaver Vale.
Wigan-based Rothwell Plumbing was selected to install the first 500 systems. The remaining systems will be built over the next three to four years. Matthew Woolley, an energy efficiency officer at Weaver Vale Housing Trust, says the first several projects were a learning experience. The earliest ones used string inverters. As decision makers at the trust learned more about solar technology, they asked contractors to supply microinverters instead.
Microinverters are “not as prone to failure,” Woolley says. “If there’s any shading, you haven’t got an issue with taking out the whole array. And if there’s a problem with one panel, other panels continue working independently.”