‘Floatovoltaics’ Make Splash with UK Solar Arrays

• World’s largest floating solar array unveiled near London;
• Water helps panels stay cooler, produce more efficiently;
• Japan now building arrays after Fukushima disaster.

The sun eventually did set on the British Empire last century, but now energy drawn from the sun is pushing the United Kingdom back into a global leadership role — at least for the time being.

Earlier this year, floatovoltaics — the aqueous equivalent to photovoltaics — made a huge splash just 20 miles south of London when a development team of Ennoviga Solar and Lightsource Renewable Energy unveiled the world’s largest floating solar array at Queen Elizabeth II Reservoir. Comprised of 23,000 solar photovoltaic panels, the $8.3-million installation furthers an initiative put forth by Thames Water. The utility aims to self-generate one-third of its energy by 2020, which would nearly triple the 12.5% it currently yields.

“Becoming a more sustainable business is integral to our long-term strategy and this innovative new project brings us one step closer to achieving our goal,” said Angus Berry, Thames Water’s energy manager. “This is the right thing for our customers, the right thing for our stakeholders, and most importantly the right thing for the environment.”

With a capacity of 6.3MW, the QE II installation will generate 5.8 kWh of electricity in its first year and assist in powering a nearby water treatment plant, meeting about 20% of the plant’s needs. However, operators says its output is sufficient to supply electricity to about 1,800 homes.

“We think that self-generation is the way forward in the imminent zero-subsidy world,” explained Ennoviga co-founder Stefano Gambro. “Using portions of otherwise fallow spaces such as this concrete-lined water reservoir allows renewable power generation to be achieved in urban centers in an environmentally and socially benign way.”

“Using portions of otherwise fallow spaces such as this concrete-lined water reservoir allows renewable power generation to be achieved in urban centers in an environmentally and socially benign way”

The array’s vast size — 618,925 sq ft, or eight pitches at London’s Wembley Stadium — covers about 10% of the QE II reservoir, which primarily supplies drinking water to nearby residents. Of note, planners say the water-borne site enabled them to circumvent approvals attending land-based development.

“There is a great need from energy intensive industries to reduce their carbon footprint, as well as the amount they are spending on electricity,” added Nick Boyle, CEO of Lightsource. “Solar can be the perfect solution.

Floating better ideas

Though relatively new, floating arrays are gaining traction due to additional benefits they confer for installations involving drinking water reservoirs, quarry lakes, irrigation canals and tailing ponds. Because water allows panels to maintain a cooler temperature than those located on land, they promote greater efficiencies during solar energy conversions. They also reduce water evaporation, and hinder algae growth.

Additionally, they assist in minimizing land use. In 2008, for example, rather than sacrifice a 3/4-acre parcel, Napa Valley, CA-based Far Niente Winery built the world’s first floating solar array (at left). Upon completion, the installation featured 994 solar photovoltaic modules resting on 130 pontoons in the winery’s irrigation pond. Supplemented by a smaller, land-mounted solar array, the installation generates up to 477KW at peak output, meeting more than 100% of the winery’s electrical requirements. In addition to the the U.S. and UK, floating solar arrays have since been adopted by enterprises in France, India, South Korea, and Singapore.

Also in Asia, Japan has embraced the concept in the wake of 2011’s Fukushima Daiichi nuclear power plant disaster, triggered by an earthquake and tsunami. Since then, Japan has focused on alternative forms of energy, having turned to floating solar arrays because land is in short supply.

Installation of water-borne arrays is relatively simple and, according to some, less expensive than assembling their land-based counterparts. In the case of QEII, panels were placed on a floating platforms and maneuvered into place, where they were attached and anchored. The completed array rests on 61,000 platforms connected by 177 anchors. Should it choose to in the future, Thames River can install additional panels to the existing array with a minimum of effort.

United Utilities Group, the UK’s largest water company, also plans to construct a similar floating array on a reservoir in Manchester, England.

Meantime, the QE II installation won’t bear its distinction of world’s largest for long. Coming on line in 2018 is electronics giant Kyocera‘s floating solar array in Japan’s Chiba Prefecture, a 50,000-panel, 13.4-MW installation to be sited on the reservoir above Yamakura Dam.