What will temporarily be the world's biggest ever floating solar panel array is due on line by today. It has been installed on part of a reservoir operated by Thames Water just to the west of London. It is expected to generate enough electricity annually to power around 1800 homes. A larger array, around three time the size, will start operation in Japan in 2018.
The array covers around a tenth of the surface area of the Queen Elizabeth II reservoir, one of a group of three known as the Walton Reservoirs in West Molesey, Surrey. These store water taken from the Thames until it flows by gravity to filter beds and other treatment works for use as drinking water. This is already used to generate green energy as there is a hydro-electric plant exploiting the height difference, the electricity being used to raise more water from the Thames.
By only covering around 10% of the surface area of the largest reservoir, their use by wildlife is not affected. The three are part of a Ramsdar site, a wetlands of international significance, called the South West London Waterbodies.
[It] comprises a series of embanked water supply reservoirs and former gravel pits that support a range of man-made and semi-natural open water habitats. The reservoirs and gravel pits function as important feeding and roosting sites for wintering wildfowl, in particular Gadwall Anas strepera and Shoveler Anas clypeata, both of which occur in numbers of European importance.
The floating PV array scheme is part of Thames Water’s strategy to contribute to the Paris Accord.
As well as setting a target of generating 33% of its own renewable energy by 2020, Thames Water is striving to become more efficient to reduce its reliance on the grid. It generated a total of 12.5% of its electricity requirements from renewable sources in 2014/2015, which is a 4% increase on the year before. In 2015, Thames Water pledged to support the objectives of the Paris Agreement to limit the global temperature rise to less than 2 degrees Celsius and this project will contribute to achieving this goal.
Using what would otherwise be “redundant” surface area is important in Japan with its high density of population on narrow coastal belts, hence their installing what will be the largest floating array on the Yamakura Dam. The design also has the advantage that the water is readily available to cool the electronics used. Smaller schemes have been installed in the USA. Ciel & Terra, one of the companies involved in the Thames scheme is installing an array on a pond in a winery in California. Clearly this is not a solution for areas of open water used for other purposes like recreation however it does open up the possibility of using storage reservoirs not normally accessible by the public for small scale electricity generation — like the one in Central Park, New York, for example.