The new Thames Water floating solar panel array on the Queen Elizabeth II reservoir near London [Image Source: Lightsource Renewable Energy]
Ennoviga Solar and Lightsource Renewable Energy are about to unveil the largest floating solar array in the world later this month. The £6 million array is located on the Queen Elizabeth II reservoir, approximately 20 miles from London, and has been commissioned by Thames Water. The electricity it generates will help to power water treatment plants supporting water networks supplying water to London and neighboring areas.
The array will have a top capacity of 6.3 MW, which means it will be able to generate around 5.8 million kilowatt hours of electricity during its first year of operation. Thames Water is aiming to generate at least 33 percent of its electricity requirements from solar by 2020, compared to 12.5 percent currently generated at 41 of their existing sites. The QEII array consists of 23,000 solar PV panels positioned on top of 61,000 floating platforms that are in turn held in place by 177 anchors. The total area covered is 128.3 hectares or approximately 6 percent of the reservoir surface.
Floating solar power arrays have a number of distinct advantages over those installed on land. One of the most pertinent of these being the constant cooling effect provided by the water upon which the floating platforms sit. These types of arrays are also easier and cheaper to build, making future addition of panels much easier than with conventional arrays and enabling significant cost reductions. Another advantage is that they use space that is not currently being used for any other purpose, and that in turn takes the steam out of the arguments of anti-solar critics with regard to use of agricultural land.
Floating solar panels also help to prevent algal growth on the water surface by shielding the water from the sun, which encourages such growth.
The QEII project will soon be overtaken by other countries, particularly Japan where floating solar projects are becoming very popular, with one massive array due to be completed in 2018. However, the UK is
Floating Solar UK is one such company. Farmer Mark Bennett, set it up in 2014 as official UK distributors of floating solar farm technology, although the company is now a subsidiary of the French Ciel et Terre firm. The two companies are working together in a Joint Venture to expand the use of floating solar throughout the UK. Floating Solar UK constructed the country’s first floating solar farm on an irrigation reservoir on Mr Bennett’s soft fruit farm, Sheeplands Farm near Wargrave, Berkshire. The 200 kilowatt array covers almost an acre of water and incorporates 800 solar panels supplied by Chinese firm Trina Solar, mounted on high-density polyethylene floats normally used for marine buoys. A soft fruit company that rents most of the land on the farm also draws water from the reservoir while purchasing power from the panels through a power purchase agreement (PPA). This helps to power four irrigation pumps with excess electricity sold on to the grid.
The array cost £250,000 to develop and was financed by a loan from the Agricultural Mortgage Corporation (AMC). Mr Bennett, expects to earn £20,500 per year over the next 20 years from subsidies, in addition to savings of about £24,000 per year from reduced reliance on the National Grid. This means the project could pay for itself within 6 years while also delivering a minimum profit of more than £620,000 over 20 years.
This technology is as ideal for lakes and other small bodies of water located on farm as it is for larger stretches of water as the Thames Water array has just proved. In fact, another water utility further north has also developed a floating solar farm, half the capacity of the Thames Water project. This is located at Hyde in Greater Manchester. Consisting of 12,000 panels and covering an area of 45,500 square metres, it represents an investment of £3.5 million by United Utilities in order to help it reduce its energy costs and customers water bills. The array will generate 2.7 gigawatt hours (GWh) per year of electricity which will be used directly by the site.
Despite the recent cuts to renewable energy subsidies inflicted on the sector by the government, Paul McCarren, the energy services director at Forrest, a contractor that helped to build the United Utilities array, estimates that ground-mounted solar farms could earn 12 percent to 14 percent returns which would still be viable at 9 percent if subsidies were slashed. Forrest maintains a pipeline of projects which will still go ahead this year even with the government cuts.
Floating renewable energy projects in the UK aren’t just limited to floating solar, as floating wind power projects are also starting to make their appearance in the UK clean energy market. In November last year for example, consent was granted to the UK’s first floating offshore wind development which will be installed off the coast of Peterhead in Scotland. The Hywind Scotland project is being developed by Norwegian company Statoil and will consist of a pilot park of five floating 6 MW turbines located approximately 25 kilometers off the coast with a generating capacity of 135 GWh per year, representing enough power to supply 19,900 houses.
The floating wind turbine project at Agucadoura, Portugal [Image Source: Wikimedia Commons]
Commissioning of the project is expected in 2017. The turbines will be secured to the seabed using a three-point mooring spread and anchoring system and will supply electricity to shore via an inter-array of cables and an export cable.
The Carbon Trust believes commercial floating wind projects such as Hywind could reduce the cost of power generation to below £100 per megawatt hour. Floating offshore wind projects could also utilize deeper water sites, thereby eliminating much of the opposition from anti-wind campaigners. These projects could utilize existing technology from the offshore oil and gas industry.
Hywind is part of Statoil’s aim to demonstrate the future potential of the technology which could introduce an increasingly competitive source of renewable energy to the UK. In October last year, Edie released a report that found floating wind turbine technology could be cost-competitive in as little as ten years, achieving a leveled cost of energy (LCOE) of less than £85 per megawatt hour.
Written by Robin Whitlock