They do it with lenses

13 January 2015

A ground-breaking experimental solar power system with the potential to generate carbon-free electricity is being pioneered in South Lincolnshire.

Surrounded by protective fencing and with its own mini control centre, the structure dominates the sky-line at the offices of sustainable development company Larkfleet Group in the small market town of Bourne.

Its innovative Solar Steam project is undergoing a series of tests this summer to further prove and develop the alternative form of renewable technology.

Larkfleet's experimental solar steam rig measures just over 13 metres (42 feet) long by 5.5 metres (18 feet) high when extended to its maximum.

The futuristic construction is essentially a collection of giant lenses designed to concentrate the energy of sunlight onto metal piping and heat water to boiling point.

The metal framework holds a series of plastic lenses which concentrate refracted sunlight onto a 9 metre (30 feet) long metal pipe to heat water circulated inside. Full-size systems will be very much larger.

To maintain maximum power generation the lenses need to constantly track the sun in both azimuth and elevation – and this needs to be fully automated.

"The principle is already proved and we are now looking at enhancing the tracking system to make it fully automatic," said Simone Perini, a solar energy expert who joined Larkfleet's R&D team from Cranfield University last year.

"Lenses are less expensive to produce than vast arrays of glass mirrors now being used on comparable power generation systems throughout the world," he explained.

"It is challenging but a lot of work has been done already and it is an innovative project with great potential. For the same reason is very exciting."

Data will be gathered during a summer of testing before an evaluation phase leading to the next stage of development starts in September.

As well as developing the system itself, Larkfleet is also assessing the potential market for such solar steam renewable technology.

One possibility is using solar powered steam to generate electricity by driving a turbine – but it has many other potential uses so there are big incentives to make it as efficient as possible.

"We believe this is the sort of system that could be attractive to SMEs in the small scale solar market for any process heating system that requires heat of between 80 and 250 degrees," said Matthew Hicks, the group's renewables investment director.

"It would be extremely valuable in parts of the world where the sun is the only readily available source of energy and could be used to power desalination plants, refrigeration, sterilisation, chemical purification and numerous kinds of waste treatment," he added.

Karl Hick, CEO of the Larkfleet Group, says the system – already attracting interest from around the globe – could eventually be integrated into traditional power stations to reduce the burning of fossil fuels.

"The solar steam could be fed to the power station generators so gas or coal would only need to be burned at night or on days when solar power is not enough to meet demand," he suggests.

"The solar steam rig provides an opportunity for looking into a new method of low carbon energy generation and is very much a long-term project – we will trial the technology fully before coming to any conclusions about its future potential."

Larkfleet Group is a privately-owned house building and development organisation with a strong record in creating high quality homes and communities.

It specialises in building energy-efficient housing and continually invests in research and the development of innovative new sustainable building designs, materials and construction methods.

It is also a major developer of sustainable energy projects and a provider of energy-efficiency improvements for new and existing buildings.

Larkfleet Group companies are currently developing large photovoltaic (PV) 'solar farms', adding PV panels to new and existing buildings at a variety of scales, and refurbishing existing homes to reduce their carbon footprint, energy use and energy costs.