They do it with lenses

Hot and sunny days like the current mini-heatwave across the UK are just what are needed for the testing of a ground-breaking experimental solar power system which has the potential to generate carbon-free electricity in a new way.

The pioneering solar steam project is undergoing a series of tests this summer to further prove and develop the system as a potential alternative form of renewable technology.

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

With the support of Cranfield University and its own modest R&D budget, the Larkfleet solar steam plant is believed to be the largest practical demonstration anywhere of a fresnel lens (as opposed to fresnel reflector) system for the concentration of solar power. 

The futuristic construction is essentially a collection of giant lenses - manufactured in plastic to keep costs low - designed to concentrate the energy of sunlight onto metal piping and heat water to boiling point.

It measures just over 13 metres (42 feet) long by 5.5 metres (18 feet) high when extended to its maximum and the metal framework holds a series of 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 so the rig needs to be automated.

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

Light weight, low cost plastic lenses make accurate tracking possible both horizontally and vertically using relatively light mechanisms.

An automated dual-axis tracking system being developed as part of the project will concentrate solar irradiation with limited external input.

The system creates a solution for industrial heat users in areas of high direct sun/clear sky locations for modular thermal energy production deployment

"Cost reductions and accurate tracking more than compensate for any loss of optical quality,” explains Perini. “Plastic lenses are less expensive to produce than vast arrays of glass mirrors now being used on comparable power generation systems throughout the world.

"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.

A quick search under solar steam on the internet does reveal a plethora of small scale amateur projects using a few lenses. “The difference here in Bourne is that we are running a full-scale demonstration R&D project,” says Perini. “I did find a similar plant being built in Japan but this was based on a point focus solar furnace so is quite different.”

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

One possibility is using it 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," says 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.

The system - already attracting interest from around the globe - might even 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," Hicks 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.

Photos & article by Clive Simpson

Building for the future

A positive and infectious energy surrounds Karl Hick. He's a potent mix of athlete, scientist, accountant and developer. And the list of nine companies on his business card seemingly leaves no stone unturned.

With an award-winning home builder to head up, not to mention a timber frame firm, a healthcare and retirement homes specialist, an energy company, a waste company, a renewables firm, and two product supply companies, this is a man with an insatiable appetite for business.

He's been at the helm of the hugely successful Larkfleet Group for a dozen years now, running a growing portfolio of interconnected companies that are steadily setting new national benchmarks in home construction and renewable energy.

Larkfleet - based in Bourne, South Lincolnshire - specialises in building energy-efficient housing and investing in research and development of innovative new building designs, materials and construction methods.

The company is also a major developer of sustainable energy projects, as well as being a provider of energy-efficiency improvements for new and existing buildings.

"From the outset I wanted it to be a different company - built around a sustainability ethos," he says.

"At the time this was a unique proposition in the industry and others were not interested in such a long term approach."

Larkfleet was initially focused entirely on house building and but recognising the opportunity for diversification, the scope was quickly expanded to embrace developing more energy-efficient and sustainable homes, and renewable technologies.

"I can't put the world right but I can do my little bit to help the green industry and make it a commercial success," he says.

Larkfleet - one of the few builders to offer solar panels on new homes as standard - has now built more than 2,500 homes, developed some of the country's biggest solar energy parks and is exploring renewable technologies in waste and power.

Typical of the latter is a new research project to generate ‘carbon-free' electricity via an experimental solar power system installed on land at the Bourne headquarters.

Its panels focus the sun's rays onto water-filled metal tubes and the energy generated can be harnessed to heat water or produce steam to drive a generator for electricity.

The panels are mounted on a rig which rotates to track the movement of the sun through the sky.

Karl hopes that such a system - which is attracting worldwide interest - can be integrated into traditional power stations.

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

"This is very much a long-term project - we will trial the technology fully over the next couple of years before coming to any conclusions about its future potential."

The solar steam initiative is very much a product of his enquiring mind and science background.

In his younger days Karl was also an accomplished athlete and it is the competitive edge from his achievements on the track that he brings to the business world.

His pioneering spirit can also be seen behind the development of two prototype homes alongside the company offices - a Green Deal Eco House and a new PassiveHouse, a test home using new materials and construction methods.

The Green Deal Eco House demonstrates how buildings can incorporate both Green Deal and ECO-funded energy saving measures in housing and commercial buildings.

Larkfleet's PassiveHouse shows how lightweight pultruded glass-reinforced plastic (GRP) composite beams and panels could revolutionise the way in which future homes are built.

The house is designed to be ‘factory built' using mass-produced modular components that can easily installed on site with minimal labour and waste, all much quicker than a traditionally built house.

Its light weight also offers the potential for building such homes on foundations that would rise in response to flooding.

Another aspect of Larkfleet's sustainable energy business is developing large photovoltaic solar farms, adding solar panels to new and existing buildings, and refurbishing existing homes to reduce their carbon footprint, energy use and energy costs.

"The reason solar works so well in the UK is because you need a combination of sun and relatively cool temperatures for optimum energy output," explains Karl.

He describes it as a "very simple technology" but one that still needs government support in order to make it practical to deliver.

"We can do a lot more with solar energy generation in this country and it is something I think should be developed and supported more," he says.

"Wind should also be used more. People don't seem to want it but it is one of our biggest resources in the UK - the difference may come if the lights go out and then people will say ‘why didn't we invest in wind power'?"

Karl believes that if the subsidies given to the nation's nuclear power industry were matched for renewables the country would be in a very different situation.

"Thirty per cent of our energy could come from solar and it would be much cheaper, cleaner and simpler than nuclear," he says.

The scientist who became one of the country's most innovative developers has created a company of our time - a true leader when it comes to home building, sustainable development and renewable energy projects.


The above is adapted from Larkfleet Ascending - an article written by Clive Simpson for The Business Moment magazine.