Hot news in cleantech: 24-hour PV; solar windows; fuel-saving F1 flywheels

“If you ever want to have round-the-clock solar, which the whole world does want to have, you have to have storage. Anything that can make it so that we have more on-demand power, especially with renewables, is going to be a big factor.” So said Bill Gross, cleantech champion and 1996 founder of Idealab, in a January telephone interview before traveling to this year’s World Economic Forum in Davos, Switzerland. And what Bill says… well. Anyway, it seems the people at US smart grid specialist S&C Electric were paying attention, because the Chicago, Illinois-based company has revealed it is set to start work on a pilot project that will integrate energy storage technology with solar photovoltaic panels to provide households with solar power through the night. BusinessGreen spoke this week with S&C Electric Europe’s managing director Andrew Jones, who said the £200,000 project involved the installation of a 75kW lithium ion battery system at an undisclosed eco-home project, to test the ability of households to store the solar energy generated during the day and release it through the night, when people get home from work and start turning things on.

Jones says the company expects the battery to provide power for around 50 homes in the development, based on the assumption that the average home uses around 1.5kW of electricity. “The system can also control how you feed energy back to the grid. Without that control you would have to dig up the road and add cables to export the unused solar power,” he said. As is often the case, the cost of this innovative technology, as with all energy storage technologies, is currently too expensive to enjoy widespread adoption, but Jones predicts that costs are likely to fall as the wide range of technologies currently under development mature. And he has a message for governments – who are obviously yet to take Bill Gross’s message on board: “One of the challenges for energy storage is there are not the clear market signals for firms to invest in the technology and bring the costs down,” Jones told BusinessGreen. “There needs to be a signal from policymakers to show storage firms the market will be there if they invest in bringing costs down.”

Solar generating windows, German style

Another week, another solar innovation, with the honours this week going to German company,  Heliatek – a Dresden-based start-up that has developed a new kind of panel made of small, organic molecules deposited on polyester films. MIT’s Technology Review reports that the technology, not unlike that used for displays on phones and flat-screen TVs, produces panels that are flexible and much lighter than conventional solar panels, but which generate just as much electricity. These characteristics have seen the company working with a building materials company to integrate their panels into concrete facades. And, not unlike Australia’s own Dyesol, Heliatek is also working to incorporate its solar panels, which can be semitransparent (like tinted glass), into windows.

Heliatek’s key innovations are the active materials in its solar cells and the process for making these cells, says Technology Review. And while there’s nothing new about organic solar cells, Heliatek’s are made using short molecules called oligomers, instead of the more commonly-used, longer molecules called polymers. Oligomers are more stable and more efficient, and this efficiency is boosted by Heliatek’s newly adopted manufacturing process – an innovative roll-to-roll approach that deposits the materials on polyester – which allows it to make a “tandem solar cell,” with two layers for absorbing light and producing electrons. In the current design, explains TR, both layers are tuned to convert the same wavelengths of light. But the company could also tune layers to different wavelengths and thus convert more of the solar spectrum.

At this stage, Heliatek’s panels convert only 8 per cent of the sun’s energy into electricity – compared 14-15 per cent for conventional silicon solar panels (polymer solar panels are 3 to 5 percent efficient). But the company says its technology’s good performance in low light and high heat can make up for this. According to Heliatek CEO, Thibaud de Séguillon, recent tests in Singapore showed that the company’s panels generated slightly more electricity over the course of a month than conventional silicon solar panels. The firm, which is backed by Bosch and BASF (BASF is working with Heliatek on improving the tandem solar technology), among others, is hoping to raise around €60 million – on top of €28 million raised so far – to move its technology from a small, proof-of-concept production line, to a 75MW factory. It expects to reach large-scale production in four to five years.

F1 technology on the buses

While the world waits for the electric vehicle revolution to take hold, there are some people out there working hard on ways to make regular, internal combustion engines more fuel efficient, and less carbon intensive. The following innovation, however, was not originally made for such a purpose – not for strictly regular vehicles, anyway. The Guardian reports that a fuel-saving flywheel first developed for use in Formula One racing cars, but abandoned before it could be used due to a change in the sport’s rules, is set to be retrofitted to London buses. Six prototype buses owned by one of the UK’s largest buses operators, Go-Ahead, are being fitted with the flywheels for a trial beginning later this year in and around south-west London. And, as it turns out, the leap from a Formula One car to a London Bus is not such a great one. “The forces exerted by a 15-tonne city bus constantly stopping and starting to pick up and drop off passengers is actually very similar to those experienced by a Formula 1 car,” said Ian Foley, managing director of Williams Hybrid Power, a subsidiary of  Williams F1, the Oxfordshire-based racing team behind the technology.

Williams F1 predicts that its carbon-composite flywheel technology – a variation on a theme that has long been used to store rotational energy – could help a city bus cut its fuel consumption by as much as 30 per cent. If successful, and funds forthcoming, Go-Ahead will look at fitting the flywheels across its 4,000-strong fleet of buses, says the paper. “Within three months of the trail starting, we’ll know if this technology is right for us,” said Phil Margrave, Go-Ahead’s group engineering director. “There have been lots of flywheel trials over the years, but for various reasons they have failed. Twenty years ago, one came on the market, but it was too noisy and this concerned passengers.”