CLEANTECH BUZZ: Floating solar

Australian solar tech outfit Sunengy – a privately owned group that has developed and patented a Liquid Solar Array (LSA) concentrated solar power collector – has entered into a partnership with India's largest integrated private power utility, Tata Power, to build a pilot plant for its low-cost, floating-on-water, solar technology in India by the end of this year.

The LSA was invented by Phil Connor, Sunengy executive director and chief technology officer, and passionate solar advocate. It works using traditional Concentrated Photovoltaic (CPV) technology – a lens and a small area of solar cells that tracks the sun throughout the day. Floating the LSA on water reduces the need for expensive supporting structures to protect it from high winds. The lenses submerge in bad weather and the water also cools the cells which increases their efficiency and life-span.

Connor says the LSA technology, when located on and combined with hydroelectric dams, offers the reduced cost and 'on demand' 24/7 availability necessary for the broader uptake of solar power. Connor says that – despite hydropower supplying 87 per cent of the world's renewable energy and 16 per cent of the world's power – it is limited by its water resource. He said an LSA installation could match the power output of a typical hydro dam using less than 10 per cent of its surface area and supply an additional six-to-eight hours of power a day. By way of example, Sunengy modelling shows that a 240MW LSA system could increase annual energy generation at the Portuguese hydro plant, Alqueva, by 230 per cent.

“LSA effectively turns a dam into a very large battery, offering free solar storage and opportunity for improved water resource management,” Connor said in a company announcement. “LSA needs no heavy materials or huge land acquisitions and is effectively cyclone proof,” he said. “If India uses just 1 per cent of its 30,000 square kilometres of captured water with our system, we can generate power equivalent to 15 large coal-fired power stations.”

Construction of the pilot plant in India is set to commence in August this year. Sunengy also plans to establish a larger LSA system in
NSW's Hunter Valley in mid 2012 before going into full production.

Solar share

Arizona power company Trico Electric Cooperative is taking a canny approach to wooing customers who like their electricity from clean energy sources, but would rather not – or could not – install a rooftop PV system where they live. The company is building a mid-sized solar farm next to its office in Marana, reports getsolar.com, which will work much like an urban cooperative garden, in that people from the surrounding communities will buy clean energy generated at the PV array.

Trico plans to install 840 solar modules on the site and will offer customers the option to buy the output generated from a quarter-panel, half-panel or full panel for $US230, $US460 or $US920 respectively. Each of the solar modules is capable of producing 230 watts of power – and a full panel would offer 36 kilowatt hours' worth of credit to customers' electric bills, said Trico spokeswoman Romi Carrell Wittman. Basically, customers who buy a full panel's worth of electricity will get a credit of $US5 per month as long as they use the clean energy the PV array generates, on top of the savings gained from deriving a higher percentage of their energy from solar, says getsolar.com.

Wittman says the project is attracting a lot of community interest – and not just for reasons of economy. Apparently green-minded Arizonians are already entering into similar agreements to purchase energy from mid-sized solar farms, like a 1.6MW photovoltaic array Tucson Electric Power installed. In contrast to Trico, TEP's program lets customers buy blocks of 150kW hours to replace an equivalent amount of energy on their power bills for $3 extra a month. Cost savings would arise over the long-term because the rate is locked-in, says TEP spokesman Joe Salkowski. "You do lock in the rate that you're paying for that solar power for 20 years," says Salkowski. TEP customers can buy as many blocks as they want – Salkowski told reporters he had bought seven blocks – enough to power his entire home – for only $21 extra dollars on his monthly energy bill. "We're expecting big things from this program. It's been very popular so far," Salkowski said.

Sugar sweet

Photosynthetic microorganisms like algae are usually prized for their ability to produce oils, says Kevin Bullis in Technology Review – not so for New Jersey-based start-up Proterro. The synthetic biology company is instead focusing on algae-based sugar production. The aim: to make biofuels cheaper by cutting the cost of making sugar – the basic building block for biofuel ethanol, as well as the starting point for new processes for making other types of biofuels. The majority of the sugar for biofuels is made from corn or sugarcane, while some companies are developing ways to make sugar from cellulosic materials like grass and wood chips. But as a feedstock to make biofuels, sugar is still too expensive, says Kef Kasdin, Proterro's CEO. According to Kasdin, Proterro's microorganisms, a type of cyanobacteria, can produce far higher yields of sugar per acre than sugarcane and other conventional sources.

Which is where Proterro's microbes come in – they naturally produce sucrose when the water that they're growing in becomes too salty, says Bullis; a built-in defense mechanism to stop them from losing water by osmosis. Proterro has identified the genes that trigger this mechanism and engineered the organisms to switch it on. Researchers have also engineered the organisms to secrete the sugar, making it easier to collect. Conventional methods of algae or cyanobacterial fuel-making require the organisms to be harvested and dewatered – the oil or sugar is then isolated from the rest of the biomass, says Bullis, which is one reason algae fuels are expensive.

Knock on wood

While most major automakers are at least some way towards producing their own electric vehicles, a number of them – including BMW, Mercedes-Benz and McLaren – are also using their brand and technical knowledge to produce seriously green vehicles – of the two-wheeled, pedal-powered variety, that is. And while in doing so, they tend to use the same high-tech, lightweight materials used in their cars, like carbon fiber and aluminum, Audi's latest US bicycle offering has taken a different tack, says Gizmag's Darren Quick, by teaming up with Renovo Bicycles to create the "duo" – a line of bikes that feature frames made of hardwood.

According to Renovo, their trademark wooden bike frames are "the smoothest bike you'll ever ride, stealth quiet, lightweight and responsive, stiff as you want." The website also says the company's "hollow wood and laminated bamboo frames will forever change your understanding of what a bicycle should be, and how brilliantly these natural materials perform when designed to their strengths." And while the company stresses that it has chosen to work with wood for it engineering properties and not because it is sustainable, the duo's frame is indeed sustainable, as well as recyclable and biodegradable – although carbon fiber and aluminum are still used in the bike's components.

Three different models of the bike are on offer – the Duo City, the Duo Sport and the Duo Road. The City, says Quick, is a daily commuter and "sees the rider sitting in an upright position to provide comfort over short distances and visibility while cruising through traffic in urban areas." It 32mm puncture-resistant tires, LED lights, fenders and a rack. And "to ensure the rider doesn't arrive for work with the pants covered in grease, the bike's drivetrain features a grease-free Gates CenterTrack belt drive coupled to a Shimano Nexus 8-speed internal hub gear."

The woods for the frames are selected to match the look of Audi's car interiors and all of the duo line are hand-made at Renovo's Portland, Oregon, studio, says Quick. Audi says the line of wooden bikes is "an embodiment of its core principles of progressive innovation that also blends craftsmanship and styling with performance and technology." But Quick adds, "don't hold your breath for an Audi four-wheeled vehicles to feature a wooden chassis any time soon."