Solar energy is the hot power source to watch
In theory, solar power is ideal. It’s clean, producing no air pollution or green house gases. It doesn’t require flooding huge areas or disrupting river ecosystems, as hydro power often does. And it’s plentiful: in just one hour, enough sunlight falls on the earth to supply the energy needs of everyone on the planet for an entire year.
But it has always been something of a black sheep in the clean-energy family. It can be expensive: a full set of panels for your home can cost tens of thousands of dollars and it isn’t considered very efficient. With typical solar panels, only about 15 percent of the energy that falls on them is converted into electricity (wind turbines average more than 20 percent efficiency, and coal-powered plants 30 percent or more). So while wind farms are sprouting up all over Europe, biofuels are on the rise and hydro is a Canadian staple, affordable solar power has seemed relatively inaccessible.
But that’s changing. Engineers are creating new technologies that are not only cheaper but also more efficient than traditional flat panels, bringing us closer to the solar Holy Grail: producing electricity for the same price as fossil fuels.
Cutting the silicon costs
One of the biggest obstacles to solar power has always been cost. Silicon, used as a semiconductor to create electricity, is expensive and the global shortage of polysilicon — the kind used in most solar panels — isn’t making it any cheaper. So scientists are thinking of clever ways to do more with less of it. One way to get more bang for your buck is to stack solar cells on top of each other, creating what’s called a triple-junction cell. By layering three semiconductors, each capturing a different kind of light (blue, green or red), you can produce more electricity over the same area.
Michigan-based united Solar Ovonic has products we can buy for our homes and/businesses that use triple-junction technology and only a small amount of silicon. Moreover, the solar cells can be mounted onto stainless-steel foil (as opposed to glass) and are virtually unbreakable. It manufactures solar roof shingles, solar battery-chargers that come in sheets that can be neatly folded up, and peel-and-stick laminates that can be stuck onto a metal roof of, say, a shed or warehouse. They are understandably popular. Last year, united sold enough units to power more than 15,000 homes.
Another simple and elegant method is to focus sunlight with lenses and mirrors. Solfocus, a California-based company, has combined mirrors with triple-junction techniques. The curved mirrors in its solar panels concentrate the sunlight by 500 times. And by focusing the already concentrated sunlight onto triple-junction cells that don’t use silicon, Solfocus reduces the amount of semiconductor needed by a factor of a thousand to produce the same amount of electricity. The company is working on its first commercial installation in Spain, and expects to have finished products for the commercial market by late this year.
Prism Solar Technologies, based in New York State, has come up with a colourful way to focus sunlight: holograms. Its solar panels use a form of gelatin sandwiched between panes of glass to create a holographic effect. They aren’t just pretty– they require 20 to 70 percent less silicon than a conventional panel. “We’ve basically displaced much of the expensive component and replaced it with an inexpensive gelatin material — essentially a high-tech Jell-O –and it’s a great way to concentrate sunlight in low light conditions, such as late afternoon,” says Prism Solar CEO Rick Lewandowski. Canadians should be able to buy these rainbow-coloured panels to install on the roofs of our homes by 2008.
The future looks bright
Some solar companies are going even further by sunning silicon altogether. Research groups worldwide, such as Australian company Dyesol, are using inexpensive pigments based on natural compounds, such as green dyes that mimic chlorophyll. Although no commercial products are ready, the industry is buzzing that dye-sensitized cells could be a huge breakthrough.
But by far the biggest buzz is over solar cells that can be painted onto flexible surfaces with the same kind of roll-to-roll manufacturing used in printing presses. This will be much quicker and cheaper than the high-tech airtight labs where the solar panels of yesteryear had to be assembled before being ready for real-world use, and likely won’t contain silicon. And they’re cheap to manufacture.
Meanwhile, New York State-based DayStar Technologies makes thin film from tiny particles of copper, indium, gallium and selenium (CIGS). These films are much lighter and thinner than aluminum foil, and the company anticipates they could be used to cover the wings of airplanes or be draped over satellites. California’s Nanosolar has also been generating an enormous amount of hype recently with CIGS thin films. It is in the process of constructing the world’s largest thin-film factory in San Jose, and should have commercial products ready within the next few years.
Also coming up on the horizon is Massachusetts-based Konarka, which will start commercializing its solar plastics this summer. These can be coloured and printed in virtually any style: brick patterns for walls, camouflage, anything you like. Moreover, the plastic is so light and flexible, the company envisions it could be incorporated onto the surface of just about anything: blinds, awnings, windows, MP3 players, laptops and phones (enabling them to charge themselves) – even clothing. Director of business development Jamie Braman won’t divulge exactly what products carrying this solar technology will be coming out soon, but he says, “We’re going to be like the Intel microprocessor inside a computer – the solar power behind other people’s products. You’ll see stuff popping up on the market soon.”
University of Toronto hotshot engineer professor Ted Sargent is also developing paint-on silicon-free solar cells, except his go one step further: they use light that you can’t even see. His solar paint uses infrared light, and thus can use up to 30 per cent of the sunlight that bathes the earth (as opposed to regular photovoltaic cells, which can only use up to 6 per cent), so the potential for using infrared is huge.
Solar is powerful
Clearly, solar power is on the ascent. “One of the biggest changes I’ve noticed,” says Brian Wilkinson, owner of Montreal-based Matrix Energy, “is that people don’t walk away from you at cocktail parties when you tell them what you do. Twenty years ago, people wanted to talk about anything but solar energy. Now they ask questions. It’s no longer looked down on as something that isn’t proven.”
California is in the middle of installing a million solar roofs on homes and businesses across the state. Huge solar farms are being constructed in the Nevada desert, Spain and Portugal. This spring, several companies, including OptiSolar Farms Canada Inc. and SunEdison Canada LLC, announced new solar farm projects to create power for commercial and residential use in southern Ontario, which will use vast arrays of panels linked directly to the grid. Thanks to new incentives from the Ontario government, purchasing solar energy will cost no more than from any other source of power. And with all the new innovations coming our way, there’s little doubt that solar is going to become more versatile, more powerful and more affordable.
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Home Solar Home
If you want to harness the power of the sun but can’t cover your roof with solar panels, there are other things you can do to capture the sun’s energy and save money at the same time.
“Solar hot water is a far more cost-effective application than solar electric power right now,” says Bill Eggerston of the Canadian Association for Renewable Energies. “About 20 per cent of your annual energy bill goes to heating hot water.”
EnerWorks, a Dorchester, Ont-based company, has been providing solar hot-water heathers to homeowners for he past two years (it was also chosen by The Home Depot to do its residential installations). These systems – which run residential water through pipes placed on the roof and heat it with the power of the sun – can cut your household water-heating bill by anywhere from 50 to 60 percent. The initial installation is high (about $6,000; about $1,000 less if you get an eco-energy audit and apply for government rebates), but, says CEO Ken Arnold, “as a rule of thumb, the system will pay for itself in about five to eight years.”