ENVIRONMENT

THINKING BIG & GREEN

ALEXANDRA SHIMO May 14 2007
ENVIRONMENT

THINKING BIG & GREEN

ALEXANDRA SHIMO May 14 2007

THINKING BIG & GREEN

ENVIRONMENT

Small sacrifices will be essential to preserve the environment, but some scientists are thinking of even grander solutions BY ALEXANDRA SHIMO

GREEN REPORT

1. SOLAR-POWERED PAINT

WHO’S BEHIND IT: Edward Sargent, Department of Electrical and Computer Engineering, University of Toronto.

HOW IT WORKS: Solar-powered paint would redefine what it means to be wired. By creating a material that is thin enough to spray on, any surface could generate electricity, as it’s exposed to sunlight. A pair of pants could power your iPod. The roof and doors of houses could become mini-generators. The solar material is made of semiconductors one thousandth of a millimetre thick—weatherproof, washable and dyeable, says Sargent.

COST: One-tenth the cost of existing solar panels. For enough solar paint to cover a favourite jacket, it would cost about $10. DOWNSIDE: At the moment it’s only onetenth as efficient as conventional silicon solar panels. But, in the past two years, Sargent has increased efficiency 1,000-fold, and researchers expect to achieve similar efficiency as conventional panels within five years.

2. DESERT MIRRORS

WHO’S BEHIND IT: Dr. Gerhard Knies, TransMediterranean Renewable Energy Co-op, and Dr. Franz Trieb, German Aerospace Centre.

HOW IT WORKS: Desert mirrors heat water, creating steam to drive a nearby power station. The linchpin is the special panels that produce concentrated solar power with the intense, direct sunlight found in deserts. COST: The energy costs the same to produce as oil at $50 a barrel. These solar stations cost more to build than their oil-powered equivalents, but they would cost much less to run. H DOWNSIDE: It would take about 64,500 sq. km of desert mirrors to feed the world’s current electrical needs. Then you’d need to build a super-grid to get the power to consumers. Last month, the German environment minister met ministers from North Africa to talk about the chances of such global co-operation.

3. SEWAGE-FUELLED CARS

WHO’S BEHIND IT: Used in 30 cities in Sweden, and hundreds of thousands of cars in Argentina, Pakistan, Brazil and Italy.

HOW IT WORKS: Swedish sewage, or at least some gaseous remnants of it, is powering public buses in some cities. Its fermentation produces methane, referred to as biogas, collected from sewage treatment plants, landfills and abattoirs. In Stockholm, taxis, garbage trucks and several thousand cars are running on biofuel. There is even a biogas train linking Linköping and Vastervik 80 km away. COST: About $1 per litre of biogas, if the gas is produced locally. DOWNSIDE: Biogas isn’t available everywhere in Sweden, so a biogas car has to be made with two fuel tanks; cars also have a more limited driving range with biogas.

4. SULPHUR PARTICLES

WHO’S BEHIND IT: Lowell Wood, University of Houston.

HOW IT WORKS: Planes would scatter sulphur particles in the atmosphere, which would reflect sunlight and cool the earth. Although the proposal releases an acid-rain-making pollutant, it would mimic the natural cooling of the earth caused by sulphur-emitting volcanic eruptions, thus countering the effect of C02 emissions.

COST: $1 billion per year.

DOWNSIDE: One of a number of so-called geoengineering projects that would potentially alter the climate of the entire planet, rather than tackling the root causes of global warming. Once decried as being far too dangerous since a small miscalculation could have farreaching effects, geoengineering projects are now being considered by reputable scientists including Bert Bolin, former chairman of the UN’s Intergovernmental Panel on Climate Change. Why the change of heart? It might be too late for an ounce of prevention.

5. BIOREACTORS

RESEARCH SCIENTISTS: GreenFuel Technologies, Cambridge, Mass.

HOW IT WORKS: A few dozen kilometres west of Phoenix, algae grows in nutrientrich water inside a small greenhouse adjacent to the Redhawk Power Station. In this pilot bioreactor, carbon dioxide gas from the plant is pumped in, and the algae converts the carbon gas to oxygen and sugars via photosynthesis. The sugars are metabolized into a range of renewable fuels.

COST: $25 million to build a one-squarekilometre bioreactor, and $3.8 million per year to run. Those costs are offset by up to $5 million a year from selling biodiesel. DOWNSIDE: These reactors are limited in terms of how much C02 they can scrub. To mitigate just one per cent of carbon emissions from a medium-sized power plant, it would take a one-square-kilometre plant.

6. MAKING CLOUDS WHITER

WHO’S BEHIND IT: John Latham of the U.S. government’s National Center for Atmospheric Research, Boulder, Colo.

HOW IT WORKS: If you spray sea water into the sky, white clouds form, sunlight hits the droplets and refracts. Less light makes it to the ocean, which cools the earth. Latham proposes using 1,000 unmanned ships to scatter the water, and satellites to control the whole process.

COST: Roughly US$l-billion set-up cost DOWNSIDE: One concern is whether the clouds might reflect too much light—sunlight is essential in the production of hydroxyl, the atmosphere’s chemical cleansing agent. Lose too much hydroxyl and we could end up with a buildup of a plethora of pollutants—smog, acid rain, ozone and methane.

7. ARTIFICIAL TREES

WHO’S BEHIND IT: Klaus Lackner, EwingWorzel professor at Columbia University, Department of Earth and Environmental Engineering, New York.

HOW IT WORKS: Modelled on real trees, these synthetic versions absorb carbon dioxide at a much faster rate. Their “leaves”—which look like Venetian-blind slats—would be covered in a chemical that reacts with the carbon dioxide, removing it from the atmosphere and collecting it as a liquid at the bottom of the tree. The liquid can then be stored below ground or used to make carbonate rocks, which can be made into building materials. COST: A 10 x 10-m tree would cost approximately US$30,000 per year to run and would capture about 1,000 tonnes of C02 per yearequivalent to the emissions from about 204 cars in Canada.

DOWNSIDE: These trees consume energy to work. And once you have collected the carbon dioxide, what do you do with it all?

8. SMART APPLIANCES

WHO’S BEHIND IT: Joe Short, director, Dynamic Demand, a U.K.-based NGO. HOW IT WORKS: Essentially, this small, inexpensive technology regulates when fridges and other applicances are switched on. Machines like fridges can delay when

they need to consume power because they store a lot of cold air that tides them over. So a kitchen appliance that can adjust its electricity consumption

according to the traffic on the grid saves energy and carbon emissions. Even small time adjustments—a matter of minutes—can make a huge difference in efficiency.

COST: $6-7 per fridge

DOWNSIDE: Modifying the world’s fridges would be a slow and gradual process. The British government is researching the viability of the technology.

9. REFREEZING THE ARCTIC

RESEARCH SCIENTIST: Peter Flynn, Poole Chair in Management for Engineers, University of Alberta.

HOW IT WORKS: 8,000 unmanned barges are towed to the Arctic. Once there, these 100-m boats automatically pump sea water across the ice, which freezes in the cold air, thickening the ice and preserving the cur-

rents of water that stabilize land and sea temperatures across Europe. “Think of a cold drink,” says Flynn.

“A little bit of ice cools down a lot of water.”

COST: A one-time $50-billion expenditure to buy the boats and tow them up there; $5 billion each year in running costs.

DOWNSIDE: Highly expensive. Also, this is designed more as an “emergency response” than a workable solution to climate change. It doesn’t cool the planet at all, but merely mitigates one climate change problem—the weakening of ocean currents.

10. WEIRD-SHAPED PLANES

WHO’S BEHIND IT: “Silent” Aircraft Initiative, Cambridge-MIT Institute.

HOW IT WORKS: Ironically, this green proposal came out of wondering what to do about airport noise. The Cambridge-MIT Institute teamed up with an international team of graduate students, professors and commercial-airline engineers and produced an aircraft concept design that would be near-soundless and about 24 per cent more fuel efficient than current commercial aircraft.

COST: Unknown

DOWNSIDE: The technology to build one of these planes won’t be ready until about 2030, and it’s not clear whether the aircraft manufacturers would invest in such a radical overhaul to conventional plane design. M