Cool Technologies

Some of the most effective ways to cut our dependence on oil are startlingly simple. Here are 10 of our favorites
Clean Stoves
Wind Farms
Cool Roofs
Oil-free Food
Daylit Schools
Gas from Trash
Heat-collecting Roofs
Renewable Energy Incentives
Electric Hub Motors
Shoe Generators

Clean Stoves

Michelle Burkhart

Fuel-efficient, smoke-free wood-burning stoves, designed by an Oregon research center called Aprovecho, are helping to reduce the millions of deaths caused by smoke-inhalation from open, chimney-less cooking fires. Two billion people cook over open fires in the developing world and most of these fires burn inefficiently. This leads to high wood consumption and therefore deforestation and high emissions of greenhouse gases and pollutants. Stoves designed by Aprovecho achieve near complete combustion, which reduces greenhouse gas emissions and cuts wood consumption by an average 60 to 70 percent compared to open-fire stoves.

In Central America, residents have built hundreds of thousands of Aprovecho-designed stoves in their homes. Dean Still, Aprovecho's Appropriate Technology Coordinator, explains that Aprovecho travels to countries around the world bringing only the principles for an “insulative combustion chamber.” This chamber's high temperatures transform most of the smoke into heat. For the rest of the stove design, Aprovecho looks to the local community to build an affordable stove with locally available materials, and community women work with Aprovecho to design a stove to match their needs. Aprovecho then works with local nonprofit organizations to build and give away the stoves or teach locals how to build them for their homes or to sell. 

A recently constructed Aprovecho bread oven for a Ugandan bakery consumes 5 kilograms of wood to bake 17 kilograms of bread; the bakery's previous stove consumed 200 kilograms of wood.

For more information, see



A Mighty Wind

Michelle Burkhart

In southeastern Colorado, the recently installed 162-megawatt Colorado Green (CG) windfarm is breathing life back into the suffering rural economy and providing enough low-cost electricity to power 52,000 households. CG created over 300 installation jobs (half of them to locals) and 15 to 20 full-time operation and maintenance jobs. Landowners, many of them ranchers, benefit too. They earn between $2,000 and $5,000 annually per turbine leasing their land. CG's 108 turbines use less than two percent of the 11,000 acres of the range land they stand upon—equivalent to space for one less cow for the entire acreage. Prowers County's tax base will also enjoy a 35 percent boost from the project, according to County Assessor Andy Wyatt.

And the windfall does not stop there. The windfarm is generating an economic ripple throughout the community. For example, David and Aracelli Fernandez, who live near the windfarm, made $800 worth of burritos a day to feed the installation workers and, in turn, spent their income in the community.

Wind energy is the world's fastest growing form of energy production. Costs in many locations are now lower than for new coal-fired power plants, the cheapest traditional way of producing electricity. CG's wind energy costs 3.2 cents per kilowatt-hour, whereas energy from a new coal plant costs about 5 cents per kilowatt-hour. Tom Potter of the New Center for Rural Economics & Energy says, “A windfarm will produce more jobs, income, and career opportunities than a coal plant of comparable size.”

Cool Roofs

Carolyn McConnell

City dwellers are all too familiar with the heat-island effect that makes cities, with their black asphalt, baking concrete, and dark roofs, hotter than the countryside. But few know how simple some of the solutions are. Simply painting dark roofs white can significantly reduce city temperatures and cut electricity use for air conditioning.

For instance, painting 15 percent of Los Angeles' roofs white could reduce temperatures by 6 degrees and smog by 10 percent, producing ozone reductions equivalent to taking 3 to 5 million cars off Los Angeles freeways, according to the Architects/Designers/Planners for Social Responsibility newsletter. A study funded by the EPA found that buildings in Sacramento, California, whose roofs were light-colored and reflective used 40 percent less energy than those with darker roofs. With buildings consuming 36 percent of the U.S. energy supply each year, the effects could be dramatic. The group estimates that the U.S. could save $750 million per year if dark roofs in cities were replaced with light-colored roofs. Phoenix alone could save $37 million per year.

Even more energy savings can be had with green roofs—roofs covered in a thin layer of soil and hardy vegetation. Widely used in Europe, these roofs mitigate the heat-island effect, reduce stormwater run-off, improve urban air quality, and insulate buildings in both winter and summer, lowering energy use for heating and cooling.

Oil-free Food

Darrin Burgess

Physicist Albert Bartlett has called modern agriculture “the use of land to convert oil into food.” Agriculture consumes large amounts of petroleum to fuel machinery and make synthetic fertilizers, pesticides, and herbicides. Agriculture accounts for 17 percent of U.S. energy consumption—nearly all from petroleum—and it takes the equivalent of 400 gallons of oil to feed each American for a year. How would you farm without oil?

In 1989, Cuba faced just this question. When the Soviet Union collapsed, $6 billion in Soviet subsidies to Cuba vanished overnight. Worst hit were flows of fossil fuels and their derivatives from the oil-rich Soviets. Fuel supplies fell by 50 percent; petrochemical fertilizers and pesticides fell by 70 percent; food and other consumer goods fell by 50 percent. Cuba's per capita caloric intake fell by 30 percent and food was tightly rationed.

In 1993, the Cuban government dumped its moribund industrial agriculture system: More than half the state farmland was turned into worker-owned co-operatives. Lacking access to fossil fuels and the petrochemical fertilizers derived from them, Cubans turned to organic agriculture, building a model for intensive urban gardening that has answered many questions about whether organic farming can feed the world.  In Havana, half of the city's vegetables are grown within or around the city by 26,000 farmers using worms to turn waste into rich compost, and using crop rotation and companioning of crops to enrich the soil.

The Cuban government funds research that has discovered hundreds of pest-controlling plant, fungi, and insect species. Government programs have trained thousands of workers to use draft animals, which provide useful compost and work small plots more efficiently than heavy machinery.

Although it now has the world's largest organic agricultural system, Cuba's chief export crop, sugar, is still mainly grown using a scarce supply of chemicals. Exports of organic sugar are increasing, however. While Cuba succeeded in reducing its reliance on imported food, it must still import basics like rice, beans, and meat.

But unlike neighboring Latin Americans whose countries have higher per capita GDPs, Cubans are universally fed, family farms are thriving, and organic agriculture is relieving them of a crippling reliance on petroleum.

Let There be Sunlight

Michelle Burkhart

In low-income central Washington, DC, at the new Barnard Elementary School, large energy-efficient windows and a two-story atrium flood classrooms and hallways with daylight. According to Shirley Hopkinson, the school's principal, students are calmer, happier, and more cooperative with one another. Fighting is almost eliminated. Grades and test scores have improved, attendance is up for students and teachers, and parent participation is up.

Barnard Elementary is one of hundreds of schools that have turned to “daylighting” to cut energy costs and improve student and teacher achievement. According to the American Solar Energy Society, a school of Barnard's size that includes energy-efficient designs and daylighting saves about $13,000 annually on energy-related utility costs in comparison to a standard elementary school of similar size. And a study on the effects of daylighting by the architectural firm Heschong Mahone Group found a 21 percent improvement in student performance between windowless classes and classes with plenty of daylighting.

Daylit schools are also heightening student and parent awareness about energy conservation and renewable energy. According to Hopkinson, televisions and lights were continuously left on in empty rooms at the old school. Now, students and teachers carefully turn off equipment when finished.

Gas from Trash

Darrin Burgess

“What a feeling, to be driven through Zurich in a 430-horsepower truck, knowing that the energy needed to power the vehicle is produced from banana peels,” gushed a Swiss Federal Councilor at a recent award ceremony honoring Walter Schmid.

Since 1991, when Schmid set up a trial Kompogas plant in Rümlang, Switzerland, what began as a hobby on his home balcony has expanded into a national operation that fuels several thousand automobiles, and by the end of this year will feed energy made from composted food waste directly into the power grid of the Swiss city Passau Hellersberg.

Kompogas is a for-profit company that manufactures auto fuel and compost, and collects revenue to remove cities' biowaste. In Zurich alone, five plants ferment organic scraps from homes and restaurants to produce fuel for 1,200 cars and trucks—including the local McDonald's entire fleet.

Kompogas has proved to be such a success that Germany has adopted the technology and plans to ban all untreated organic waste from landfills by 2005. In the Kompogas plant, organic matter is ground into small bits, fed into a giant tank and heated to about 135 degress Fahrenheit. In this environment, microorganisms thrive and feed, releasing a gaseous waste byproduct of methane and carbon dioxide. It can be burned in automobiles to produce 80 percent less smog-creating chemicals than gasoline. It is considered carbon neutral, because the carbon dioxide emitted from an exhaust pipe will equal the amount of carbon previously extracted from the atmosphere by the growing plants. According to Kompogas engineer René Leisner, a typical car can travel 62 miles on 220 pounds of scraps. The remaining waste is then composted for fertilizer.

If Europeans processed all their solid waste, the biofuel could run 10 percent of their automobiles and reduce their total carbon emissions by nearly 10 percent, according to the Kompogas website,



Simple Solar

Pamela O'Malley Chang

Generating electricity from your rooftop might take high-tech solar panels, but generating heat from the sun on your roof can be a simple, low-tech project. Heat-collecting roofs can be built by do-it-your-selfers using either found materials or off-the-shelf components, or they can be engineered and installed by solar heating specialists. And they can be cheap.

Anyone who has been surprised at getting hot water from the garden hose some sunny afternoon has demonstrated the basic concept of heat-collecting solar roofs: a fluid held in a dark-colored sunlit container gets hot. This hot fluid can be used directly—for washing or heated swimming pools, for example—or it can be used to heat something else—a baseboard heater for your living room, say.

Solar roofs come in two categories: heat-collecting and solar electric (photovoltaic, or PV). PV roofs can provide all of the electricity for an energy-conserving household but will cost upward of $15,000, even factoring in state incentive rebates. Unless this cost is folded into the purchase price of a new home, many homeowners will balk at paying so much for a retrofit whose payback period may well exceed their tenancy.

Heat collecting is simpler. Innovators have collected solar heat by dripping water over metal roofs, or built water-filled bottles into sunlit walls, or created shallow roof ponds. Solar water heating has been commercially available for homes since the 1970s.

My local San Francisco Bay Area solar contractors gave me quotes of about $5,600 to install a fully engineered solar hot water heating system for an average single-family house. The U.S. Department of Energy estimated installed costs of $1,000-$3,000 in 2000 for a basic system. A four-person family normally spends $300 a year on electric hot water heating, so a solar system could pay for itself in four to 10 years, but have a 15- to 40-year lifespan. The savings in carbon dioxide emissions (depending on where your electricity comes from) is equal to not driving 15,000 miles per year or planting two acres of trees. If your conventional hot water tank has reached its 10-year life expectancy, think about converting to solar, especially if you live in a sunny climate.

Pamela O'Malley Chang is an architect, acupuncture student, and YES! contributing editor.

The States Step Up

Doug Pibel

As the federal government continues to concentrate on fossil fuel, and as the catastrophic consequences of that concentration become clear, the states are leading the way toward renewable energy. Thirty-two states now offer direct rebates or grants for green energy equipment or generation. New York, for example, rebates up to 60 percent for photovoltaic installations and 15 to 70 percent for wind power. Wyoming offers grants of up to $3,000 for residential photovoltaic arrays.

Other state financial incentives include personal, sales, and property tax breaks, and low- or no-interest loans. The state of Connecticut, for instance, has loans of up to $15,000 at interest rates from 1 to 6 percent to assist low income families in making conservation improvements and installing alternative heating systems. The same program offers loans of up to $60,000 per building for multi-family units, at 3 percent or 6 percent, depending on tenants' income, for making efficiency improvements.

States are also using laws and regulations to move people toward renewable energy. Thirty-two states and the District of Columbia have net-metering laws; utilities voluntarily offer net metering in an additional six states. Net metering allows on-grid users of alternative power sources to sell excess electricity back to utilities, usually at retail rates. When customers with photovoltaic arrays, wind turbines, or other renewable power sources produce more electricity than they are using, their power meters run backward.

Twenty-three states and the District of Columbia now require utilities to disclose to their customers the sources of the power they use. Another six states require utilities to provide customers with green energy alternatives. Several states, along with some municipalities, require that all new construction of government buildings be energy-efficient and use green power as much as possible.

In Arizona, Colorado, New Mexico, and Texas, utilities considering extending power lines to remote areas must determine that the cost of the extension is less than the cost of providing off-grid power to those locations.

At, the Database of State Incentives for Renewable Energy, you'll find a state-by-state tabulation of renewable energy incentives.



Goodbye, Internal Combustion

Rik Langendoen

A Dutch company is testing a century-old idea as an alternative to the internal combustion engine. E-Traction has developed an electric hub motor that combines a wheel and motor into one operating unit. The company has demonstrated a 50 to 70 percent reduction in fuel consumption using this technique.

A major source of vehicle inefficiency is the drive train that connects the engine to the wheels. The E-Traction design overcomes that inefficiency by making the electric drive motor a part of the wheel. A small diesel generator charges a bank of batteries that provides the electricity necessary to drive the motor. During braking, the motors become generators that charge the batteries.

E-Traction's bus is called “The Whisper” because it is so quiet. The company is also working on new buses that are predicted  to be significantly more fuel efficient, as well as two SUVs: a Mercedes Jeep and a Range Rover. The SUVs will have four motors, one on each wheel—a simple and efficient way of making a vehicle four-wheel drive.

For more information see



What's that Squidging Noise?

Darrin Burgess

Bob Komarechka, a geologist from Sudbury, Ontario, spends many tedious days in the field lugging rock samples and electrical instruments. Two seemingly unrelated desires—one for a pair of comfortable gel-cushioned soles, the other for an alternative to frequently changing his instruments' failing batteries—led to an epiphany.

In May 2001, Komarechka received a U.S. patent for a shoe design that uses the rolling motion of walking to produce a steady flow of electric current. When a person steps forward, fluid is forced out of a sac in the heel through the blades of a small turbine into another sac in the toe, where the fluid is held by a check valve. When the foot rolls onto its toe, the fluid is squirted back through the turbine and into the heel. Both the turbine and a microgenerator are located between the sacs, in the center of the sole, and a socket connects a wire to electrical devices.

Using calculations based on the average person's weight, Komarechka believes that the shoes could generate a steady three watts of electricity—enough to power a hand-held computer, a GPS device, or a radio, or to continuously recharge batteries.

No prototype exists yet, although Komarechka is waiting for replies from Reebok, Nike, and the U.S. military. “I know I can make it work,” he says. “It's fairly straightforward.”