Conscious Choice: Taming the Global Warming Dragon

July 1999

Taming the Global Warming Dragon

Options, developments, and long-term solutions

by Ana Arias Terry

Let’s hope old dogs really can learn new tricks. Because if we represent the figurative old dog, the only way we’re going to tame global warming and stay healthy as a species and as a planet is to pursue — in earnest — the new tricks found in clean, renewable energy. One thing is sure: our track record in twentieth-century energy use won’t be nominated for any awards in the near future.

Strong evidence indicates that over the past 100 years our use of fossil fuels has increased carbon dioxide (CO2) levels in the atmosphere by 30 percent. In the U.S., highly polluting fuels such as coal, oil, and natural gas account for more than 85 percent of overall energy consumption. Internationally, fossil fuel power plants pump out 60 percent of overall greenhouse gas emissions. Medical institutions such as Johns Hopkins and Harvard University Medical School have released information noting that, already, infectious diseases and deaths resulting from heat waves may be attributable to global warming (or is that global warning? ).

While no single magic lamp can fully address our energy needs of the future, perhaps the answer lies in a combination of clean assorted energy technologies that share two important qualities — they don’t demolish the environment or exhaust natural resources.

Solar Sustainability

It’s hard to go wrong with solar power. It’s free, non-depleting, and domestic. According to a report by the Union of Concerned Scientists, it is considered the most environmentally harmless energy source because its technologies don’t produce water or air degradation, don’t wipe out natural resources, and don’t put at risk public safety or health.

Solar systems are modular — which means they can be designed to meet any magnitude of need — and can be enlarged with ease to accommodate energy changes. Solar cells, or some types of solar collector, make up systems that produce energy, cool and heat buildings, and destroy dangerous pollutants. The main solar energy technologies are comprised of photovoltaics (PV), concentrated solar power, and solar cooling and heating systems.

PVs are among the fastest growing and most common solar technology. Often referred to as modules or cells, PVs take advantage of semiconductor components to convert sunlight directly into electricity. When sunlight beams on the semiconductor matter it yields an electric current —power. Because solar cells don’t have any moving parts, they offer great portability and convenience for numerous applications, including the powering of remote homes, road signs, water pumps, space satellites and vehicles, communication stations, cellular phone transmitters, radios, navigation buoys, corrosion protection for docks and pipelines, calculators, watches, medical and recreational refrigerators, street and billboard lights, accessory systems for RVs, fans, utility grids, and household appliances. But can solar electricity through PVs alone fully power a home? You bet. Over 25,000 such homes exist today.

Rooftop solar panels can greatly offset the electricity needs of buildings and homes. In summers they often generate more electricity than needed by the owners. The surplus can be sold to electric utilities to reduce the level of energy pumped from polluting fossil fuel plants. Barring transmission constraints, if only one percent of the nation’s land area had PV panels installed, U.S. electricity needs could be met.

Concentrating solar power systems make electricity with heat. Collectors use lenses and mirrors and divert the concentrated sunlight to a receiver that’s attached on top of the focal point of the system. Heat is produced when receivers absorb and convert the light. The heat then gets funneled to an engine or steam generator where it’s converted into electricity. Three primary kinds of concentrating solar power systems include central receiver system, dish/engine systems, and parabolic troughs. The largest solar energy power plant in the world is a parabolic trough system based in Southern California, which provides 350,000 individuals with energy for their needs.

Solar heating and cooling systems heat a liquid, the air, or a fluid, which then gets converted, indirectly or directly, to heat. Solar collectors make up the guts of most solar energy systems. Passive systems use natural ventilation and design to generate heat, whereas active systems employ fans or pumps to move heated water or air throughout the building or home. The most popular type of solar collector for residential space heating and cooling and water heating is the flat-panel collector. It consists of a large, insulated, flat-box with at least one glass cover. Dark-colored metal plates inside the box absorb the heat. The heat stored in the plates then heats the liquid or air flowing through the tubes.

The pace of solar technology development is ramping up; new solar technologies are springing forth annually. For example, homes can now benefit from a new solar air collector that had been previously available for commercial purposes only. The transpired collector consists of black, perforated metal which eliminates the glazing costs, the metal box, and insulation of other collectors. It can produce temperatures 50 degrees F higher than the outside temperature on a sunny, winter day and enhance indoor air quality by preheating fresh outdoor air directly. Another example of new technology is a more promising variation to the parabolic dish concentrator that produces power by using mirrors to reflect sunlight and create heat.

On the PV front, while three basic kinds of silicon solar cells exist with varying price tags and efficiencies, cells made of gallium arsenide (still under development) appear to provide higher efficiencies and the most promise in terms of future costs and growth.

But even low-tech solar technology, such as solar box cookers, can be used for both cooking and purifying water. They’re cost-effective and easy to construct and use.

Wind

The energy from wind is an indirect source of solar energy. Temperature variations on the surface of the Earth are caused by sunlight, and wind is primarily the result of these temperature variations. Growing at a clip of 20 percent annually, wind power has the distinction of being the fastest growing energy source worldwide. The U.S. alone generates enough wind power to meet yearly residential requirements for one million individuals.

To produce energy, wind turbines use blades (a rotor) to convert the power of moving air into electricity and mechanical energy. The blades are turned by the wind through lift. Because the speed of wind goes up with height, wind turbines get installed on towers. Electric power applications include grid-connected power plants, grid-connected systems that are dispersed (where wind turbines can generate electricity for farms, businesses, and homes already connected to a utility grid), and stand-alone, remote systems including rural home power and telecommunications. Mechanical applications include heating water, drying grain, irrigation, and water pumping.

Wind power represents a renewable energy source that doesn’t contribute to temperature changes and poses a small environmental impact. Despite public misconception, wind farms only use a small percentage of the land on which they reside. Approximately 95 percent of the land on a wind farm can still be used for activities such as farming, ranching, or forestry.

Biomass

Biomass energy is obtained from organic matter such as animal wastes and plants. Currently, the most popular type of biomass is wood, but the term also refers to wastes such as sawdust, paper, yard clippings, methane (from trash that’s decomposing), manure, and sewage. Approximately 45 percent of renewable energy in this country comes from biomass.

The two current methods for obtaining biomass energy are through crops ("energy crops" or "power crops") grown specifically for energy use and leftovers from plants used for other applications.

Because most biomass is still burned today, it does release gases and pollutants that contribute to temperature change. Conventional biomass combustion systems produce air emissions similar to coal-power plants, and more advanced technologies such as gasifier/combustion turbine combinations generate emissions similar to natural gas power plants. However, there is a process that can convert biomass into energy that generates few or no emissions. When plant material gets heated instead of burned, it breaks down into numerous solids, liquids, and gases. These goods can then be processed into liquid and gas fuels such as alcohol and methane. If they’re then run through fuel cells, the hydrogen-rich fuels get converted into water and electricity while generating few or no emissions.

And there is another scenario in which the emissions of carbon dioxide would be almost non-existent. In power crop environments, the carbon dioxide that’s released when biomass gets burned becomes reabsorbed into these plants. In such truly sustainable fuel cycles, CO2 emissions would be minor.

Fuel Cells

Hydrogen fuel cells offer a high-technology, clean and renewable energy source. NASA has been at the forefront of this technology. For years they’ve used it for electricity and for powering spacecraft. By allowing oxygen to mix with hydrogen, methanol, or natural gas, fuel cells generate electricity without combustion. An electric current occurs when the fuel is introduced to an elecrolyte close to the electrodes.

Fuel cells are expected to provide a significant breakthrough into the general populace by providing not only a clean alternative to the generation of electricity, but also in powering power plants, buildings, cars, buses, bicycles, golf carts, and other vehicles.

Tomorrow’s fuel cell car should be 98-100 percent cleaner than today’s cars. When they run on renewable fuels, the fuel cell alternative cars reduce gases that trap heat by 85-100 percent. Advanced fuel cell cars are projected to be able to travel between 250 and 400 miles before having to refuel, and attain 70-80 miles per gallon.

All of the major car manufacturers are developing fuel-cell cars, often in partnership with fuel pioneering organizations. It’s a good thing. Passenger cars consume six million barrels of oil daily (or 85 percent of oil imports). If only 20 percent of vehicles were using fuel cells, oil imports could be slashed by 1.5 million barrels daily.

Hypercars, envisioned by the Rocky Mountain Institute (RMI) combine designs that are ultralight and ultra-aerodynamic, have a hybrid-electric drive system, and have the potential of achieving 90 miles per gallon in the short term and 200 miles per gallon long-term. Fuel cells are being considered for hypercars, and RMI thinks that this approach to designing and building cars could speed up the acceptance of fuel cells. The bottom line is that since hypercars require significantly less power, they’ll also need much less fuel-cell capacity than a hefty, conventional auto.

Geothermal

It’s likely a word you haven’t heard since high school, but geothermal energy is a hot possibility. You may remember that geothermal energy is created when water rushes through warmed, porous rock. This energy can be used to generate power, heat, and steam for homes and buildings. Iceland leads the way with geothermal energy, just about every building in the little nation gets heated by hot springs. Some worldwide applications of hot spring water, for example, include heating greenhouses, deicing streets, drying fish, heating fish and spas, and enhancing the recovery of oil.

According to the Union of Concerned Scientists, geothermal energy is not replenishable, but it’s still considered almost inexhaustible due to its vast quantity. However, even with its impressive role in displacing usage of 1.2 million barrels of oil yearly, much of these forms of energy can’t be economically tapped with the technology available today. Up to this point, the only hydrothermal forms that have been captured are steam emanating from the ground and boiling hot water. The potential for using hot rocks underground is significant as a way to extract geothermal heat, but costs have yet to be competitive, particularly since wells have to be dug extremely deep. Geothermal energy contributes relatively clean heat. Open-loop geothermal plant systems produce small amounts of carbon dioxide — approximately five percent of what coal or oil plants emit. Closed-loop systems generate almost no emissions.

Hydroelectric

Hydroelectric power is a more problematic source of renewable energy. It takes advantage of the energy of moving water to drive water turbines and thus create electricity. On the plus side, this power produces no pollution, is renewable, and the water can be used again for other purposes. Large-scale systems use dams to block rivers, where water gets funneled through turbines when power is called for. Small, "run-of-the-river" systems simply allow the water to flow continuously.

The U.S. leads the world in hydropower production — it has a capacity to meet the energy needs of 28 million homes. Internationally, hydropower represents the largest source of renewable energy. Unfortunately, hydropower plants create severe environmental problems that impact nearby areas — reservoirs can cover sensitive locations, towns, and farmland, and affect wildlife and fish habitats. Still, the small run-of-the-river systems can be sustainable and nonpolluting if developed and maintained correctly. Many such small hydro projects are being developed in more than 100 countries.

Long-Term Solutions at Home and Abroad

Funding for clean renewables represents an important component of a sustainable, long-range plan to curb global warming. The conclusions of a study by five national labs in 1990 revealed that if R&D budgets were augmented by the construction cost of a single nuclear power plant — $3 billion amortized over 20 years — renewable energy could generate a half to two-thirds of total energy use in the U.S. by 2030.

If we’re not already immersed in an alternative, clean, renewable energy environment — and even if we are — the most crucial action we can take to restrict alterations to climate change is to improve the energy efficiency of our planet. If we want a successful solution to global climate change, we must tame the emissions discharged by cars. And, as with any problem, we must leap into action in our own backyard first. Cars and trucks in the U.S. alone generate more carbon dioxide than all of Japan. Closer yet to home, nuclear investments have straddled Illinois with the most expensive electric rates in the Midwest. Renewables have been largely ignored, so far, but they offer considerable advantages. According to a 1998 study by the Union of Concerned Scientists, the technologies with the most promise for Illinois are solar power, wind power, and biomass.

How do we get the new technologies under way? Long-term solutions require that we examine policies that drive the competition of fossil fuels vs. clean technologies. We must be ever vigilant of practices and policies that may stack up against the fair development of clean technologies or that try to pass off emission standards that are not comparable for all energy generating plants. The primary catalyst for the current restructuring of options for generating electricity is the advent of new technologies.

If the new rules of the marketplace are planned to encourage cleaner, renewable energy alternatives, we could realize lower prices, healthy competition, and environmental betterment. They could also offer an increase in the diversity of benign fuels (and thus a better mix of energy generating technologies that make the country less vulnerable to erratic prices), and a lessened dependence on international petroleum and its potential depletion. Utility customers must be given green energy choice selections, be well-read on the pros and cons of those choices, and know that organizations offering green energy alternatives have fair access to the grid and to them as customers.

As consumers and conscientious individuals, we have the power to chose a cleaner, healthier environment through more energy efficient home heating systems, appliances, lighting, and electronics, starting from the bottom up. We can lobby for legislation, of course, but we can also vote with our wallets; we can opt to select efficient, less polluting products, such as those that that show the Energy Star label developed by the U.S. Environmental Protection Agency and the U.S. Department of Energy.

The air up there doesn’t adhere to human-made boundaries of neighborhood, town, city, state, or country. Whatever we release to the atmosphere in one little corner of the Earth can have a direct or indirect impact on some other location halfway around the world. It’s our choice. Let’s make the right one.

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