In honor of Earth Day we’re offering an overview of sustainable energy sources taken from Clean Energy Nation: Freeing America from the Tyranny of Fossil Fuels by Congressman Jerry McNerney, a renewable energy expert, and technology writer Martin Cheek .
The sun annually provides more than 10,000 times the amount of energy we can use in a year. Currently, solar-produced electricity makes up less than 1 percent of the world’s production of power.
Exciting innovations: * A thermal technology that collects sunshine, through the strategic arrangement of hundred of flat mirrors, and re-directs it to a central receiver linked to a large solar power plant. * Commonplace applications of a technology originally developed for space exploration satellites: photovoltaic cells that absorb direct sunlight to generate electricity.
Drawbacks: The power of the sun depends on the seasonal climate and weather of a location. There’s also the obvious fact that sun power can be produced only during daylight hours. Although sunshine is free, solar energy is not yet cost competitive with fossil-fuel energy.
Outlook: To maximize the potential of sun power, scientists must develop more efficient and cost-effective energy storage systems and ways to transport power in a specific region.
About 2 percent of the sun’s energy received by our planet is converted into air motion. Today, the U.S. gets a little over 1 percent of its electric power supplied by wind energy.
Exciting innovations: * State-of-the-art windmills, featuring aerodynamic turbine blades inspired by modern airplane design.
Drawbacks: Aside from the inconsistent delivery of wind, ideal wind farm sites are often far from urban areas where demand is greater, thus requiring substantial money to construct transmission lines and substations to bring the wind-generated electricity to customers. Power harvested from the wind must also overcome common misconceptions: wind turbines are noisy (not modern models) and wind turbines massacre birds that get caught in the path of the spinning blades (more birds are killed by farming pesticides and free-roaming house cats).
Outlook: As turbine technology improves and mass production reaches a critical cost-effective level, wind as an energy resource will continue to see major growth opportunities.
Nearly three-quarters of our globe is covered by this versatile liquid substance. About 24 percent of the world’s electric power is currently produced by hydropower, the force of water. In America, hydropower makes up 12 percent of the generated electricity.
Exciting innovations: *An invention for an ocean-powered energy source applying the gravitational energy from the rise and fall of the tides. * A novel technology called ocean thermal energy conversion (OTEC), working on the principle that the sea collects most of the sun’s energy that shines on it.
Drawbacks: The massive dam structures necessary to hold back water are expensive and time-consuming to build. They also require continuous maintenance to make sure they are safe from a calamitous failure. What’s more, dams have a severe impact on the environment, often disrupting the local plant and animal ecology.
Outlook: Innovative approaches to harvesting ocean energy are still in their pioneering stages. With enough research and development, however, they might provide an important energy resource during the coming decades.
Consider a battery that collects energy from the sun and stores it in a system that creates no pollution, costs zero dollars to build, and recharges itself. This “battery” is green vegetation, the source of all biofuels, which power human beings. Americans are increasingly looking at the biofuels ethanol (an alcohol made from crops such as sugarcane and corn) and biodiesel (a vegetable oil made from crops including canola and soybeans) to power vehicles.
Exciting innovations: * Finding energy gold in America’s garbage: landfill sites featuring a buried web of perforated pipes that collect the methane released from decomposed vegetable matter and carry it to a power station, where it is burned to generate electricity.
Drawbacks: Many farmers are not yet using cost-effective techniques to grow biofuel crops. Money for water, fertilizer, and diesel fuel for harvesting equipment adds to the price of production and makes biofuels—especially corn-based ethanol—less competitive than fossil fuels. Also, critics warn that using fertile land to grow biofuel crops will lead to food shortages and raise prices at the supermarket.
Outlook: Overall, much more research and development needs to be done to implement the large-scale production of biofuels for our nation’s transportation needs. Yet, in the next few decades, life power will almost certainly help America gain its energy independence from fossil fuels while strengthening our nation’s agricultural economy.
Uranium, the element at the foundation of nuclear power, can be found extensively throughout the planet. It is 500 times more plentiful than gold. A modern nuclear plant produces about 1,000 megawatts of power to supply electricity to 400,000 homes.
Drawbacks: Nuclear energy is expensive to produce commercially. Nuclear reactors typically cost $3 billion or more to construct, and often face massive cost overruns. There’s the fear of a nuclear reactor meltdown made all too real with the catastrophic incident at Japan’s Fukushima Daiichi nuclear power plant. There is also the dilemma of how to dispose of radioactive waste without hazard to public safety or the environment. Another problem has to do with the threats to national security we face in the post-9/11 world. A nuclear power plant could be an attractive target for a terrorist strike.
Exciting innovations: * A special type of nuclear energy plant called a fusion reactor, which would generate power by fusing the nuclei of hydrogen atoms. If researchers can find a way to do this, safely and economically, we would have access to massive reservoirs of energy.
Future outlook: Although it holds tremendous promise for humankind, fusion power appears to be decades away. In the meantime, policymakers will continue to weigh the benefits of nuclear power against the costs and the dangers.
Natural hot springs, geysers, and erupting volcanoes give evidence to the tremendous energy supply kept deep within the Earth. Today, the world annually produces about 8,000 megawatts of electrical power from geothermal energy, out of which the U.S. taps 2,800 megawatts.
Exciting innovations: * Geothermal power stations. Usually small, these plants produce low cost steam energy without any toll on the natural world.
Drawbacks: Power plants can be built only in specific regions of our planet where molten rock is near enough to the surface to heat water. What’s more, these stations might trigger seismic activity along earthquake fault lines.
Outlook: With technological advances in geothermal systems, Americans might one day soon safely and economically tap into the energy of the tremendous heat in the heart of our planet.
The most abundant element, hydrogen makes up about 75 percent of the universe’s elemental mass. In a gaseous state, hydrogen can be combusted to run turbines to generate electricity.
Exciting innovations: * Technologies using the simplest life forms—algae and anaerobic bacteria—to split water molecules, thus releasing the hydrogen atoms from the oxygen, and to release the hydrogen contained in carbohydrates in the waste at food-manufacturing plants.
Drawbacks: A great deal of money will be needed to construct hydrogen-production plants and also to equip the world’s vehicles with fuel cells or hydrogen-burning engines. Another challenge is public concern about hydrogen’s potential volatility—fueled by horrific newsreel images of the hydrogen-filled passenger airship Hindenburg bursting into a fireball. However, hydrogen is significantly less flammable than either gasoline or natural gas.
Outlook: Despite its many benefits as natural, plentiful, nonpolluting energy medium, hydrogen has to overcome daunting financial hurdles in order to compete with fossil fuels.
ABOUT THE AUTHORS
Congressman Jerry McNerney, Ph.D., was elected to California’s 11th congressional district in November 2006. Reelected in 2008 and 2010, he is a member of the House Commit tee on Science, Space, and Technology, the Subcommittee on Energy and the Environment, and the Subcommittee on Investigations and Oversight. Prior to his time in Congress, he served as an energy consultant for Pacific Gas and Electric, Flow Wind, and The Electric Power Research Institute. He lives in Pleasanton,California.
Martin Cheek has worked as a journalist, specializing in science and the high-tech industry, for more than two decades. He lives in Morgan Hill, California.