Frequently Asked Questions About Renewable Energy

What is renewable energy?
Renewable energy is energy that comes from sources that are naturally replenished.

What are some common forms of renewable energy?
Ultimately, all renewable energy used on earth is solar energy. Solar thermal energy and photovoltaic devices make direct use of solar radiation, but wind, hydroelectric, and biomass energy are also driven indirectly by the sun. Geothermal energy is technically nonrenewable, as it is driven by limited steam reservoirs in the ground, but it is usually classified as renewable due to its wide perception as a clean way to generate electricity.

What are some advantages of using renewable energy?
Petroleum and natural gas are expected to become scarce in the coming decades. Coal and uranium offer longer-term energy supply, but they too will eventually run out. In addition, all of these fuels produce environmental impacts that threaten our health and quality of life. Renewable energy sources are clean and will not run out in the foreseeable future. Because of their consistent long-term availability, renewable energy resources are also inherently more stable in price than fossil fuels. Many renewable energy technologies are modular and portable, making them practical anywhere from a city center to a remote mountaintop. And renewable energy is naturally decentralized, offering us a safer and more robust alternative to today's giant-scale power plants and their vulnerability to fuel price swings, natural disasters, and terrorism.

What's the connection between renewable energy and hydrogen and fuel cells?
At SERC, we specialize in developing systems that integrate renewable energy with hydrogen and fuel cells. Renewable energy is naturally intermittent. Hydrogen provides a means to store renewable energy for times when the sun doesn't shine or the wind doesn't blow. When these resources are available, they can be used to generate electric power for immediate use, with surplus energy being converted to hydrogen using an electrolyzer. The hydrogen is stored until renewable energy is unavailable, at night or on cloudy or windless days. A fuel cell then converts the stored hydrogen to electric energy. Hydrogen thus offers a solution to renewable energy's key deficiency, i.e. that it's not always available when we need it. To learn more about the connection between renewable energy and hydrogen and fuel cells go to the solar hydrogen cycle web page.

Isn't renewable energy too expensive to be commercially viable?
On a dollars-per-kilowatt-hour basis, renewable energy is still generally more expensive than fossil fuels, although its cost is decreasing all the time. In some energy markets, new wind turbines are already less expensive than new conventional power plants. As fossil fuels become scarcer in the future, renewable energy will be more economically attractive. While recent growth in the renewable energy industry is in part due to government and utility incentives, it must be noted that conventional fuels also benefit from direct and indirect subsidies, including externalization of the social costs created by polluting power plants.

Can I meet all my energy needs with renewable energy?
It is feasible for most homes to generate all or most of their energy on-site using photovoltaics and other technologies. However, bear in mind that a dollar spent on making your home more energy efficient is money better spent than the same dollar putting solar modules on your roof. If you are considering installing renewable energy equipment, work first to make your home as energy efficient as possible.

Renewable-powered transportation is another matter. In wealthy countries, where nearly every household owns at least one car, it is probably not realistic to anticipate that renewable energy will enable us to continue with business as usual. A more modest and efficient transportation system might be sustainably run on renewable energy.

Could we really run our whole global economy on renewable energy?
The same point holds true on a global scale -- the more energy-efficient we make our society, the more feasible it will be to convert to an all-renewables economy. "Sustainable" as renewable energy may be, it cannot indefinitely support unsustainable growth in global energy consumption. Wealthy countries have the most room for improvement: per capita energy consumption in the U.S. is six times that of the rest of the world, and over ten times greater than in developing countries. Some good news: the surface of the Earth receives ten thousand times as much solar energy each year as is consumed by all human activity.

Is it true that a photovoltaic module can't generate as much energy in its lifetime as it took to manufacture it in the first place?
This claim is often heard from renewable energy skeptics. If true, it would put the sustainability of PV power in considerable doubt. A study by the National Renewable Energy Laboratory, however, determined that PV modules require only one to four years to produce the total energy consumed in their manufacture, depending on the type of module. Comparing this to an expected 20- to 30-year module life expectancy suggests that PV module production is a net energy generator. The Solarex Corporation built a photovoltaic-powered "breeder" PV module manufacturing plant in Frederick, Maryland in 1982, demonstrating how PV power can be truly self-sustaining.

Do wind turbines kill birds?
This is another area of concern for people who worry that renewable energy is not as sustainable as it's made out to be. It has been documented that certain types of wind farms can present a hazard to some species of birds, depending on location and other factors. However, wind turbine and tower designs are evolving to address this issue by reducing rotational speeds and eliminating tower features that make the turbines attractive places to roost. Siting of new wind farms takes bird habitat and migration routes into account. It's worth noting that vehicles reportedly kill over 1,500 times as many birds in the U.S. each year as do wind turbines.

The underlying point raised by these last questions is a valid one: all means of producing energy have some environmental impact. Scientists and engineers need to keep working to minimize these impacts through technical solutions, but the real onus is upon the rest of us to use energy efficiently and wisely.

See our links page for information on where to explore renewable and sustainable energy topics in greater depth.