NARRATOR: Most of the electricity we generate comes from fossil fuels.
Fossil fuels, like coal, oil, and natural gas, were created over hundreds of millions of years from decaying prehistoric plants and animals buried underground. And even though they’re still relatively abundant, the more we consume, the less we have, and the more difficult and expensive they are to extract.
On top of that, burning fossil fuels releases greenhouse gases and other pollutants that threaten our health and the long-term well-being of our planet.
What we need are alternative energy sources—that won’t run out and will have less of an impact on the environment.
The types of alternatives people most often talk about are “renewable” energy sources. But what exactly does that mean?
A renewable is a source of energy so plentiful that it might as well be limitless as far as humankind is concerned. So, no matter how much of it we use, there will always be more available.
The most obvious renewable is our planet’s greatest energy resource: the Sun. The Sun has produced light and heat for more than 4 billion years and is expected to continue to burn brightly for billions more.
The energy our planet receives from the Sun has a tremendous influence on what happens here on Earth. Not only would it be dark and cold without it, but life wouldn’t exist. And without the Sun, the wind wouldn’t blow, and rivers and ocean currents wouldn’t flow either.
Most renewable energy technologies use energy from the Sun in one form or another. For example, solar technologies collect the Sun’s energy directly, in the form of light or heat. Other technologies—such as wind, hydroelectric, and biomass technologies—take advantage of the Sun’s energy after it’s been converted into the kinetic energy of flowing air and water, or the chemical energy stored in plants.
Besides the Sun, only two other energy sources are plentiful enough to be considered renewable. Both geothermal energy—the naturally occurring heat coming from Earth’s core—and tidal energy—the movement of rising and falling ocean tides caused by the moon’s gravitational pull—have the potential to be steady sources of energy—no matter how much we use.
At the moment, solar and wind power look like the most promising renewables. But scientists and engineers are trying to find ways to put all of these limitless supplies of energy to work, to reduce our reliance on fossil fuels and create a cleaner, more sustainable future.
Tidal power footage courtesy of Ocean Renewable Power Company.
ARCHIVAL MATERIAL CREDIT
Ocean Renewable Power Company