可再生能源

风和水的运动, 太阳的光和热, 植物中的碳水化合物, and the warmth in the Earth—all are energy sources that can supply our needs in a sustainable way.

A variety of technologies are used to convert these renewable resources into electricity. Each comes with its own unique set of 好处 and challenges; collectively, they represent our best hope in the fight against climate change.

太阳能 energy—power from the sun—is a vast and inexhaustible resource that can supply a significant portion of global electricity needs. 在美国, over two million households already have solar panels on their roof; utilities and companies across the country are also investing in solar farms to capture the sun’s energy at a larger scale.

太阳能基本上是无碳的. A small amount of pollution is created during the manufacturing process, and disposal is an ongoing challenge; however, 所用的燃料(太阳)是免费的, 是丰富的, 而且不会造成污染.

风 turbines harness air currents and convert them to emissions-free power. Plentiful and inexhaustible in the United States and around the world, wind power is one of the fastest growing renewable technologies and has the potential to provide a significant portion of our electricity needs.

目前, 风能在美国电力中所占比例相对较小, though it’s expected to grow as more utilities invest in wind farms, and as offshore wind—wind turbines located in the ocean—becomes more common.

而不是能源本身, energy storage technology is a critical component for creating a low-carbon electricity system. The technology takes various forms—older facilities use pumped water, while newer systems deploy lithium-ion batteries—but the fundamental goal is always the same: storing electricity to use later.

Just as the invention of refrigeration changed how people consumed food—allowing them to 存储它 before eating—energy storage can revolutionize how we use energy. 它让我们在最便宜的时候生产清洁能源, 存储它, 在需要的时候把它放回电网. Using storage in conjunction with solar and wind energy helps ensure that power is available even when the sun isn’t shining and the wind isn’t blowing.

在美国, large-scale storage operations are still relatively rare. But as the amount of wind and solar grows—and the number of coal plants drops—storage will become ever more important for an 高效清洁电网.

可再生能源不仅限于太阳能或风能. Geothermal plants gather heat from the earth to generate steam and produce electricity. Hydroelectric dams exploit the movement of water to turn turbines. New hydrokinetic technologies harness the power of ocean’s currents and tides. And bioenergy—the burning of biomass to generate power—may offer a sustainable use for crops and waste wood.

The key thing tying all of these technologies together is their ability to create electricity with minimal harmful side-effects. 替代能源——化石燃料——既不可持续也不安全.