"onesixth" - 1 õppematerjal

Renewable energy

resources. Hydropower plants can cause low dissolved oxygen levels in the water, which is harmful to river habitats. Hydroelectric power plants don't work for a very long time. Silt, or dirt from a riverbed, builds up behind the dam and slows the flow of water. Geothermal energy Geothermal energy is the heat from the Earth. It's clean and sustainable. It can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about onesixth of the carbon dioxide that a relatively clean naturalgasfueled power plant produces. Unlike solar and wind energy, geothermal energy is always available, 365 days a year. It's relatively inexpensive. There are three types of geothermal power plants: dry steam, flash, and binary. Geothermal energy is generated in over 20 countries. The United States is the world's largest producer. In Iceland, many of the buildings and even swimming pools are heated with geothermal hot water.