Furthermore, many people would object to having large tracts of land covered with solar cells. Under current economic and technological conditions, solar cells and solar heating technologies will only supplement, and not replace, other energy sources. Biomass Biomass includes wood, grain, sugar, crop residues, and municipal garbage. The wastes may be burned in power plants or converted to methane or liquid fuels. Unfortunately, mercury, cadmium, lead and other toxic heavy metals are often present in garbage and municipal waste incineration plants often release mercury into the atmosphere or produce an ash that is toxic in these metals.
Water falls through the dams and rotates shafts in turbines to produce electricity.
Unfortunately, hydroelectric dams often disrupt wildlife in and along rivers. For example, dams along with Columbia River of Oregon and Washington State have greatly cut salmon populations. The dams prevent the salmon from migrating up and down the river and spawning. The proposed dam will be 610 feet high and will span 6,864 feet across the valley of the Yangtze River. Over the years, the flooding Yangtze River has killed millions of people.