Read the following passage carefully, then write True (T) or False (F) for each statement.
The search for alternative sources of energy has led in various directions. Many communities are burning garbage and other biological waste products to produce electricity. Converting waste products to gases or oil is also an efficient way to get rid of wastes.
Experimental work is being done to derive synthetic fuels from coal, oil shale, and coal tars. But today, that process has proven expensive. Other experiments are underway to harness power with giant windmills. Geothermal power, heat from the earth, is also being tested.
Some experts expect utility companies to revive hydropower that provided one third of the elcctricity used in the United States fifty years ago, but today it supplies only 4 per cent. The oceans are another potential source of energy. Scientists are
studying ways to convert the energy of ocean currents, tides, and waves to electricity. Experiments are also underway to make use of temperature differences in ocean water to produce energy.
Question: Fifty years ago 4 per cent of the electricity in the United States was provided by hydropower.