The chemical industry uses energy both to supply heat and power for plant operations and as a raw material for the production of petrochemicals, plastics, and synthetic fibers. According to the most recent Manufacturing Energy Consumption Survey (MECS), the U.S. chemical industry consumed about 5.3 quads (quadrillion Btu, or 10¹⁵ Btu) of energy in 1994. This represents about 7% of domestic energy use and about 25% of all U.S. manufacturing energy use. Energy purchases cost the industry about $18 billion in 1994 [MECS 1994], about 5% of the value of shipments that year.