Various forms of energy consumed in the United States since 1850. QBtu means quadrillion British thermal units 100 sE8面i Hydroelectric A:5~-…- Nuclear electric Geothermal 18501860187018801890190019101920193019401950196019701980199020002010 Figure 1.1 Various forms of energy consumed in the us since 1850Various forms of energy consumed in the United States since 1850. QBtu means quadrillion British thermal units. Figure 1.1 Figure 1.1 Various forms of energy consumed in the US since 1850