What Are the Advantages and Disadvantages of Hydrogen as an Energy Resource?
Figure 6-21 lists the advantages and disadvantages of using hydrogen as an energy resource. The DOE has a goal of hydrogen energy providing 10% of all U.S. energy consumption by 2025. Even if this is only partially accomplished, it could (1) greatly reduce emissions of CO2 (unless most of the hydrogen is produced from carbon-containing compounds) and other air pollutants and (2) decrease U.S. dependence on oil imports. 6-5 GEOTHERMAL ENERGY How Can We Tap the Earth’s Internal Heat? Going Underground Heat contained in underground rocks and fluids is an important source of energy. Over millions of years, this geothermal energy from the earth’s mantle (Figure 2-9, p. 24) has been transferred to underground reservoirs of (1) dry steam (steam with no water droplets), (2) wet steam (a mixture of steam and water droplets), and (3) hot water trapped in fractured or porous rock at various places in the earth’s crust. If such geothermal sites are close to the surface, wells can be drilled to ext
