2.4 Addressing current and future hydropower challenges
Facing future power challenges
Today, hydropower accounts for about seven percent of overall US energy consumption, however three states - Washington, California, and Oregon - possess more than half of the nation's hydropower capacity. In the Western United States, hydropower represents about 40 percent of the total energy capacity in the region.
As a result of increased power demand since Folsom's construction, the initial three generators were upgraded in 1972 from a nameplate capacity of 162 MW to 198 MW of power. In addition, current construction will raise the dam approximately 7 ft, providing more head for power supply. By 2050, California’s population is expected to grow from the 2005 level of 37 million to 55 million, and as a result the state will need roughly twice as much energy in 2050 as we use today (http://ccst.us/publications/2011/2011energy.pdf).
If you examine the simplified equation for hydropower generation, you should see that a doubling of power output would require a doubling of the discharge, Q (assuming that head, H, remains constant):
2 * P = (η 2* QH) / (1.181 * 10^4)
Figure 2.4a Current and projected doubling of future power demand, with associated outflow necessary to meet that demand (assuming H remains constant).
Click on the button below the graph to display the average monthly inflow into Folsom dam. Compare the inflow (dotted purple line) with the current level of outflow (solid blue line) and outflow necessary to meet a doubling of demand (dashed blue line). What do you think about the capability of Folsom to meet the projected doubling of power demand?
Increasing hydropower capacity
Only about 3 percent of the roughly 79,000 dams in the United States have hydropower plants and can generate electricity. One approach for meeting projected future power demands involves adding hydropower capacity to existing dams. A 2011 report by the Department of the Interior shows that the department could generate up to one million megawatt hours of electricity annually by adding capacity at 70 of its existing facilities.