Base-load power refers to electric generation resources that operate continuously and are available 24 hours a day. Base-load power plants provide reliable power to maintain a large-scale electrical grid and generally shut down only for scheduled maintenance or emergency repairs. Typically, they require large upfront capital investments but provide reasonably low-cost electricity. In contrast, peak-load power plants generally run only when demand for electricity is high, such as during summer afternoons when air conditioning loads are high.
Idaho has historically relied on hydropower and coal-fired generation for its base load, supplemented by natural gas generation. Each plays a significant role in supplying stable power to Idaho customers and, collectively, enabling Idaho to enjoy relatively low electricity rates. As the state requires more power to meet its growing needs, it is important to understand the status and prospects for future development of each.
Hydroelectric power has historically supplied the bulk of Idaho's power, contributing significantly to the state's low electric rates. Development has been unable to keep up with Idaho's growing demand for energy, however, and hydropower today provides only 48 percent of the state's electricity. Opportunities for further development still exist, but environmental considerations represent a significant obstacle to future large-scale projects. As interest in noncarbon fuels grows, opportunities to develop additional hydropower resources could emerge. Its future in Idaho could include, but is not limited to, low-head operations, pumped storage and in-stream technologies.
Coal-fired generators located in other Western states provide 42 percent of Idaho's base load. To reduce transportation costs, coal-fired plants are often located near mining operations. Because these sites are miles away from large load centers, long-haul transmission lines are necessary to move coal-generated electricity.
The future of coal as a base-load power source is uncertain because of greenhouse gases associated with its use and the possibility of increasingly strict regulatory requirements. The cost to produce "clean" coal is unknown and poses significant risk to investors. As a result, the Idaho Legislature has deferred action on siting new coal-fired plants in Idaho.
Natural-gas plants generate a relatively small portion of Idaho's electricity, providing peak-load and short-term, base-load power. Natural gas plants produce fewer greenhouse gases than do coal plants and are easier to site and build; therefore, natural gas appears to be the fuel source of choice to serve short-term base-load needs. On the other hand, its price may continue to climb as more utilities choose to supplement their base load with natural gas plants.