Maximizing Hydropower Generation with Observations and Numerical Modeling of the Atmosphere

The ongoing drought in California seems to indicate that water managers are now paying greater attention to the use of numerical models of the atmosphere for short-term (7–10 days) weather forecasts. At the time of writing this article, a bill to Congress was being formulated that essentially aims to make the rule curves for large dams more adaptive through the use of numerical models for weather forecast. The use of such models is expected to reduce wastage of impounded water for dam managers and allow more flexibility in water storage and release during periods of anomalous/ off-season big droughts or floods. The purpose of this opinion article is to shed light on the current state of hydropower generation in the United States and discuss how the use of such numerical models of the atmosphere can also maximize energy production while conserving water or protecting against floods. As a clean and renewable energy source, hydropower has been extensively exploited by human beings for over 100 years. According to the 2014 Hydropower Market Report released by the Department of Energy (DOE), there are 2,198 active hydropower plants with a total operational capacity of 79.64 gigawatts (GW) in the United States. Hydropower accounts approximately 7% of the total power generated in the United States (Uria-Martinez et al. 2015). Unfortunately, hydropower generation capacity has stagnated the last two decades since the 1990s owing to lower economic growth (Hall et al. 2003), stricter environmental regulations, a stagnant energy market, and recent breakthroughs in the shale gas and oil industries (such as fracking). Nevertheless, hydropower remains the single largest source of renewable energy because of its relatively low-cost and sustainable characteristics. Compared to other renewable energy sources, hydropower has several unique advantages (USBR 2005). For example, a dam, which is normally considered an expensive investment to build, has a long service life spanning at least 50–100 years. Hydropower remains a more stable and durable source compared to wind or solar power, which are vulnerable to changing or unpredictable weather conditions. Hydropower production is relatively easier to ramp up or scale back depending on the transient nature of power demand. There are also no greenhouse gas emissions as byproducts during hydropower generation. A few U.S. states that are gifted with abundant water resources and topography have already harnessed hydropower as a clean and reliable electricity generation source, such as Washington, Oregon, and California (Fig. 1). Collectively, these three states have the largest installed hydropower capacity, which is equivalent to half of the total installed capacity across the United States. Among these three states, Washington has the largest share with approximately 30.4% of total hydropower generation in the United States, which also amounts to 70% of total electricity generation in the state of Washington. Oregon and California contribute 13.5% and 6.3%, respectively to the national grid in hydropower sector. Compared to the Northwest’s large amount of installed capacity, the Northeast has the most hydropower facilities, which typically are aged and small-capacity. The states that rely more on locally available hydropower apparently have lower electricity price compared to other states that have limited access to hydropower generating resources (UriaMartinez et al. 2015). Because building a new power plant is expensive, the low prices are usually in the states that have extensive power facilities where owners have already paid off the capital cost. The three northwestern states (Washington, Oregon, Idaho) are clear examples of cheap electricity pricing due to abundant hydropower resources.