Raquel Baranow - Flickr

Hydropower Wanes Amid a Dry Year in the American West

A Western drought year spells trouble for the region's usually reliable hydropower

By guest author Paige Lambermont
August 10, 2021

The Western region has had an incredibly dry year, a fact which is obviated by the fires that are currently raging across much of the region. There are currently active fires in California, Oregon, Washington, Idaho, Wyoming, Montana, Utah, Colorado, Arizona, and New Mexico, and the smoke from the fires has drifted all the way to the East Coast. Although fires are one of the most visible consequences of drought years, they’re far from the only problem that they cause. Hydropower generation is greatly affected by the water levels in reservoirs, rivers, canals, and other water sources.

Usually, a stable source of electricity, the southwest’s hydro plants have increasingly had to accommodate new periodic energy generation by wind and solar generators, making hydroelectric generators less consistent and require more maintenance as production is ramped up or down to meet demand.

The impact of the unusually arid year on hydropower is already clear, with the May data from the Energy Information Administration showing a 27.1 percent year-over-year decrease in hydropower generation in the west.

This decrease is concerning because hydropower is usually a reliable generation source, and power generation problems in some western states, California most notably, have been a growing concern in recent years. The state has gone as far as to get approval from the Federal Energy Regulatory Commission (FERC) to intercept power traveling to other states on its transmission lines when the state is in an energy pinch. This new ruling will stave off blackout possibilities in the near term, but will almost certainly be contested by nearby states including Arizona who would be negatively impacted by the new FERC rule. 

Hydro is a mainstay for grid reliability as intermittent sources like wind and solar play an expanded role in the region. Many hydroelectric power generation sources can move between no output and maximum power output quite quickly, allowing them to be utilized when the wind doesn’t blow or the sun doesn’t shine. States with high levels of wind and solar grid penetration rely on hydropower and other cycling resources like natural gas to quickly make up the grid shortfalls created by the problem of intermittency. Although some portion of the year-over-year decrease in hydroelectric power generation may be attributable to an increase in wind and solar penetration, drought conditions in the western U.S. are a primary driver of the decrease in output

And, as water levels fall short, decreased hydroelectric availability will create additional issues for states already experiencing power problems.

The dry conditions are posing greater challenges for some power generating facilities than for others. California’s fourth-largest hydropower generator, the 644 MW Edward Hyatt Power Plant which uses water from Lake Oroville, is projected to shut down due to low water levels in the lake for the first time in its history this year. 

Another example of this is Nevada’s Hoover Dam. The iconic structure on Lake Mead has a normal capacity of 2,074 MW, but at present water levels, its output is 25 percent lower at 1,567 MW. Each foot that the lake’s water level lowers results in a loss of about 6 MW of capacity. At a water level below 950 feet, the dam wouldn’t be able to generate any power at all (On August 3rd the water level sat at 1,067 feet).

The May data already showed a 27.1 percent decrease in western power generation, but drought, and all that comes with it, has continued across much of the west. As fires and irrigation remain top-of-mind issues, it is also important to take into account the other consequences of water shortages, especially the threat they can pose to already strained power grids.

Dry conditions create economic issues in addition to their more visible impacts, but unstable grids pose a serious threat to energy availability and affordability both at the residential level, and in the commercial sector which cause cascading cost consequences across industries.

A stable grid can handle climate insecurity, but when politicians choose winners and losers, some people lose power.

This piece was produced by Paige Lambermont, a Policy Associate at IER