California drought means less electricity from hydropower


When California needs extra power, it generally imports hydropower from the State of Washington. This year though, a bit ominously, not only is there a California drought, the Pacific Northwest is also short on water. This means less hydropower for everyone.

Since 1989, hydroelectric dams have accounted for varying portions of electricity generated within California, from 11% in 1992 (reflecting a low water year) to a high of 28% in 1995 (a high water year).

Absent output from in-state hydroelectric resources, CAISO [California Independent System Operator] has tended to import more power from neighboring regions as well as increase output from thermal sources of generation. Much of the imported power comes from hydroelectric dams located in the Pacific Northwest, which is also experiencing low water supply.

Big hydropower and the Renewable Portfolio Standard

Quebec hydropower
Quebec hydropower

Should big hydropower be counted as renewable energy towards meeting a Renewable Portfolio Standard for a state? It generally isn’t, but that could be changing as states scramble to meet their RPS goals.

Construction of big dams is indeed destructive to surrounding area. Really massive dams can heighten the risk of earthquakes. However, virtually all potential sites for big hydropower in the US are already being taken so few if any new ones will be built. Hydropower certainly is renewable, so why not count it as such?

One problem is that if big hydro is counted as renewable, then states will need far less new renewable energy to meet goals and thus less development of renewables within states. In New England, big hydropower is indeed available, but it comes from Canada. New transmission lines will need to be built. NIMBYs don’t like that.

The Connecticut Senate just passed a bill saying large hydro, including Canadian power, can be used to meet their RPS. The governor of New Hampshire strongly opposes it.

All across the U.S., state governments are wrestling with their renewable energy standards, weighing the costs associated with renewable energy economic development against the perceived added electricity costs to ratepayers.

Run-of-the-river hydropower

Chief Joseph Dam, WA. Run-of-the-river hydropower. No sizable reservoir. Wikimedia Commons

Small hydro may have a promising future, especially run-of-the-river hydropower. Dams are not needed, eliminating the major problems of destruction of habitat and large areas by flooding plus the inevitable silting up of dams. Instead, water is diverted to power turbines then released downstream.

The power generated by run-of-the-river hydropwer compares favorably to wind and solar.

“When utilities start comparing our output with that of small wind or medium sized solar projects, their eyes open wide and they become quite interested because they realize that we are generating much more power, and power that is reliable and predictable”

Hoover Dam. Lake Mead. Big hydropower

Standing on Hoover Dam

The turbines at Hoover Dam have a nameplate capacity of 2.08 GW, making it one of the largest hydro plants in the country and equal to nuclear and big coal plants. The Dam certainly is immense, 650 feet long and 229 feet tall. Lake Mead stretches for 110 miles behind it.

Who are the principal contractors for [Hoover Dam] energy?

The States of Arizona and Nevada; City of Los Angeles; Southern California Edison Co.; Metropolitan Water District of Southern California; California cities of Glendale, Burbank, Pasadena, Riverside, Azusa, Anaheim, Banning, Colton, and Vernon; and the city of Boulder City, Nevada.

Interesting, isn’t it, that much of the power goes to southern California. Power (and water) in the US west is like that. It often comes from hundreds of miles away.

Hoover Dam has all the cheery ambience of a grumpy military encampment. Armed guards inspect your vehicle before you enter. Signs in the parking lot warn that video cameras are everywhere, specify what size packs can be carried, and sternly admonish that no knifes are allowed. This presumably to prevent someone with a Swiss Army Knife  from hijacking the dam. Yes, I understand the need for security but it was way too militarized for me, as increasingly are many of our public facilities.

Hydro does indeed create clean energy but at the cost of flooding huge swaths of land. However the resultant lakes can also become popular recreation areas as Lake Mead has. After several decades though, lakes behind dams start to silting up. Lake Mead “lost about 15 percent of its capacity between 1936 and 1964 due to silting–more than five million acre-feet.” For this reason, big hydro is viewed suspiciously by some renewable energy advocates. As for building new big hydro plants, this is probably a moot question, as most of the good locations are already taken.

Lake Mead bathtub ring. Water levels are low, but better than two years ago
Lake Mead marina. It closed two years ago due to the drought.