Washington State: Big Hydro Development

At around the turn of the last century, dam technology was reasonable for energy generation. Given the large water resources in Washington, hydroelectric power became the clear best choice for energy generation.

First dam (Mossyrock, still in operation) had a Nameplate capacity of 300 Megawatts and was built in 1905. (Note: Nameplate capacity is total potential capacity; actual operation usually produces about a factor of two less power due to strong seasonal fluctuations in water flow).

Given the population at the time, 300 MW is a large unit capacity - more on this later.

Hydroelectric growth is fairly slow (see graph below). Between 1905 and 1931, 8 new dams were built which raised the total nameplate capacity to 1000 Megawatts in 1931. Still, at that time, this was sufficient to support a regional population of 2 million.

We will soon enter the era where single dams are now at least 1000 MW.

In 1933 the Rock Island Dam (near Chelan) (625 MW) on the Columbia is completed:

In 1938 The Bonneville Dam is completed (1100 MW); second power house added in 1982 to produce another 1100 MW. This dam would be come a high priority WW II Japanese air target in any mainland attack.

In 1941 the gigantic Grand Coulee Dam first came on line with a nameplate capacity of about 2000 MW; since then two new powerhouses have been added bringing it to a total nameplate of 6800 MW.

The Grand Coulee Dam was the largest concrete structure ever built. This barricade, which raises the water surface 350 feet above the old riverbed, is 5,233 feet long, 550 feet high, and contains 11,975,500 cubic yards of concrete.

This structure was essential to the infrastructure of the American West and the Bureau of Land Reclamation. When Grand Coulee is finished, the total hydropower nameplate capacity in Washingtion is now 10000 MegaWatts. Also at this time, the population is 2.4 Million people. Now the population is closer to 7 million and the amount of hydropower has not scaled with population growth.

Despite its age, Grand Coulee Dam is still the 5th largest hydroelectric facility in the world:

An Aside: Below are shown the other large dam projects in the world. With the exception of the three gorges dam, the other ones are all located in tropical climates. Instead of reducing greenhouse gas emissions, these dams end up being net GHG emitters due to all the biomass emissions (mostly methane) that are associated with large pools of relatively stagnant water (e.g. the dam reservoir) when they develop in the tropics. Very few people are aware of this, let alone actually believe it when I say it in class but there is Plenty of scientific evidence to back up this claim.

  1. Three Gorges @22,500 MW (!!!) multiply by about 9 to get US capacity addition equivalent of 200,000 MW

  2. Itaipu in Brazil/Paraguay border @14,000 MW

  3. Simon Bolivar in Venezuala @10,200 MW Net GHG Emitter!!

  4. Tucurui Brazil @ 8370 MW Net GHG Emitter!!



Now back to our regularly scheduled program: By 1959, 4 other large Dams are constructed on the Columbia river raising the total nameplate capacity to 16000 Megawatts. By 1968, 4 more Dams had been added (none have been added on the columbia since) and total nameplate capacity is now 23000 Megawatts. Note that apparent salmon declines began in the 1980s, long after the dam network was in place.

From 1968 to 1975, 3 large Dams are constructed on the Snake River (in Washington State - there are other dams in Idaho) bringing the total hydro nameplate capacity to 25600 Megawatts, essentially what it is today. In Graphical Form, this history looks like the following:

That basic waveform is duplicated when one consider all sources of power generation in washington state. At present, hydro in WA makes up about 65-70% of its nameplate power generation.



For many decades Washington state produce far more power than it needed relative to the size of its population. Therefore it was a net exporter of electricity (mostly to California). However, those days are long gone due to increased population in WA and reduced streamflow/snowpack. WA state simply no longer produces excess power for export.