Grand Coulee: The Grande Dame

Grand Coulee, the second largest dam in the world stands 550 feet tall, is 500 feet thick at the base, and just 57 feet shy of a mile long. She has 6.8 million kilowatts of power capacity from her 33 generators producing about 21 billion kWh of power each year. That is ~10% of all the hydroelectric energy produced annually in the US! She is a peaking plant, but her response when called on is far from any sneaky-peeking-around-the-corner one. At the beck and call of Bonneville Power and Light, it takes just 20 seconds until she explodes into life with one or more of her 800 MW generators belching out a 40-foot diameter bubble of blue air as the incoming water expels the compressed air primer.

While it took 12 million cubic yards of concrete, about 8,000 workers, and 14 years to build her, it was really Mother Nature that did the heavy lifting in digging out the 1.27 million acre-foot lake when she ruptured prehistoric ice dams and flooded the entire Columbian basin with glacial Lake Missoula.

It would cost some $7 to 8 billion to build Grande Coulee Dam today. That’s about $1.10 per Watt of capacity – very attractive from a cost standpoint no matter how you slice it! However, Grand Coulee’s construction flooded more than a little bit of land…80 times the area of Rhode Island! So, dams like this, with the drastic environmental consequences they impose, are most unlikely to be built anymore. As such, hydropower is developing a new face — one that is much more in sync with the environment. Small, distributed run-of-the-river diversions selectively placed to deliver power with ultra-low ecological impacts are, we believe, the wave of the future. LPS’s modular hydropower systems can make such projects economical.