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0 pointsghshephard11y ago0 comments

Just a pedantic note - I don't think you would price Hydro Plants power stores based on GW-Hr capacity (that's just the size of the lakes/water reservoirs, which might store petawatt-hours of capacity depending on the geography), but on the rate/number of pumps, right?

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dragontamer11y ago· 1 in thread

Yes, due to Pumped Hydro's benefits... the major cost is the size of the generators.

A single 100MW turbine can store weeks-and-weeks of power if drawing from any small lake. But for it to be useful to a lot of people, you probably need to build a gigawatt scale turbine.

With that said, the Bath County generator is the largest in the world, and is close to 30 GW-hr of capacity (3GW of power. Yes, it can empty the lake in 10 hours, and refill it in another 10 hours)

ghshephardOP11y ago

I just lost 45 minutes reading about the Bath County generator - that has 50% more generation than Hoover Dam. Amazing.

In terms of Storage Capacity of a Dam, I checked: http://www.nps.gov/lake/learn/nature/storage-capacity-of-lak...

The water available for power generation starts at 1050 feet, and goes to 1221.4

The Capacity goes from 11,474,857 acre feet to 31,141,756 acre feet. So Hoover Dam has an operational storage of 19,666,899 foot acres

The Turbines have a capacity of 2,080 MW. From: http://www.usbr.gov/lc/region/pao/brochures/faq.html#capc we discover

What is the maximum capacity of these works?

About 118,000 cubic feet per second: 32,000 cubic feet per second for power generation and 86,000 cubic feet per second of valve discharge. One cubic foot per second of water equals nearly 7 gallons passing a given point in one second.

So, dividing 19666899 foot acres / 118000 cubic feet/second = 6,408,487,134,720 gallons / 882,701.2987 gallons/second = 7,260,085.76644 seconds = 2,016.69049 hours (only 12 weeks)

So, the operational storage capacity of Hoover dam is 2 GW * 2000 Hours = 4 Terawatt Hours. I realize these are entirely different projects, but it's interesting to get a gut sense of how incredibly large the Bath County generators are - not only do they generate power going down - they can also pump that water up.

Incredible - wonder of the world.

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