One question I have is whether there are inexpensive things that can be done to raise electrical production from existing hydroelectric sources--does anyone know?

A question I raised with Bureau of Reclamation engineers at a hydro-electric conference a few years ago.

Generally speaking, US Gov't dams have 1920s to 1950s/1960s design turbines, said turbines are poorly maintained (wear on blades reduces % efficiency below design %), and the ratio of "spill water" (water let over dam during high water without producing power) is based on economics of when the dam was built.

They estimated that the US Gov't could easily get 5% more electricity with economically justified steps. (Raise maintenance to a high standard, use newest tech in generators & turbines (say 2% improvement since 1950s), add smaller generators for low flow & to reduce spill##) Give new marginal large hydro power the same value as wind and that % grows.

Example, house power (internal use) at Hoover Dam is a couple of Peltons (1 or 2 MW from vague memory) that have not been touched since built. My SWAG is rebuilding them could up efficiency at least 10%.

Ontario is in midst of major improvements at Niagara Falls (Sir Adam Beck)#. 14.4 m diameter tunnel will reduce friction losses, new/enlarged power plant will reduce the time that water spills unused (above requirements ) from 40% to 15%.

BTW, I strongly urge a recalculation of the water spilled for tourists at Niagara Falls. Reduce hours & days of max spill flow, reduce the max spill flow, reduce the overnight spill flow, enlarge Sir Adam Beck (Ontario) even more and enlarge Robert Moses (New York). Reducing spill at Niagara Falls (now 4+ GW of hydro) is cheap, easy, quick renewable energy and = to one years new wind (roughly).

Best Hopes for more Hydro,

Alan

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http://www.opg.com/power/hydro/new_projects/ntp/index.asp

## Example. Dam has two 40 MW generators. At low flow, they either shut down or operate at dismal efficiency. Add 6 MW generator. More efficiency at low flow and an extra 6 MW when water would otherwise be spilled. Relatively easy (sometimes) to add small generator to powerhouse with two large generators.

Also 40 MW + 6 MW can be more efficient than 2 x 40 MW at some mid-range flows.

I believe that the article missed that Manitoba has 5 GW of new hydro they are actively shopping. Wisconsin bought 800 MW of that 5 GW. Their scheme uses the "other Great Lake" Lake Manitoba as the storage reservoir.

Yes, I think upgrade of old infrastructure is the real story here. Most of what is out there is very old technology. In Minneapolis, some of the turbines are a century old. Estimates are that replacing those with the latest technology would yield more new net energy than would damning up more of the Mississippi. I suspect that this is true in many areas around the country.

Hydro is not renewable in exactly the same sense as wind and solar. Damns, unlike wind or sunlight, silt up. And damage is not only to ecosystems but often to human lives and cultures.

A possible use of existing hydro that the author didn't mention, as far as I could see, was as storage for other renewables that are intermittent. Filling the reservoir when it is windy and sunny and draining it when it is neither is an essentially "free" way to even out the intermittency that is so famously put forward as a drawback to these true renewables.

What seems to be a permanent drying of the west will make hydro less and less viable in much of that part of the country. How low is Lake Powell now? Over 100 feet?

From a 2003 news article about TVA's Apalachia Dam upgrade:

The improvements at Apalachia are part of an $875 million program to upgrade 92 generating units at 26 of TVA’s 29 hydroelectric dams. Begun in 1992, the program is halfway to its goal. When completed in 2015, it will increase the life of the upgraded plants by 50 to 60 years and add about 700 megawatts to the TVA system.

This is what should be done to all federally owned hydropower plants.

What was the MW for installed TVA hydro before this program ? Any estimate on increased MWh ?

Thanks,

Alan