hydropower

Is tidal energy a possibility in Puget Sound?

Seattle may not be solar-panel savvy or a wind-power winner, but could it be a viable source of tidal energy? That's what a number of scientists, governmental bodies, and public utilities folks are trying to figure out. And they shared their progress, and their plans for the future, with attendees at the Puget Sound Georgia Basin Ecosystem Conference in Seattle.

Generating tidal energy involves taking advantage of the rhythmic rise and fall of tidal currents by planting some sort of windmill-ish technology below the surface of the water, especially in areas where water flow is restricted into a narrow passageway, such as an inlet.

Like their land-based brethren, though, these underwater windmills could have environmental impacts that include affecting salmon and marine mammal migration, disturbing bottom fish habitat, and impacting fish harvests. But just how much of an impact would tidal power have on the Puget Sound -- and how would that balance with the benefits of renewable energy generation? Well, unfortunately, no one really knows. There are limited studies on actual impacts -- and limited on-site experimentation as well.

CAP releases interactive U.S. map of per-capita emissions

The Center for American Progress has an interactive map up, showing per-capita CO2 emissions from U.S. states. No big shock — the big emitters are the big coal users, and the low emitters are the big hydro users. The point CAP is pushing is this: “The 10 cleanest states based on per capita emissions … […]

Verdant Power shows it’s got the RITE stuff

    This is a guest post by my travel partner, Todd Dwyer, head blogger for Dell’s ReGeneration.org. —– Four times a day, without fail, New York City’s East River will change directions. It’s been doing that for ages and will continue to do so long after we are gone. The tides are a constant, […]

‘Run of river’ projects set for a boom?

When I bought my house, I didn't realize that the stream that travels its acres is perennial and spring-fed ... which seemed like the perfect scenario for a microhydro generator. These units make a lot of power all day and night, unlike solar and (usually) wind. It works by siphoning off a portion of water to run through a pipe, then through a generator, and then back into the creek. Voilà! So I did the measurements and found 140 gallons per minute, which is about enough for the purpose, but less than a 20 foot drop in elevation, which is the killer. Microhydro usually requires either high head or high volumes to pencil out, but I have barely the minimum of each.

At best, it would account for 20 percent of the house's needs -- not quite good enough for me to think too deeply about the capital expense or the fact that the town's Conservation Commission probably wouldn't allow the use. Other nearby commissions have also been unfriendly to residents employing or proposing it on their properties, even though microhydro is not a consumptive use and requires no dams.

I have some small consolation, though, knowing that all the electricity in this portion of my county's grid is already 100 percent hydro, due to its proximity to the Deerfield River (one of the most developed rivers in the country, with small dams working up a good portion of its length from southern Vermont into western Massachusetts). Which is nice, in a way: the next nearest power plant to my community uses coal from a mountaintop removal mine in Appalachia, so this somewhat green power is welcome.

So I was interested to see news that small hydro is possibly on the verge of a boom, with new estimates of 30,000 MW of potential small hydro capacity in the U.S. alone. This would build on small hydro's ubiquity in the industry, if the article is right that 80 percent of the existing hydro projects in the U.S. are low power (under 1 MW) or small hydro (1 to 30 MW).

The industry is saying it can get more power out of falling water without any more dams:

Some of world’s purest water and pristine ecosystems under threat

International Rivers is fighting to preserve biodiversity against the large companies that want to dam this river:

The Pascua River, in Chilean Patagonia, is one of the most pristine and unknown regions on the planet. Why? For one, it is extremely difficult to even get there. Secondly, once you actually see the river, doing anything other than standing with your mouth open and hands over your ears is virtually impossible. This is a rip-roaring, roller-coaster of a river with rugged, impassable canyons and unsurvivable Class 6+ whitewater.

Grand Canyon flood supported by feds, criticized by park officials

Federal flood control managers will let loose a rush of water through the Grand Canyon on Wednesday, which the feds say is necessary to restore sand banks and side pools, and National Park Service officials say is unnecessary, aimed at pleasing hydropower companies, and could irreparably destroy the habitat it’s meant to restore.

And you thought the subprime mess was bad for the homebuilding industry

Well, this is certainly bad news for anyone in the Phoenix real estate market. 

Dam it all

Tucuruí, Brazil's second largest dam has many times the GHG emissions of a natural gas plant of the same capacity -- though there is fierce argument over whether that output substantially exceeds what a natural watercourse would produce. (The emissions are due to methane from trapped organic matter in the dam.)

There is now a proposal to tap that methane to run gas turbines and produce electricity, reducing the emissions many times, since CO2 from burning the methane has a much lower impact than the methane itself. It would also close to double the electrical output from the dam. This seems very close to an acknowledgment that critics of methane from dams are correct. Outside of estuaries, I don't know many natural water courses that might be tapped in such a way. I have to admit that it is an ingenious solution to the problems of dams as methane sources.

Why we gotta knock solar?

Can we please, once and for all, stop decrying solar energy for being too area-intensive? See, for example, the oft-cited statistic that to power its economy, the U.S. would need "10 billion meters, squared, of land." America isn't exactly short on square meters, and awfully sunny ones at that. But 10 billion square meters sounds a lot bigger than it really is.

10,000 square kilometers (100km x 100km) form a square you could drive around entirely, at legal highway speeds, in four hours. (Less if you speed.) 10,000 square kilometers is also roughly one-fortieth the area that the human species has already occupied for hydroelectric reservoirs -- all to produce, according to the IEA, 15 percent of current global electricity demand. (This certainly overstates the efficiency of large dams, which do not produce 100 percent of the world's hydroelectric power.)

Get that? For vastly less space than we already consume for the pittance we get from hydroelectric dams, we could power the world. Space is not the limiting factor -- and soon enough, cost won't be either. Which will leave mulish stupidity the remaining roadblock.