Sunday, September 20, 2015

Dams and Carbon

National Geographic has a feature this week on which cities around the world are doing the best at phasing out power from fossil fuels. Scanning their table, I see that the cities doing best by this metric mostly rely on hydropower, that is, on dams. In other contexts National Geographic has been a big supporter of dam removal, and they wrote a skeptical piece on Brazil's plan to generate power with a huge system of new dams on Amazon tributaries. Well, which is more important? Free-flowing rivers or reducing CO2 emissions?

At this point in time I lean toward reducing CO2 emissions. But whatever we choose, we have to recognize that there is no free lunch anywhere.

1 comment:

G. Verloren said...

The vast majority of C02 emissions come from vehicles, not from power generation. Meanwhile, water conservation and control is a major issue. In the larger balance of things, I'd say these two concerns end up being roughly equal.

Why can't we push for less carbon AND fewer dams? They're not mutually exclusive, despite sometimes being framed in that light.

It's also important to look at this question in a larger context. The NatGeo article is about cities phasing out fossil fuels for power generation, but it is important to remember this is a slow process that has been ongoing for some time now. Hydroelectric power quite naturally is going to be highly represented in those cities which have to date moved furthest away from fossil fuel power generation, because other preferable alternatives like solar are only now approaching technological maturity, and consequently have yet to be implemented.

Hydroelectic power is certainly not the optimal choice with its many negative side effects, but the cities which have thus far been able to offload their power production away from fossil fuel simply haven't had any other alternatives until now. It has been useful as a stop-gap technology, but as we go forward it will be critically important to reaffirm the failings of hydroelectic power production, and stress the usage of alternate sources which are finally becoming viable instead.

We absolutely can both reduce carbon emissions AND reduce our reliance on dams - we simply choose to spend our collective resources elsewhere. The world spends amounts approaching $2 trillion dollars annually, and employs a huge percentage of the world's scientists and engineers, purely on endeavors of war. Think of the difference that could be made if we were to instead dedicate even just a fraction of those resources to solving global energy problems.