09 August 2013

Energy Generation - Big vs. Small - What is Appropriate?

Are big dams the best value for the money spent? Recently a researcher contacted me regarding Inga Dams and the contrasting advice from IEA (International Energy Agency) for small scale energy generation in rural Africa. A conversation then ensued that got me thinking about the feasibility and reality of such steps toward small scale energy generation - how small? Who would fund this? Who would maintain this? Who would implement this? How could such a disparate grouping of facilities be maintained?

With a new era of big dams in effect - and the World Bank getting back into the game of loans for big dams - these questions need to be revisited.

Hydrogen cell generators were being developed a decade ago to answer the dilemma of alternate energy generation. In Ethiopia the Ethiopian Electric Power Company is exploring wind, solar, and even geothermal alternatives - they have active contracts to explore and even some projects in effect. Wave energy generation using turbines is now taking off in the Pacific close to Oregon, USA. But, over the years I have followed development of alternative energies, I do not see the acceptable silver bullet. Moving away from business as usual with central power generation in a large facility - all that require water by the way - would mean big changes in supporting infrastructure. High cost, presumably. Could moving in the direction of localized energy generation through one of these technologies be the answer and big business is just standing in the way with large loans for big dams or petroleum corporation kickbacks to power people (like governments) and OPEC and all the usual suspects? It is not conspiracy I suggest, but just human's aversion to change and other human preference for advantage. Some people live comfortably while other people live uncomfortably, as friends in Southeast Asia would put it. Uncomfortable has varying degrees. I think of the evidence of rapid climate change all over the world, and specifically changes to hydrologic cycles in big rivers - precipitation changes, temperature changes...okay so change is inevitable, but this type of rapid change will result in some major changes to how we do business anyway.

I thought about dams and generators, my internal non-engineering background questions about suspending 375MW generators in high head zones - like waterfalls - without the dam walls and extensive problematic infrastructure - I mean this is done in the ocean to capture wave energy, why not in rivers? I remembered seeing small generators in rivers in Albania and Bosnia a decade ago. They were just as good at powering a small business as the diesel generators that came on every time a town was "ska dreet"(without electricity).

I also thought about a series or cascade of smaller dams, like Sino-hydro is constructing on an upper tributary of the Mekong in Laos. There are some colleagues of mine from Oregon State University who were looking at the advantage of big vs. small dams on China's rivers. I believe that they concluded that several small dams could actually be more damaging than one big dam within certain parameters, like environmentally. I think of Grand Coulee dam on the Columbia. Big damn dam. Has resulted in a halt of salmon migration into Canada. Complete block of the passage of these fish. So, whoever used to rely on this particular source of food is out of luck. This is not just humans, but bears, plants, other fish, and things I don't really know enough about, but know enough about complex systems to know that we probably don't even begin to comprehend the extent of impact. Okay, so a series of small dams can be more detrimental than one big dam is that one big dam is built with appropriate technological design - not like Grand Coulee. Fair enough. Now it is time to turn back to engineers and determine if their designs have actually had any appropriate innovation in the last 50 years. There certainly have been a huge amount of dams build in that timeframe - about 50,000 globally - so, innovation has taken place? The Xayaburi Dam project has gates for sediment in the base, this seems to be a good innovation. They also put a fish passage in place - but these are questionable in most circles as I understand it - probably has to do with the physical water movement vs. the biology of fish used to more manageable water flow rates. I hear they blow up when they hit the high pressure of turbines, unless they can internally change their pressure, and there are folks trying to train fish to do just this. Sounds weird as I write it.

I am not sure even where I stand on such questions. Certainly I understand the desire for electricity in much of the world that does not have the infrastructure currently - electricity for many things from domestic use to industry and large-scale agriculture. I see the benefits of such electricity in abundance in parts of the United States and Europe - a black-out or brown-out gets international news coverage - unlike the daily experiences in many major cities of other countries I have visited this year in East Africa and Southeast Asia.