It will not be possible to stop or even slow down construction of these main-stem dams without coming up with alternative sources of energy. Fortunately, there are other, and better, ways to generate power for the region.
Existing dams could be retooled to increase their efficiency and limit their environmental impact. Other options include developing small-scale hydro- power in Vietnam and solar power in Vietnam and Thailand. In fact, according to a recent study by the International Center for Environmental Management, an NGO, developing a thoughtful combination of renewables could supply several times as much energy by 2025 as the amount expected to be generated by the proposed dams. And improving energy efficiency and implementing conservation measures — say, to cut electricity consumption in large commercial buildings throughout Thailand — could mean substantial savings and help curb demand.
Yet innovative energy projects rarely seem attractive, or competitive, against large hydropower projects, partly for lack of substantial financial backing up front. And the mega-dams tend to attract too much support. They are capital-intensive, which means that they boost foreign direct investment and stimulate G.D.P. growth (at least temporarily). They also allow host governments to collect money quickly by granting construction rights to private developers. And in countries where the rule of law is weak, they provide opportunities for skimming and cronyism.
But proponents of large dams almost always underestimate the environmental costs while overestimating the rates of return. And such projects can spur get-developed-quick schemes at the expense of broad social and economic progress.