Hydropower can be an environmental and human disaster – but do the risks have to be so big?

Matt Ferrell describes the climate opportunities presented by small-scale hydropower turbines. These clever machines have potential to generate reasonably large and consistent amounts of energy without meaningfully altering a river's flow, potentially without stopping fish migrations, without displacing people upstream (reservoir), and, perhaps most importantly, without risk of massive dam failure, which results in death and destruction downstream. The turbines can also be effectively deployed in places with limited grid access on account of their small size. I imagine that maintenance costs are also on the lower side.

They are already deployed in various places around the world. The technology appears to be effective, with a high capacity factor, and it also isn't that expensive. But it does have some drawbacks, mainly that the turbine design he discusses generally doesn't work below freezing temperatures. And because they don't rely on massive reservoirs, seasonal droughts can affect real generating capacity (real output), though not relying on reservoirs is the point. And of course they are simply small; a single one of these obviously isn't replacing the Three Gorges Dam.

Some small-factor designs are more fish-friendly than others. But there exist many traditional hydropower dams which can be fitted with fish-safe modifications, i.e. diverting the fish through special tubes, sending them over the dam through fish spillways, or designing turbines that won't hurt them to begin with. Using such technology, I don't see any reason why all small-factor turbines could not be similarly designed to be completely fish-safe for any kind of fish. It seems like a pretty good thing for society to invest in.