Re-Thinking Hydro-Electricity

Most of the electricity British Columbians use is hydro-electricity. BC has two advantages: mountains and location, namely the west "wet" coast. 

We get a lot of moisture-laden air coming off the Pacific. In order to keep heading east the clouds must lighten their load which is achieved by raining on the various mountain ranges (there's more than just the "Rockies"). 

The mountains get the rain and, because they're mountains, gravity gets involved. That's kinetic energy, the torrents that begin as rivulets and gather to become wild-water rivers that race to the sea.

Mountain valleys are also ideal for the construction of dams that store some of that water and transform it from kinetic to potential energy in sometimes massive reservoirs and artificial lakes. Those dams can then release water into long chutes where it again becomes kinetic energy harvested by turbines at the bottom. That kinetic energy is then transformed by those turbines into hydro-electricity.

There are several environmental drawbacks to dams. The concrete used in construction is, well, concrete, a major source of emitted CO2. The reservoirs destroy the ecosystems of the valleys flooded. Then there's the fish. Species such as salmon can be prevented from reaching their spawning areas. One problem is the turbine, the spinning blades of which can simply slaughter fish trying to pass through.

Necessity is called the "mother of invention." In the American context, necessity includes coming up with sources of clean-ish electricity to replace dependence on fossil-fueled electrical generation. But, what about the fish?

A California company, Natel Energy, has partnered with a Bill Gates company to produce a new, more fish-friendly turbine blade.   Natel was founded by siblings, Abe and Gia Schneider, both engineers.

“Climate change is water change,” explains Gia. “We saw an opportunity to rethink hydropower facilities with civil and environmental engineering techniques, using fish-safe turbines, machine learning and satellite imagery.” Indeed, extreme year-on-year climate variability and unpredictable rainfall will only make innovative solutions more urgent. If done sustainably, hydropower can work as a green fuel source with a number of side benefits, including flood control, irrigation, drought mitigation and water supply.

A pinwheel configuration (rather than spokes issuing straight out of a turbine’s hub) means the turbine’s blades deliver a glancing blow instead of a knife-like strike. “From an engineering perspective, a thick blade creates a pressure zone that helps shed material out of its path, almost like an airbag for the fish, so the impact is minimal,” says Abe.

Here's an example of the Natel design.

Instead of an array of thin, sharp blades - Veg-o-Matic style - the Natel design uses just a few, thick blades. The company has spent a couple of years testing the design, including developing "sensor fish" like these:

These sensor fish have been used to gauge the lethality of  conventional turbine fans and the newer design. Retrofitting new turbines on existing hydro dams is deemed prohibitively expensive but the Natel design has been engineered as a direct replacement on the existing turbine.

In Phase I, the company designed two versions of its LP turbine and was able to demonstrate a savings of 30% to 40% in the levelized cost of energy. 

The basic idea is that the new turbine’s “low-head” modular design lends itself to low-cost installation on existing dams while reducing the need for expensive new infrastructure. Phase I was promising enough for the Energy Department to chip in another $1.5 million just a couple of days ago.

The Natel blade can also be used on other sources of flowing water.

According to Natel, installation sites could include irrigation canals and ambient river currents in addition to existing dams.

As Cleantechnia.com points out, an expansion of hydro-electricity generation is inevitable across the United States were, currently, only three per cent of US dams generate electricity.

A DOE assessment found that more than 90% of U.S. dams are used for services, such as regulating water supply and controlling inland navigation, and lack electricity-generating equipment. The assessment found that existing U.S.non-powered dams could provide up to 12 gigawatts (GW) of clean, renewable hydropower capacity from 50,000 suitable non-powered dams.

Will this eliminate environmental concerns about dams? Of course not. It's no magic wand. That said it seems to be much more fish friendly and, in British Columbia, anything that can reduce stresses on our salmon stocks is worth a careful look.