These days, when we talk about renewable energy, we mostly talk about wind and solar, followed by various biofuels, hydrogen, and geothermal. We almost never hear anything about hydropower, despite the fact the fact that hydropower is by far our largest source of renewable energy, providing a full 7 percent of our electricity needs.
That’s because most of the action has been in these other areas which have experienced enormous growth rates, starting, as they have, from humble origins.
Recent activity in the hydro sector has fallen into three major areas:
- Purchases of large power contracts from mega-hydro projects in Quebec;
- Investment aimed at extracting more power from our existing infrastructure;
- Development of new types if hydro generation, primarily aimed at coastal areas.
When we talk about imported energy, we are usually thinking about oil. But the fact is, we import about one percent of our electricity (43.8 terawatt-hours in 2010) from Canada, the vast majority of which comes from hydropower. Canada has vast hydropower resources, which it has been exploiting aggressively, particularly in Quebec, which has close to 50,000 MW of hydroelectric generation capacity. That is roughly equivalent to the entire wind generation capacity of the U.S. — pretty impressive for a province twice the size of Texas, with the population of New York City. This means that not only does Quebec get 97 percent of its electricity from hydro, giving it the nominally lowest GHG emission profile per capita in North America, but there is still quite a bit left over for export.
Officials on both sides of the border are looking for ways to strengthen this exchange. Large deals have been brokered to major cities in the Northeast.
But there are problems. There is a lack of transmission capacity, low natural gas prices threaten hydro’s cost advantage, and there are concerns about the impact on jobs.
In fact, the New York Public Service Commission just approved a $2.2 billion, 330 mile long, high-voltage power line to bring 1,000 MW of hydro power to the Big Apple in the hopes of reducing prices. That will certainly help improve transmission capacity. Costs will be borne by the developers, not the ratepayers.
Another problem is that a number of the 30 states with some form of renewable portfolio standard (RPS) will not accept imported hydropower towards their renewable goals. Take Connecticut, for example. The conflicts they’ve been having over whether or not they should import power from Quebec underscores many of the issues surrounding hydropower. The state’s RPS calls for 20 percent of all electricity from renewable sources by 2020. Presently, that does not include hydropower. The state’s Dept. of Energy and Environmental Protection (DEEP) wants to change that.
Environmentalists don’t mind, so long as it replaces coal and gas and not wind and solar. DEEP argues it will introduce competition, lowering rates. The state senate approved the move last week. The adjusted RPS will allow hydro to provide up to 1 percent towards the state’s renewable power goal. Most of that power will come from Hydro Quebec’s $1.2 billion Northern Pass project, which proposes to flood thousands of acres. Not only does this flooding disrupt pristine natural ecosystems and eliminate huge expanses of forest, the resulting rotting vegetation gives off a great deal of greenhouse gases, either CO2 or methane, depending on the presence or absence of oxygen.
This gives the lie to the claim that large hydro projects like this are greenhouse gas-free. Recent studies in fact, show that these greenhouse gas emissions, when considered on a per kW basis, are comparable to natural gas powered plants.
Similar concerns and worse have been raised regarding China’s Three Gorges Dam, the largest hydropower project in the world. Even Chinese officials now admit that the project has been an environmental catastrophe. In addition to the problems described above, this $24 billion, 18,000 MW project, has been triggering landslides, altering entire ecosystems and endangering the lives of the millions of people who live in its shadow.
Here in the U.S., hydro investment has been focused on “low-impact” projects, which generally means no new dams. Less than 3 percent of the 80,000 dams in the U.S. are powered, which means there is considerable untapped potential.
In Washington State, the legislature is debating whether efficiency upgrades to existing hydro-power installations such as the Grand Coulee Dam should be considered renewable energy.
One DoE study on hydro-power identified the following opportunities:
- Using hydropower to address changes in electricity supply and demand. This could provide more flexible reserve power options and reduce wear and tear on conventional thermal-generating equipment, increasing in the total annual value of hydro-power by 40 percent.
- Expanding the effective operating range of hydro-power units — by reducing the minimum amount of water needed to operate the turbines. This can increase the production value of plants by 60 percent.
- Cutting-edge plant designs using pumped storage to provide grid services while pumping water would result in an 85 percent increase in production value.
- Treating pumped storage units as a unique “asset class” would allow the creation of alternative business models that could make investment in pumped storage more attractive by integrating with variable renewables.
There are also some dramatic technological breakthroughs in the works for new ways of capturing power from water. Most of these involve either riverine or tidal systems.
According to the Electric Power Research Institute (EPRI), riverine, or hydrokinetic energy sources could add an additional 3 percent of the national electricity demand, bringing the hydro-power total up to 10 percent. About half of that comes from the lower Mississippi, with another 17 percent coming from Alaska. The theoretical estimate actually went as high as 25 percent of the total U.S. demand, but that was scaled back due to constraints involved in developing these resources. It’s worth noting that a number of today’s fossil energy sources (e.g. tar sands, shale gas, etc.) were once considered economically unrecoverable.
Take a look, for example, at Verdant Power. Their Free Flow turbines attach with a pivoting mount to the bottom of rivers, allowing them to track tidal flows. They have projects planned for the East River in New York and on the St. Lawrence in Cornwall, Ontario.
The far greater opportunity however, lies in ocean tidal power, which the EIA estimates could contribute as much as 100,000 MW (twice as much as Quebec’s hydro) by 2050. EPRI estimates that technically recoverable wave power could provide 25 percent of America’s electric demand.
There are various types of tidal systems, including the barrage, the tidal fence, and the tidal turbine, as well as the oscillating water column, and the heave surge device. Some companies involved in this space include Ocean Power Technologies, which partnered with Lockheed Martin on a 19 MW project in Australia. Aquamarine Power, a Scottish company with an offshore pump called an “oyster” which powers an onshore hydro plant, claims they have a worldwide potential of 64,000 MW.
Last summer, Ocean Renewable Power Co. became the first grid-connected tidal energy project without a dam in America when they installed a 180 kW unit, the first of several planned turbine generators in Cobscook Bay, Maine.
As we move forward into a world where our phones and computers are becoming untethered and distributed, our power generation systems seem to be following the same pattern, extending all the way into the domain of the world’s grand dams.