DOE Vows To Expand Hydropower in America

Last week, the Department of Energy, under President Obama, released a plan to expand hydropower by 50% through electrifying existing dams and emplacing pumped hydro storage at existing non-powered dams to facilitate more intermittent renewables like wind and solar onto the electric grid.

According to DOE's Hydropower Vision, the United States could increase its hydropower electricity generation capacity from about 100 GW to 150 GW by 2050 by energizing existing dams (dams that presently have no ability to produce power), upgrading plants already producing power with more capacity, and constructing new pumped hydro storage facilities to support renewables.

The biggest challenge to bringing non-hydro renewables onto the grid is to do so while gaining the maximum benefit for lowering carbon emissions, making sure they do not

- displace other low-carbon sources like hydro and nuclear as they often do now, or

- bring on more natural gas to buffer the renewables’ intermittency.

Almost 90% of America’s low-carbon energy sources come from hydropower (21%) and nuclear power (67%), which together avoid almost a billion tons of CO2 emissions each year. But both hydro and nuclear had the majority of their builds before 1990.  The existing hydro fleet was constructed over the course of an entire century and constitute the longest-lived energy facilities in the world. Many will exceed 100 years of operation.

If we are to achieve any of the low-carbon goals we have set out for 2030 and beyond, hydropower and other renewables must increase significantly and nuclear power has to maintain its share of power, and even increase by 2030.

"Hydropower has provided clean, affordable, and reliable electricity in the United States for more than a century, and pumped-storage complements today's rapidly growing variable technologies such as wind and solar," Energy Secretary Ernest Moniz said in a statement.

But what about pumped hydro storage? As described in the report, DOE looks to increase the nation's current pumped hydro storage capacity from about 22 GW to 36 GW. It is the majority of the planned new hydro but is different from traditional hydroelectric generation.

Pumped hydro storage stores energy by moving water between two reservoirs of different elevations. Water is pumped from the lower reservoir, using some form of energy like wind or solar, up into the higher reservoir, where it is stored as gravitational potential energy until needed. Then it is let out through turbines just like any hydrolelectric plant, and generates electricity.

Although pumped hydro storage loses about 30% of the original energy, pumped hydro storage is a dispatchable source, deployable whenever needed, and can be used to capture wind and solar power that are intermittent and non-dispatchable.

To help assist this expansion in hydropower, DOE is providing $9.8 million to fund a dozen projects aimed at reducing construction costs and schedule for pumped hydro storage and non-powered dams.

As it turns out, only 3% of American dams generate electricity. The others provide navigation, flood control, irrigation, water supply and/or recreation without power, but most can be upgraded to supply electricity.

The hydroelectric dams that produce power in this country include about 2,200 hydroelectric plants totaling 80 GW, and 42 pumped storage facilities generating about 22 GW. They produce about 7% of our electricity. But 70% of these are less than 10 MW (0.01 GW). Half of them are privately-owned and half are federal, but almost all of the generation capacity is in the federal dams. While the Pacific Northwest leads the nation in installed capacity, the Northeast has the highest number of dams.

DOE understands that this vast network of dams can be used to generate a lot more low-carbon energy, essential for achieving any serious decline in carbon emissions.

"If this level of growth is achieved, benefits such as a savings of $209 billion from avoided greenhouse gas (GHG) emissions could be realized, of which $185 billion would be attributable to operation of the existing hydropower fleet," said DOE.

It is ironic that the two largest providers of low-carbon electricity, hydro and nuclear, have the most onerous regulatory hurdles that make construction lengthy and expensive. Ten years is common for merely licensing. Once built, however, both enjoy the longest of facility life-times, the lowest production costs per kWh, and produce vastly more power than any other type of energy facility before they die.

The Grand Coulee Dam on the Columbia River in Washington State has produced over 1.4 trillion kWhs in its lifetime, an amazing amount of carbon-free power. But it would be extremely difficult to build Grand Coulee Dam today.

So, the biggest hurdle facing hydropower is the complicated and capricious regulatory and licensing processes. Just as with nuclear, this uncertainty increases costs and can even kill projects halfway through the process, making them unattractive to investors. And development of new hydroelectric projects is unlikely without new technology, DOE added.

According to LeRoy Coleman of the National Hydropower Association, “This report puts the need to modernize our licensing process into clearer focus. The status quo is hampering the development of hydropower. We can’t reach 50 additional GW by 2050 without a licensing process that is timely, coherent and more collaborative. With this new DOE roadmap in hand, we can unlock hydropower’s ability to help secure our clean energy future.”

Then there’s the water supply issue - climate change itself is reducing supplies and creating record droughts across the western United States. "Climate change creates uncertainty around water availability for hydropower generation, and this uncertainty can affect the long-term outlook of the hydropower industry," DOE wrote in their report.

Presently, pumped storage accounts for 99% of energy storage in the world and is likely to always exceed battery storage as the primary storage technology. You need lots of water and a favorable landscape, but when you meet these two criteria, pumped hydro storage is a very attractive way to bring intermittent renewables onto the grid without sacrificing existing hydro and nuclear.