Big pumped-storage projects studied
Hydropower pumped-storage is moving west, and for the first time projects that use the technology for electric generation are on the drawing board in Nevada.
Two sites in Humboldt County are being developed by Winnemucca Farms Inc. while Gridflex Energy LLC, a private company based in Boise, Idaho, is hoping to build plants in three locations, in Clark County, Ely and a spot straddling Lyon and Mineral counties.
All five projects have received preliminary permits from the Federal Energy Regulatory Commission, the first official step in what could be a near decade-long process from concept to energy production.
“All are in the early stages of development,” says Matthew Shapiro, chief executive officer of Gridflex. “We’re doing a lot of market research, feasibility screening, outreach to utilities. We look at the market for generating capacity in various utilities within range of the projects, look at the cost of peak and off-peak energy, wind and solar on the grid, and balance all of that with the capital costs of projects, which vary widely depending on the site.”
Gridflex estimates both its sites will cost just over $1 billion to build. The average pumped-storage plant producing 500 to 1,500 megawatts of power costs between $1 billion and $2 billion to build, according to the National Hydropower Association.
Winnemucca Farm’s two sites are expected to each produce 400 MW. Gridflex’s site in Ely, called the White Pine Pumped Storage project, is being designed to generate 750 MW, while its planned plant in Lyon and Mineral counties, called the Black Mountain Pumped Storage project, is on tap to produce 750-1,000 MW.
Driving renewed interest in pumped storage, which grew up decades ago around the nuclear energy industry on the East Coast, is the push to renewable power like solar and wind.
“Nuclear produces a lot of energy at night, but they wanted them running at steady state when demand dropped off,” says Jeff Leahey, director of government affairs with NHA in Washington, D.C. “We’re seeing sort of the same thing now as more and more (renewables) are being put on the system.”
The purpose is to provide stability to an electrical grid relying on intermittent power sources such as wind and solar.
Pumped storage systems consist of two reservoirs located at different elevations with a connecting tunnel to move water between them. When energy demand is low, and energy costs less, the system powers up and pumps the water to the higher reservoir, where it is stored. When energy demand peaks, the stored water is released to flow back into the lower reservoir, passing through a turbine to produce power.
The technology has its deterrents due to environmental impacts, especially when rivers are dammed in open-loop systems. But all the plants being considered here are closed-loop systems, meaning they do not have an ongoing connection to a water source. Instead, the reservoirs are filled and self-contained. Additional water is added periodically to make up for evaporation and seepage.
“We have 36,000-acre-feet of water that could be directed towards this particular use,” says Sam Routson, chief administrative officer with Winnemucca Farms in Winnemucca. “Depending on (the size of) reservoirs, we’ll determine how much is needed for initial fill, but the engineers are saying about 3,000 acre feet for maintenance of water levels in the system. And we’ll take water-saving measures by covering the surface with floatable voltaic panels.”
Gridflex is looking at covering its reservoirs with hexagon-shaped disks to reduce evaporation by as much as 90 percent, says Shapiro.
Gridflex’s White Pine site would need about 5,500 acre feet of water for the initial fill while the Black Mountain plant would require 6,000 acre feet.
“For White Pine, it’s a little easier, two major water rights holders approached us,” says Shapiro. “Either of those has more than adequate supply for what we need for that project. For Black Mountain, it’s not as straightforward. But we’re talking with existing water rights holders, including mining, which have more than we need for initial fill. And we’re looking at a pit west of Yerington that’s filled with 35,000 acre feet. The Walker River budget is very tight.”
Water may be an obstacle in arid Nevada, but topography is a major plus, naturally providing sites that can reduce construction costs. Both Winnemucca sites, for example, and Gridflex’s Black Mountain site have natural basins for the top reservoirs that require little to no construction.
Routson says the Winnemucca Farm’s sites have a vertical drop of 1,000 feet between top and bottom reservoirs. Gridflex’s Black Mountain site has a 2,100 foot drop, while its White Pine site has a 2,300 foot difference, the biggest drop of any pumped storage facility in the United States, says Shapiro.
Other hurdles remain, though. After receiving the preliminary FERC permit, a developer has three years to perform market, environmental and feasibility studies as well as talk to stakeholders such as water rights owners, local municipalities, utilities and the Bureau of Land Management.
Once that’s done, the developers submit all that to FERC to apply for a license. FERC takes over from there, conducting environmental impact statements on each project.
Part of one Winnemucca site is on BLM land, so it must also apply for right-of-ways to use the land. All of Gridflex’s two northern locations are on BLM land, so the developer will also need to provide the BLM with a fair market appraisal for the land, which the BLM uses to charge for its use, according to Brenda Linnell, a realty specialist in the BLM’s Ely office.
Previous pumped storage projects were mostly built by utilities, but with the westward expansion many of the projects are being financed and built by developers. So the developers also have to obtain power purchase agreements from utilities as part of the process to receive final FERC approval for their projects. In Nevada, that also means approval from the Public Utilities Commission.
The final FERC approval process can take up to five years, says NHA’s Leahey, and construction another two years. But there is some good news: the House of Representatives unanimously passed a hydropower bill that streamlines the application process for closed loop pumped-storage projects, reducing it to two years. The bill was introduced into the Senate last week.
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