pumped storage projects consume more electricity than they generate by recycling water to provide "peak" power
Source: Federal Energy Regulatory Commission (FERC), Diagram of a Pumped Storage Project
Virginia has two "pumped storage" projects generating electricity. Appalachian Power built its Smith Mountain Lake facility in the early 1960's. Two decades later, the Virgina Electric and Power Company (now Dominion Energy) built the Bath County Pumped Storage Station. It is the largest pumped storage project in the world.1
Utilities know they are unlikely to get public approval and government permits now to build another dam across a major river for a new hydropower facility, but do see potential to create another pumped storage facility in Virginia.
Pumped storage projects are hydropower operations. They rely upon a pair of reservoirs at different elevations. Water from the upper reservoir flows down through turbines that produce electricity, just as in any hydropower plant.
What is different from standard hydropower projects is that some or all of the water is captured in the lower reservoir, rather than allowed to run downstream. When demand for electricity is low, typically at night, water from the lower reservoir is pumped back upstream to the upper reservoir. That restocks the reservoir, and allows the same water to spin the turbines the next day when demand for electricity peaks again.
The capacity of a small stream to create electricity, such as Little Back Creek and Back Creek in Bath County, is magnified by stockpiling and recycling water between the reservoirs.
pumped storage power plants can generate electricity when demand peaks in the afternoon, then use excess baseload power from coal-fired or nuclear plants to "recharge the battery" at night
Source: US Energy Information Administration, Hourly Electricity Demand in the PJM Interconnection (July 13-19, 2013)
Most hydropower facilities generate a surplus of electricity, but pumped storage projects consume more electricity than they generate by pumping water uphill water to provide "peak" power. They are valuable to utilities because they serve as massive batteries, able to provide power quickly and inexpensive to shut down when power is not required.
At the moment, excess baseload power is available only at night. Coal-fired and nuclear power plants, supplying baseload power, produce the excess. Pumped storage facilities produce hydropower, but the original source of the energy to pump the water uphill was not "renewable." If Virginia built enough solar facilities to generate a surplus of electricity in the early afternoon, then renewable energy could be stockpiled for later use by pumping water uphill.
the Bath Pumped Storage Project consumes more electricity than it generates, and annual reports include a minus symbol for net generation
Source: US Department of Energy, Electricity Data Browser
The first pumped storage project in Virginia was constructed after World War II. It was constructed where the Roanoke River cuts through Smith Mountain Gap, a site that had been considered for a hydropower dam since 1924. The pumped storage project, with an upper reservoir created by Smith Mountain Dam and a lower reservoir created by Leesville Dam, provided generation flexibility for Appalachian Power. Smith Mountain Lake reached its full size ("full pool") in 1966.2
The utility relied upon coal-fired power plants, baseload facilities that operated constantly. There was insufficient demand for all the electricity that could be generated during the weekends, but it was not efficient for power plant operators to cool and reheat coal-based boilers for short periods of time.
Appalachian Power determined that its excess electricity could be economically used by stockpiling water in Leesville Reservoir during the week, then pump it back up to Smith Mountain Lake on weekends. That water could then be reused, flowing through the Smith Mountain Dam turbines when demand increased again on Mondays.
It was cost-effective to build a pumped storage facility that generated power for only a portion of the week to meet peak demand, compared to building another baseload plant whose output would not be needed during the low-demand weekends. Today, the Smith Mountain Lake project has a quicker response cycle:3
As population and the economy grew in the 1960's, other utilities saw a similar need for flexibility in meeting peak demand. In the 1970's, four pumped storage projects were proposed in Virginia. Three were authorized by the Federal Power Commission, and one was built.
The Virginia Electric and Power Company (now Dominion Energy) obtained a preliminary permit in 1971 for a project using Goose Creek and Bottom Creek, tributaries to the South Fork of the Roanoke River. That permit expired in 1975.
In 1976, the Southside Electric Cooperative of Crewe obtained a preliminary permit for the Randolph Project, a series of five hydroelectric projects on the Roanoke River upstream of Kerr Reservoir that together would generate 4,090MW. A lake was planned downstream from each dam, capturing water that could be pumped back above each dam to generate electricity again.
The small utility did not follow-through with the expensive required studies, so the Federal Energy Regulatory Commission permit was cancelled in 1978.
In 1977, Appalachian Power proposed a 3,000MW pumped storage project in Scott and Wise counties. The upper reservoir would have been constructed on the South Fork of the Powell River, with a lower reservoir on Stony Creek. It withdrew its application in 1979, in part because lands in the area could be eligible for designation as wilderness.4
Construction of the Bath County Pumped Storage Station started in 1977, but was suspended in 1980 after the Virginia Electric and Power Company recalculated its peak power demands. When Appalachian Power was unable to get approvals to build its planned pumped storage project in Canaan Valley, West Virginia, the two utilities negotiated a deal. Appalachian Power purchased 40% of the Bath County project, and obtained a share of the hydropower from that site. The Bath County Pumped Storage Station was completed and went into operation in 1985.5
Unlike coal-fired and nuclear power plants, hydropower plants can generate and dispatch electricity with no "warm-up" time. Pumped storage plants recycle the water that flows through the turbines, trapping it in a lower lake and pumping it back upstream for reuse.
The elevation change between lakes normally ranges between 100-2,500 feet. Projects with less than 300 feet of elevation difference are designed for multiple purposes, especially flood control.6
In 2017, the General Assembly modified Section 56-585.1 of the Code of Virginia. It declared that it was in the public interest to build a pumped storage project within the boundaries of the Virginia Coalfield Economic Development Authority - Lee, Wise, Scott, Buchanan, Russell, Tazewell and Dickenson Counties plus the City of Norton).
in 2017, the General Assembly authorized a new pumped storage facility within the boundaries of the Virginia Coalfield Economic Development Authority
Source: ESRI, ArcGIS Online
Only five utilities are authorized to provide electricity within the seven counties and one city included in the Virginia Coalfield Economic Development Authority, but the state legislature authorized any utility to build such a project. Dominion Energy quickly expressed its interest publicly, even though the location was far outside the utility's authorized service territory.7
in 2017 Dominion Energy proposed building a pumped storage project with the boundaries of the Virginia Coalfield Economic Development Authority - far outside of its service area
Source: Virginia State Corporation Commission, Electric Service Territories
The new law pre-empted the responsibility of the State Corporation Commission to evaluate alternatives before approving such a project. That would help Appalachian Power or Dominion Energy get authorization for a pumped storage project, even if a power plant fueled by natural gas would be more cost-effective. The direction from the General Assembly was an example of how the legislature had reduced the role of the State Corporation Commission since the mid-1990's and increased the role of politics in setting energy policy within Virginia.
Southwest Virginia officials had previously managed to get the General Assembly to endorse construction of Virginia Hybrid Energy Center in Wise County, which burned waste coal and biomass to generate electricity. The cost-per-megawatt of the Virginia Hybrid Energy Center ended up substantially higher than later facilities that were fueled by natural gas.
Despite that experience, in 2017 the legislature again cleared the way for a utility to build a pumped storage project in Southwest Virginia even if that technology or location was not the most cost-effective approach.
Three legislators proposed the project, not a utility company that had identified a need for another project in the region, to generate jobs just like the Virginia City Hybrid Energy Center. An influential blogger associated with Dominion Energy described the political direction to construct the Hybrid Energy Center and a pumped storage project as:8
Wise County has the Virginia Hybrid Energy Center at St. Paul, and one proposed location for a pumped storage project is near Appalachia on the west side of the county
Source: ESRI, ArcGIS Online
The action by the General Assembly gane a green light for the utility to incest in an economically-depressed region, but there were still major hurdles for constructing an actual project. No pumped storage project in the US has utilized coal mines as one of the storage reservoirs for a pumped storage project, and sulfur within remaining coal could cause the water to become acid enough to damage turbines. The spinning equipment has very narrow tolerances, so the threat of metal corrosion would require expensive maintenance.
Construction would create hundreds of jobs, but those would exist only for a brief period and could be filled by construction workers who migrate to the project from outside Southwest Virginia. A pumped storage facility would create 10-15 high-paying, permanent jobs. The utility would pay increased property taxes to the county in which the project was constructed, so at least one local jurisdiction in Southwest Virginia would receive long-term benefits.9
If a pumped storage project was built in Southwest Virginia using coal mines, it would probably be a "closed loop" project, two reservoirs with no connection to an existing waterbody. Siting of a closed loop project should be easier, since no natural stream habitat would be flooded to create the two reservoirs. The environmental impacts of "open loop" pumped storage projects, such as Smith Mountain Lake and Bath County Pumped Storage Station, are much greater since they utilize existing streams.
pumped storage requires at least two reservoirs, but one or both could be underground rather than on the surface
Source: Dominion Energy, Powering Southwest Virginia
A pumped storage project associated with utility-scale solar plants could stimulate the construction of new data centers in Southwest Virginia. The region offers low costs for land and labor, and officials at the state and local levels are highly-motivated to support new economic development.
There are advantages to building new data centers in Northern Virginia, which already has all the infrastructure required for transmitting "bits" worldwide, but rural areas are also attractive. Microsoft has already located a major data center in Mecklenburg County. If Southwest Virginia could provide a highly-reliable supply of 100% renewable energy, and if it had high-speed broadband capacity, the region might compete with Loudoun and Prince William counties for construction of future data centers.10
Local economic development planners dream of the possibility that green energy could stimulate the region into becoming "Silicon Hollow." The local governments were the first in Virginia to cooperate on attracting major industries by agreeing to share revenues, in hopes of luring Motorola into building a computer chip fabrication plant. They got the General Assembly to pass the Virginia Regional Industrial Facilities Act and created Commerce Park in Pulaski County. The localities in Southwest Virginia that belong to "Virginia's First Regional Industrial Facility Authority" plan to use that revenue sharing authority so the entire region will benefit, no matter where the pumped storage project is built.11
only California generates more electricity from pumped storage projects than Virginia
Source: Federal Energy Regulatory Commission (FERC), Licensed Pumped Storage Projects Map
In September, 2017, Dominion Energy announced that its site selection process had identified two candidates, the old Bullitt coal mine in Wise County and a site near East River Mountain in Tazewell County. Each site included 4,000 acres of land. Dominion packaged the proposal with a claim that renewable energy would be use to pump water back to the upper reservoir, to enhance support from the general public.
Groundwater naturally flooded the Bullitt Mine once coal mining operations ceased. By one preliminary estimate, four billion gallons of water filled the maze of rooms left underground after 19 billion tons of coal was removed between 1969-1997.
Dominion suggested the mine could provide a lower reservoir site in a closed-loop project. The lowest point in the mine was only 130 feet underground, so a surface reservoir would be located at a higher elevation rather than at the mouth of the closed mine. The Wise County project would produce just 150 MW of electricity.12
the Bullitt Mine is located just west of the Town of Appalachia in Wise County
Source: ESRI, ArcGIS Online
The other location, the Tazewell Hybrid Center project near East River Mountain, would use two generating units to produce 446MW of electricity for up to 10 hours. The upper reservoir would be 893 feet higher than the lower reservoir. Dominion Energy had previously acquired 2,100 acres for a wind project that it later abandoned.
To fill the reservoirs, Dominion Energy proposed to pump water from flooded mines near the West Virginia border, and to use that source to replace water as needed to compensate for evaporation. The pipeline would parallel an existing 765kV transmission line for most of the route between the flooded mines and the pumped storage reservoirs.
The Preliminary Permit Application submitted to the Federal Energy Regulatory Commission for the Tazewell Hybrid Center stated:13
Like the Virginia City Hybrid Energy Center built by Dominion in Wise County, the locations were in the service area of another utility rather than in territory allocated to Dominion Energy. Dominion Energy could distribute the electricity via the PJM transmission grid to meet its customer needs, or simply sell the electricity at peak power prices to any other utility connected to the PJM grid.
Dominion Energy could negotiate a deal to share/sell peak power from a new pumped storage facility to Appalachian Power, the largest utility serving Southwest Virginia. The two utilities already share ownership of the Bath Pumped Storage Project.
the Tazewell Hybrid Center pumped storage project near East River Mountain would rely upon water from flooded mines near the West Virginia border
Source: Dominion Energy, Tazewell Hybrid Center Figures