The Eldorado Pumped Storage Project
Norman Rogers
30-January-2020
The Idaho company Gridflex Energy, LLC is proposing a pumped storage project to be located in remote mountains 20 miles south of Las Vegas. They have filed some preliminary paperwork with the Federal Energy Regulatory commission.
https://elibrary.ferc.gov/idmws/file_list.asp?document_id=14827339
The document submitted to FERC can be downloaded here.
A pumped storage facility stores electricity by using two reservoirs, an upper and lower reservoir. To store electricity water is pumped from the lower to upper reservoir. To recover the stored electricity water from the upper reservoir passes through a turbine that operates a generator. The water is returned to the lower reservoir. About 20% of the initial electricity is lost in the process.
The project proposed by Gridflex (alternative A) requires constructing dams to create artificial upper and lower lakes separated vertically by 1470 feet. The total length of the dams would approach 2-miles and be as high as 110 feet. Each lake can store 5500-acre feet of water. Three tunnels of diameter 22 and 25 feet and a total length of nearly 3 miles would be constructed. A powerhouse 400 feet long would be built by excavating rock.
The system could accept 600 megawatts to pump water and produce 750 megawatts when generating electricity. Electricity could be provided for approximately 8 hours before the upper lake would run dry. It is estimated that the project would generate 1.3 million megawatt hours of electricity per year.
My rough estimate of the cost based on comparisons with similar projects is $2.5 billion. The cost of storing and recovering the electricity would be in the range of $150 to $250 per megawatt hour depending detailed analysis. That would have to be added to the cost of the solar electricity input to the project, about $80 per megawatt hour unsubsidized. The total cost of the electricity would then be in the range of $230 to $330 per megawatt hour. This is extremely expensive electricity and the cost should be compared to $20 per megawatt hour, the marginal cost of electricity from existing and required natural gas backup plants.
Under existing law this project might qualify for federal subsidies if it were combined with a solar plant. But much of those subsidies are phasing out by 2022. The renewable energy industry is trying to convince congress to subsidize stand alone energy storage projects. If all the subsidies came together and the project were 75% subsidized, then the electricity would cost in the range of $57 to $82 per megawatt hour. That is still expensive.
The only reason that this project makes any sense is the Nevada renewable energy mandate that requires 50% of electricity to be from renewable sources by 2030. Most of this new renewable electricity will have to come from solar. But solar energy is delivered in the middle of the day, while electricity is needed in the late day and early evening as well as all night. The only way to get to 50% with solar is to store the electricity and release the stored electricity later in the day. The alternatives for storing electricity are pumped storage or batteries. Both are expensive. The Crescent Dunes thermal power plant stored energy in the form of heat in a tank of molten salts. That plant failed to work well and is probably headed for bankruptcy.
The renewable energy mandate results in increasingly impractical and pointless projects.
The location of the project is shown by the red marker below:
Norman Rogers
30-January-2020
The Idaho company Gridflex Energy, LLC is proposing a pumped storage project to be located in remote mountains 20 miles south of Las Vegas. They have filed some preliminary paperwork with the Federal Energy Regulatory commission.
https://elibrary.ferc.gov/idmws/file_list.asp?document_id=14827339
The document submitted to FERC can be downloaded here.
A pumped storage facility stores electricity by using two reservoirs, an upper and lower reservoir. To store electricity water is pumped from the lower to upper reservoir. To recover the stored electricity water from the upper reservoir passes through a turbine that operates a generator. The water is returned to the lower reservoir. About 20% of the initial electricity is lost in the process.
The project proposed by Gridflex (alternative A) requires constructing dams to create artificial upper and lower lakes separated vertically by 1470 feet. The total length of the dams would approach 2-miles and be as high as 110 feet. Each lake can store 5500-acre feet of water. Three tunnels of diameter 22 and 25 feet and a total length of nearly 3 miles would be constructed. A powerhouse 400 feet long would be built by excavating rock.
The system could accept 600 megawatts to pump water and produce 750 megawatts when generating electricity. Electricity could be provided for approximately 8 hours before the upper lake would run dry. It is estimated that the project would generate 1.3 million megawatt hours of electricity per year.
My rough estimate of the cost based on comparisons with similar projects is $2.5 billion. The cost of storing and recovering the electricity would be in the range of $150 to $250 per megawatt hour depending detailed analysis. That would have to be added to the cost of the solar electricity input to the project, about $80 per megawatt hour unsubsidized. The total cost of the electricity would then be in the range of $230 to $330 per megawatt hour. This is extremely expensive electricity and the cost should be compared to $20 per megawatt hour, the marginal cost of electricity from existing and required natural gas backup plants.
Under existing law this project might qualify for federal subsidies if it were combined with a solar plant. But much of those subsidies are phasing out by 2022. The renewable energy industry is trying to convince congress to subsidize stand alone energy storage projects. If all the subsidies came together and the project were 75% subsidized, then the electricity would cost in the range of $57 to $82 per megawatt hour. That is still expensive.
The only reason that this project makes any sense is the Nevada renewable energy mandate that requires 50% of electricity to be from renewable sources by 2030. Most of this new renewable electricity will have to come from solar. But solar energy is delivered in the middle of the day, while electricity is needed in the late day and early evening as well as all night. The only way to get to 50% with solar is to store the electricity and release the stored electricity later in the day. The alternatives for storing electricity are pumped storage or batteries. Both are expensive. The Crescent Dunes thermal power plant stored energy in the form of heat in a tank of molten salts. That plant failed to work well and is probably headed for bankruptcy.
The renewable energy mandate results in increasingly impractical and pointless projects.
The location of the project is shown by the red marker below:
