To compare the cost of Compressed Air Energy Storage (CAES) with Pumped Hydro Storage (PHS), we need to consider both the capital costs and operational efficiencies of these technologies.
Cost Comparison
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Compressed Air Energy Storage (CAES):
- Capital Cost: CAES costs can vary widely depending on the location and availability of suitable underground caverns. On a cost-per-kWh basis, CAES has been reported at approximately $119/kWh for ideal locations near naturally occurring caverns. However, when considering the capital cost per kilowatt, CAES facilities can range from $850 to $1,250/kW.
- Installed Cost for LDES: Fully installed systems have an average global capex cost of $293/kWh.
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Pumped Hydro Storage (PHS):
- Capital Cost: PHS systems are typically more expensive upfront. They require large reservoirs and significant civil engineering, leading to higher costs. A 100 MW, 10-hour installed PHS system is estimated to cost approximately $262/kWh.
- Reservoir and Powerhouse Costs: The major components include the reservoir ($76/kWh) and powerhouse ($742/kW), indicating significant initial investment.
Efficiency and Operational Costs
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Compressed Air Energy Storage (CAES):
- Efficiency: CAES systems generally have lower efficiency, typically ranging from 40% to 52%, due to energy losses during compression and expansion.
- Operational Costs: These include electricity costs for air compression and natural gas for heating the air during expansion. Increased natural gas prices can negatively impact CAES economics.
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Pumped Hydro Storage (PHS):
- Efficiency: PHS systems are relatively efficient, with round-trip efficiencies often above 70% to 85%, making them more energy-efficient than CAES.
- Operational Costs: PHS operational costs are generally lower since they primarily involve electricity for pumping water and mechanical maintenance. They do not require additional fuels like natural gas.
Conclusion
- CAES offers competitive capital costs, especially when sited near natural caverns, but suffers from lower efficiency and higher operational costs due to energy losses and fuel requirements.
- PHS is more efficient and has lower operational costs but requires significant upfront investment and suitable geography, limiting its potential deployment areas.
Both technologies are crucial for long-duration energy storage, but their viability depends on specific regional conditions and energy needs.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-cost-of-compressed-air-energy-storage-caes-compare-to-pumped-hydro-storage-phs/
