Differences in Scalability and Costs
- Scalability Costs: Small PSH projects generally cost more per kilowatt compared to large projects due to economies of scale. For every 10x increase in power capacity, system costs decrease by approximately 16% in terms of $/kW, with a more conservative estimate due to factors like geology and storage head.
- Component Costs: Large projects benefit from reduced costs per unit for components such as pumps and turbines, as well as civil engineering works like dams and tunnels. In contrast, smaller projects have higher unit costs for these components.
- Economies of Scale: Large-scale PSH facilities can spread fixed costs over a larger capacity, leading to lower costs per megawatt-hour (MWh) compared to smaller projects.
Configuration and Design Differences
- Reservoir Size: Smaller PSH projects might require proportionally larger reservoirs for the same amount of stored energy, which can increase costs. However, higher heads in some projects reduce reservoir size needs, affecting costs positively.
- Construction Methods: Innovative construction methods, such as using vertical shaft drilling for pump-turbine housings, can significantly reduce costs for both large and small projects but may be more feasible for smaller sites due to reduced complexity.
Cost Models and Estimations
- NREL Cost Model: The National Renewable Energy Laboratory (NREL) provides a bottom-up cost model for PSH projects that allows users to estimate costs based on specific site conditions. This model includes provisions for small PSH systems (<25 MW) and can adjust for various design choices.
- Cost Ranges: Total project costs for PSH plants have been estimated to range from approximately $2,300 to $3,500 per kilowatt, depending on project specifics. For small-scale or high-head projects, these costs might vary based on site conditions and design decisions.
Performance and Efficiency
- Efficiency and Energy Costs: Pumped hydro storage offers one of the lowest costs per megawatt-hour of any energy storage technology, typically between $200 and $260 per MWh, due to its high round-trip efficiency and long project lifespan.
In summary, while large PSH projects generally benefit from economies of scale and reduced unit costs, small projects can still be viable with efficient design and construction methods. However, the costs per unit of energy stored or generated are typically higher for smaller projects.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-main-differences-in-costs-between-large-and-small-pumped-hydro-storage-projects/
