Pumped Hydro LCOS Calculator
This calculator estimates the levelized cost of storage (LCOS) for a pumped hydro storage project -- the all-in cost to store and re-deliver one megawatt-hour of electricity across the facility's full operating life, rolling upfront capital, charging energy, round-trip efficiency losses, and operating costs into a single cost-per-MWh figure. It pairs naturally with our Pumped Hydro Storage Sizing Calculator for translating a reservoir volume and head into the energy capacity this calculator needs, and our Flow Battery LCOS Calculator for a direct comparison against a vanadium flow battery system over the same lifecycle.
The system's continuous power output rating, set by turbine and pump sizing.
See the Pumped Hydro Storage Sizing Calculator to estimate this from reservoir volume and head. 4,000 MWh at 500 MW represents an 8-hour duration.
Turbines, generators, and powerhouse infrastructure typically cost $1,500-2,500/kW.
Reservoir and civil works cost per kWh of storage is comparatively low at pumped hydro's massive scale -- a key reason pumped hydro remains cost-competitive for very large, long-duration storage despite high total project cost.
Pumped hydro typically achieves 75-85% round-trip efficiency, among the highest of any grid-scale storage technology.
How many full charge/discharge cycles the system performs per year. Pumped hydro is often cycled daily or near-daily, but many projects cycle less due to water management and seasonal considerations.
Pumped hydro facilities commonly operate 50-100 years -- among the longest asset lives of any grid-scale generation or storage technology.
Annual operating and maintenance cost as a percentage of total installed cost, applied each year over the plant life.
The price of the electricity bought to pump water uphill. Off-peak, curtailed solar, or surplus wind commonly runs $10-40/MWh.
(power rating (MW) × 1000 × power-related capital cost ($/kW)) + (energy storage capacity (MWh) × 1000 × energy-related capital cost ($/kWh))
energy storage capacity (MWh) × cycles per year × plant life (years)
(total installed cost + lifetime charging cost + lifetime O&M cost) ÷ lifetime energy discharged (MWh)
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →Pumped hydro's decades-long operating life is the real economic advantage: amortizing a $1.1 billion project over 60 years and 15,000 lifetime cycles produces an LCOS around $72/MWh in this example -- meaningfully lower than a comparable flow battery system's roughly $157/MWh, despite pumped hydro's much larger absolute price tag. This is the core lesson of long-duration storage economics: total installed cost matters far less than cost per unit of energy delivered over the asset's full operating life, and few technologies can match pumped hydro's combination of massive scale and multi-generational longevity.
How pumped hydro LCOS is calculated
This calculator estimates the levelized cost of storage (LCOS) for a pumped hydro storage project -- the total cost to store and re-deliver electricity across the facility's full operating life, divided by the total energy discharged over that life. Eight quantities tie the calculation together.
Total Installed Cost ($) = (Power Rating (MW) × 1000 × Power-Related Capital Cost ($/kW)) + (Energy Storage Capacity (MWh) × 1000 × Energy-Related Capital Cost ($/kWh)). The first term is the fixed power cost: converting the power rating from megawatts to kilowatts (× 1000) and multiplying by the cost per kW of power-handling infrastructure (turbines, generators, penstocks, powerhouse) gives a cost that does not change with how many hours of energy the system stores. The second term is the energy cost: converting the energy capacity from megawatt-hours to kilowatt-hours (× 1000) and multiplying by the cost per kWh of energy-storage medium (reservoir construction, civil works, water infrastructure) gives a cost that scales directly with storage capacity. Summing the two gives the all-in upfront capital cost. At the defaults (500 MW, 4,000 MWh, $1,800/kW, $50/kWh), that is (500 × 1000 × $1,800) + (4,000 × 1000 × $50) = $900,000,000 + $200,000,000 = $1,100,000,000.
Lifetime Cycles = Cycles per Year × Plant Life (years). Multiplying the annual cycle count by the operating life gives the total number of charge/discharge cycles the system performs. At the defaults (250 cycles/year and 60 years), that is 250 × 60 = 15,000 cycles.
Lifetime Energy Discharged (MWh) = Energy Storage Capacity (MWh) × Lifetime Cycles. Multiplying the energy capacity by the lifetime cycle count gives the total energy discharged over the project's full life. At the defaults (4,000 MWh and 15,000 cycles), that is 4,000 × 15,000 = 60,000,000 MWh.
Lifetime Charging Energy Required (MWh) = Lifetime Energy Discharged (MWh) ÷ (Round-Trip Efficiency (%) ÷ 100). Because round-trip efficiency means you always get back less than you put in, the charging energy required exceeds the energy discharged. At the defaults (60,000,000 MWh and 80% RTE), that is 60,000,000 ÷ 0.80 = 75,000,000 MWh.
Lifetime Charging Cost ($) = Lifetime Charging Energy Required (MWh) × Charging Electricity Price ($/MWh). Multiplying the total charging energy by the price of that electricity gives the lifetime cost of the energy bought to pump water uphill. At the defaults (75,000,000 MWh and $30/MWh), that is 75,000,000 × $30 = $2,250,000,000.
Lifetime O&M Cost ($) = Total Installed Cost ($) × (Annual O&M Cost (%) ÷ 100) × Plant Life (years). Applying the annual O&M percentage to the installed cost and multiplying by the operating life gives the total operating and maintenance cost over the project. At the defaults ($1,100,000,000, 1.5% and 60 years), that is $1,100,000,000 × 0.015 × 60 = $990,000,000.
Total Lifetime Cost ($) = Total Installed Cost ($) + Lifetime Charging Cost ($) + Lifetime O&M Cost ($). Summing the upfront capital, the lifetime charging cost, and the lifetime O&M cost gives the all-in cost of owning and operating the facility across its full life. At the defaults, that is $1,100,000,000 + $2,250,000,000 + $990,000,000 = $4,340,000,000.
LCOS ($/MWh) = Total Lifetime Cost ($) ÷ Lifetime Energy Discharged (MWh). Dividing the total lifetime cost by the total energy discharged gives the levelized cost per megawatt-hour delivered -- the single all-in figure that lets you compare this pumped hydro project against other storage technologies or against the revenue you expect it to capture. At the defaults, that is $4,340,000,000 ÷ 60,000,000 = $72.33/MWh.
Two notes on the model. First, this is a simplified undiscounted LCOS: it does not apply a discount rate to future costs, does not model capacity degradation or major equipment refurbishment, and treats cycles, O&M, and charging price as constant across the full life -- a more detailed model would discount future cash flows and account for periodic refurbishment of turbines and generators over a multi-decade operating life. Second, the result is most sensitive to plant life (which, at 50-100 years, is exceptionally long for pumped hydro and drives the capital cost amortization), energy-related capital cost per kWh (which is comparatively low thanks to cheap reservoir storage at scale), and charging electricity price (which compounds across thousands of cycles), so the editable fields let you substitute project-specific values. Data sources: Pumped hydro capital cost ranges and operating life from DOE (Department of Energy), NREL (National Renewable Energy Laboratory), and IRENA (International Renewable Energy Agency) energy storage technology assessments; pumped hydro round-trip efficiency ranges from DOE and NREL studies; pumped hydro power-related and energy-related cost decomposition from industry benchmarks and feasibility studies; LCOS methodology from standard levelized cost of storage frameworks. Verification: with defaults (500 MW, 4,000 MWh, $1,800/kW, $50/kWh, 80% RTE, 250 cycles/yr, 60 years, 1.5% O&M, $30/MWh), Total Installed Cost = $1,100,000,000, Lifetime Energy Discharged = 60,000,000 MWh, LCOS = $72.33/MWh.