Pumped storage is the main storage technology used in the US. The 1970s saw a large rollout of pumped hydro plants which were economically viable due to high oil prices, and high cost of intermediate load and peak energy. Costs for pumped hydro plants in the late 70s were estimated to be in the range of USD 110 to 280 per kW compared to USD 175 to 275 for natural gas combined-cycle generators of a similar capacity. In addition, the use of oil and gas fuel was restricted in new power plants under the ‘Powerplant and Industrial Fuel Use Act’. Therefore, there was sufficient base load capacity, but limit load-following and ‘peaking’ power plants.
Then low gas prices in the 1980s, improvements in gas turbine technology and the repeal of the ‘Powerplant and Industrial Fuel Use Act’ resulted in a move away from the construction of new pumped hydro and towards load following and peaking gas plants.
Currently the US has around 21 GW of pumped storage capacity. By 2025 it is estimated that an additional 10 GW of pumped storage capacity could be developed.
In recent years there has been an increase in new pumped storage projects and refurbishment of existing capacity. In order to meet state renewable portfolio standards (RPS) for grid-connected intermittent renewable capacity, storage capacity needs to be added to the electric grid.
The number of licences awarded for hydro projects have down in recent years, although many have an expiration date a long time in the future. During the first three quarters of 2010, ten hydroelectric projects have been granted a license and one hundred and four projects are pending pre-permits from FERC including seven pumped storage projects. Many of these projects may not come to fruition and not all projects need FERC approval to go ahead, and the majority are likely to be a relicensed project