This system would provide large-scale energy storage with a capacity of 100 MW-hrs of electricity. It is equivalent to the amount of electricity used by about 33,000 homes for one hour.

Big offshore wind turbines can be used to re-charge pumped hydro storage tanks on the seafloor. Pumped hydro is extremely efficient, with nearly all of the energy stored as pumped hydro being recoverable. This is because the height, or "head" doesn't change much, and also because hydro power is the most efficient way to generate electricity. Modern hydro turbines can convert as much as 90 percent of the available energy into electricity.

Basic Design:

- 38 air-filled pipes
- made with 2.5-inch thick AISI 4620 Steel or equivalent
- 120 inches in diameter
- 50 meters long
- watertight with hemispherical caps
- sunk to a depth of 3500 meters under the ocean
- connected to vertical pipe so wind turbines can re-charge with 5000 psi compressed air
- each pipe mass is 265 tonnes, displaces 365 tonnes of water, and needs >100 tonnes of ballast mass to sink (stone)
- 38 pipes require 3800 tonnes of ballast mass in total
- floating pipes can be towed out to sea by tugboat
- 2 or 3 barges would also be needed to carry all the necessary ballast to sink them to the bottom.
- the pipes can be assembled at sea, ballast added, and slowly lowered using cables to the seafloor, while simultaneously attaching sections of a vertical compressed air conduit (not unlike an offshore oil drilling platform)

The ocean is deep. In fact, most of it is deep. Officially anything deeper than just 200 meters is considered the “deep sea”, but the average depth of the entire ocean is about 3.5 km.

If the pipe sections are sealed before they are submerged and lowered to the sea floor, then they are fully charged right from the outset. No energy input is needed. This is in contrast to nearly every other kind of energy storage system, such as thermal, flywheel, compressed air, or chemical batteries, where they are initially depleted, and large amounts of energy or electricity are needed to charge them before they can be used for the first time. Offshore deep sea pumped hydro does not have this drawback. By its nature it is fully charged as soon as it is installed.

Such an installation would be designed to be in service for at least a century, and therefore the cost could be spread out over the next 100 years.

The Abyssal Plains make up most of the world's oceans, so there is no shortage of space to put these deep sea pumped hydro energy storage systems: