A system for desalinating water is disclosed. The system comprises a subsea reverse osmosis unit located beneath the surface of a body of water, a first liquid column comprising seawater, a second liquid column comprising desalinated water with a salinity less than seawater, and a brine discharge outlet. Due to the difference in density between the seawater and the desalinated water, the gravitational hydrostatic pressure of the first liquid column may be greater than the gravitational hydrostatic pressure of the second liquid column. At least a portion of the pressure difference for reverse osmosis desalination may be provided by the difference in gravitational hydrostatic pressure between the first liquid column and the second liquid column. A significant reduction in desalination energy consumption may be enabled by discharging the brine at an elevation lower than the maximum elevation of the first liquid column or the second liquid column.

The present application pertains to systems and methods for desalination. In one embodiment the system employs a first storage reservoir configured to be near the surface of a body of water and configured to store a low density fluid. A second storage reservoir is configured to be located below the surface of the body of water. A desalination system is operably connected to the second reservoir. Desalinated water is produced by allowing desalination permeate to displace low density fluid in the second reservoir and transfer the low density fluid from the second reservoir to the first reservoir. Desalinated water is exported by transferring low density fluid from the first reservoir into the second reservoir to displace desalinated water from the second reservoir into a water export pipeline.

A subterranean energy storage system configured to store and subsequently release potential energy. Storage of potential energy is achieved by the transfer of a pseudo fluid from a first storage tank to a second storage tank located above the first storage tank, and is subsequently released by the transfer of the pseudo fluid from the second storage tank to the first storage tank. To transfer the pseudo fluid between the first and second storage tanks, the subterranean energy storage system comprises at least one continuous conveyor mechanism extending through at least one transport shaft, wherein the at least one continuous conveyor mechanism comprises a plurality of vessels arranged along a length of the continuous conveyor mechanism. The subterranean energy storage system further comprises an energy transfer means operably connected to the at least one continuous conveyor mechanism to transfer power to and from the subterranean energy storage system.

Disclosed techniques include energy management with multiple pressurized storage elements. Energy is obtained from one or more energy sources. Energy requirements are modeled over a first time period and a second time period. A first subset of the energy that was obtained is allocated for storage in a first energy store based on the modeling. A second subset of the energy that was obtained is allocated for storage in a second energy store based on the modeling, where the second energy store comprises a pressurized storage element. Energy is routed to the first energy store from the second energy store based on the modeling. Recovering energy further includes using the energy routed to the first energy store or the second energy store, based on the modeling.

A method for liquid air and gas energy storage (LAGES) which integrates the processes of liquid air energy storage (LAES) and regasification of liquefied natural gas (LNG) at the import terminal through the exchange of thermal energy between the streams of air and natural gas (NG) in their gaseous and liquid states and includes harnessing the LNG as an intermediate heat carrier between the air streams being regasified and liquefied, recovering a compression heat from air liquefier for LNG regasification and utilizing a cold thermal energy of liquid air being regasified for reliquefaction of a part of send-out NG stream with its return to LNG terminal.

Disclosed are a power plant that uses a synchronous generator using a working fluid for generation of electric power, and a method of controlling the power plant, the power plant and the control method having an advantage of preventing damage to the power plant during synchronization with an electrical grid. The power plant comprises a pump for compressing a working fluid, a heat exchanger for heat transfer from an external heat source to the working fluid transferred from the pump, and a power turbine generator for generating a rotational force by using the working fluid heated by the heat exchanger, generating electricity using the rotational force, and supplying the electricity to an electrical grid.

The devices, systems, and methods described herein are directed to buffering the electrical energy output from a PV array before storing the electrical energy in a battery storage system of the PV system. In some examples, a buffering module receives electrical energy from one or more PV cells at a first level that exceeds a threshold charging rate of a battery storage system. The buffering module temporarily stores the electrical energy before outputting the electrical energy to the battery storage system at a second level that is at or below the threshold charging rate of the battery storage system.

The method according to the invention relates to the storage of energy in the form of a compressed fluid which is pumped into a container (2) arranged below a water surface (4) to store the energy, wherein the fluid entering the container displaces an existing content, comprising water, from the container and into the surrounding water, and compressed fluid is removed from the container (2) to remove energy, wherein surrounding water flows back into the container according to the volume of the removed, compressed fluid, characterized in that the container (2) is provided with flexible walls at least in some parts and is arranged on a seabed (6) or lake bed (6) and there is covered by ballast (15) such that it is pressed against the substrate even when completely filled with compressed fluid.

A combined gas-liquid two-phase energy storage and power generation system includes a compressed gas storage unit, a first gas pipeline, a liquid piston device, a hydraulic energy conversion unit and a first pumped power generation unit. The combined gas-liquid two-phase energy storage and power generation system connects the liquid piston device and a first port group of the hydraulic energy conversion unit and receives/outputs the hydraulic potential from/to the first port group, and connects the first pumped power generation unit with the second port group of the hydraulic energy conversion unit and receives/outputs the hydraulic potential from/to the second port group.

A power storage and discharge system includes one or more power receiving points of an AC source supplied from a predetermined power system, and an AC-DC converter for converting the AC source supplied from the predetermined power system into a DC source. Any of two or more equally dividable storage battery groups is charged based on the DC source converted by the AC-DC converter. AC power is discharged or generated due to discharging by a discharge resource using the charged DC source. The power receiving points of the AC source include one or more power receiving points, disposed from an upper side toward a lower side with respect to the predetermined power system, other than a point where the power discharged or generated due to discharging by the discharge resource is interconnected to the power system.