Energy may be stored by injecting fluid into a fracture in the earth and producing the fluid back while recovering power and/or desalinating water. The method may be particularly adapted to storage of large amounts of energy such as in grid-scale electric energy systems. The fracture may be formed and treated with resin so as to limit fluid loss and to increase propagation pressure. The fluid may be water containing a dissolved salt or fresh water and a portion or all of the water may be desalinated using pressure in the water when it is produced.

A process for treating waste water, including the steps of extracting by forward osmosis treated water from a wastewater feed stream and transferring it to a saline draw stream, and extracting from the saline draw stream treated water by a reverse osmosis process.

An electrolyzer operates within an energy system, for example to provide grid services, energy storage or fuel, or to produce hydrogen from electricity produced from renewable resources. The electrolyzer may be configured to operate at frequently or quickly varying rates of electricity consumption or to operate at a specified power consumption. In one process of operating an electrolyzer, a series of dispatches is received indicating a specified power consumption for a period of time. The dispatches may occur at least once every 30 minutes. The electrolyzer is operated according to the dispatches. Hydrogen produced by the electrolyzer is discharged to a natural gas system.

Materials, such as biomass feedstocks (e.g., plant biomass, animal biomass, and municipal waste biomass) are processed to produce useful products, such as fuels. Conveying systems, such as flowing gas conveying systems and such as closed-loop flowing gas conveying systems are described.

An engineered ecosystem, moderating eight primary systemsthermal management, atmospheric optimization, radiation controls, hydrological systems, energy systems, material flows, systems management, and built systemsto provide homeostatic regulation of cascading flows of matter and energy.

Materials (e.g., plant biomass, animal biomass, and municipal waste biomass) are processed to produce useful intermediates and products, such as energy, fuels, foods or materials. For example, systems equipment, and methods are described that can be used to treat feedstock materials, such as cellulosic and/or lignocellulosic materials, using an array of vaults.

A wastewater purification system is provided. The wastewater purification system comprises a chamber. One or more wastewater nozzles are positioned near the top of the chamber. An intake duct is further provided to supply chilled air into the chamber, and one or more exhaust ducts are provided to remove the chilled air from the chamber. One or more perforated receptacles positioned near the bottom of the chamber to collect solid byproducts, and a watertight receptacle at the bottom of the chamber to collect a liquid product. The wastewater enters the chamber as wastewater droplets via the one or more wastewater nozzles, wherein the wastewater undergoes freeze separation due to heat exchange with a high mass flow of the chilled air between the intake duct and the one or more exhaust ducts.

Disclosed are methods to predict the occurrence of polarization and the design and operation of electrochemical systems to maintain a current density below the limiting current density and avoid instability.

Saline water from a body of water is desalinated using a water purification system. Chambers of a plurality of tanks are filled with a volume of saline water. The saline water is heated to increase a pressure and produce water vapor within the chamber of each tank. A condensation valve disposed within a condensing tube is moved to an open position such that the water vapor is released into a respective condensing tube. The water vapor is condensed to provide potable water.

A dialysis system for determining an amount of total chlorine in a partially purified water sample is disclosed. The system includes a water machine that produces at least partially purified water including an at least partially purified water sample and a dialysis machine that provides a dialysis treatment to a patient. The dialysis machine receives the at least partially purified water from the water machine to prepare dialysis fluid for the dialysis treatment. The system also includes a total chlorine detector configured to receive the at least partially purified water sample, at a first time apply a source voltage to the at least partially purified water sample, and at a second time stop applying the source voltage to the at least partially purified water sample and instead monitor a sensed electrical parameter to determine an amount of total chlorine in the at least partially purified water sample.