Please read this article carefully if you want to learn everything there is to know about mechanical energy storage.
Strong substitutes for electrochemical battery storage are provided by mechanical energy storage, which operates in intricate systems that use heat, water, or air with compressors, turbines, and other machinery.
Both the U.S. and the energy sector For on-demand renewable energy that can be stored for a few days, the Department of Energy is funding research and development in mechanical energy storage.
We’ll talk about mechanical energy storage in this article. Please keep reading.
Pumped Heat Energy Storage
Pumped heat energy storage transforms electrical energy from the grid into thermal energy, which is then stored as a thermal potential. When operating at maximum efficiency, the system can store energy in tanks for a number of days or even weeks before reverting to electrical energy.
The system can then supply electricity at rated power for more than 10 hours. By expanding the size of the storage tanks, the system’s capacity can be further increased.
With U.S. assistance, SwRI is constructing a demonstration system for pumped heat energy storage. Supercritical carbon dioxide power systems that are compatible with energy storage systems have been designed, developed, and operated with a wide range of expertise by the Department of Energy.
Pumped Hydropower Storage (PHS)
One of the most popular energy storage technologies in use today is pumped hydro-storage. PHS technology is practical and enables the long-term storage of significant amounts of energy. (Source: ijert.org)
Utilizing the gravitational potential energy of water, pumped hydro-storage systems store electricity. The fundamental mechanism of energy conversion in this system relies on the movement of water from a higher to a lower point, as shown in the following figure.
The system operates under two different schemes. The first is the “pump scheme” (charging), in which electrical energy is supplied from the electrical grid during cheap, off-peak periods of surplus electricity in order to feed a motor that mechanically drives a pump that raises water from the lower basin to the upper one.
The second method is a “turbine scheme” (discharging), in which water simply flows naturally downward (from the upper basin to the lower one) and powers a turbine, which in turn powers mechanically a generator rotor to produce electricity that is fed back into the electrical grid during times of peak demand.
Compressed Air Energy Storage
Similar to pumped storage hydropower plants, compressed air energy storage (CAES) plants compress and store ambient air in an underground cavern during times of excess power instead of pumping water between reservoirs. The air is heated and expanded in a turbine to produce power when it is needed.
SwRI is engaged in a wide range of projects advancing CAES technology, such as the creation of heat exchangers and isothermal compression technology in addition to reciprocating and centrifugal compressor technologies to increase machinery effectiveness and range.
A piston that produces compressed air in a CAES cavern is covered by a patent that belongs to the Institute.
Flywheel Energy Storage
In high-speed rotors connected to a motor or generator and typically operating in vacuum environments, flywheel energy storage systems store energy as kinetic energy. The flywheels are excellent for short-duration, fast-response backup power because they decelerate in discharge mode.
SwRI is engaged in projects that advance the technologies of flywheel components, such as rotordynamic modeling, auxiliary bearings, and magnetic bearings.
A newer technology called isothermal compressed air energy storage (CAES) aims to get around some of the drawbacks of conventional (diabatic or adiabatic) CAES. The air is compressed to about 70 bar before storage in traditional CAES using turbomachinery.
Without intercooling, the air would heat up to about 900K, making the processing and storage of the gas impossible (or prohibitively expensive). Instead, the air is compressed and heated in stages, resulting in a lower final temperature that is close to ambient.
There is no longer a need to reheat with natural gas thanks to Advanced-Adiabatic CAES, where the heat of compression is stored separately and returned to the compressed gas upon expansion.
Emerging Energy Storage Technologies
Science and engineering services that support the development of mechanical storage and other emerging energy storage technologies include:
- Machinery development
- Cycle and system analysis and optimization
- Materials engineering
- Site evaluation and feasibility studies
- Preliminary design
- Systems Integration
- Software development