Introduction to mechanical energy storage:
When talking about energy storage it is now common to think about Li-ion batteries, due to their success in the automotive sector, portable electronic devices, and stationary applications. In the last few years Li-ion batteries started to be constantly adopted in stationary energy storage with a power output of few kWs up to MWs scale. Although a powerful device, their application can hardly cover the entire range of power and energy demanded by the electricity grid. If one end is dominated by Li-ion batteries, on the other end, pumped hydro energy storage is the reference system to deliver large power output, and store large amounts of energy able to generate electricity for days. Pumped hydro energy storage was the first large power plant built to generate electricity, and still nowadays is the reference technology for large power output.
Between these two main technologies, a number of new technologies with a power output of tens of MWs are currently approaching the market. In the new report released: "Potential Stationary Energy Storage to Monitor", IDTechEx investigated this new group of technologies aiming to address MWs of power output and long storage time.
The technologies defined as mechanical energy storage include different types of technologies, all of them characterised by a large power output from MW size, and a simple mechanical working principles. Among them:
- Gravitational Energy Storage
- Compressed Air Energy Storage
- Liquid Air Energy Storage
Power and storage capacity comparison of different technologies
These technologies are based on simple mechanical working principles, which allow them to employ well known components, like pumps, ventilators, cranes, and do not employ dangerous materials. A simple working principle implies high round-trip efficiencies, in most cases close to 80%. Finally, differently from electrochemical systems, mechanical energy storage systems are not affected by self-discharge, allowing them to store electricity for an indefinite amount of time.
Large amounts of energy, similarly to mechanical energy storage systems, could also be stored by hydrogen and ammonia. Storing electricity as chemical energy implies the adoption of other technologies like fuel cells, which strongly affect the overall efficiency of the system.
The growing interest in the renewable energies, driven by the necessity to decarbonise the electricity market, is leading to a growing adoption of energy storage devices. While renewable electricity sources allow us to reduce polluting emissions, their variable nature requires extra systems to adjust the timing of energy production and energy consumption. In addition, the adoption of renewable energies is leading to an upgrade of the electricity grid, shifting the power grid from a centralised model, to decentralised energy production. Therefore, the role of energy storage is constantly growing, and with it the technologies involved.
Due to growing interest in energy storage devices, in particular for grid application, IDTechEx releases the new report titled: "Potential Stationary Energy Storage to Monitor", introducing an emerging group of technologies.
The report begins with an introduction about the electricity grid, explaining the role of energy storage systems, and the market these devices can address. In the following chapters, the different mechanical energy storage technologies are investigated. For each technology the working principle is initially explained, followed by an analysis of the main companies involved, showing the main advantages and disadvantages of the systems analysed. Moreover, the executive summary provides the reader with a comparison of the different technologies, showing the different TRL (technology readiness level) and MRL (manufacturing readiness level) of the technologies analysed in the report. A comparison of mechanical energy storage with Li-ion batteries and redox flow batteries allows the reader to appreciate the differences between these technologies. In conclusion, a market forecast for the period 2020-2030, in terms of installed power, energy and market size is provided, together with the technology breakdown.
Market forecast, and market forecast breakdown - IDTechEx Source