Trigeneration Energy Storage

About

Tri‐generation Resorption Efficient Energy Storage System—TREES The Problem It is estimated by the UK Government (Department for Business, Enterprise and Regulatory Reform) that 40TWh per annum of recoverable low grade heat is wasted in the UK in 2008. Globally, it is estimated that around 140 GW of large scale energy storage is installed in electricity grids, which indicates opportunity for utilising the redundant heat in a more efficient manner. In order to achieve this utilisation, there is an increasing need for intelligent thermal chemical storage systems which can be used when required, to upgrade low grade heat for higher temperature use leading to contribute to the huge heat demand across UK (which accounts for 40% of total energy consumption), or used to offset electricity and/or cooling demand within a plant. The Solution; The technology relates to a novel thermal‐chemical system based on sorption cycle, Tri‐generation Resorption Efficient Energy Storage (TREES) system. The developments have explored the integration with turbomachinery for better energy provision and management with greater flexibility and scalability. By using reversible chemical reactions, for example between refrigerant gases (such as steam or ammonia) and solid sorbents (such as metallic oxides, alkaline and halide salts), the proposed system can achieve the utilisation of ultralow‐to‐low grade heat and electrical power (either cheaply available from grid or from renewable generation such as solar PV or wind turbine) or the storage of them in long term (with minimal losses) at low pressure, and then to flexibly satisfy the demand for electricity, heating and/or cooling. As resorption cycle comprises at least two reactors, one containing high temperature salt (HTS) and the other low temperature salt (LTS). An initial UK and PCT patent application has been granted for this technology. Initial setup process includes: A1) Low grade heat is used and stored through chemical reaction with the co‐product of electrical power by expanding the high pressure working fluid through a generator. A2) Electrical power and ultralow grade heat is utilised and stored through chemical reaction, as the compression makes it possible to recover the thermal energy from ultralow level. B1) The chemically stored energy is recovered to deliver cooling if the reverse reaction occurs at the ambient temperature. B2) The chemically stored energy is recovered to deliver heating if at least ultralow thermal energy is utilised. B3) The chemically stored energy is recovered to deliver electrical power if at least ultralow thermal energy is utilised with an expander/ turbine. The core advantages of this technology is its flexible capacity and scalability, as this implied an ability for the system to be installed at multiple locations, in contrast to some other Energy Storage System technologies which are restricted in scale and therefore in their geographical siting. The Opportunity The initial analytical results have been encouraging and has demonstrated the potential of TREES for a number of avenues, e.g. maximising the utilisation of recoverable low grade heat, storing thermal and electrical energy, contributing to decarbonisation, minimizing environmental impact, increasing the penetration of renewable energy and so on. We have identified some immediate areas requiring further investigation, e.g. there are countless reactant materials to be tested, cycle optimisation, advanced cycle development and operation strategy for whole system development. The University is seeking engagement with potential stakeholders and commercial organisations to work on collaborative development programs to take this technology forward towards successful commercialisation.