Large Scale Energy storage offers the opportunity to store, or ‘bank’ ‘wrong time’ energy and time-shift it to periods of peak demand or hold it in reserve. This is critical to enable the use of intermittent renewable power (e.g. wind or solar) when the customer needs it, not just when it is available. It can equally “provide shape” to must-run generation (i.e. nuclear or Energy from Waste/biomass), moving excess off-peak energy to the peak demand and pinch points. It also reduces both the capital cost and carbon footprint of electricity networks by making them more efficient; with stored reserves – not over-capacity of generation in reserve – to manage supply and demand.
Electricity supply and demand have to match on a second by second basis. Historically, the balance is achieved by significantly overbuilding generation, transmission, and distribution assets, and specifically keeping enough quick response generation in reserve. This is unlike any other commodity market, where storage/reserves are used to manage supply and demand, including unexpected imbalances.
Currently, quick response reserve generation includes (i) ‘spinning reserve’: generation plants burning coal or other hydrocarbons, but producing reduced power so as to be in a state of readiness; or (ii) gas and diesel generators: quick to start but environmentally poor.
Emission and environmental legislation, plus the simple cost of building over-capacity into the network is driving the need for a zero emission solution.
Primary applications in current market
- “shaping” inflexible plant (e.g nuclear).
- “firming” intermittent plant (e.g. wind, solar).
- use as a trading tool by traders or consumers of electricity.
- providing ancillary services (peaking, reserve, reactive power etc) to the grid operator.
- network applications, particularly deferring network expenditure to resolve constraints.
- back-up/security of supply for larger consumers.
- waste heat to power.
- cold can also be of value to co-located processes.
The applications are not necessarily mutually exclusive. It is possible to blend income streams from different applications.