What is an Energy Storage System for EVs?

Bridging the infrastructure and demand gap

Energy Storage Systems

With the Government announcing some electric hubs on motorways will make use of Energy Storage Systems, you might be wondering what the heck one is.

An Energy Storage System (ESS) is a giant battery pack connected to the grid that stores a tremendous amount of energy for use at a later time.

ESSs store at least several megawatt-hours of energy (there are 1,000kWhs in 1MWh). An ESS can supply power on-demand for EV charging as a standalone power source and supplementary to the grid.

ESSs are crucial for electromobility (or e-Mobility), creating connected infrastructures that enable the electric propulsion of vehicles and fleets.

What does an ESS do?

An Energy Storage System bridges the gap between grid infrastructure and rapid charging demand. It effectively fills in for poor grid infrastructure, but also helps balance generation and supply with a scalable architecture.

ESSs bolster grid efficiency and supply in several ways:

  • Integrates with the grid to supply reliable power
  • Stores energy for use during demand peaks
  • Flattens demand peaks, reducing stress on the grid
  • Reduces power fees related to short-time peak loads
  • Supports maximum loads for rapid charging infrastructure

The ESS can also power the lights and heating systems in electric hub facilities, effectively reducing demand on the grid across the hub, as well as provide power in the event of power outages.

Additionally, Energy Storage Systems are bidirectional, so they can feed the grid with electricity. Batteries dedicated to grid applications help supplement demand, so when the local grid needs power, the ESS is made available.

How does Energy Storage System work?

ESSs store energy in quiet periods and release energy in busy periods, solving several challenges related to poor grid infrastructure.

ESS schematic example

ESSs charge from the grid, but they are rated to hold enough energy to meet maximum demand for several weeks without charging.

In theory, the ESS can charge hundreds of vehicles at peak times and then charge itself when demand on the grid is lowest. Or, it can stay topped up above a certain level at all times with a trickle charge, depending on the configuration.

When specifying ESSs, the battery chemistry, cell and system must be considered, so that the device provides optimal performance.

ESSs can also connect to solar panels and other renewable energy systems, charging with 100% clean energy and acting as a link between renewable energy devices and rapid chargers.

ESSs are necessary for the transition to electric vehicles because many of the service stations across the UK’s motorways do not have a sufficient grid supply for rapid charging infrastructure.

National Highways to invest £11m in energy storage

The Government-owned company National Highways will make an £11 million investment in ESSs over the next few years.

With the growth in demand for rapid chargers comes pressure to power them, especially in areas without significant grid infrastructure. By investing in ESSs, more motorway services can offer rapid charging infrastructure.

“These new Energy Storage Systems and the rapid chargers they supply will ensure that motorists are unlikely to be caught without somewhere to charge, which is a fantastic move for drivers and the environment accelerating the speed in which we transition to new electric vehicles.”

Malcolm Wilkinson, head of energy at National Highways

The £11 million allocated investment is being covered by National Highways’ Designated Funds programme, which bridges the gap in investment in social and environmental issues related to UK roads.

Further reading

If you like this article check out our guide to Vehicle to Load (V2L).

Jakk is the founder and chief editor of Top Charger. He drives a Volkswagen ID.3 Family Pro Performance, and despite having a lead right foot, he consistently gets over 200-miles of range.