Battery energy storage systems are often quoted in terms of their power (measured in megawatts or kilowatts). However this is not helpful unless there is an indication of how much electrical capacity is offered by the system. It is a common mistake is to use the term capacity when referring to the power rating of the battery system.

A Battery Energy Storage System rated at 400MW cannot be compared with a 400 MW Power station. A power station can produce 400 MW of power continuously, apart from short periods of shut down from time to time for servicing. As long as there is energy to drive the drive the turbines which themselves drive the electricity generator, 400MW will be available to distribute into the national grid.

A Battery Energy Storage System will have a limit to the power it can supply to the electrical grid. The energy rating, or battery capacity, of the battery system measured in Megawatt-hours MWh indicates the amount of electrical energy that can be stored and delivered into the National Grid. But it provides this power for a limited amount of time. Statera Energy have now stated that their proposed BESS can deliver 400 MW for 6 hours, that is to say that the planned capacity of the BESS is 2400 MWh. The product of MW output and time in hours cannot exceed 2400 MWh.

A summary of the top Battery Energy Storage Systems which are in use or under construction are listed on the website referenced here.

These are:

Vistra Energy Corporation
This Energy Storage Facility is the world's biggest battery energy storage system so far
Moss Landing, California, US Power rating of 400MW
Capacity 1,600MWh
Manatee Energy Storage Center Florida, US
132 Energy Storage Containers over 40 acres
340,000 solar panels across 751 acres
Power rating of 409MW
Capacity 900 MWh.
Victorian Big Battery Geelong, Australia Power rating of 350MW
Capacity 450 MWh
McCoy Solar Energy Project Mohave Desert California Power rating of 230 MW
Capacity 920 MWh
Elkhorn Battery Elkhorn California
256 Tesla Megapacks (3 MWh each)
Power rating 182.5MW
Capacity 730 MWh

The 2400 MWh BESS proposed by Statera would be housed in 600 12m shipping containers, each weighing 44 tonnes. They would be delivered to the site via Glennie Way through Chickerell to Coldharbour.

The map shows the proposed site of the BESS and the projected route to deliver the containers is shown in dark blue.

Such large containers would require articulated lorries to transport them.

Currently, Europe's largest Battery Energy Storage System is at Pillswood, Cottingham East Yorkshire. This is 196MW and was developed by Harmony Energy. There is also a 320MW Battery Energy Storage System being developed at London Gateway.

As shown in the table above, the largest Battery Energy Storage System so far is at Moss Landing California. If the project at Chickerell were to get the green light, residents of Chickerell and Southhill would have the doubtful distinction of being next door to one of the World's largest Battery Energy Storage Systems.

Moss Landing

The site proposed by Statera Energy for their monster Battery energy Storage System is in the middle of a residential area.

Yet in comparison the Battery Energy Storage System at Moss landing is well isolated.

The nearest conurbation to Moss Landing is San Jose, about 55 miles to the North, while San Francisco is a further 43 miles to the North.

As can be seen from the map, the Moss Landing Battery Energy Storage System is situated in a region surrounded by Wildlife area and Marine Reserves.

There are some tourist attractions along the beaches but there no hotels and very few (if any) residential properties