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Battery Energy Storage FAQs

We’re often asked questions relating to Battery Energy Storage Systems (BESS). We’ve pulled them all together in this handy explainer to help answer all of your Frequently Asked Questions (FAQs) about Battery Energy Storage.

Powerstar Battery Energy Storage

How does a battery energy storage system work?

A battery energy storage system (BESS) is an electrochemical device that charges (or collects energy) from the grid or on-site generation such as Solar PV and then discharge that energy later to provide electricity or other grid services when needed.

This can allow for using less grid energy at peak times which are often charged at a more expensive rate and charging the battery from the grid when energy prices are much lower or from your own on-site power generation systems.

Can I access grid service contracts with a Powerstar BESS?

Yes accessing grid service contracts is another benefit of a Powerstar battery energy storage System. These contracts allow you to use your BESS system to generate income from your battery system which will reduce your overall energy costs and reduce the overall payback time of your investment.

These contracts can take some time to put in place with your DNO and often require the services of a third-party aggregator to manage your asset and ensure your contractual obligations are fulfilled. The aggregator will usually take a percentage of the money generated as a fee for managing the contract.

How can a battery system replace a UPS?

A Powerstar BESS features ultra-fast switching which can connect the battery to your site supply in less than 10ms and thus protect all equipment from power disruptions. This works in a similar way to a traditional uninterruptable power supply but doesn’t continue to contribute to energy bills and potentially carbon emissions as they need to partially discharge and recharge in order to monitor incoming power from the grid.

A Powerstar battery storage system also has a power management software that will forecast and manage multiple power loads as well as on-site generation to achieve the cheapest, greenest and most stable electrical supply for your site.

Solar panels

Do I need solar photovoltaics (PV) for a BESS to help my business?

No, you don’t need Solar or other methods of on-site generation for a Battery Energy Storage system to help your business. You can charge your BESS system at times of lower demand and cheaper electricity and discharge the battery when electricity is more expensive allowing you to reduce how much you pay overall for your electricity.


Does Powerstar’s BESS have NHS HTM compliance?

Yes, in fact we are the only battery energy storage company to achieve HTM (Health Technical Memoranda) compliance for NHS installations & the only company to install a Battery Energy Storage System and UPS system for the NHS to date.

What are the advantages of battery energy storage systems?

  • Improved energy efficiency – Battery energy systems offer improved self-reliance by allowing you to store energy at off-peak prices and then use it at times of peak prices or to sell the energy back to the grid through a grid service contract.
  • Improved energy resilience – They also offer improved resilience and a vital insurance policy for businesses by allowing the BESS to function as a UPS system. This means they can keep your critical systems running in the event of a blackout or brownout.
  • Reduced energy wastage, lowering energy costs – For businesses with onsite generation, they reduce wastage. For example, when solar PV is generating energy which is not all being used this can be stored to be used when needed or for supplying the national grid for a profit.

How much does a battery energy storage system cost? – What size battery system will I need?

Every site is different. There are a range of factors that influence the accurate sizing of equipment, each of which needs to be factored into an accurate design. Please contact one of our experts at or call us on 01142 576 200 and we can talk through your options and arrange an installation feasibility study.

How much is an installation feasibility study?

An installation feasibility study for a Battery Energy Storage installation is typically £450 for a standard site. The cost of the survey will be credited off any eventual order.

Speak to our team to see how much a Battery Energy Storage System can help save your business today

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Related case studies

NHS: Rotherham General Hospital

Powerstar were engaged to replace a large hospital’s existing Uninterruptible Power Supply (UPS) system with a more efficient, intelligent Battery Energy Storage (BESS) alternative.

Stoba Prazisionstechnik UK Ltd

Stoba is a mass manufacturer and supplier of metallic parts and high quality components to the automotive industry that operates internationally.

South Staffordshire Council

South Staffordshire Council were looking to install a battery energy storage system that provided them with site-wide UPS resilience

Racing Engine Manufacturer

This racing engine manufacturer was struggling with grid constraints blocking the installation of vital new equipment.

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