Battery Energy Storage Systems (BESS): The 2024 UK Guide

In this guide, our expert energy storage system specialists will take you through all you need to know on the subject of BESS; including our definition, the type of technologies used, the key use cases and benefits, plus challenges and considerations for implementation. You should come away from reading this, knowledgeable on the subject and why BESS is advantageous to your commercial business operations in the UK.

What is a Battery Energy Storage System (BESS)?

By definition, a Battery Energy Storage Systems (BESS) is a type of energy storage solution, a collection of large batteries within a container, that can store and discharge electrical energy upon request. The system serves as a buffer between the intermittent nature of renewable energy sources (that only provide energy when it’s sunny or windy) and the electricity grid, ensuring a reliable and consistent supply of cheap, low carbon power. BESS plays a crucial role in facilitating the integration of renewable energy into the grid, enabling us to harness the sun’s energy during the day and the wind’s energy at night, ensuring a steady supply of electricity for our homes and businesses.

How does a BESS work?

A crucial component of the BESS operation is its Energy Management System (EMS), which intelligently controls the charging and discharging of the batteries. Wattstor’s unique Podium EMS, for example, allows for day-ahead forecasting of price, generation, load and battery state of charge. Podium EMS in particular optimises the operation of the BESS based on various factors, such as energy demand, electricity prices, and the state of charge of the batteries, ensuring efficient and effective energy storage and distribution. This isn’t standard functionality for regular battery storage solutions, however. According to the National Grid, “Intelligent battery software uses algorithms to facilitate energy production and computerised control systems are used to decide when to store energy or to release it to the grid.

Hardware components of BESS

The hardware components of a BESS system comprise the physical infrastructure that enables the storage and discharge of electrical energy. Including:


Individual batteries form the core of the BESS system, storing electrical energy through electrochemical reactions. These batteries are typically made up of lithium-ion cells due to their high energy density and long lifespan.


Cells are grouped together into modules to achieve the desired energy capacity and power output. Each module contains a specific number of cells connected in parallel and series to maximise the system’s performance.

Battery Packs 

Modules are further integrated into larger battery packs to meet the specific requirements of the application. Battery packs combine multiple modules to achieve the desired energy capacity and power output.

Power Conversion System (PCSs) 

PCS’s are responsible for converting the DC voltage from the batteries into AC voltage compatible with the grid or other loads. They ensure efficient power transfer between the batteries and the external electrical system.

Software components of BESS

The software components of a traditional BESS system control the operation of the hardware and optimise the system’s performance. These components include:

Battery Management System (BMS) 

The BMS is responsible for monitoring and managing the health and performance of the batteries. It ensures the safe and efficient operation of the batteries, preventing overcharging, over-discharging, and other potential hazards.

Energy Management System (EMS) 

The EMS optimises the operation of the BESS, considering factors such as the grid conditions, energy pricing, and user preferences. It determines the optimal charging and discharging strategies to maximise the system’s value and minimise costs.

Grid Management System (GMS) 

The GMS facilitates the interaction between the BESS and the electricity grid. It ensures that the BESS operates in a synchronised manner with the grid, providing stability and ancillary services.

Data Analytics Systems

These systems collect and analyse data from the BESS and external systems, providing valuable insights into the system’s performance, energy consumption trends, and potential issues. This data is used for system optimization, maintenance planning, and regulatory compliance.

Key applications for BESS in the UK

Battery Energy Storage Systems play a pivotal role across various business sectors in the UK, from commercial to utility-scale applications, each addressing specific energy needs and challenges.


In the commercial realm, businesses deploy BESS for a variety of purposes. One key application is for load shifting on-site generation, charging the battery from surplus solar or wind energy and discharging it later in the day to reduce grid import. Moreover, BESS is often used for peak shaving – reducing power usage during peak demand times to lower energy costs. Additionally, BESS aids in load levelling, helping businesses smooth out energy consumption throughout the day, thus optimising energy usage and reducing strain on the grid. Wattstor achieves load levelling through its innovative Smart Charging feature, charging when there are excess renewables on the grid when prices are lower and discharging when there’s a shortfall or when prices are higher


For industrial applications, BESS plays a critical role in energy saving, carbon reduction and grid stabilisation, ensuring consistent power supply and mitigating the variability of renewable energy sources. Moreover, it facilitates the integration of renewable energy into the industrial sector, supporting the shift towards more sustainable industrial processes and reducing Scope 1 and 2 emissions.


At the utility scale, Front of Meter (FoM) BESS are crucial for ensuring a consistent and reliable energy system through grid support services. It helps in managing the challenges posed by the intermittent nature of renewable energy sources and keeps the supply and demand of electricity in balance. By storing excess energy during times of high renewable production and releasing it when demand is high or renewable generation is low, BESS ensures stability and reliability in the energy grid. This not only supports the integration of more renewable energy sources but also enhances the overall efficiency and resilience of the national grid.

Business benefits for implementing BESS

The implementation of Battery Energy Storage Systems brings numerous benefits, significantly impacting the energy sector and broader socio-economic landscape in the UK

Increased cost savings 

One of the key advantages of BESS for businesses is the opportunity for significant cost savings, primarily through effective load shifting. This involves purchasing electricity at low prices and storing it for use during peak demand periods when electricity costs are higher. This strategy not only reduces energy bills by selling the stored energy at higher rates but also aligns with the core benefit of load shifting in the context of the UK market.

Additionally, BESS facilitates peak shaving, which is particularly relevant in the UK for minimizing peak kW consumption. This helps businesses avoid additional charges from the grid or Distribution Network Operators (DNOs). Moreover, companies utilizing renewable energy sources like solar or wind can store surplus energy generated, thereby decreasing dependence on grid power and further minimizing energy costs.

Reduce Scope 1 & 2 carbon emissions  

For businesses committed to sustainability and reducing their Scope 1 and Scope 2 carbon emissions, BESS is a key enabler. By optimising the use of renewable energy sources, businesses can lower their reliance on fossil fuels, thereby reducing their greenhouse gas emissions. This not only aids in meeting internal sustainability targets but also aligns with broader national and global environmental goals. In addition, demonstrating a commitment to sustainable practices can enhance a business’s reputation, appealing to environmentally conscious consumers and investors.

Improved energy security

BESS provides businesses with a higher degree of energy price security and independence. In an era of increasing energy price volatility and potential grid instability, having a dedicated energy storage system means businesses can maintain operations during price spikes or grid failures. This is particularly crucial for industries where continuous power is essential, such as manufacturing, healthcare, and data centres. The ability to store and access their own power supply reduces business vulnerability to external energy disruptions, ensuring operational continuity.

Challenges to implementing BESS in the UK

While Battery Energy Storage Systems present numerous benefits, there are also several challenges and considerations that must be addressed for effective implementation.

Technical challenges 

One of the primary technical challenges is the lifespan, efficiency, and degradation of batteries. The efficiency of a battery system can decrease over time due to repeated charging and discharging cycles, leading to reduced storage capacity and effectiveness. This degradation factor necessitates careful management by experienced specialists and integrated software. The performance of different types of batteries can vary significantly under different environmental conditions, requiring careful selection based on specific use cases.

Economic considerations

The initial investment in BESS can be substantial. The cost includes not just the batteries themselves but also associated hardware, installation, and integration into existing power systems. This upfront cost can be a significant barrier for many businesses and residential consumers, despite the long-term savings and benefits. That’s why Wattstor has created a unique Fully Funded Energy System solution that alleviates capital expenditure in a partnership-style contract.

Navigating policy regulation 

Navigating the regulatory and policy landscape is another challenge. In the UK, policies regarding energy storage, grid integration, and subsidies for renewable energy are continually evolving. Staying informed and compliant with these regulations is crucial for successful BESS implementation. Additionally, policies can greatly influence the economic feasibility of investing in BESS, affecting decisions for businesses and individuals.

Case study of a successful BESS project

Integrated EMS & BESS for Industrial Wood Plant: Wattstor deployed a bespoke energy management system, Podium EMS, and created a tailored BESS to ensure maximum return on their solar investment.

Along with the solar panels and 236 kWh battery, some of the operational load is also managed on the closed-loop system. This flexibility also means that energy consumption, generation and storage is optimised towards the energy markets. This helps  to avoid exceeding the site capacity, and takes advantage of avoiding price peaks.

The use of Wattstor’s platform also means that the end user can integrate further generation, storage, operational load or electric vehicle charging without needing to upgrade their EMS in the future.

Funding battery energy storage systems

Wattstor’s fully funded energy systems enable sites to create significant savings, make money from electricity markets, boost green credentials, and stabilise electricity prices. All without risk. Find out more about funding here

By working with Wattstor, sites gain access to these benefits without upfront capital expenditure. Create your ideal energy ecosystem with terms to suit every business, community and site type. Fully-funded financial plans create savings, simplicity, and sustainability.

Speak to an BESS specialist today

Get in touch with Wattstor’s specialist team on Our enery experts can evaluate your site requirements and discuss how battery energy storage systems can add a predictable revenue stream to your business.

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