In this era, an enterprise seeking to multiply its success must consider the availability and reliability of its energy supply. As the cost of battery storage systems in the UK continues to fall and the government makes the market more favourable, business owners wonder how to optimise the new environment. The challenge is usually the same for would-be investors in battery storage systems – the battery options are so many that it can be overwhelming.

It’s not only in the UK where Battery Energy Storage Systems (BESS) are booming. China, Australia, the US, and others are all experiencing increased interest in the solutions. This quick guide focuses on the UK market, where eCactus Solar UK is an importer and distributor of battery energy storage systems (BESS). We will discuss the systems’ working principle, their advantages, the related policies, regulatory frameworks, and much more. We will also tell you why our battery storage systems in the UK are among the best.

Overview of Battery Energy Storage Systems

A Battery Energy Storage System (BESS) is an electrochemical device that stores energy from wind, solar, and other renewable energy sources, or the grid, for later use. The usage of these systems can be seen across different industries, with the most prominent being residential, commercial, and industrial.

A BESS is not only a source of revenue and an enhancer of energy independence, but also a way of safeguarding the grid, benefiting utility companies.

The UK is enjoying a significant rollout of BESS technology, with the government intent on actualising the net zero emissions goals.

How the BESS works

A BESS is charged by energy from a renewable energy source or the grid. It uses the energy storage technology to store the energy. Several instances may prompt the release of this energy, but mostly this happens during grid balances, power blackouts, and peak energy demand.

BESS have several components that combine to enable the system to work optimally. Central to this are computerised control systems that direct energy from the renewable energy source or the grid to the battery system for storage.

Here are the main components of typical Battery Energy Storage Systems:

1. Storage: (Battery system, battery pack, module, cell, mono-cell)
2. Monitoring and Control: (Local Micro-grid Controller, Battery Management System (BMS))
3. Power Conversion System (PCS)
4. Temperature Control: (Fire Suppression System, Environment Sensor & Control System)
5. AC Transformer
6. DC switch
7. AC circuit breaker

For the amount of energy stored and duration of storage to be economical, the batteries need to be of the highest quality. Lithium-ion batteries are the most popular, but there are other options in the UK market, as we will find later in this guide.

With time, the BESS technology has advanced to suit the prevailing market needs. For instance, some systems can now harness the power of artificial intelligence (AI) and data-based solutions to enable the systems to serve the users even more optimally.

Historical development of Battery Storage Systems in the UK

The UK has experienced a remarkable increase in the uptake of BESS projects in the last decade. Most of the developments started after 2016, as the table below shows.

Table 1: The Built Capacity of Utility Battery Storage in the UK (Source: UK Battery Storage Project Database report; March 2022)

Market trends in the UK and globally

Like in many countries in the EU region, the battery storage systems UK market is on an upward trajectory. As of 2022, the market value was GBP 310 million (USD 379 million) and is expected to continue growing until 2028.

There are many local and international players in the UK market. The number of these players is expected to increase in the future thanks to these and other market-friendly factors:

• Ambitious goals for renewable energy integration: In line with the government’s goals to enhance carbon reduction and renewable energy production, BESS technology can help integrate solar, wind, and other renewable energy sources.
• The government’s energy storage goals: The government is enhancing the transition to a low-carbon system, and energy storage is one of the enhancers of this goal.
• Incentives and subsidies on renewable energy: The government provides incentives and subsidies that encourage the uptake of renewables. BESS merged with renewables can ensure the optimisation of the incentives and subsidies.
• Integration with electric vehicles (EV): Given the increasing number of electric vehicle users in the UK, BESS technology has an excellent opportunity for growth. Some areas of impact are vehicle-to-grid (V2G) solutions and grid impact management.
• Robust government policies: There is an enabling environment for the growth of this technology as the government moves to use flexibility services and ease grid access through reforms.
• Net-zero goals for 2050: BESS is one of the innovations that emanate from the UK government’s goal of a net zero carbon economy by 2050.
• Reliable balancing services: With conventional power plants becoming obsolete, BESS can take up the gauntlet through balancing services that help keep the grid stable.

What are the technological options for battery energy storage solutions in the UK?

Several technologies can suit energy storage requirements. The most popular ones are lithium-ion, flow, lead-acid and solid-state batteries.

Lithium-Ion Batteries

This is undoubtedly the most popular battery technology due to its reliability and effectiveness.

Since lithium-ion batteries were made commercially available in the 1990s, the technology has grown tremendously. Their relevance in consumer electronics can be attributed to the following advantages:

• Safety
• Cost-effectiveness
• Recharging and discharging without memory effect
• High energy-to-weight ratio
• Superior power density

Lithium batteries are preferable for Battery Energy Storage Systems, particularly for their capability to support discharging with rapid response times. This attribute is crucial for the stability of the national grid because it enables effective frequency response.

Flow Batteries

Flow batteries are popular for their capability to support lengthy energy storage. This battery type is based on the energy differences that certain elements such as metals exhibit when they are in the oxidation state. There are three categories of flow batteries, membrane-less, redox, and hybrid flow.

The exact operation mechanism may differ for each type, but the concept of a flow battery is the same. The name of the battery originated from the fact that the electrolyte flows through the system. Of the three categories, membrane-less flow batteries are the most modern technology. This type of flow battery has no separation in the electrolyte.

Lead Acid Battery

Lead acid batteries have been around for some time now. They are typically suitable for backup power and other applications where cycling is less frequent. This type of battery comprises a sulfuric acid water solution as the electrolyte and lead electrodes. While the battery performs well in extreme temperatures and has a low cost per watt-hour, it charges slowly, has low specific energy, and is not environmentally friendly.

Solid State Battery

Replacing a liquid-based electrolyte with a solid-based electrolyte results in this modern type of battery technology. Based on early indications, this battery will bring longer life, enhanced safety, and superior energy density. However, the technology is still in the infancy stage and is yet to be released for commercial applications, so we can only wait. For now, the manufacturing process for the battery is expensive and intricate.

Since these options each have pros and cons, it is better to look at the specific requirements of a battery storage project before settling on any of them. The leading factors for the best battery energy storage solutions are the required capacity, available space, and charging/discharging requirements.

Tips for choosing the right BESS technology

So, which of the categories would be suitable for a project? We recommend the following considerations or steps:

• Look at the specific project requirements
• Do extensive research concerning the existing solutions for similar projects
• Insist on data-driven decisions.

It is always advisable to seek the help of a professional provider to get the best from a BESS installation.

Different Sizes and Configurations of Battery Storage Systems   

In the UK, different sizes and configurations of battery storage systems are used. Utility-scale installations are the largest with a net generation capacity that varies between a few MWh, to over 100 MWh with typical installations being in the 50-100 MWh range. These systems are usually managed by independent power producers and utility companies and offer grid support services.

Electricity end users can operate the smaller scale BESS installations that don’t tend to exceed a capacity of 1 MW. Most of these battery storage systems are powered or charged by solar power.

Based on siting and taking the case of a PV + battery storage system, these are the possible system configurations:

Independent: The PV and battery systems are at distinct locations and don’t share control or common components.

DC coupling for flexible charging: The PV and battery storage are coupled at the DC side and have a common inverter. The battery can charge from the grid and PV because the inverter is bi-directional.

DC coupling for PV charging: Although the configuration is similar to that of DC coupling for flexible charging, only the PV can charge the battery.

AC Coupling: The battery storage and the PV systems are co-located and have independent inverters.

UK Government Policies and Regulations

As the battery storage systems UK industry has grown tremendously in the last five years, several standards, codes, guidelines, and regulations have been developed locally and internationally. In the UK, there are safety standards and regulations that focus on the following elements:

• Product Safety
• Grid Connectivity
• Electrical Installation
• Dangerous Goods

The UK government also offers grants and incentives to businesses for qualifying green projects. Since these are often available at the local level, the best strategy is to check for any support in your area through the government website. The Smart Export Guarantee (SEG) is one such initiative.

Considerations for Buying and Installing BESS in the UK

For a UK battery storage system projects to be economically and financially viable, they must meet a few requirements. One of the key factors is the cost of storage. The cost of batteries may be reduced, but it still influences the decision to invest in the system. What is the MW/MWh ratio? This is an important question to ask regarding the battery. The terminal value is also a critical point to consider concerning storage cost.

The available commercial services are also worthwhile to consider. Access to valuable capacity, ancillary services, and other markets can bring immense value to the project.

It is also important to consider the policy environment before investing in a battery storage system. The project economics in the UK are now favourable thanks to the friendly government policies.

Applications of BESS Technology

Here are a few applications of this technology in commercial and residential projects:

Peak demand management

Grid operators in the UK are encouraging the uptake of BESS to help manage the challenges of peak demand. The application cases are varied and the BESS operator can earn revenue from the investment through processes such as frequency response and energy arbitrage.

Load optimisation

Load optimisation concerns analysing the demand-based electricity rates from utility companies and avoiding excessive costs.

Renewable energy integration

As the UK continues to transition to renewable energy, the challenges of integrating renewable energy sources into the energy grid become even more evident. Apart from being diverse, renewable energy sources are typically intermittent. Without a way of integrating them smoothly into the grid, installations may have limited use. BESS technology offers integration of these sources for commercial application.

Micro-grid solutions

Microgrids are small-scale power grids that operate independently from the National Grid. These decentralised systems are regarded as the future of electricity generation. Battery storage systems can increase the reliability and economic viability of these systems.

What are the alternative energy storage technologies?

Many may wonder whether the dominance of pumped storage in the UK and Europe is ending with the entry of BESS. This hydroelectric storage method uses excess electricity to pump water to an upper reservoir which is then released to a lower reservoir in high demand, turning turbines to generate electricity.

Compressed air energy storage stores surplus energy as compressed air. This air is released during peak times to drive a turbine to generate electricity.

There is also flywheel energy storage which stores energy as kinetic energy to spin a flywheel during times where demand is low, storing energy. When demand is high, this kinetic energy gets converted back to electrical energy whilst the flywheel’s momentum drives a generator to produce electricity.

Electric Vehicle Charging and BESS

Electric Car Charging

Consumer demand for electric vehicles in the UK is growing. By August 2023, there were at least 850,000 fully electric vehicles and 530,000 plug-in hybrid vehicles in the UK. Alongside this growth has been a high demand for battery storage solutions.

Charging electric vehicles using BESS provides valuable support to the charging infrastructure. When the power demand is extremely high at peak hours, charging stations can draw part of their power from batteries. The charging experience is flawless with less strain on the grid.

Three years ago, the UK parliament acknowledged the effect the growing EV charging demand has on the national grid. Consequently, the transport committee recommends the strengthening of the National Grid to prevent blackouts in the country.

With a Photovoltaic Energy Storage and Charging Energy Storage System, it is now possible to directly use solar power for electric vehicles.

Challenges and Prospects of Battery Storage Systems

BESS are useful in the UK energy future, but one outstanding challenge is the risk of thermal runaway. This is a phenomenon whereby battery malfunction, damage or misuse prompts reactions that release heat. The resulting negative feedback loop can result in a fire or even an explosion.

There have been serious accidents related to this technological risk. Not that the project developers are not ready for this challenge. Indeed, project developers are keen on mitigating this and other related challenges throughout the life of a BESS project.

Despite such challenges, the prospects of BESS in the UK are bright. We believe their role in the UK’s net zero grid goals is immense. The market is still growing and will continue on that trajectory well into the future.

With the planned phase-out of coal power plants this year, the expected shortfall of traditional generators will require compensation to maintain the supply/demand balance. Battery storage has a competitive advantage in counteracting this imbalance.

As the government pushes for even more renewables to support the grid and other factors add to the viability of this technology, there is no better time to join the BESS market. We are at the forefront as the market evolves and are ready to support our clients in every way possible.

eCactus BESS Solution

Why use eCactus BESS and related products?

In conjunction with our supply partners, with their deep expertise and extensive market experience, we offer storage systems that are competitive and customer-specific.

With our battery energy storage solutions, you experience the real value of storing electricity when it is more affordable and releasing it when prices escalate.

At eCactus Solar, we supply top-tier BESS products, including the Agave home battery energy storage system. This innovative product is always ready for a blackout at home with a switching time of <10MS (Fitted with a built-in Emergency Power Supply (EPS) port ready for an emergency circuit to be installed). It also has a remarkable power density of 89Wh/kg. It is ideal for power backup, load shifting, and self-powering.

The Agave 10.24kWh Battery Storage System

We also have the ECOS home energy management solution, an iOS and Android-based product that gives real-time data, energy summary, and instant alerts. Customise it the way you want and get deep insights into the performance of your system.

As a testament to the quality and success of these and other products, we recently made an outstanding contribution at the SNEC 2023 in Shanghai, China.

For more about our battery storage systems, please contact us.