Why battery storage is crucial to a zero carbon future for Brighton and Hove

In the early Twenty First Century renewable energy has gone from being a fringe sector to now accounting for over a third of the UK’s electricity supply.

The most common renewable energy sources include a mixture of solar, wind, or hydro power, all of which are non-polluting sources of energy that come from our natural environment.

A notable consideration is that these sources of energy are intermittent. They are subject to variations in weather conditions which impact the reliability of energy generation. Examples include cloudy days which can limit the effectiveness of solar power, or an absence of wind which is needed to animate the blades of wind turbines.

The ability to store electricity so that it can be deployed at times when renewable generation is low is essential for guaranteeing a secure and reliable electricity supply.

The way we power our lives is changing at a rapid pace and in the coming years battery storage technology will play an increasingly vital role in Brighton and Hove’s journey towards a net zero carbon city.

What are the financial benefits of battery storage technology?

Since 2010 more than a million sites across the UK have installed solar PV systems.

In almost all cases, there will be occasions when the amount of electricity that is being generated by the solar panels is greater than the demand on site. In this instance, the excess solar electricity will typically be exported to the National Grid for use elsewhere. The most obvious example of this would be for a domestic property where the occupant is not at home during the day.

Many properties across Sussex are able to benefit from exporting excess solar electricity by taking advantage of the Feed-In-Tariff, which provides financial compensation for solar power generators.

Unfortunately, the UK Government put an end to the Feed-In-Tariff in April 2019, and even before that happened, the value of scheme had greatly diminished. Since 2016, the Feed-In-Tariff has paid only around 4 pence per kilowatt hour of electricity produced.

When we consider that the average price for purchasing electricity from an energy supplier is 17p, we can see that there is much greater economic benefit from using the solar energy that is generated, rather than exporting it to the grid.

By adding battery storage to a solar panel system, property owners can store any excess electricity that they have generated during the day for use at a time when they need it, which in many instances will be in the evenings and early mornings.

Research from the Energy Saving Trust estimates that adding battery storage technology to a solar power system will increase the proportion of electricity used on site by 35 – 75%.

By reducing the amount of electricity that they need to purchase from an energy supplier, solar PV and battery owners can expect to make significant savings on their energy costs.

Taking advantage of 'Time of Use Tariffs'

Despite the fact that electricity demand varies depending on the time of day and the day of the week, most homes in Sussex pay a single rate for their energy regardless of when they use it.

However, the increasing proliferation of renewable energy sources throughout the South East means that in the near future, the price of electricity will vary throughout the day depending on the level of available electricity at any one time.

Following the basic economics of supply and demand, the cost of electricity will become cheaper during times of abundant supply and low demand (e.g. 3pm on a weekday in the Summer) and more expensive during times of scarce supply and high demand (e.g. 8am on a weekday in Winter). This is what is referred to as a ‘Time of Use Tariff.

The idea behind these tariffs is to incentivise energy customers to shift their consumption behaviour in order to consume less energy when costs are high, and save high consumption activities (laundry, dish-washer, etc) for times when prices are at their cheapest.

SunAmp thermal energy storage technology installed by BHESCo at the Alistair Fleming Showroom on Lewes High Street

Homeowners who have battery storage can take advantage of Time of Use Tariffs by programming their battery to charge at times when there is lots of renewable energy being generated and when energy prices are at their lowest. They can then use this energy at a later time when energy generation is lower and electricity prices are high.

In this way, even without solar panels, customers who have a battery installed can save money by  avoiding purchasing energy from their supplier when costs are at their highest.

Is battery storage appropriate for your home or business?

As with all energy projects, the suitability will depend on a number of variables specific to your circumstance, such as:

  • the energy demand of the property (times & volume)
  • potential to combine with solar power or heat pumps
  • the heating provision of the property (gas powered or electric)
  • demand for electric vehicle charging

For properties that have solar PV systems installed, the most important metric influencing the economic feasibility of battery storage is how much excess electricity is generated by the solar panels on a regular basis.

Where this is a considerable volume of excess generation then installing batteries to soak up that excess makes sound financial sense.

For smaller systems where most of what is generated is utilised on site then a battery may not be such a wise investment.

When the factors are favourable, the addition of battery storage can certainly deliver significant benefits to property owners.

According to the Energy Saving Trust there are some utilities that claim the combination of solar, battery storage and a ‘grid service’ tariff could cut the average homeowner’s electricity bill by as much as 70%1.

How much can you expect to pay for a battery storage system?

For a long time the cost of installing battery technology has been prohibitive for many property owners who otherwise would be interested.

Fortunately, much in the same way as happened with solar power, the cost of battery storage technologies have plummeted in recent years as larger players have entered the marketplace and production efficiencies and supply chains have improved.

The rapidly expanding market for electric vehicles has played a key role in driving down production costs of battery storage.

Research by the Bloomberg New Energy Finance finds that the cost of lithium-ion batteries have fallen 76% since 2012, a trend that will continue its downward trajectory over the coming years2.

A typical domestic property in Sussex would be suited to a 4kW battery which will cost in the region of £5,000 – £6,000 for a good quality lithium-ion unit from a well known brand such as Tesla or Powervault. 

Using battery storage to create a new income stream by offering flexibility services.

As Brighton and Hove continues on its journey to Net Zero emissions, we will see a phasing out of fossil fuels as an energy source and an increase in renewable electricity consumption.

Over the next decade, electricity will replace oil and gas when it comes to heating our homes and powering our transport networks. This greatly increased volume of electricity will create stress on the capacity of the regional electricity grid across the South East.

To help manage system overloads and to avoid having to disconnect some energy generators, UK Power Networks will be increasingly offering financial incentives for those who can support the network by absorbing electricity at times when supply outstrips demand.

This is referred to as ‘Flexibility Services’ and offers battery owners a new source of income as they will be paid to take excess electricity from the grid or be offered low tariff prices to do so. The potential to be offered advantageous rates in return for flexibility services could even be extended to include hot water cylinders.

Conversely, participating in flexibility services also gives battery owners the opportunity to sell electricity to the national grid when electricity demand is higher the available generation capacity. This could become known as ‘Time of Export Tariffs’.

In both of these examples, individual property owners will need to agree to allowing their battery to be controlled remotely by a third party and then pooled with other batteries to create a large enough ‘Virtual Power Station’ to bid for contracts with the National Grid.

Combining battery technologies with big data, microgrids and the emergence of the 'Prosumer'

Battery storage will also form a key pillar in the development of low carbon microgrids across Sussex and Kent, enabling whole communities to become energy independent.

These technologies will give consumers more control over the way that they engage with their energy supplier, by giving them access to the energy market. No longer will they simply consume energy, they can produce and trade it through microgrids, leading some industry experts to refer to the emergence of a new kind of actor in the energy market – the ‘prosumer’.

To gain maximum effectiveness from a microgrid we will see an increasing use of ‘Big Data’ analysis coupled with weather forecasting to accurately predict times of electricity scarcity and abundance, enabling the microgrid controller to decide when is the right time to use, store, purchase, or sell electricity.

CASE STUDY - Dyke Golf Club, Brighton

In 2017 BHESCo designed and installed a 7.7kW roof-mounted solar PV array at the maintenance shed of Dyke Golf Club, which is linked to a 10kW battery bank.

Over their operational lifetime we expect this combination of technologies to reduce energy costs by £9,254 in addition to lowering carbon emissions by 45 tonnes CO2.

What different types of battery are available?

There are a number of battery storage solutions available, each with differing costs, pros, and cons.

Here are some of the most common and their key points:

Lead Acid

  • The oldest and cheapest type of battery
  • Relatively low limit on the number of charging cycles
  • Not as environmentally sustainable as other options


  • Favoured by brands like Tesla, Moixa and Powervault
  • Low maintenance
  • Can be wall-mounted
  • Higher number of charge-cycles than lead acid


  • Low maintenance
  • Almost limitless charge cycle
  • Rapid charge and discharge
  • Less effective at delivering low charge over longer periods

I'm interested in battery storage technology - what do I do now?

Before making an investment in a new battery storage system for your home or business it is vital to ensure that battery storage is a suitable match for your needs and expectations.

An energy survey from BHESCo will assess your current energy consumption behaviour and recommend the most-cost effective solutions to help you save money and reduce your environmental impact.

As part of our analysis we will examine the feasibility of renewable energy technologies and battery storage technologies for your property, as well as quantifying the anticipated benefits to be derived from making improvements to the energy efficiency of the building.

Our geographic reach covers East and West Sussex, so if you are located in these counties please do contact BHESCo to bgein your journey toward low-carbon energy independence.


1 – https://energysavingtrust.org.uk/blog/domestic-solar-plus-battery-storage-revolution-electricity-market

2 – https://www.bloomberg.com/professional/blog/battery-powers-latest-plunge-costs-threatens-coal-gas/