Energy Storage


Battery energy storage provides four major benefits to your business; additional revenue, control of site power demand to increase savings, back-up power and power shifting from renewables to increase savings and reduce dependence on the grid.

Battery storage is not a new technology but the recent advances in software used to control the batteries are what make it so incredibly valuable to businesses today. The software cleverly maps the internal data of your site(s) from its plant to on-site generation and grid connection capacity. It assesses your electricity rates, Feed in Tariff (where applicable) and maps an energy profile. This information is then combined with external information, such as weather forecasts from the Met Office and demand response signals from National Grid, to influence control over your battery system and existing Building Energy Management System (BEMS).

This helps us to:

  1. Minimise battery degradation and losses
  2. Optimise the system according to internal and external conditions
  3. Aggregate the service from multiple sites to maximise value


containerised battery









ENERGY ARBITRAGE – Balance an intermittent supply from your renewable energy system

One of the long-standing issues with most renewable energy sources is the intermittency of the supply. Wind can be difficult to predict and solar can only provide power when the sun is shining. This creates challenges with balancing the grid and making the most of your renewable energy when it is available. Power stored in a battery for use when needed mitigates this problem.

The greatest income is earned from your system when you use the power yourself instead of exporting it back to The National Grid. This is because the cost of buying energy from The Grid is up to three times the rate you will receive from exporting it. The ideal scenario for a renewable energy system is therefore 100% self-use.

In the majority of cases, however, this 100% target is not met because the peak demand from the site does not match with the peak production times from the system. If we can shift the power from peak production times to peak demand times then this opens a window of opportunity for saving energy and earning further revenue.





Our grid supply is under tremendous pressure; battery power can be used to reduce demand at peak times and earn additional revenue through a number of National Grid incentive schemes.

We can use a combination of National Grid incentive schemes and techniques to maximise revenue and increase your savings. We can forecast what a day’s import and on-site generation is likely to look like and make adjustments accordingly to optimise grid rates, on-site renewable energy generation and battery supply with any of the above schemes. This will provide the lowest electricity cost and maximise income at any given time.

The incentives and contracts may include:

  • Demand Side Response – reducing your power requirements at peak times
  • STOR (Short Term Operating Reserve) – providing power or demand reduction to the grid
  • Frequency Response and Enhanced Frequency Response – assisting the grid with balancing demand and supply
  • Triad Reduction – reducing your power consumption during the three most expensive half hour periods
  • Grid rate and pass through charge optimisation – purchasing the lowest cost of electricity and avoiding charges associated with consuming power during a Triad
  • Grid constraint assistance – reducing the impact of an intermittent supply from renewables
  • Peak lopping – clip off high but short duration peak demands



Back-up or standby power is a hugely valuable service, particularly as we face uncertainty over future grid stability. The advantage of choosing a battery for back-up power over a traditional diesel generator is that the battery unit pays for itself via the above incentives and it will never fail because it is continually used and monitored. The unit can switch on in less than 100 milliseconds, providing seamless cover to your business.



We can support you in obtaining funding to invest in a battery unit and we offer a free installation service. You will receive an agreed annual income and free standby power but without having to pay for the cost of the unit.



We only work with the highest quality products and most trusted suppliers including, Tesla, LG Chem, SAMSUNG and NEC Systems; so you can count on a reliable and predictable level of performance.

Most systems have a 10,000 cycle life. Depending on how the system operates, this means up to a 15 year life and a drop to 70% of the original, day one performance. Tesla in particular can offer a minimum energy throughput warranty to guarantee your battery’s storage capacity and supply performance.



High energy users will see the greatest benefit from our battery solutions but almost any organisation would see attractive savings.

The combination of on-site renewable energy generation with batteries and grid management services will depend on your organisation’s energy profile. A solution will be designed with your specific requirements in mind to deliver the lowest energy cost. We can work with most existing systems so, regardless of your current energy management situation, we can usually improve on your current savings.

We can design your energy system from scratch, ensuring all technologies are compatible and appropriately scaled. Your new energy infrastructure may include on-site renewable energy generation but it doesn’t have to. The savings and revenue from careful energy management and battery services alone can still be significant.

Absolutely. Our battery energy storage and grid management services are the perfect add-on for those looking to increase their existing savings.

Batteries can also be paired with generators to strike the optimum balance between price and energy efficiency from your supply at any given time in the day. This could lead to tremendous savings for those businesses that have a constant or high energy demand.

Generators are most cost-effective when they are running at capacity. However, because a typical company’s energy profile often produces short spikes in energy demand – which the generator must be able to meet – they often run at a fraction of their capacity. A battery can alleviate this issue by supplying power during peak demand periods.

GMI Energy’s subsidiary, GMI Power, are specialists in back-up generators and uninterrupted power supply (UPS). Whether you have an existing generator or not, we can ensure that you have a secure back-up in the event of a power cut whilst reducing your overall energy costs.

We can help those who require an off-grid solution or suffer from a potentially intermittent grid supply. Using a combination of on-site renewable energy generation, battery storage and a generator we can balance the demand. This is particularly useful for those companies that encounter short periods of high load and prolonged periods of low load.

Previous battery energy storage units have comprised of lead acid. This is not suited to frequent cycling when the battery is charged during the day and then releases power at night as it greatly reduces the lifespan of the battery. Another issue with lead acid is that it is often insufficiently charged; a full charge takes 16 hours, which no solar PV system can deliver.

Lithium-ion batteries actually perform better on a partial charge and lithium-ion is far more resistant to frequent cycling than lead acid. The biggest drawback of lithium-ion has been the cost but with a rapidly growing global mass market for lithium-ion, the price of the technology has fallen drastically.