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Breaching your limits? Constraint management with battery energy storage

We spoke to our Technical Sales Manager, Jonathan Mann, about why more companies are breaching their capacity limits and the ways that battery energy storage can help.

31/07/2023

For a long time, electricity was an abundant resource in seemingly endless supply. However, the drive to decarbonise is leading to increased demand for energy, and sometimes the local grid has not kept up with that demand.

If your site’s energy usage climbs higher than your agreed capacity limit, you can very quickly run up big bills in surcharges. We spoke to our Technical Sales Manager, Jonathan Mann, about why more companies are breaching their capacity limits and the ways that battery energy storage can help.

Where battery storage can support projects

For charging hubs which include multiple charge points or to support high-powered chargers.

Where battery storage is not applicable

On-street residential where space is limited or lamp-post charge points.

Can you explain what is meant by a capacity limit?

Every business has a maximum import capacity (MIC). This is the maximum amount of electricity that your premises can draw from the electricity network. Your MIC is part of your energy supply agreement and is set by the distribution network operator (DNO), which manages your region’s infrastructure.

MIC is measured in kilovolt Amps (kVA) – and just to confuse matters, it is also sometimes referred to as your Available Supply Capacity or Maximum Power Requirement. The aim of an MIC is to give every business enough energy to meet its operational needs, and your fair share of the available power.

If a business is consistently using more than its allocated capacity, it can be charged up to twice as much per kVA for the additional power used. And businesses that regularly exceed their capacity can face penalties of up to three times the standard rate that they pay for energy. When we’re in the midst of an energy crisis, no business wants to face those additional costs. Ultimately, businesses that constantly breach their limit run the risk of having their supply cut off.

Is this a recent problem?

The legislation changed in 2018 and a lot of businesses increased their MICs at the time to avoid the new surcharges. However, very few organisations had the foresight to realise that electrification was going to push them over their MIC in the coming years.

The primary causes could be anything from a site expansion or introducing new equipment which increases your energy use. Decarbonisation measures such as heat pumps and electric vehicle charge points have had an impact – both are high-load items that draw down a lot of energy. Adding one or two EV charge points in the early days of electrification probably didn’t cause MIC breaches, but as the EV transition has gathered pace it requires more and higher powered charge points at commercial premises.

If you are running a lot of vehicles, you want to switch them to EVs and you therefore need a significant number of chargers, you are going to need a much higher MIC. In some cases, an upgrade simply isn’t possible due to local or regional infrastructure constraints – put simply, our grid was not designed for this level of demand. While work is ongoing to make it fit for purpose, some areas are not there yet.

Jonathan Mann, Technical Sales Manager, Connected Energy

Are any particular businesses affected more than others?

Any power hungry businesses are more likely to be closer to their MIC so sectors such as manufacturing tend to be more affected than others. However, those pushing hard on decarbonisation are often feeling the pain of this issue and anyone at the forefront of electrifying their fleet could also be impacted.

Can a business increase its MIC?

It is possible to apply for an increase in an MIC. However, increasingly companies are finding that this option has gone. Premises will typically be on a shared connection with your neighbours. If one of your neighbours has already increased their MIC and taken whatever spare capacity was available, then you could be in for an expensive time.

This is because increasing your MIC will require a reinforcement of the local network to cope with higher demand. Along with the expense, these infrastructure upgrades can take months, even years, as there is often a long waiting list.

Furthermore, in some cases, an upgrade simply isn’t possible due to local or regional infrastructure constraints – put simply, our grid was not designed for this level of demand. While work is ongoing to make it fit for purpose, some areas are not there yet.

How can battery energy storage help to overcome this problem?

A battery energy storage system (BESS) is an ideal way to support a site that is facing higher bills due to MIC breaches. A BESS can store energy during off-peak times for use when electricity demand spikes on site. For example, your premises could draw down energy throughout the night when the site is dormant, and then use that electricity throughout the day when there is high demand. This has the additional benefit of also buying cheaper electricity at night if your site is on an off-peak tariff.

We’ve recently been working with a manufacturing site in North West England which had been breaching its capacity limits for the last two years. The site is facing large fines from the DNO and has even been threatened with their electricity being cut off if they do not take action.

The site had an import capacity of 1,200kVA with an annual consumption of 5,160MWh and a peak demand of 1,490kW. Through our feasibility studies, we assessed the site’s energy data and created a model to assess the ability of a BESS to maintain the site’s maximum need whilst avoiding breaching the connection.

With the inclusion of just one of our 300kW/360kWh systems, we found that we could reduce the amount of time breached from a staggering 455 hours a year to just 15 hours a year.

The graph shows the example site with and without the inclusion of a BESS. You can see on the light green spikes on the graph where the site currently breaches its MIC but would not breach it with a BESS deployed.

How do I know if a BESS stacks up financially?

The graph is part of a feasibility study we conducted for the client, for this very purpose. Connected Energy can carry out a feasibility study to show you exactly what your excess costs are at present and how much you could save by deploying an E-STOR battery energy storage system.

Our advanced modelling system reviews your energy data and site’s assets including energy intensive equipment, renewable generation, and EV charging. Contact us for a bespoke study.

Let's connect!

Get in touch with our team to discuss whether battery energy storage can work for your business, and how we can offer a free feasibility study.