Electricity capacity is becoming an important consideration for developers, property owners and anyone looking to invest in or make changes to an existing asset.

Whether you are looking at a new development, buying an existing building, planning a refurbishment or considering a change of use, there is often one fairly simple question:

Is there enough power available for what we want to do?

Unfortunately, getting the answer isn’t always quite as simple.

The amount of electricity a project needs, what is already available to a property and what the wider electricity network can accommodate all need to be considered.

Understanding this early can help avoid surprises later and give you a much clearer picture of potential cost, programme and risk.

What do we mean by electricity capacity?

Put simply, electricity capacity is the amount of power that can be provided to a property or development.

There are two things we normally need to understand.

How much power does the project need?

And can the electricity network provide it?

For a new development, this could mean working out the expected electricity demand and then understanding how a new connection could be provided.

For an existing property, there may already be an electricity supply. The question then becomes whether that supply is suitable for what you want to do next.

A refurbishment, extension, change of use, new occupier, EV charging or a move from gas to electric heating can all increase the amount of electricity a property needs.

This is why electricity capacity isn’t only something to think about on new developments. It can be just as important when looking at an existing building or asset.

What are kW, kVA and MVA?

These are terms you will regularly see when talking about electricity capacity.

kW means kilowatts. This is the amount of power actually being used.

kVA means kilovolt-amperes. Electricity connections are commonly discussed and sized in kVA.

MVA means megavolt-amperes. One MVA is equal to 1,000 kVA and you will normally see this used when talking about larger electricity requirements or network infrastructure.

For most clients, however, the terminology isn’t the important bit.

What matters is making sure the amount of electricity being requested is sensible for the project.

Ask for too little and you could find that the development or property doesn’t have enough capacity later.

Ask for far more than you actually need and you could make the connection more expensive or complicated than it needs to be.

Getting the demand right from the start is important.

How much electricity will a project need?

There isn’t one standard answer.

Two developments of a similar size can have very different electricity requirements.

Heating and cooling, EV charging, lifts, mechanical equipment, commercial kitchens, industrial machinery and the requirements of future occupiers can all make a difference.

The move towards electrification is also increasing demand.

A building that may previously have used gas for heating, for example, could need considerably more electricity if that heating is replaced with an electric system.

At the early stages of a project, you probably won’t know the exact electricity requirement. That’s normal.

The aim should be to establish a sensible estimate using the information available at the time. That estimate can then be updated as the design develops.

The important thing is to start thinking about it early.

What about an existing building?

Existing buildings can sometimes be overlooked because they already have an electricity connection.

Having a connection doesn’t necessarily mean there is enough capacity for what you want to do with the property.

It is worth understanding what supply currently serves the building, how much capacity it has and how much electricity the property is actually using.

You can then compare that with what you are planning.

For example, an existing office might have operated perfectly well for years with its current electricity supply.

If the building is refurbished and new electric heating, cooling and EV chargers are added, its future electricity requirement could be very different.

The same applies to an industrial property taking on new equipment or a commercial building being changed to another use.

There can also be opportunities.

An existing property with a good electricity connection and spare capacity could be attractive for certain future uses.

So before assuming that you need a completely new connection, it is worth understanding what you already have.

Where does the electricity come from?

Most properties and developments are connected to the regional electricity distribution network.

These networks are operated by Distribution Network Operators, usually referred to as DNOs.

The DNO owns and operates the local electricity network in its area.

Depending on the project, Independent Distribution Network Operators (IDNOs) and Independent Connection Providers (ICPs) can also form part of the connection process.

There is another important part of the picture, though.

The DNO network doesn’t operate on its own.

The distribution network is connected to the wider electricity transmission system. This includes Grid Supply Points and National Grid transmission infrastructure further upstream.

This matters because capacity can be affected by constraints at different points on the network.

For example, a local DNO substation might appear to have capacity available, but there could be a constraint further upstream.

That upstream constraint could affect how much additional electricity the DNO can provide, when it can be provided or what work is needed before the connection can happen.

So seeing available capacity at the nearest substation doesn’t necessarily mean that capacity is available to your project.

You need to look at the wider picture.

What can electricity capacity maps tell you?

DNO capacity maps are a useful place to start.

They can help you understand the electricity network around a property or development and may show things such as substations, voltage levels and an indication of available capacity.

They are particularly useful when looking at a site for the first time.

But they do need to be used carefully.

If a capacity map shows available capacity at a nearby substation, that doesn’t mean the capacity has been reserved for your project.

It also doesn’t guarantee that your project can connect to that particular substation.

There could be constraints further upstream. Other projects may already have connections agreed. The network could change before your project reaches the application stage.

The actual connection point may also be somewhere different from the one that appears obvious on the map.

Capacity maps are therefore a useful starting point, but they aren’t confirmation that power is available.

How do you get more certainty?

If you need more certainty, you will normally need to engage with the relevant DNO.

How far you go with this will depend on where the project is in its lifecycle.

At a very early stage, a desktop review may be enough to understand whether electricity is likely to be a major issue.

As the project progresses, more detailed discussions with the network operator may be needed.

Eventually, this may lead to a formal connection application.

The DNO can then assess the amount of electricity being requested and look at how that demand could be connected to its network.

Sometimes the answer will be relatively straightforward.

Other times, the DNO may identify reinforcement works, upstream constraints or a different way of connecting the project.

This is why there can be a big difference between an early indication of capacity and an actual connection offer.

What happens if there isn’t enough capacity?

A lack of immediately available capacity doesn’t necessarily mean the project can’t go ahead.

It simply means you need to understand what the options are.

The electricity network may need to be upgraded. This could involve work to cables, substations or other parts of the network.

There may also be another way of connecting the site.

It can also be worth looking again at the amount of electricity being requested.

Does the project genuinely need all of that capacity?

Does it all need to be available from day one?

Will the development be built in phases?

Has future demand been included that won’t actually be needed for several years?

The idea isn’t to reduce the electricity requirement just to make a connection easier.

It is about making sure you are asking for the right amount of power at the right time.

If network upgrades are required, timing also becomes important.

Electricity network works can take time to plan and deliver. Finding out about a major constraint late in a project can therefore cause much more of a problem than identifying it during the early stages.

Why look at electricity capacity early?

Electricity is sometimes treated as something that can be sorted out later.

That can be risky.

The electricity position could affect whether a site or property is suitable for what you want to do with it.

It can also affect the design, project budget, programme, phasing and overall development strategy.

If you are buying an existing asset, the same principle applies.

If your plans depend on additional electricity capacity, it makes sense to understand whether that capacity is likely to be available before making major investment decisions.

You don’t necessarily need all the answers on day one.

You just need enough information to understand whether there is likely to be an issue and what you should do next.

The electricity network is changing

The amount of electricity being requested from the network is increasing.

Electric vehicles, electric heating, industrial electrification and other changes are creating new demand across the UK.

The way electricity connections are managed is also changing.

This means electricity capacity should always be treated as a point-in-time assessment.

Capacity that appears to be available today may not necessarily still be available in the future.

Equally, a network that is constrained today may change as upgrades are completed or other projects change.

This is why current information is so important when assessing a development or existing asset.

Five useful questions to ask

When looking at electricity capacity, there are five simple questions that can help.

1. What do we already have?

If there is an existing electricity supply, understand it before assuming something new is needed.

2. What do we actually need?

Work out a sensible estimate of the electricity requirement based on what you are planning.

3. What does the network look like?

Look at both the local DNO network and any wider upstream constraints that could affect the connection.

4. When do we need more certainty?

Decide when it is appropriate to move from an early desktop assessment to formal discussions or an application with the DNO.

5. What does this mean for the project?

The important thing isn’t just whether capacity exists.

You need to understand what the electricity position means for cost, programme, risk and the overall project strategy.

Final thoughts

Electricity capacity can look fairly simple from the outside.

Find the site, look at the nearest substation and check whether the capacity map shows anything available.

In reality, there can be a little more to it.

You need to understand what electricity the project actually needs, what is already available, what the local network can accommodate and whether there are any constraints further upstream.

For a new development, doing this early can help prevent the electricity connection becoming an unexpected problem later.

For an existing asset, it can help you understand whether the current supply is suitable for future plans and whether there are opportunities within the infrastructure already in place.

Ultimately, it comes down to three things:

What have you got?

What do you need?

And what is the most practical way of getting from one to the other?

Need help understanding electricity capacity?

norwen provides independent utilities infrastructure advice for new developments and existing assets.

We help clients understand existing electricity supplies, future demand, network capacity and potential constraints, and establish a practical way forward for new or increased connections.

This article provides general information only and is not project-specific professional advice. Electricity network capacity, connection arrangements, costs, industry requirements and regulatory processes can change over time. Project specific advice should be obtained before making investment, design or development decisions.