What is maximum export capacity?
Maximum export capacity, or MEC, is the agreed limit on power your site can send into the electricity network [S1]. It differs from the capacity to import power. G100 Issue 2 describes controls for export, import or both at the connection point [S2]. Check the agreement before sizing solar generation or battery discharge. Checked October 2026.
What does maximum export capacity mean for your site?
Maximum export capacity (MEC) is the power limit agreed with your network operator for sending electricity from your connection into its network [S1].
Why it matters for your site: your solar and battery design must manage the combined flow at that boundary. G100 Issue 2 provides a framework for customer limitation schemes that monitor and control import or export there [S2].
National Grid Electricity Distribution records MEC in kilovolt-amperes (kVA), alongside maximum import capacity (MIC), where applicable [S1]. Read maximum import capacity for the opposite direction. Import permission does not establish an equal export allowance.
Can your solar array be larger than the export limit?
G100 offers a way to manage constrained connection capacity through an agreed limitation scheme [S2]. Ask your distribution network operator (DNO), the local network company, whether that approach suits your project.
For an assumed illustration, not a quote, consider generation of 80 kilowatts (kW) while your building uses 30 kW. The surplus is 80 − 30 = 50 kW before battery charging or export controls. If the assumed accepted export limit is 20 kW at the relevant operating power factor, the design must manage the remaining 50 − 20 = 30 kW. These are assumptions showing instantaneous power balance, not a generation forecast or permission to connect.
Read G100 export limitation for control arrangements. Ask how the system responds when the battery cannot accept more energy or site demand falls.
How should batteries be included?
Request a diagram showing all generation, storage and the measurement point. G100’s overview describes observing device behaviour through flow measured across the connection point [S2]. Ask the designer to demonstrate the limit with solar and battery discharge operating together.
Next step
Bring your agreement to the site-power tool and cut energy costs hub, then get matched with an installer that covers your area.
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Common questions
Where can you find your agreed export limit?
Start with the connection agreement. National Grid Electricity Distribution says agreed MIC and MEC values, where applicable, are recorded there and may also appear in the electricity supply contract [S1].
Is MEC measured in kWh?
No. It is a power limit, not an energy total. The cited network records MEC in kilovolt-amperes (kVA); use the unit in your own agreement [S1].
What details support a request to change capacity?
The network requests supply identifiers, company and site details, contacts, existing and proposed capacity, and a completed application form for increases [S1].
Does G100 address import as well as export?
Yes. Issue 2 describes customer limitation schemes controlling export, import or both. Ask which flows your proposed scheme measures and controls [S2].
Does having an export meter establish permission to export more?
No. MEC is a value agreed with the network, not a value established by the presence of a meter. Ask the network to confirm any proposed change [S1].
Ask about your site
Sources
- Changing your electricity load, National Grid Electricity Distribution,Last checked 19 October 2026
- Engineering Recommendation G100 Issue 2 overview and summary guide, Energy Networks Association,Last checked 19 October 2026