EVs, heat pumps, solar panels, home batteries. They're connecting to Britain's local electricity
network at a pace it was never designed for. The wires under your road are becoming the front line
of the energy transition — and most people have no idea.
EVs on UK roads
1.8m
plus 1m plug-in hybrids, 2025
Heat pumps installed 2025
51.9k
4.5x the rate of five years ago
Public EV charge points
73.7k
+38% year-on-year, end 2024
UK electricity demand 2025
322TWh
First two-year rise in 20 years
Figure 01
How fast are low-carbon technologies connecting?
Annual UK installations across the four key low-carbon technologies since 2019.
Each one connects to the local distribution network — the cables and substations that serve homes and businesses.
The growth in every category is accelerating, and the local network has to absorb it all.
Building chart
DESNZ · SMMT · Zapmap · UKPN DFES 2025
Why this matters for the local grid
A typical gas boiler draws nothing from the electricity network. Replace it with a heat pump and
you're adding 2-4 kW of continuous electrical load. Add an EV charger and that's another 7 kW
in the evening. The street-level cables and transformers that serve your home were often installed
in the 1960s and rated for a fraction of this. When enough homes on one street upgrade simultaneously,
the local network can hit its limit — and someone's connection gets delayed or refused.
The bottleneck nobody talks about
The transmission queue — 700+ GW of projects waiting — gets all the headlines.
But for most households, the real queue is local: the LV substation on your street,
and how much headroom it has left.
Figure 02 — Live data
What the grid looks like right now
As more homes electrify, the carbon case for doing so gets stronger every year — because the grid
is getting cleaner. The numbers below are live, pulled from the Carbon Intensity API on page load.
They show why switching to electric makes more sense today than ever before.
Live — updated on load
Carbon intensity right now
--gCO₂/kWh
Fetching...
Index
--
vs 24hr rolling avg
Biggest source
--
Fetching...
Low-carbon share
--%
renewables + nuclear
Fetching live generation mix
api.carbonintensity.org.uk
Figure 03 — Interactive
What electrifying a street actually adds up to
A typical residential street of 40 homes, with a substation rated at 500 kVA.
Use the sliders to set how many homes have each technology — and watch the
substation load update in real time. See exactly when the network hits its limit.
■ EV chargers0%
■ Heat pumps0%
■ Solar panels0%
ℹ
Each slider controls how many of the 40 homes on a typical street have that technology.
A 7 kW EV charger adds roughly 4.8 kVA per home at evening peak (after diversity).
A heat pump adds around 2.2 kVA. Solar panels offset load —
but only during daylight hours, not at the evening peak when the grid is most stressed.
Current substation load
120kVA
of 500 kVA capacity
Within limits
At the current settings, the substation is operating comfortably within its rated capacity.
Drag the EV and heat pump sliders right to see how quickly demand can build.
Building model
Illustrative model — based on published DNO load data
What happens when the limit is hit
DNOs have to upgrade transformers and cables before they can allow more connections.
In practice this can take months to years, and the cost — which is ultimately socialised
through network charges — runs to thousands of pounds per property.
Smart charging and flexibility markets can help flatten the peak, but the infrastructure
still needs to be there underneath.