The South West advantage: renewables on the doorstep
Cornwall is the UK's most renewable county by generation percentage. On a good day, Cornwall produces enough electricity from wind, solar, and tidal sources to power many times its own residential demand. The surplus needs to go somewhere. When grid demand is low, as it is overnight, that surplus pushes the South Western England Agile price down sharply.
The renewable mix in the South West is unusually diverse. Offshore wind capacity in the Celtic Sea is expanding, with multiple large-scale projects now operational or under construction. Onshore wind turbines across Cornwall and Dartmoor contribute to the grid throughout the year. Solar capacity is the highest of any UK region by installed capacity per household. And tidal generation, emerging in the waters around Cornwall and the Bristol Channel, adds a generation source that operates independently of wind conditions.
The consequence for Agile customers is a regional overnight price profile that is frequently in the 2-3p range. When multiple generation sources are running simultaneously overnight, prices can fall to near-zero. Plunge pricing events, where prices go to zero or below, are more common in the South West than anywhere else in England. A South West household running an EV overnight can, in active periods, achieve an average effective charging cost below 3p/kWh across a winter quarter.
The South West's advantage is not confined to the very cheapest slots. Even on moderate generation nights, the regional overnight floor tends to be lower than the national average. The distribution network in the South West is also relatively straightforward to maintain, covering a modest residential population spread across a manageable geographic area. Network charges per unit are lower than urban regions, which contributes another fraction of cheapness to the Agile rate.
London's challenge: demand density and transmission costs
Greater London presents the opposite energy profile to the South West in almost every respect. Nine million people concentrated in 607 square miles create the highest electricity demand density in the UK. Commercial, industrial, and residential demand peaks simultaneously in the morning and evening. The grid infrastructure required to serve this density is among the most complex in Europe.
Local generation in London is minimal. A small number of solar installations on rooftops and a handful of district energy schemes contribute marginal amounts, but London imports essentially all of its electricity from the national grid. Every unit consumed in Brixton or Bishopsgate has been generated somewhere in the Midlands, the North, or Scotland, and transmitted hundreds of miles to London's substations.
That transmission has a cost. Maintaining the high-voltage cables, managing grid congestion on the routes into London, and operating the dense urban substation network all add to the distribution charge component of London Agile prices. UK Power Networks, London's DNO, operates one of the most capital-intensive electricity distribution networks in the country. Those costs are spread across London's bills.
The result is that London Agile overnight rates typically sit in the 6-12p range. On a quiet low-demand night, London can reach 4-5p. On a high-demand or low-generation night, overnight prices may barely drop below 12p. The pattern of overnight cheapness versus evening peak exists in London exactly as it does everywhere else. The numbers are simply higher.
Evening peak rates in London on Agile mirror the national pattern: 5pm to 8pm typically sees rates of 30-50p/kWh and occasionally higher during cold snaps. The peak-to-trough spread in London is actually quite large, giving London customers a real incentive to shift usage, even if the overnight floor is higher than in the South West.
The average price gap: how many pence per unit?
Across 2025-2026 rolling data, the typical overnight rate comparison between the two regions is as follows:
South Western England overnight average (11pm to 6am): approximately 3-5p/kWh across the year, with winter wind-heavy quarters bringing this closer to 2-4p and calmer summer quarters bringing it to 4-6p.
London overnight average (11pm to 6am): approximately 7-11p/kWh across the year, with winter periods at 6-10p and calmer summer periods at 8-12p.
The gap between the two regions is typically 4-6p per unit. On 1,000kWh shifted to overnight annually, this represents a regional difference of approximately £40-60 per year in favour of the South West. For a higher-consumption household shifting 2,000kWh annually, the gap widens to £80-120 per year.
It is worth being precise about what this comparison means. The gap is not the saving. The saving for both regions is calculated against the 26.11p/kWh July 2026 price cap. Both the South West and London are saving substantially against that benchmark. The gap is the additional saving the South West achieves over London, not the saving either achieves over doing nothing.
Annual saving difference: what it means in pounds
For a fully engaged Agile household with a 3,500kWh annual electricity consumption, an EV, and consistent overnight scheduling of flexible appliances, the annual savings look broadly like this:
South Western England: The combination of low overnight rates and frequent plunge pricing events typically produces annual savings of £450-550 against the standard price cap. An EV owner charging twice weekly can push this toward £600 in a strong wind year. This is the realistic top end of English Agile saving.
London: The same household engagement in London, with the same flexible load shifting and EV overnight charging, typically produces annual savings of £280-380 against the price cap. The overnight rates are higher, but the evening peak is equally expensive and equally worth avoiding. The fundamental saving is real and significant.
The difference between these two households is £170-220 per year. That is meaningful money. It is also not a reason for a London household to hesitate about Agile. A £280-380 annual saving is more than most households achieve from any other single bill optimisation they could make. The South West household saves more. Both save a lot.
Is it worth moving for cheaper electricity?
A mildly absurd question that turns out to be worth addressing, because the property market in South West England is genuinely attractive to many households for entirely unrelated reasons. If you are considering a move anyway, the energy economics of where you are going are a legitimate factor to understand.
A rural property in Cornwall or Devon with high renewable local generation, strong solar potential on an owned roof, and Agile pricing that regularly reaches 2p overnight is a genuinely different energy proposition from a London flat. Add in the possibility of a home battery system that charges during overnight and plunge windows, and the economics of rural South West living versus urban London include an energy dimension that adds up to several hundred pounds per year.
For most people, electricity price differentials between regions are not a moving decision. They are a fact about where you live. What you do with that fact is the thing you control. If you are in the South West, the combination of your regional prices and consistent Agile behaviour is one of the most favourable electricity cost profiles in England. If you are in London, your saving is smaller but still substantial, and your behaviour, specifically avoiding evening peak and scheduling overnight, is the primary driver of that saving.
Both regions reward the same habit: checking AgileAlert each morning, setting appliance timers to overnight windows, and never running high-draw appliances between 5pm and 8pm. That habit works everywhere. The reward is largest in the South West. It is worth having in London too.