Is electricity greener at certain times? A practical guide for building owners
Running electrical equipment at a different time can sometimes reduce the carbon associated with its use. It does not automatically reduce your bill or improve your EPC. For a Midlands landlord or building owner, the useful starting point is to separate three questions: how much energy does the building use, when is that energy needed, and what does your tariff charge?
What does electricity carbon intensity mean?
Carbon intensity describes the carbon dioxide emissions associated with each kilowatt hour of electricity. NESO publishes national and regional forecasts for Great Britain. The mix changes as demand and available generation change, so a single annual figure cannot describe every hour. Great Britain here means England, Scotland and Wales; Northern Ireland is part of a different electricity system.
A forecast can help you compare possible operating times. It is an estimate of the electricity mix, rather than a guarantee that switching one appliance will deliver a particular carbon saving. It also does not describe every lifecycle impact of manufacturing, constructing and maintaining energy equipment.
Why can wind turbines be turned down?
Having plenty of renewable generation does not mean the network can move unlimited power. NESO explains that equipment has safe operating limits. If power cannot be transferred between regions, the operator may ask generators to change output. In some circumstances wind generation is reduced in one area while generation elsewhere increases to keep the system operating securely.
This is a network constraint. It explains why a national headline about abundant wind is not enough to decide the best operating schedule for an individual building. Regional information is useful context, but it is not a bespoke instruction from your local network operator.
Start with flexible uses, rather than essential services
Make a short list of electrical uses whose timing can genuinely move. Depending on the property, this might include vehicle charging, a scheduled cleaning task or another non-essential load. Then check operating needs, equipment instructions and the tariff. Keep occupant comfort, ventilation, safety and any required hot-water temperatures protected.
For heating and cooling, ask the maintenance contractor or controls specialist what can be adjusted safely. A timer change can have knock-on effects on warm-up time and comfort. Avoid switching equipment off simply because a dashboard shows a higher-carbon period.
Will a greener time also be cheaper?
Check your own contract. A carbon-intensity forecast is not an electricity-price forecast. Ofgem explains that smart meters can provide more up-to-date consumption information and access to more flexible tariffs, but the actual rates and conditions depend on the supplier and contract. For commercial premises, review the business tariff rather than assuming household offers apply.
A low-carbon period and a low-price period may overlap, but treat that as something to check. Moving the same amount of consumption on a flat unit rate does not, by itself, reduce the energy charge. Extra consumption introduced by the new schedule could undo a hoped-for benefit.
Keep EPC performance and measured performance separate
A commercial EPC is a modelled asset assessment under defined assumptions. A live grid dashboard or a change to your tariff does not automatically alter the certificate. Improving equipment, building fabric and qualifying controls is a separate assessment question.
If your objective is a better EPC or a MEES improvement plan, establish the existing rating and supporting evidence first. If your objective is lower actual consumption, monitor the meter data and operating conditions. A good plan can address both aims, while measuring them separately.
A practical two-week trial
Choose one genuinely flexible load and record its present schedule and consumption. Agree a small schedule change, then compare consumption, cost and comfort over a similar operating period. Note changes in occupancy, weather or production. Use the result to decide whether to continue, adjust or stop; a short trial is useful operational evidence, not proof of a guaranteed annual saving.
NRG can help you understand your building's EPC and model suitable improvement options before you commission works. Send the property address, existing certificate and the outcome you want to achieve.
