Balancing supply and demand
Though we can easily produce enough energy from renewables to meet our needs overall, making sure we meet energy demand at all times is a critical question for a 100% renewable energy system, where demand and supply fluctuate independently. This was a key research area for the latest report.
In Zero Carbon Britain: Rethinking the Future, we show that even in years like 2010, where cold, dark, windless winters on either side might prove challenging for our energy system, we are always able to 'keep the lights on' with our renewable energy mix, and without using nuclear.
How we do it
In our scenario electricity supply from renewables exceeds demand 82% of the time. We manage variability to meet demand 100% of the time by:
- Shifting energy demand by using 'smart' appliances, demand management, and short-term energy storage (pumped storage, batteries, heat storage and hydrogen) for storage over hours or days. This means supply meets demand a further 3% of the time.
- Using long-term energy storage (for weeks or months) in the form of carbon neutral synthetic gas to cover demand the remaining 15% of the time. This represents only 3% of total electricity supply, but is crucial to managing variability as it can be dispatched quickly as and when necessary.
ZCB hourly energy model
The ZCB energy model used to develop this scenario is one of the most detailed studies of energy variability to date. The model uses hourly weather data (sunlight, wind speeds, temperatures etc.) over ten years – a total of almost 88,000 hours – to test the scenario under real life conditions.