As we continually work to balance the system, we can ask generators of all kinds – not just wind farms – to come on or off the grid to help us balance supply and demand, or to manage ‘constraints’ – effectively bottlenecks – in the network.
This is something we do many times every day, and have done for many years. It is a normal part of our job, and we have a number of well-proven tools to help us do it, including buying generation onto or off the network one or two days ahead of real time, and bids on the balancing mechanism within one or two hours of when the energy is needed.
Our demand forecasting team is always planning ahead, so we can make sure there is enough back-up power available to cover any potential shortfall, whether that’s due to a power station breakdown or an unexpected event.
For instance, in very high winds, many wind farms will shut down their turbines for their own protection, often automatically. When that happens, we can use our backup generation to balance the system.
Sometimes it works the other way too. In early January 2012, we asked some wind farms in Scotland to stop generating for a few days. This was for two reasons.
First, the very high winds were affecting the transmission network, causing constraints. Also, demand in Scotland was low because of the New Year Bank Holidays, so that additional energy wasn’t needed.