So, some big news for energy geeks - the Power Available signal goes live @ng_eso today? What does that mean and why is it important? A/1

Well, as you know, the output of a wind farm is based on current weather conditions. A wind farm of 100MW does not always produce that. Maybe only 80MW. /2

Furthermore, like all generators, wind farms may be asked to turn down generation to manage the system. For example, if demand is lower than expected, generators will offer to turn down. /3

So a 100MW wind farm, only producing 80MW due to lighter winds, may be asked to turn down to 50MW for a period (a so-called BOA - Bid-Offer Acceptance). /4

But when happens at the end of the contracted turn down? Or what if the system needs an injection of power suddenly? Well, to date it would usually be a gas turbine or battery that would step in. This is where the Power Available signal is so important. /5

As of today, the Control Room can make use of the PA signal to see what the maximum output of a wind farm is at any given moment - the Power Available signal. They can see the difference between the current output and what is available, and make use of that spare capacity. /6

This means they can call on that wind farm if needed for frequency response. Wind is fast reacting, and very cheap, which makes it ideal for FR, but to date has not really been used as the volume available for the ESO to use has not been clear. /7

Since 2016 new wind farms have been required to have a mandatory frequency response capability, but we have not been able to use it. The importance of the PA signal? From today we can make more use of wind in system services.

That means cheaper and cleaner power for all. /end

PS. This has been a couple of years of really quite complex work from @ng_eso and input from the industry. So excited that we have finally got a live signal! In particular Jean Hamman, who neglected to talk about it in his "day in the life of.." series https://www.nationalgrideso.com/news/day-life-operational-energy-manager