How does PJM dispatch electricity over the day?
Conventional nuclear or fossil fuel power plants are called on first because of their relative low cost to operate and ability to deliver power into the grid at all times and are called baseload plants. Others plants operate as “spinning” reserves waiting to be called on by PJM as the load increases during the day. They are backed off as the load decreases at the end of the day. Most natural gas plants operate in this manner because they have higher operating costs and can deliver energy quicker when called on by PJM. PJM insures the lowest cost electricity is dispatched first.
