What does merit order
In the energy industry, the term ‘merit order’ describes the sequence in which power plants are designated to deliver power, with the aim of economically optimizing the electricity supply. The merit order is based on the lowest marginal costs. These are incurred by a power plant and refer to the cost of producing a single megawatt hour under recent conditions. The merit order is separate from the fixed costs associated with a power generation technology. According to the merit order, power plants that continuously produce electricity at very low prices are the first to be called upon to supply power. Power plants with higher marginal costs are subsequently added until demand is met.
The merit order is just one possible model for creating a functional electricity market. It assumes that power plant operators are always trying to cover the cost of the next megawatt hour produced; they would not produce it otherwise. Power plants with low marginal costs can therefore offer a lower price for their electricity, and they are in turn called upon more often than power plants with higher marginal costs. The merit order is designed to shed light on how pricing works on the electricity market; it is not a fixed "law" that coordinates the use of power plants.