All utilities in Massachusetts charge separately for the level of electric use called demand. A simple analogy - if your overall use of electricity (the total amount you use over time) is equivalent to the miles you travel in a car, then your demand level is equivalent to the speed you are traveling.
Our Demand meters record the highest level reached each month. The demand charge recovers the cost of having a dedicated supply of energy output on demand - whether we use it or not; a type of overhead cost. If a business operates all of its equipment for just part of the day but then doesn't use them for the rest of the day, the owner may find that, while the quantity of energy used may be low, the charge for peak demand drives up the overall bill. A business that cycles some of its equipment on while others are off throughout the day will effectively keep its peak demand lower and enjoy a lower bill.