What is Peak Demand?
Adapted from the Metropolitan Area Planning Council (MAPC):
Each year, the single hour in which the electric grid experiences its highest – or peak – demand, typically occurs in the summer. This annual peak tends to correlate with high temperatures and occurs in late afternoon when buildings are using the most electricity to power the air conditioning and other loads. Typically, a handful of other days each year will also have demand that comes close to the annual peak. Providing enough electricity to meet these relatively few peak days has important environmental and economic impacts:
During these times of high demand, our dirtier fuel sources (i.e. coal, oil, kerosene, and inefficient fracked gas) come online. Reducing demand during grid-wide peaks displaces comparatively more emissions than at other times by reducing the use of these high-emitting facilities.
In order to ensure that there is enough electric “capacity” available on the grid to meet demand in future years, the grid operator ISO-New England (ISO-NE), has a program that pays energy generators if they meet future generation commitments. To make these payments, ISO-NE assesses a capacity charge, which is incorporated into your electricity supply rate (as opposed to the utility’s distribution rate).
ISO-NE determines the quantity of capacity to charge each business or municipal building based solely on the demand in that building during the one annual peak hour on the grid. Given the right forethought, this provides businesses and municipalities the opportunity to save big by “peak shaving”, “load-shedding,” or reducing consumption, during the expected annual peak hour – sometimes as
much as 30% of their bill.
In the Berkshires:
There are three fossil fueled peaking power plants in Berkshire County: Woodland Road, Doreen, and Pittsfield Generating. Woodland Road and Doreen are both over 50 years old and run on kerosene, a highly polluting fuel. In 2018, Woodland Road emitted 9,180.5 lbs of NOx and Doreen emitted 6,377.2 lbs. In 2018, Pittsfield Generating, which runs primarily on fracked gas and occasionally on fuel oil, emitted 20,936 lbs of NOx. Additionally, Pittsfield Generating is a significant source of greenhouse gas emissions. In 2018, its emissions constituted 15% of the city of Pittsfield’s entire stationary energy emissions. These emissions were generated in a short period of time, as all three plants run infrequently.
Woodland Road and Doreen have operating capacities of 20.4 MW and 21.1 MW, respectively, and had capacity factors of 0.1% in 2018. Pittsfield Generating is larger. It has an operating capacity of 175.5 MW and had a capacity factor of 5% in 2018.
These polluting facilities, which sit idly by most of the time, cost ratepayers millions of dollars. Strategen Consulting estimates that ratepayers have paid about $104,573,520 in the last ten years and are likely to pay $34,543,080 in the next four years to keep all three plants online.
How Can You Help Shave the Peak?
Or: MAPC’s Peak Demand Notification Program: Each morning from June to mid-September, MAPC sends out an email that assesses the risk that the annual peak could occur that day and, if so, at what time. The notifications also include an outlook for the next week so businesses & municipalities have time to plan ahead. MAPC develops this assessment by analyzing data provided by the grid operator, ISO-NE.
» Sign up here
(Short link for this page: tinyurl.com/PutPeakersInThePast )