In many Marblehead households, we follow a similar weekday routine when we get home in the late afternoon from work, school and daily activities. We turn on lights, air conditioners, ovens, cooktop ranges, washers and dryers. We run the dishwasher, turn on the television and charge electronic devices. In a growing number of households, we’re plugging our electric vehicles into chargers. This all generally occurs between the hours of 4 p.m. and 8 p.m.
This window of increased demand for electricity isn’t just happening in Marblehead, it occurs across Massachusetts and the rest of New England at the same time. The organization responsible for planning for the generation and transmission of this increased electric demand is our regional grid operator, the Independent System Operator for New England, or ISO-NE, which has established a detailed set of rules that retail utilities like the Marblehead Municipal Light Department (MMLD) and National Grid must comply with.
Each year, the single hour in which the electric grid experiences its highest — or peak — demand typically occurs on a hot weekday in the summer, between 4 p.m. and 8 p.m. A handful of other days each year will also have demand that comes close to the annual peak.
Providing enough electricity to meet the relatively few peak days that occur each year has important environmental and economic impacts.
First, ISO-NE pays electric generators, such as Marblehead’s Wilkins diesel generator, to be “on call” — ready to supply additional energy on demand. The ISO also assesses all retail utilities like MMLD a “capacity” charge to cover the costs of ensuring there is enough electric power capacity to meet the anticipated annual peak demand.
This capacity charge is based solely on the town’s total energy use* during the ONE annual peak hour on the grid. This charge is added to the wholesale energy (kWh) cost that MMLD pays for one full year. In recent years this charge accounts for about 37% of a customer’s total energy charge. (*Energy use is the kWh charge you see on your bill, and includes generation, transmission and capacity charges.)
Locally, the town’s distribution system — poles, transformers and wires — must also be sized to meet peak demand. The greater the peak demand, the greater the cost to the distribution system. Proactively managing peak demand therefore also helps defer the town’s electric distribution system’s capital expenses, which are reflected in MMLD customers’ monthly base charge.
Second, not all electrons flowing to meet our demand are created equal. Electricity produced by sources like nuclear, solar and wind are cleaner than fossil fuel alternatives. Some of these carbon-free sources of electricity are now also proving to be more cost competitive.
During times of high demand, generators that are on stand-by most of the year are dispatched by ISO-NE to run. Like the Wilkins diesel generator, these “peaker plants” are dirtier and less efficient fossil fuel sources, generate higher levels of air pollutants and greenhouse gasses, and because they are standing idle most of the year, are much costlier to operate. Reducing demand during grid-wide peaks therefore displaces more greenhouse gas emissions than at other times, by reducing the use of these dirtier energy sources.
So what can we do? Here are four easy tips.
Tip one: Simply be aware of peak demand and what the best times to use energy are: weekdays before 4 p.m. and after 8 p.m., and on weekends.
Tip two: Manage your energy use. Appliances that heat or cool like dryers, air conditioners and heat pumps, electric cooktops and ovens, use a lot of power. So do car chargers. Plan to shift your non-essential usage on weekdays to before 4 p.m. or after 8 p.m. If your cooktop range and oven are electric, consider grilling or eating cold meals on peak demand days.
You can earn up to $10 per month, per device, from MMLD if you enroll your car charger, thermostat or other smart device in the Connected Homes program, allowing MMLD to manage your demand during system peaks. The program is specifically designed to better manage the electric load, reduce costs and keep rates low. Find out more at nextzero.org/marblehead/connected-homes/.
Another option is to program air conditioners, thermostats or heat pumps to run a few degrees higher during warm days. You can do this manually as well.
Tip three: Talk this up. Tell neighbors, friends and family members about the importance of limiting energy use during peak demand hours. Let them know it impacts our local communities in terms of the environment, cost and health, especially for economically disadvantaged communities where many peaker plants are located. All of our small changes can have a big effect when adopted on a large scale.
Tip four: Sign up to get peak demand notifications and heed the alerts. You can sign up HERE for notifications through Marblehead’s CodeRed (reverse 911) program. More information on the importance of peak shaving can be found at greenenergyconsumers.org/shavethepeak.
The whole community benefits with lower rates and lower polluting emissions when we manage our energy demand and reduce usage during peak times. For the good of our community, we all need to be smart about our energy use.
Lisa Wolf is the newly elected chair of the Marblehead Municipal Light Board.