From ecoRI News (ecori.org)

This past weekend was one of the most energy-intensive in New England history, relying on dirty backup power plants that run on oil and coal to keep up with demand.

According to preliminary data from grid operator ISO New England, July 20 and July 21 were the fourth- and fifth-most energy intensive weekend days on record. On Saturday, electricity demand reached 23,852 megawatts. Sunday peaked at 23,786 megawatts. The highest for any day was set Aug. 2, 2006, a Wednesday, when the energy load reached 28,130 megawatts.

“New England's power system was able to withstand the heat and humidity over the course of this weekend's heat wave and operated under normal conditions,” ISO New England spokeswoman Ellen Foley said.

But on both weekend days coal and oil generated as much as 8 percent of the electricity. New England has three coal-fired power plants: the 440-megawatt Merrimack Station in Bow, N.H.; two 47-megawatt generators at the Schiller Station, in Portsmouth, N.H.; and the 384-megawatt Bridgeport Harbor Generating Station, in Bridgeport, Conn.

While renewables held steady at about 5 percent of the energy mix, about 80 percent of that power came from burning high-polluting wood and trash.

High-polluting trash/wood-fired power plants accounted for most of the renewable energy used on July 20. (ISO New England)

Ratepayers have options to reduce the energy load during high-demand days. The Shave the Peak program run by the Green Energy Consumers Alliance uses text alerts and emails to deliver energy-saving actions during the hottest hours each summer. The goal is to limit the need for energy from high-polluting power plants, which sit idle most of the year.

Typically, New England’s remaining oil and coal power plants run for a few hours each during summer heat waves to meet the spike in electricity demand.

Tips include delaying use of large energy-intensive appliances, such as laundry dryers and electric stoves, until cooler times of day, when air conditioners are turned down and electricity demand falls.

Battery-storage incentive

Homeowners interested in adding backup battery power to their solar panels have a few days to take advantage of an incentive from National Grid.

The ConnectedSolutions program reduces the peak energy load by paying the owner of home battery-storage systems for its stored electricity during periods of high energy demand.

In Rhode Island, National Grid will pay $400 per kilowatt “performed” for electricity it draws from home storage systems during summer energy spikes. The Massachusetts program pays $225 per kilowatt performed during summer heat events and $50 per kilowatt in winter. In both states, the five-year contract promises to draw electricity from no more that 75 events annually.

The deadline to submit an application for both Rhode Island and Massachusetts has been extended to Aug. 1. The battery systems can be installed to new or existing home solar arrays.

Although the battery system is connected to the electric grid it can still provide a backup electricity supply to the residence during a power outage.

According to an article in Bloomberg, a customer with a single Tesla Powerwall battery system could earn up to $1,000 annually from the program. Other eligible battery systems are offered by Pika Energy, Sonnen, and Sunrun. These vendors manage each customer’s storage system using information from National Grid. The battery companies also issue payments to the homeowners.

National Grid hopes to sign up 50 customers in Rhode Island and 230 in Massachusetts.

The estimated cost for a new battery system before tax breaks and incentives is about $8,000. The estimated payback period is about five years.

National Grid benefits by having renewable power to draw from while reducing its need to invest in infrastructure to address spikes in electricity use.

“Calling on batteries to discharge during peak times reduces the loads on the grid when it is most important,” said Ted Kresse, spokesman for National Grid. “It also helps to decrease distribution, transmission, and generation costs. In the future, we hope to also use batteries to help support even more growth of renewable and distributed energy generation.”

Battery-storage systems paired with solar arrays are expected to gain popularity as prices for solar equipment and battery prices drop. There is also a 30 percent federal tax credit for the cost of solar and battery systems.

Tim Faulkner is an ecoRI News journalist.