ISO New England reliance on natural gas-fueled electricity has skyrocketed over the past 15 years and the regional grid is now working to blend more variable energy resources into the mix, ISO-NE Vice President/System Planning Stephen Rourke said recently.
Rourke discussed the issue in a March 29 presentation in Boston.
“New England is transitioning to a system with decreasing amounts of traditional resources (coal, oil, nuclear) and increasing amounts of renewable energy,” Rourke said.
Transmission investment will be needed to incorporate large amounts of wind power, Rourke added.
The ISO-New England official said the region has undergone a rapid transformation between 2000 and 2015, with a dramatic increase in power from natural gas displacing two other fossil fuels – oil and coal.
In 2000 natural gas accounted for only 15% of the electricity produced for ISO-NE. By 2015, the natural gas share was nearly half, 49%, Rourke said.
During the same period coal’s share of electric generation in ISO-NE has gone from 18% to 4% and oil has gone from 22% to 2%, according to materials from his presentation.
The other major source of electric generation for ISO-NE remained relatively flat over the period, declining from 31% to 30%. The rest of ISO-New England’s power generation is met by a combination of hydro and other renewables (which increased from 13% to 15%) and pumped storage (down from 2% to 1%).
Power plant emissions of carbon dioxide (CO2), sulfur dioxide (SO2) and nitrogen oxides (NOx) have all dropped significantly with the changing fuel mix.
The trend toward greater reliance on natural gas should only increase in the near future. More than 4,200 MW of non-gas generation have recently retired or announced plans to retire by 2017. That’s in addition to the 3,200 MW of oil, coal and nuclear retired in the region between 1997 and 2012.
In December 2012, ISO-NE identified 28 generators (not including nuclear) which were considered “at risk” for retirement.
New England states pushing more renewables
Meanwhile the New England states are moving to encouraging more renewable energy. Maine, New Hampshire, Rhode Island, Massachusetts, Connecticut and Vermont all have renewable portfolio standards (RPS) that target renewable penetration of anywhere from 10% to 59% by 2020. (Vermont, which has the 59% RPS target does classify large-scale hydro as renewable).
A 2009 study for New England governors identified up to 12,000 MW of onshore and offshore wind resources in the region. But potential wind generation is often remote from load centers and additional transmission would be needed, Rourke said.
The transmission proposals are coming forward. As of Jan. 1, eleven elective transmission projects had been proposed in the ISO Interconnection Queue, totaling more than 7,000 MW of potential transfer capability, Rourke said.
ISO-NE is also moving toward more of a hybrid grid with distributed resources being added to the grid-connected generation. Currently most solar photovoltaic (PV) resources in New England don’t participate in the region’s wholesale power markets.
Since 2013, the ISO has led the regional Distributed Generation Forecast Working Group (DGFWG) to collect data on distributed generation (DG) policies and implementation, and to forecast long-term incremental DG growth in New England. The group focuses on resources under 5 MW that are connected to the distribution system.
New England’s solar PV capacity is forecast to grow from 900 MW in 2014 to 2,400 MW in 2024.
“Over the past year, four battery storage projects totaling almost 150 MW of capacity applied for interconnection to the regional power system,” Rourke said.
New England has a long history of deploying pumped-storage hydro power. Flywheel technology is also being added for energy storage, Rourke said.