The average real-time price of wholesale power in New England fell by more than a third last year, according to the 2015 Annual Markets Report by the Internal Market Monitor of ISO-NE.

Prices dropped more than $22/MWh to $41, as the average price of natural gas fell 41% to $4.73/MMBtu in 2015, from $7.99/MMBtu in 2014.

The report by the Monitor said the wholesale power markets operated competitively last year. The prices of both natural gas and wholesale power were the lowest since 2012, with natural gas generating 49% of the electricity produced in the region.

“Natural gas prices fell last year with increased domestic production, above-average storage levels nationally and mild weather that moderated demand for natural gas for heating and power generation for most of the year,” said Jeffrey McDonald, ISO-NE’s vice president of market monitoring. “Because of the moderate demand, there was sufficient space in the region’s natural gas pipeline infrastructure to deliver low-priced natural gas to the region’s generators. The New England markets were competitive in 2015, as demonstrated by the close linkage between natural gas and wholesale power prices.”

The Monitor also reported that total costs — including energy, capacity, ancillary services and transmission — fell about 25%, from about $12.4 billion in 2014 to about $9.3 billion in 2015.

At 126,833 GWh, total electricity usage in New England was 0.3% lower in 2015 than in 2014.

– William Opalka