OREANDA-NEWS. The share of oil in New England's power generation surged in the past month, contrasting state policies that direct a transition to carbon-free energy sources and the need to use the most CO2-intensive generating fuel to back up the northeast grid when demand spikes.

Oil for two consecutive winters has been the regional grid operator's preferred backup fuel because natural gas, which normally accounts for half the generation, at times is scarce at any price on the constrained interstate pipeline system.

But the considerable decrease in oil prices since last summer has made the fuel attractive for economic dispatch. Natural gas was more expensive than fuel oil in almost every trading session since 10 February. Algonquin Citygates spot natural gas prices in February averaged a premium of almost \$4/mmBtu to the regional fuel oil benchmarks.

Electricity generated by units burning oil on 1-22 February totaled 639,443 MWh, Independent System Operator data show. That three-week total exceeds the oil burn in New England for all of 2012 and 2013 combined.

Oil use for power generation is normally limited because of environmental restrictions. The fuel accounted for 1.1pc of total generation in 2014. But its share on February days when load spiked was close or matched other sources of generation. Oil on 16 February accounted for 23pc of generation, about the same as nuclear units and natural gas-fired plants. Coal's share also was higher than normal.

Gas units and wind farms account for almost all proposed new capacity in New England. State governments are spurring their utilities to contract more renewable energy and load management tools. But for now, the dirtiest energy resource appears to have no alternatives for making sure the lights stay on.