Recent extreme cold weather in the Northeast boosted natural gas demand beyond the capacity of the natural gas delivery system that supplies New York and New England. As a result, the spot price of natural gas rose above the price of distillate and residual fuel oil (on an energy-equivalent basis) in the Northeast on some days this winter (Figure 1). Because decisions regarding the dispatch of electric generation units are generally based on variable operating costs, the use of oil for power generation can increase when natural gas prices are higher than distillate or residual fuel prices in cases where fuel-switchable or oil-only units are available to operate. ….
via EIA: This Week in Petroleum http://ift.tt/1itBZcw