As the weather grows colder, refineries manufacture most (about 90%) of the heating oil consumers need, but they also draw on supplies produced earlier in the year.
Maximum inventory of heating oil in the reserve will be two million barrels. The Department of Energy believes that a two-million-barrel reserve will provide relief from weather-related shortages for approximately ten days, which is the time for ships to bring heating oil from the Gulf of Mexico to New York Harbor. See EIA's information on the Northeast Heating Oil Reserve.