AUGUSTA – With prices for fuel oil and firewood rising, some Mainers are turning to coal as a source of cheap energy.

Maine has only a handful of dealers left who sell coal, whose popularity as a heating fuel has been on the downslide since the introduction of central heating a century ago. Coal use hit rock bottom in the 1990s when a glut of cheap oil hit the market.

But of those Mainers who still use it, coal remains most popular on the islands because it’s easier and cheaper than wood to deliver. Some fishermen choose coal over wood because they can leave home all day and let a coal fire keep burning by itself.

Anthracite is the highest grade of coal. It produces more heat per dollar than wood, wood pellets, propane, natural gas, electricity or fuel oil. In today’s market, $9 of coal produces as much heat as $12 of seasoned wood and $15 of fuel oil.

Bill Clarke, who supplements his oil-fired furnace with coal to heat his historic Yarmouth home, said his coal stove reduces his total heating bill by about $100 a month.

“It doesn’t replace oil, but augments it,” said Clarke. “It helps us get through the winter.”