The iceman no longer cometh, and neither does the milkman. But if Charlie Burkhardt has his way, there soon will be home delivery of wood pellets. Mr. Burkhardt, who heads the New England Fuel Institute, foresees the day when his oil-delivery trucks will be hauling wood pellets to homes heated by wood gasifiers. With funds supplied by the Department of Energy, the fuel institute is testing for home use wood gasifiers developed by Vermont Wood Energy Corporation.
The wood gasifier is not a new concept. The technology was developed in Europe during the fuel shortages of World War II and continues in use today, primarily in Scandinavia. But the prototypes conceived by Vermont Wood Energy Corporation are the first to be adapted for residential use.
Wood pellets fed into the gasifier are subjected to a primary and secondary burn.
The initial heating stage causes a reaction that releases gases which, in turn, are burned by using a measured quantity of oxygen.
There are several advantages to a gasifier not enjoyed by coal or wood-burning stoves. First, there are no emissions. Virtually all of the potential byproducts in the wood are utilized in the gasification process. This eliminates the hazardous creosote buildup in wood stoves as well as the air-polluting potential of coal stoves.
Thus, the gasifier, which stand 5 feet high, can be placed in a closed room without access to a chimney. There also are safety checks that warn if gases produced in the system, such as carbon monoxide and propane, are leaking.
As now designed, the gasifier would be retrofitted onto an already existing oil burner in the home. After installation the cost of operating the gasifier would be almost 40 percent cheaper than running the oil burner. Mr. Burkhardt estimates that the wood pellets could be burned for the equivalent of 79 cents per gallon of fuel oil.
Right now fuel oil is selling at an average $1.30 but is expected to continue to rise in price.
With testing of two of the five prototypes just now getting under way in Stowe, Vt., Phil Rich, president of Vermont Wood Energy Corporation, is hesitant about predicting what the efficiency of the gasifier might be. Yet he says he believes the gasifier "is several times more efficient than the way most wood stoves are operated."
Mr. Rich also says it is difficult to project the cost of mass-produced gasifiers, given the exaggerated cost of the five handmade prototypes. But he does give a guess of about $2,500, plus or minus $500, with the possibility of that figure being even lower because the design does not include any expensive items or materials.
The Vermont Wood Energy Corporation was set up four years ago by five Vermonters interested in designing an environmentally safe alternative to oil heating.
Only one of the five, Peter Bauer, who designed the gasifier, gets a small salary. The others maintain separate careers --Mr. Rich is a consulting forester, for example -- while volunteering their services to the corporation.
The decision to retrofit the gasifier to an existing oil burner was made early. The number of housing starts in New England are too few to justify designing a system that would replace conventional oil burners. Retrofitted, the gasifier will remove 25 to 30 percent of the workload from the oil burner.
Mr. Burkhardt estimates that 743,000 out of the existing 2.5 million oil burners in New England could be fitted immediately with a gasifier (if they were in production), while many more could accommodate a gasifier with minor adjustments.
Most of the industrial gasifiers in use today are run on wood chips, byproducts of the lumber industry.
The Vermont company's gasifier runs more efficiently on processed wood pellets because the moisture content is constant, allowing for a more consistent burn. Currently, there is only one production plant in the country which bags and sells wood pellets, but three other companies have plans for similar plants in New England once the market develops.
To stoke the gasifier, wood pellets are batch-loaded once or twice a day. Vermont Wood Energy Corporation is interested in developing an automatic feeder that would require only a biweekly loading by a wood-pellet deliveryman, which Mr. Burkhardt envisions, but the funds to develop such an innovation are still unavailable.
The company struggled for funding through the four years of its existence until Mr. Burkhardt learned of the design. His extensive contacts in Washington enabled him to line up funding at the Department of Energy to test the device.
A big cloud hangs over the project, however. DOE budget cuts will likely bring an end to funding for the project beyond the fo ur-month test now under way.