|If oil prices rise substantially, wood alcohol may be the best and most environmentally friendly substitute. However the increased demand for wood may make it uneconomic for home heating. Prospective purchasers of new heaters should beware!
|The Scientific American Article by C.J. Campbell and Jean H. Laherrère (May 1998) predicts that world oil production will start to fall between 2000 and 2010. The price rises of 1973 were possible because of the dominant 36% share of world oil production by OPEC countries. Predictions show that by the year 2000, OPEC’s share will be 30%, increasing to 50% by the 2010. Production outside Middle East countries is already in decline, with little prospect of major new discoveries.
Campbell and Laherrère suggest liquid fuels could be produced from natural gas, but a better solution for Australia is suggested in the Bureau of Transport and Communications Economics (BTCE) report 94 (Transport and Greenhouse). BTCE costs the viability of replacing petrol with wood alcohol. They predict this be done for about 20c/litre by 2010.
|To solve what might otherwise have been an oil price crisis and balance of payments problem for Australia, 25 million hectares of trees will be required in the long run. There are currently about 10 million hectares suitable for planting trees. To meet the extra demand, wood may have to be grown on land currently used for farming or other land uses, or converting farms to farm forestry. In the unlikely event that surplus trees could be produced, there could be a healthy export market for wood alcohol.
The sustainable future therefore lies in using wood to replace oil and so reduce total greenhouse gas emissions, rather than burning wood in highly polluting heaters, which at the same time produce more greenhouse gases than most other forms of domestic heating. As well as being sustainable, gasohol and diesohol are generally less polluting than pure petrol and diesel. The replacement of wood heaters with solar roof collectors, or passive solar designed new houses would add to the benefits. Even if ideally operated to AS4013, a new wood heater produces more particulate pollution heating a single house than heating 700 houses with gas.
Viability of Solar Heating In Armidale
Even the least sunny winter month in Armidale, the roof of a 100 m2 house will receive an average of 312 kW hours of solar radiation per day. Because of the low sun angles, most of this falls on the northern side of the roof. Over 18 waking hours a day this works out at 17kW. Gilmour and Walker (1995) report that the mean home heating need both in New York and Oregon, with a much colder climate is 3.6 kW. Heat pump technology, similar to that used currently by solar water heaters, could be developed and used to transfer a proportion of this heat to inside the house. This could work for both new and old houses and would seem to be a sensible, cost effective, environmentally friendly way forward. Wood may be replaceable, but if burned in closed heaters, produces quantities of methane and carbon monoxide, 23 and 5 times more powerful greenhouse gases than CO2, resulting in much higher greenhouse gas emissions than alternative heating (Table 1). It is therefore important that alternatives to wood heaters be developed and used.