In terms of energy returned on energy invested (EROEI, or EROI), biofuels generally seem very poor:
But as this site points out, wood gas has some advantages: "Converting biomass to a liquid fuel like ethanol or biodiesel can consume more energy (and CO2) than the fuel delivers. In the case of a wood gas car, no further energy is used in producing or refining the fuel, except for the felling and cutting of the wood. This means that a woodmobile is practically carbon neutral, especially when the felling and cutting is done by hand."
It can even make sense in the more elastic terms of money: the UN Forestry Department did a study in 1986 and looked at power generation for a sawmill, using wood waste generated on site so that there was no purchase cost. The savings were significant:
As the sawmill example shows, there is plenty of mileage in intelligent problem-solving at the local level, and there is no one-size-fits-all solution. Long-term and big-picture planning are needed, but subsidies and other kinds of central government interference can skew cost-benefit analyses and result in misallocation of resources.
Of course, one could wonder why we zoom about so much in the first place: