Efficient uses of biomass resources for bioenergy based on regional supply and demand in New Zealand

This project evaluates the conversion factors for wood to a range of consumer energies.

The study highlights that woody biomass is unique among major energy sources in that it is renewable, dispatchable, storable, nationally distributed, and capable of supplying energy continuously rather than intermittently. Biomass can also act as a multi-vector energy resource, capable of producing heat, electricity, liquid fuels, and gaseous fuels such as synthetic natural gas (SNG).

The most efficient use of woody biomass is direct combustion for industrial and commercial heat production, achieving conversion efficiencies of approximately 82%. Combined heat and power (CHP) systems are the next most efficient pathway, with overall efficiencies of around 71% when heat is the priority product. By comparison, conversion of wood into liquid transport fuels is substantially less efficient, typically achieving only 48 50% conversion of the original biomass energy into liquid fuel due to the high oxygen content of wood. Wood to SNG to heat is estimated to be around 65% with further losses dependent on the use of the heat (CHP 56% or power only 40%).

Accordingly, the highest-value application of biomass in most regions is the displacement of coal used for space heating or industrial process heat. After coal displacement, the next preferred use is substitution for natural gas, either through direct conversion of industrial boilers to wood fuel systems or through production of synthetic natural gas that can utilise an existing gas pipeline network. A caveat being that the SNG route is at a lower technology readiness level than direct combustion of wood chip or pellets.