From Peter Rowland
The idea of debiting the energy put into any energy scheme against that which it produces in its lifetime is clearly the proper way forward. But a paper I have written on this topic (“The total energy audit”) goes further, in that any proposed scheme or system for energy production should also undergo a “total carbon audit” to determine that it does not ultimately produce more carbon dioxide than it saves. In the nuclear case, for example, the CO2 emissions resulting from the manufacture of concrete, steel structures, vehicles, transport flasks and the long-term storage of spent fuel should not exceed those saved by actually going nuclear.
It’s a similar case with biomass fuels. These are normally regarded as carbon-neutral because CO2 produced in their combustion was taken from the atmosphere when the plants from which they came were photosynthesising. But if they require transport or fertilisers, and the manufacture or use of these items produces CO2 of fossil-fuel origin, they will cease to be carbon-neutral. We should therefore be thinking intensively about how to make “closed-cycle” biomass schemes where all processes get their energy from biomass.
Before there is huge investment of resources in any proposed scheme, both audits – energy and carbon – should be carried out. Accurate figures for these may not be available, but even a ballpark figure is better than none to start databases with, and precision can be improved and the relative viability of schemes revised as better databases are built up by experience.
London, UK
