rative. Set a level, observe the effect, make a correction in the following period, etc. Landfill tax is planned to be varied in just this way. But surely we can predict the levels needed? Look at the power sector, for example. Table 1 shows the level of carbon tax needed to switch the technology of choice to a lower or zero emissions option when existing plant is retained.
             Table 1: Required carbon tax to equalise generation costs (£/tC)
             existing coal (baseload) existing coal (mid-merit) new CCGT (baseload)
             Note: 1 combined-cycle gas turbine.
             · a tax of £10/tC would justify replacing existing baseload coal stations with new CCGTs;
             ...