Following PCGE, we take total decommissioning costs for nuclear to be about 15% of the overnight cost. We assume that these are met by a charge against electricity revenue that is paid into a decommissioning fund that earns interest. Whether 15% is likely to be an under — or an over estimate is difficult to predict. On the one hand it seems that the cost of decommissioning old nuclear liabilities often turns out to be more difficult and more expensive than expected.9 On the other, as experience is gathered with decommissioning, changes are being made to the design and operation to reduce ‘back-end charges’, especially through waste avoidance and simpler dismantlement. On balance, it seems that 15% is likely to be an overestimate for future nuclear plant. In any event, its impact is small: using the figures just given, the contribution of nuclear decommissioning to the LCOE is only $0.6 per MWh(e). Decommissioning charges for non-nuclear technologies are likely to be even smaller and they are ignored here.

Operating and maintenance (O&M) costs

PCGE presents O&M costs per MWh(e) for each power plant submitted by the individual countries. The variability in the nuclear O&M costs is relatively high even when restricted to Europe and North America. Overall average values for these countries (rounded to the nearest whole number) were used and are shown in Table 5.2 . This shows that onshore wind has the highest O&M costs. Next highest is nuclear closely followed by coal.