Figure 9.44 shows how the COE from fusion compares with that from other energy sources [28]. Each entry has two bars showing a minimum and a maximum value, the difference depending partly on location and partly on technology. For fossil fuels, the maximum is the cost including the expense of carbon sequestration. For fusion, the maximum and minimum represent the range of the reactor models ABCD described above. These data for other energy sources are from the IEA report of 1998. Fuel prices and interest rates have fluctuated so violently in recent years that the comparison has not been updated. However, the levelized COEs of nonfu­sion sources are available for 20 056 and 2010.7 The data for 2010 are shown in Fig. 9.44. For comparison, the fusion COE given in Fig. 9.44 is reproduced in Fig. 9.45. That graph shows also the breakdown between capital costs and

operation and maintenance costs, as well as the estimated cost of carbon capture and sequestration for fossil-fuel plants. The data are from different time periods, but the difference is insignificant in view of the uncertainties involved. It is seen that the COE from fusion plants will be competitive with that from other renewal sources and from fossil-fuel plants with carbon management.

It is interesting to note that the large variability of the COE is reflected in the IEA’s 2010 report7. The figures for each energy source vary greatly from country to country. In addition, the sensitivity of the estimates to such factors as corporate taxes, discount rate, and fuel cost is emphasized.

Not included in the above analyses are external costs, which include damage to the environment, general health, and human life. Such costs have been evaluated by site to eliminate location biases. For instance, one considers the difference when a fusion plant is put in place of a coal plant in the same location. It turns out that the external costs of fusion are extremely low, ranging from 0.07 to 0.09 euro cents per kWh. Comparison with other energy sources is shown in Fig. 9.46.

The net present value of fusion takes into account the probability of success or failure. Though this obviously has a high degree of uncertainty, there is a large margin for error, since the annual world energy expenditures exceed the annual cost of fusion development by 1,000 times. It has been estimated that if fusion captures 10-20% of the electricity market in 50 years, the discounted future benefit of fusion is $400-800B; or, if the probability of failure is counted, it is still $100-400B. This means that development of fusion is worthwhile even if fusion captures only 1% of the world electricity market [27].