Decommissioning Insight 2022

5.1 Maturity of estimates 5. Appendices

Figure 19 Maturity of estimates

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Each year UK operators provide the cost classification for each of their decommissioning projects using the Association for the Advancement of Cost engineering (AACE) classifications. These seek to define the stage of each project and indicate the degree of uncertainty in the estimates. Class 4 or 5 estimates mean that the projects are in the early planning stages where the scope of work is still being defined and feasibility studies are being carried out. Class 5 estimates have an expected accuracy range of -20 to +100 percent. This range narrows over time as more work is done to increase the understanding of the work involved. Class 2 estimates represent projects that are in the contracting stage with some activities already being executed. These have a higher degree of accuracy of between -5 and +20 percent.

4% 4% 0%

4% 4% 1% 3%

4% 2% 6%

10%

12%

15%

3% 2%

3% 3%

8%

3% 1%

20%

11%

15%

17%

43%

43%

38%

40%

38%

72%

46%

37%

36%

27%

25%

2017 Decommissioning Estimate

2018 Decommissioning Estimate

2019 Decommissioning Estimate

2020 Decommissioning Estimate

2021 Decommissioning Estimate

2022 Decommissioning Estimate

Class 5 Class 4 Class 3 Class 2 Class 1 Actuals

Source: NSTA

DECOMMISSIONING INSIGHT 2022

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