CALC-054

Bottom-up lifecycle cost and discounted-cash-flow LCOE, both designs

Calculation · Cited by CLM-0240 , CLM-0241 , CLM-0246 , CLM-0259

What this is

This is the project's own arithmetic, published in full so it can be checked rather than taken on trust. It is not a source. Every input it uses is cited to a record, and the conclusion it reaches only carries as far as those inputs do.

Feeds CLM-0240, CLM-0241, CLM-0246. SHARED - three claims, one section. Answers QST-004.

Script. lcoe-model.py SECTION 4 build_lifecycle() (line 282), SECTION 5 build_annual_timeline() (line 416) and lcoe_dcf() (line 448), reported by SECTION 6 section_baseline() (line 572).

Why it was needed. This is the validation step everything else in the model rests on. If the bottom-up totals did not match NASA's published totals, no divergence found downstream could be attributed to method rather than to a broken build.

Inputs. All of CALC-053's, plus:

Quantity	Value	Source	Stated or assumed
Discount rate	3 per cent	SRC-012 p.56, a Government-financing assumption	STATED
CapEx spread	evenly over a 7.375-yr build, zero energy output during build	-	ASSUMED - this model's own timeline, not sourced
Ground-segment cost	a one-off lump at commissioning	-	ASSUMED
Maintain-phase costs	two equal lumps at operational years 10 and 20	-	ASSUMED
Operate- and Dispose-phase costs	taken as fixed lumps from SRC-012	SRC-012	STATED, 12-15 per cent of lifecycle total, not independently re-derived
RD2 capacity factor and build duration	0.60 and 12.625 yr	SRC-012	STATED, taken directly, not varied

Working, transcribed as the comparison table the script prints.

                 this model     NASA published    ratio
RD1  CapEx       $91.2 B        $90.6 B           1.01 x
RD1  FOM         $186  B        $186  B           1.00 x
RD1  launches     2,321          2,321            exact
RD1  DCF LCOE     0.6231 $/kWh   0.61  $/kWh      1.02 x

RD2  CapEx       $138  B        $137  B           1.01 x
RD2  FOM         $298  B        $297  B           1.00 x
RD2  launches     3,973          3,960            1.00 x
RD2  DCF LCOE     1.0153 $/kWh   1.59  $/kWh      0.64 x

Result. RD1 agrees to 2 per cent. RD2 does not, and the disagreement is the informative half. The underlying cost build matches within 1 per cent for both designs, so the RD2 gap cannot come from mass, launches or manufacturing. That isolates capacity factor and build duration as the place to look, which is what CALC-055 does.

Conclusion, and it is a method point. Close agreement on RD1 combined with a specific, explained divergence on RD2 is worth more than agreement on both would have been. A correct cost total does not guarantee a correct $/kWh conversion, and this pair of results is what demonstrates that.

Where this fails. An order-of-magnitude check. It does not confirm NASA OTPS's underlying spreadsheet, which was not available. The annual cash-flow timeline is this model's own construction and is not sourced - three of the four assumptions in the inputs table above are this model's, and they are the ones a challenger should attack first.

Cite this

energyaperture.com/calc/calc-054

CALC-054. The working above, not a source document.