D-14: VC Imputation — Distribution Analysis

Variable cost distributions for dispatchable technologies where D-14 imputation applies. Only observed (non-NaN, non-zero) raw VC values shown.

        MADD §5.9 Table 35: "Lower Bound Application: assign Minimum Variable Cost of its technology class."

        Current implementation uses non-zero median. This analysis shows the full distribution to evaluate alternatives.

Statistics Summary (non-zero VC only)

MIN(>0) — global minimum

E[min_h](>0) — mean of hourly min

P10

P25

MEDIAN(>0) — current impl.

MEAN(>0)

Technology	Records	NaN	VC=0	% Imputed	MIN(>0)	E[min_h](>0)	P05	P10	P25	MEDIAN	MEAN	P75	P90
Hidroeléctrica de Embalse	117,850	56,369	5,890	52.8%	0.0	46.1	26.3	45.6	59.8	76.7	99.3	103.7	129.5
Termoeléctrica CC	131,745	17,566	1,200	14.2%	63.4	81.2	64.6	167.0	184.4	209.4	220.3	263.4	329.4
Termoeléctrica TV	307,405	131,745	0	42.9%	41.9	46.7	51.2	54.4	59.2	65.6	77.1	75.5	139.5
Termoeléctrica TG	342,537	35,132	0	10.3%	180.0	191.1	219.6	240.2	270.0	299.8	313.6	347.5	424.7
Motor de Combustión Interna	1,192,280	859,750	0	72.1%	15.0	15.0	24.3	219.8	240.9	269.8	277.5	332.7	362.9

% Imputed = records with raw VC=NaN or VC=0 (reclassified by D-13) that receive the fill value.
Red = MIN(>0), the MADD-literal value. Orange = E[min_h](>0), mean of hourly minimums — a less extreme "lower bound" interpretation. Green = MEDIAN(>0), the current implementation.

Histograms (observed non-zero VC, capped at P99)

Interpretation

H. Embalse: MIN(>0) ≈ 0 (shadow price near zero), but E[min_h](>0) = 46.1 — the cheapest embalse unit at any given hour averages ~46 USD/MWh. The global MIN is an extreme outlier.
Termo CC: MIN(>0) = 63.4 but E[min_h](>0) = 81.2 — the cheapest CC plant at any hour averages ~81. P10 = 167.
Termo TV: MIN(>0) = 41.9, E[min_h](>0) = 46.7 — closest gap. TV has a tight distribution; the hourly min is representative.
Termo TG: MIN(>0) = 180.0, E[min_h](>0) = 191.1 — close to MIN because only a few TG units exist and the cheapest is stable.
MCI: MIN(>0) = 15.0, E[min_h](>0) = 15.0 — same unit always dominates. This is a single outlier PMGD with constant 15 USD/MWh; 72% of MCI records have no VC data at all.

            E[minh](>0) ("mean of hourly minimums excluding zeros") is arguably the most faithful 
            interpretation of "Minimum Variable Cost of its technology class": it answers 
            "what does the cheapest unit of this technology typically cost?" without being 
            distorted by a single extreme observation across the entire year.
            It is more conservative than MEDIAN (lower fill value → lower DIF → higher chance of being marginal)
            but avoids the pathological MIN=0 for embalse or MIN=15 for MCI.
        