US capacity response, electricity, year-over-year change

Capacity response, electricity, version 1.0

What it is. The response half of a bottleneck reading (docs/upgrade/20, Bottleneck + Response): how large the stage-weighted pipeline for the next two years is relative to what was actually built in the last two. Above 1 the reported pipeline exceeds recent delivery; below 1 it falls short.

Formula. For data month M:

response(M) = pipeline_24(M) / sum of additions over the 24 months ending at M

where pipeline_24 is the modeled us-future-capacity-pipeline value for M (weights: planned (EIA codes P, L, OT) 0.3; permitted (T) 0.6; under construction (U, V) 0.9; testing (TS, construction complete) 0.95) and additions is the observed us-generation-capacity-additions series (nameplate MW that began commercial operation, by month). The ratio is unitless. No value is produced when fewer than 24 monthly additions values exist in the window or the trailing sum is zero.

Year-over-year change. us-capacity-response-electricity-yoy(M) = response(M) minus response(M minus 12 months), in ratio points, only when both exist.

Reading it. The numerator is modeled (stage weights are assumptions); the denominator is observed. The ratio inherits the modeled badge. A rising ratio with flat additions means more paper than steel; a falling ratio with rising additions means the pipeline is being delivered.

Limits. Nameplate MW mixes technologies with very different capacity factors (a solar MW is not a gas MW); the ratio is a build-rate signal, not an energy signal. EIA excludes facilities under 1 MW.