Does cheap electricity mean dirty electricity?
2024 average retail rates from NREL’s utility-by-ZIP file, against this project’s hourly consumption-at-user carbon intensity, joined on the eGRID subregion — the finest level at which both quantities are actually defined.
Rates vintage: 2024, published annually by NREL with roughly a year’s lag. Last checked for a newer vintage 2026-08-23; none published yet.
What the data says
The correlation runs the other way: the cleanest grids are the most expensive ones, and the cheapest electricity in the country is mid-to-high carbon. On ranks — the more robust statistic at this sample size — industrial price and carbon correlate at about −0.63.
And renewables are not the reason. The renewables share of generation has essentially no relationship with price (≈0 Pearson) — the expensive-and-clean corner is California and the Northeast, whose prices carry transmission, policy and cost-of-living freight that has nothing to do with how the electrons are made. Wind-heavy plains subregions sit among the cheapest on the chart.
This is an ecological correlation across ~22 aggregate points — a description of where regions sit, not a causal claim about what a new wind farm does to a bill.
The correlations
Pearson / Spearman, across — subregions.
| Residential price ↔ carbon | — |
| Industrial price ↔ carbon | — |
| Residential price ↔ renewables | — |
| Carbon ↔ renewables | — |
The three New York subregions share one carbon value by construction — NYISO is a single balancing authority — so the effective sample is nearer 20 than 22.
How this was joined, and what it cannot say
- Rates are utility averages, not ZIP prices. NREL lists each utility’s average rate against every ZIP it serves. Averaging over ZIP rows weights a utility roughly by the size of its service territory.
- Bundled tariffs only. Delivery-only rows (16,201 of 77,013) exclude the energy itself and would understate price exactly where retail choice exists; zero rates are missing values, not free electricity. Both are excluded.
- Renewables here means generated wind, solar, hydro and geothermal as observed in EIA-930 — a physical share, not a certificate claim. Storage is excluded: it moves energy rather than generating it.
- Price is 2024; carbon is 2025–2026. 2 years of drift between the two sides of the join. The rate file is a fixed annual publication; the carbon side is a rolling 365-day window, so this gap widens until NREL publishes again.
Rates: NREL, U.S. Electric Utility Companies and Rates by ZIP, 2024 (via data.gov). Carbon and generation mix: built from EIA-930 · eLCI · eGRID
Disclaimer. Academic project. US Government data used responsibly; outputs used at your own risk, with no responsibility or liability accepted. Opinions are my own and reflect no position of my employer.