Where Our Data Comes From
Updated September 04, 2026
Numbers on this site derive from official statistical sources, primarily the U.S. Energy Information Administration (EIA). This page names the exact series, the formula, the units, the publication lag, and the refresh schedule for each. Nothing is projected or modeled by us. Two labeled exceptions to the government-source rule exist: AAA pump prices (no government source covers 50 states daily) and, on the Big Tech energy page, figures from company sustainability reports, which are always marked as company-reported and unaudited, quoted with their verbatim metric label, reporting boundary, and source page.
Electricity rates and bills
| Number | Formula | Source series | Lag |
|---|---|---|---|
| Average rate (¢/kWh) | residential revenue ÷ residential sales | EIA API v2, electricity/retail-sales, monthly, residential sector (the series behind Electric Power Monthly Table 5.6.a) | ~2 months |
| Average bill ($/month) | residential revenue ÷ residential customer count | ||
| Average usage (kWh/month) | residential sales ÷ residential customer count |
Electricity rate increases
The rate increases page compares each state's average effective residential rate (formula above) against the same calendar month 1, 3 and 5 years earlier, from the same EIA monthly series, so seasonality does not distort the change. These are realized average prices, which capture base-rate cases, riders, fuel adjustments and retail supply prices together; they are not tariff filings. When the page carries a rate-case ledger, every ledger row is verified against the state commission docket or the utility's primary filing, requested and approved amounts are reported separately and never summed, and coverage is PUC-regulated investor-owned utilities plus public power utilities with roughly 250,000+ customers.
Energy poverty and the state home-energy expenditure share
| Layer | Construction or exact source | Vintage and cadence |
|---|---|---|
| Share of statewide household income spent on home energy | EIA SEDS annual series TERCV, total energy expenditures in the residential sector, million dollars × 1,000,000 ÷ Census ACS 1-year B19025_001E aggregate household income in dollars × 100. The paired year is the newest year both sources publish. The numerator estimates purchased residential energy expenditure, including an estimated purchased share of wood; direct solar, geothermal and other energy without a direct purchase are excluded. | Annual. The current page labels its paired year; SEDS generally trails ACS. |
| Household scale and income context | ACS 1-year B11001_001E household count and B19013_001E median household income. The corresponding margin-of-error fields B11001_001M, B19013_001M and B19025_001M are fetched and retained. They are not propagated into a margin for the SEDS/ACS ratio because SEDS does not publish a compatible sampling error for that purpose. | Annual; no ACS 5-year fallback. Standard 2020 ACS 1-year estimates were not published, so 2020 is a chart gap. |
| Bundle cost at state prices | The average U.S. household's actual fuel purchases priced at each state's residential prices: Σ over the four priced fuels of state price × national per-household quantity. Prices and quantities from EIA SEDS residential series (electricity ESRCD/ESRCB, natural gas NGRCD/NGRCB, distillate DFRCD/DFRCB, propane PQRCD/PQRCB); quantities divided by ACS households. The bundle is identical for every state, so climate and usage cancel and only prices differ. Where a state has no market for a fuel (SEDS publishes a zero price with zero consumption), that fuel's national share is priced at the national price. Never a cost-of-living measure | Annual (SEDS) |
| Price and quantity effects | Exact accounting split of each state's per-household four-fuel spending gap vs the U.S.: price effect = Σ (state price − U.S. price) × state quantity; quantity effect = Σ U.S. price × (state quantity − U.S. quantity); the two sum to the gap exactly, asserted at build. Four-fuel spending is defined as price × quantity throughout; SEDS's separately published expenditures differ slightly for distillate from 2021 on (renewable heating-fuel blend requirements in NY, CT and RI), with the national gap stated on the page. Quantities are held fixed, so these are components of the observed gap, not estimates under other prices or policies | Annual (SEDS) |
| Household energy insecurity | EIA RECS HC11.1, household counts and relative standard errors for reported experiences. Shares divide each count by the table's all-homes control. | 2024 preliminary, released March 2026; checked every 6 months until final. |
| LIHEAP heating assistance | HHS LIHEAP Data Warehouse, national report field 93, HEATING1B, assisted households, total, heating. The published scope excludes territories and direct-funded tribes or tribal organizations. | FY2025 preliminary; checked every 6 months until final. |
| DOE LEAD comparison | DOE LEAD headline low-income and non-low-income averages, definition and operational 6% high-burden convention; machine-readable release at OEDI submission 6219. | 2022 data vintage, released 2024; reverified every 13 months. |
| England and EU contrast | DESNZ detailed fuel-poverty tables, England LILEE Table 1; and Eurostat ilc_mdes01, EU-27 population unable to keep home adequately warm. | England 2024 final; Eurostat 2025 final; checked every 13 months. |
The state ratio is ecological. It compares two statewide aggregates and is not the average household's burden, a low-income measure, or a threshold count. Dividing both aggregates by ACS households yields the same ratio but does not turn it into a household-level distribution. Data and interpretation are kept separate; the page's electricity-price quartiles are descriptive state associations, not causal estimates.
Utility-level rates and the ZIP lookup
| Number | Formula / source | Lag / vintage |
|---|---|---|
| Utility average rate and bill | Same formulas as above, per utility and state, from EIA Form 861-M (monthly sales to ultimate customers, residential). Months failing sanity screens (implied rate under 2¢ or over 75¢/kWh, bill under $10 or over $1,200, sales without customers) are excluded from display. | ~2 months |
| ZIP → utility mapping | NREL/OpenEI, "U.S. Electric Utility Companies and Rates: Look-up by Zip Code (2024)", CC BY 4.0. We use only the ZIP-utility assignment, never its rate columns. | 2024 vintage, updated when NREL publishes |
EIA's monthly survey covers utilities above a size cutoff (roughly 700 utility-state records per month); smaller utilities report only in the annual EIA-861 census and appear in the ZIP lookup by name without monthly numbers.
Gasoline prices by state
| Number | Source | Cadence |
|---|---|---|
| State pump prices (regular, diesel) | AAA state averages. No government source publishes daily pump prices for all 50 states (EIA's weekly survey covers ~10); AAA is the industry-standard series that EIA itself cites. | Weekly refresh of AAA's daily figure |
| Daily national module (the gas prices today section) | AAA's national averages table (current, yesterday, week ago, month ago and year ago: the comparison figures AAA itself publishes), fetched once each morning, plus the largest overnight state moves computed from the same source. Deliberately restrained: the module shows the national picture and top movers only, and the full state table above stays on its weekly cadence. Crude context is EIA daily WTI spot, which publishes with a lag of several days, stated in the module | Daily (~11 a.m. ET) |
| State fuel taxes and fees | Tax Foundation total state gasoline taxes/fees, plus the 18.4¢ federal excise | Annual |
| Crude-oil component | EIA WTI Cushing spot, monthly average ÷ 42 gal/bbl | Monthly |
| U.S. weekly average pump price (the “why are gas prices high” page) | EIA Gasoline and Diesel Fuel Update, U.S. regular all-formulations retail price, weekly since 2020. Component shares (crude, refining, distribution and marketing, taxes) are EIA's published breakdown, dated on the page | Weekly (Mon) |
| Crude and gasoline price projections | EIA Short-Term Energy Outlook annual series (WTI, Brent, U.S. retail regular), pulled from the EIA API so the page cannot quote a superseded edition. Always labeled as EIA's projection; we publish no forecast of our own | Monthly (~2nd Tuesday) |
| Refining, distribution & margins | Computed residual: pump price − crude − taxes. Includes fuel-specification and carbon-program costs embedded in prices rather than levied as taxes. | — |
| Affordability: work time per gallon (affordability page) | BLS average price of gasoline, all types, U.S. city average (series APU00007471A; the unleaded-regular series APU000074714 is shown alongside) ÷ BLS average hourly earnings, production and nonsupervisory employees, total private (CEU0500000008), both monthly, not seasonally adjusted. State rows divide the BLS OEWS median hourly wage (all occupations, by state, annual) by the AAA state price; the two carry different dates and each is labeled with its own | Monthly (BLS series); annual (OEWS) |
Oil price history (oil shocks page)
| Number | Source | Cadence |
|---|---|---|
| Refiner acquisition cost of crude | EIA refiner acquisition cost of crude oil, composite (series R0000____3): the average price U.S. refiners paid for domestic and imported crude, monthly since January 1974. The 1973–74 embargo episode uses EIA's FOB cost of imported crude (series I000000004), which begins October 1973. Both publish with roughly a two-month lag | Monthly |
| Real (inflation-adjusted) prices | Nominal price × CPI for the stated base month ÷ CPI for the price's month, using BLS CPI-U (CUUR0000SA0, all items, U.S. city average, not seasonally adjusted). The base month is the newest CPI month at or before the newest price month and is stated wherever real figures appear. October 2025 has no CPI value (BLS never published one after the fall 2025 federal funding lapse) and is omitted from real series rather than interpolated | Monthly |
Curtailment
| Number | Source | Cadence |
|---|---|---|
| CAISO wind and solar curtailment (curtailment page) | CAISO monthly curtailment totals (MWh, May 2014 onward). The fetch validates the 2024 annual sum against EIA's independently published 3.4 million MWh figure before accepting new data. Figures for other regions and countries appear only as dated, attributed statements; definitions are not comparable across grid operators, so no regions are summed or ranked | Monthly |
Home heating costs
| Number | Source / formula | Cadence |
|---|---|---|
| Delivered heat cost ($/MMBtu) | fuel price ÷ (heat content per unit × equipment efficiency), so every fuel is on one scale. Heat-content factors from EIA (gas 1.037 MMBtu/Mcf, oil 0.1385/gal, propane 0.0915/gal, electricity 0.003412/kWh); standard equipment efficiencies (gas furnace 92% AFUE, oil 86%, electric resistance 100%, heat pump COP 2.8) consistent with ENERGY STAR furnace and heat pump criteria and DOE Energy Saver guidance. | — |
| Natural gas price by state | EIA residential price ($/Mcf; 1 Mcf ≈ 10.37 therms) | Monthly |
| Heating oil & propane by state | EIA weekly residential survey (~21 states for oil, ~38 for propane), published October–March | Weekly, in season |
| Heat pump payback and incentive status | Running-cost savings are computed from the same season averages as the rows above. We publish no installed-cost estimate: quotes vary too much by home for a national average to be meaningful, so the calculator uses the reader's own quote. Federal credit status is cited to the IRS; state rebate status is deliberately not duplicated here and links to the Department of Energy, because program availability changes week to week and a stale table would mislead | With the heating data |
| Electricity by state | our EIA residential rate series (see above) | Monthly |
Prices shown are the most recent complete heating-season (October–March) average for each fuel, so summer and winter builds report the same season until a new one finishes. The calculator's heating load and heat-pump COP are user-adjustable; we do not model home climate, insulation, or time-of-use rates.
Solar payback
| Number | Source / formula | Cadence |
|---|---|---|
| Value of a kWh of solar output | the state's residential electricity rate (see above), on the basis that a kWh generated is a kWh not bought. Assumes full retail net metering; under net billing, exports are credited below retail and the value is lower | Monthly |
| Payback | quote ÷ (annual production × rate). We publish no system-cost estimate and no production model: roof orientation, tilt, and shading decide output, and every quote already states an estimated annual production, so the calculator uses the reader's own numbers. Simple payback, no financing, no rate escalation | With the rate data |
| Credit and incentive status | Federal 25D status cited to the IRS. State, utility, and net-metering rules are not reproduced here and link to DSIRE, which maintains them | Linked, not mirrored |
EV vs. gas comparison
| Number | Source / formula | Cadence |
|---|---|---|
| EV cost per mile | state residential electricity rate ($/kWh, EIA) ÷ EV efficiency. Default 3.3 mi/kWh (~30 kWh/100 mi, fueleconomy.gov). | Electricity monthly |
| Gas cost per mile | state pump price ($/gal, AAA) ÷ fuel economy. Default 27 MPG (MY2024 new-vehicle real-world average 27.2 MPG, EPA). | Gasoline weekly |
| Annual saving | per-mile gap × miles driven. Default 13,500 mi/yr (FHWA average per driver). | — |
All three defaults are user-adjustable on the page. The comparison is fuel cost only (no purchase price, depreciation, insurance, or maintenance), and home charging is priced at the average residential rate rather than a time-of-use EV tariff.
National energy totals (U.S. Energy Facts)
| Number | Source | Cadence |
|---|---|---|
| Production, consumption, trade, energy by source, CO2 | EIA Monthly Energy Review annual
series, by MSN code. Trillion Btu converted to quads (÷1,000). Note for maintainers:
TETCEUS is total energy-related CO2; TEACBUS looks like a CO2
series but returns trillion Btu of transportation energy |
Annual, revised through the year |
| Electricity generation by source | EIA electric power operational data, U.S., all sectors. The published mix is utility-scale: it reconciles to the all-fuels total using utility-scale solar plus a bucket for geothermal, biomass, petroleum and other. Small-scale solar is stated separately rather than folded in, because the all-fuels total excludes it | Annual and monthly |
| Renewable sources | Always published component by component (biomass, wind, solar, hydroelectric, geothermal). A combined renewables figure alone would hide that these behave very differently | With the annual series |
Each figure on that page carries its own "data through" label rather than a single page-wide date, because the annual totals, the generation series, and the weekly and monthly price series publish on different schedules.
World prices
| Number | Source | Cadence |
|---|---|---|
| European household electricity / gas prices | Eurostat nrg_pc_204 (electricity, band DC: 2,500–4,999 kWh/yr) and nrg_pc_202 (gas, band D2: 20–199 GJ/yr), all taxes and levies included, CC BY 4.0 | Half-yearly |
| European pump prices (gasoline, diesel) | European Commission Weekly Oil Bulletin, prices with taxes as reported by member states | Weekly (Mon) |
| U.S. comparators on world pages | EIA: our state electricity series averaged over the same semester; residential natural gas (consumption-weighted, 1 Mcf ≈ 303.9 kWh); weekly retail gasoline (regular) and on-highway diesel | Matches the European series |
| UK pump prices (petrol, diesel) | DESNZ weekly road fuel prices, ULSP and ULSD pump prices in pence per litre. The UK left the Weekly Oil Bulletin after Brexit, so it comes direct from DESNZ | Weekly |
| Canadian pump prices (gasoline) | Statistics Canada table 18-10-0001, monthly average regular unleaded at self-service stations, cents per litre. Gasoline only. At the newest month Statistics Canada publishes a Canada-wide figure for regular gasoline alone and reports diesel and heating fuel for individual surveyed cities; averaging those cities would produce a national number the agency does not publish, so we leave Canadian diesel blank | Monthly |
| Japanese pump prices (gasoline, diesel) | METI / Agency for Natural Resources and Energy petroleum retail survey, national average cash price for regular gasoline and diesel, consumption tax included, yen per litre | Weekly |
| Brazilian pump prices (gasoline, diesel) | ANP Levantamento de Preços, national average resale price for common gasoline and S500 diesel, reais per litre | Weekly |
| Indian pump prices (petrol, diesel) | PPAC retail selling prices, rupees per litre. Shown as New Delhi, not as a national average. State sales tax on fuel varies widely across India and PPAC publishes retail prices city by city rather than as one country figure; Delhi is among the cheaper large cities, so an India-wide average would be higher | Per published date |
| Currency conversion | ECB reference rates: semester average USD/EUR for electricity and gas; for fuels, the rate on each row's own date, cross-converted through the euro (GBP, CAD, JPY, BRL, INR) | Daily |
Comparability caveats are stated on each world page (consumption bands differ from U.S. usage; Euro-super 95 vs U.S. regular octane conventions; national averages throughout, except India as noted).
Every country in the pump-price table is taken from the agency that collects the price in that country. No third-party price compilation is used, and because the sources publish on different schedules, each row on that page carries its own date rather than sharing one week-wide heading.
World energy mix, production and environment
| Number | Source | Cadence |
|---|---|---|
| Energy mix, fossil-fuel share, electricity generation, oil/gas/coal production | Energy Institute Statistical Review of World Energy (successor to the BP Statistical Review), annual series back to 1965. Fossil share = (oil + gas + coal) ÷ total primary energy, on the input-energy (substitution) accounting used in the Statistical Review. Renewables already include hydro, wind, solar and biofuels | Annual (published each June) |
| Flaring and methane emissions per barrel produced | Statistical Review gas-flaring and process-methane series, combined in CO2-equivalent at 80× CO2 on a 20-year basis as reported, divided by fossil production in barrels of oil-equivalent | Annual |
| Air pollutants (SO2, NOx, PM2.5), CO2 per person, HDI | Yale Environmental Performance Index 2024 raw indicator files, joined to Statistical Review energy by country | Biennial |
These annual figures refresh once a year when the Statistical Review publishes, not on the monthly electricity cycle. Every world energy page states its data year on the page. Country pages are keyed to ISO3 codes so their URLs stay stable when display names change.
What these numbers are, and are not
- They are average effective prices. Revenue divided by sales includes every charge on the bill: energy, delivery, fixed charges, riders, taxes collected through rates. Research on consumer behavior (Ito 2014, American Economic Review) finds households respond to average price, which is why we lead with it.
- They are not tariff prices. Your marginal rate, your utility's fixed charge, and time-of-use differentials will differ from the state average.
- They are official reported data with some estimation. EIA's monthly figures come from Form EIA-861M, a survey of a sample of utilities with imputation for the rest; final census values arrive with the annual EIA-861. EIA revises recent months as final data lands. We re-fetch monthly and log every revision on the data updates page.
Publication lag, disclosed
EIA publishes monthly retail data roughly two months after the fact, typically in the Electric Power Monthly around the 25th. Every page on this site states the actual data month ("Data through June 2026"). We do not project or nowcast unpublished months; a disclosed lag beats undisclosed modeling.
Refresh schedule
The pipeline re-fetches the full EIA series and rebuilds this site monthly, after the Electric Power Monthly release. The "Updated" date on each page is a real data refresh, never a re-dating.
Revisions policy
When EIA revises a previously published value, we adopt the revision and record it (date observed, series, month, old value, new value) in a public log. History is never silently restated: see data updates.
Related resources
EIA's own Electricity Data Browser is the canonical source for this data. The Heatmap-MIT Electricity Price Hub is a complementary project that builds tariff-based estimates with component breakdowns; we link it as a resource, and none of our numbers derive from it.