Methodology

Sources, definitions and refresh notes.

This release keeps New Zealand's existing regional view and adds a deliberately scoped international selector. Each market carries its own source date, unit, consumption basis and limitation. The selector is not a cross-country ranking.

New Zealand

Regional observations come from the Electricity Authority’s EMI RegionalPowerPrices dataset. The current committed file is 20260531_AveragePowerUseAndCosts.csv, checked 21 September 2026 and covering January 2025 to May 2026. “Low user” and “standard user” are the source’s profiles. The total monthly bill is the source’s published indicative total including GST; the variable rate and network monthly charge are supporting fields.

The EMI copyright material is generally available under the Creative Commons Attribution 4.0 International licence, subject to the Authority’s legal information. Attribution used here is: “Electricity Authority, www.emi.ea.govt.nz provided by the Electricity Authority (New Zealand)”.

International snapshot

United States. EIA Tables 4 and 5A provide 2024 residential average retail rates and average monthly bills for states, census divisions, DC and the United States total. U.S. government publications are public domain; EIA asks for an acknowledgement. See the EIA release, Table 4, Table 5A and EIA reuse policy.

United Kingdom. DESNZ’s June 2026 Quarterly Energy Prices gives an all-tariff standard-electricity estimate of £1,077 for financial year 2025/26, using fixed consumption of 3,400 kWh/year. The page and release are available under the Open Government Licence v3.0. This is an average bill estimate, not the Ofgem price cap or an individual household’s expenditure.

Australia. The ABS household electricity index is the average of eight capital cities, with quarterly observations through June 2024. The current national CPI release reports electricity at +6.1% year-on-year and -1.6% month-on-month in July 2026. These are index/movement measures, not tariffs or bills. ABS material may be used commercially when the product is marked CC BY 4.0; the source product’s licence marker governs reuse, as described in the ABS conditions.

Canada. The July 2026 Statistics Canada release explicitly calls out electricity movements of +4.4% in New Brunswick and +3.3% in Nova Scotia. The initial view shows those selected provincial observations only; the full geography and history are in Table 18-10-0004-01. Reuse is governed by the Statistics Canada Open Licence, including source acknowledgement and accurate reproduction.

Europe. Eurostat’s 5 May 2026 release reports second-semester 2025 household prices for a medium consumption band of 2,500–5,000 kWh/year, including taxes and levies. The initial selector includes the six countries highlighted in that release: Ireland, Germany, Belgium, Hungary, Malta and Bulgaria. Eurostat allows commercial reuse of its statistical data with source acknowledgement, subject to its reuse policy.

Refresh procedure

From the repository root, run:

python scripts/fetch_data.py
python scripts/build.py

The fetch script discovers the current New Zealand CSV from the EMI dataset page, validates the schema, rejects duplicate month/region/profile keys and regenerates regional-power-prices.json. International observations are intentionally committed as a dated static snapshot in international-electricity.json; update them only after checking the linked official release and its licence. The build script validates both payloads and the static output before deployment.

Calculator

The running-cost estimate is watts ÷ 1000 × hours per day × tariff in currency per kWh. The visitor enters the local minor unit (for example c/kWh or p/kWh); the script divides by 100, then multiplies by days per week, 52 weeks per year and annual-to-monthly conversion. It excludes fixed charges, plan discounts, time-of-use periods, taxes outside the entered rate and appliance cycling.