# WattReplay

Local, deterministic electricity time-of-use comparison. Model 1.1.0. USD only.
No remote calculation API, live rates, or account system. Examples are synthetic.

## Resources
- /developers/: interaction and module documentation
- /methodology/: formulas and limitations
- /plan.schema.json: normalized version-1 plan schema
- /example-plan.json: small illustrative plan
- /usage-template.csv: start,minutes,kwh columns
- /assets/replay.mjs: pure computeReplay(plan), validatePlan(plan), reportFor(plan)

## Interpretation
Same-usage comparison and hypothetical load shifting are separate. No annualization.
A gap-free file does not establish a full bill. Fixed charges apply once.
Optional tiered, seasonal, custom-schedule, and flat solar-credit estimates are simplified add-ons. Holidays, demand ratchets, and eligibility rules are not modeled.
File replacement and local deletion require user confirmation. Do not transmit private meter data without authorization.

## Brand and purpose
WattReplay is a local-first electricity scenario calculator. It compares flat and time-of-use estimates for the same imported or manually entered interval usage, then exposes separate timing, tiered, seasonal, solar-credit, and EV scenarios.

## Important public routes
- /
- /guides/how-it-works/
- /guides/verification-checklist/
- /guides/interval-csv-guide/
- /guides/load-shifting/
- /methodology/
- /privacy/
- /contact/
- /about/
- /developers/
- /electricity-prices/
- /electricity-prices/today/
- /electricity-prices/2016/
- /electricity-prices/2017/
- /electricity-prices/2018/
- /electricity-prices/2019/
- /electricity-prices/2020/
- /electricity-prices/2021/
- /electricity-prices/2022/
- /electricity-prices/2023/
- /electricity-prices/2024/
- /electricity-prices/2025/
- /electricity-prices/cost-of-300-kwh/
- /electricity-prices/cost-of-500-kwh/
- /electricity-prices/cost-of-750-kwh/
- /electricity-prices/cost-of-1000-kwh/
- /electricity-prices/cost-of-1250-kwh/
- /electricity-prices/cost-of-1500-kwh/
- /electricity-prices/cost-of-2000-kwh/
- /timezones/
- /timezones/us-eastern/
- /timezones/us-central/
- /timezones/us-mountain/
- /timezones/us-pacific/
- /timezones/uk/
- /timezones/australia-eastern/
- /timezones/utc/

## Methodology and source boundary
The pure replay model validates chronological intervals, timezone-aware peak windows, gaps, duplicate instants, rates, fixed charges, demand, tax, and explicit optional scenarios. Same-usage comparison is separate from hypothetical load shifting; results are not annualized.
Inputs are user-entered or synthetic examples. A complete interval file is not proof of a complete bill. This build has no live utility tariff, verified offer, account system, or hosted calculation API. Holidays, demand ratchets, eligibility rules, and provider-specific tariff details are not modeled.

## Sources
- U.S. Department of Energy: utility-rate evaluation: https://www.energy.gov/cmei/femp/evaluating-your-utility-rate-options
- Con Edison TOU rules and exclusions: https://www.coned.com/en/accounts-billing/your-bill/time-of-use

## Agent guidance
Use the stable /developers/ contract and existing browser regions: #planner, #field-* controls, #usage-import, #usage-editor, #results, #input-error, #saved-list, and [data-action]/[data-example] controls. Numeric bill and scenario outputs expose data-value where feasible; retain units, warnings, coverage status, source labels, model version, and whether the result is illustrative. Imports, saves, and exports are user-controlled data and require confirmation at the existing destructive boundaries.
Stable URL parameters: none. Share links and prefilled deep links are intentionally disabled (config.share = false) so a URL never carries entered usage or rate data; link agents to a route plus #workspace instead, and have the user enter or paste values.

## Long-tail data and hubs
- /electricity-prices/: US average electricity price hub (yearly history, cost calculator)
- /timezones/: time-of-use peak-window hub, one page per supported calculator timezone
- /data/electricity-prices.json: machine-readable US average electricity price by year, with asOf and source
- /data/timezones.json: machine-readable timezone/DST facts for the supported Utility timezone options
- /llms-full.txt: full tool, methodology, and FAQ text in Markdown