ePricing

Origin

This started when I officially got a Tesla. A family of six in Plainfield, on ComEd, with a 7-seat Model Y that charges at home, is a different load than the Highlander it replaced. I wanted the units — not the car’s miles of range, and not the wattage printed on a charger.

Watts are how hard something is pulling right now. Kilowatt-hours are what you pay for. ComEd prices that kWh in cents. Until those three numbers sat next to each other, the bill was a mystery and the car was a guess.

ComEd lets residential customers leave the default fixed supply rate and pay the hourly wholesale market instead. Overnight is usually cheap. Summer afternoons can spike. Sometimes the price goes negative and the grid pays you to use power. That is the rate that makes sense if you can shift a car charge. ComEd publishes the live table. I needed a better way to notice. It began as alerts. It became a live price product. Then bill analytics, because the monthly PDF is where the hourly market shows up as a household story.

What I did

1. 01Shipped a single-purpose tool: current tick, cheapest and highest in range, percent of time at or below a useful threshold, and a plain-language call — laundry, EV, pre-cool, or wait.
2. 02Designed for a phone on the kitchen counter, not a dashboard committee. One number. A judgment. History if you want it.
3. 03Wired alerts off the same public feed. A GitHub Action checks ComEd every few minutes. ntfy pushes a phone notification when the price goes negative — the grid is paying you — or when it crosses 10¢ brackets on the way up or down. That is how a spike at 87¢ gets seen in the moment, not on the bill six weeks later.
4. 04Parsed real ComEd e-bill PDFs from this household and turned them into a second surface: effective rate versus the hourly market, usage next to spend, and a bill briefing that names the riders people do not understand.
5. 05Kept guests on a demo household so anyone can learn the product. Signed-in friends upload their own PDFs. Accounts do not see each other’s bills.

How it works

The live tick is the first thing on screen: current cents per kilowatt-hour, in Chicago time. Color and language follow the number — paying you, cheap, normal, high, spike. Cheap is permission to run laundry, charge the car, or pre-cool. A spike is permission to wait. Decision, not a chart.

Live UI only helps if you are looking at it. A scheduled job hits the same feed and notifies a phone when the price drops negative, climbs back out, or crosses 10¢ brackets. The original job of this project was the hour you were not watching.

The monthly bill is the other half. Supply, delivery, taxes — and riders most people skip. ePricing reads an official ComEd e-bill PDF and files a briefing: what this period cost versus the hourly market, daily burn, the Purchased Electricity Adjustment and the carbon-free credit in English. Effective rate is all-in cents per kWh. Market average is the public feed across the same dates. The difference is the story. Guests see a demo household from real statements with identifiers stripped. It does not enroll anyone. It does not control the car.

Outcome

A live product at epricing.leespringer.co. Same public feed ComEd puts on hourlypricing.comed.com — theirs is a table of numbers; this one tells you whether to run the laundry. Proof that the builder instinct — make the data decide something — works at household scale. The interesting part is not that the feed is public. It is that a family can now answer three questions from a phone: What is power worth right now? What did this month actually cost versus the market? And which line on the bill — PEA, carbon-free credit, delivery — is doing the work?