What this is
SI Energy Timer shows the hourly day-ahead price of retail electricity in
Southern Illinois, color-coded so you can see at a glance which hours are cheap enough to run
large appliances (a dryer, washer, EV charger, etc.) — and which are unusually expensive.
The app is informational only. It’s meant to help you spot patterns; it does not know your
actual tariff, your appliance sizes, or the exact moment you want to run something. Treat the verdicts
as a rough guide, not an instruction.
No professional advice
Not financial advice
Public data republished
Where the data comes from
All values are drawn from MISO’s
publicly published day-ahead market reports. MISO is the regional grid operator (RTO) that runs the
wholesale electricity market across much of the central United States.
All-in price: what “¢/kWh” actually adds up
Each hour shows a single “all-in” number built from three MISO components, all expressed in the RTO’s native unit ($/MWh), converted to the more familiar ¢/kWh (= $/MWh ÷ 10) only when shown:
- Energy (day-ahead LMP) — the clearing price for that hour.
- Ancillary services — a load-weighted share of MISO’s reserve-clearing prices (regulation, spin, supplemental). A appliance pays only its allocated share of reserves, not the full MCP, so this adder is small (~0.2 $/MWh calm, up to 1–4 in stressed hours).
- Capacity — MISO’s Planning Resource Auction (PRA) cost spread over 24 hours. Usually tiny in winter/spring but meaningfully larger in summer.
- RSG uplift — the Day-Ahead Revenue Sufficiency Guarantee, a market-wide make-whole distribution cost MISO recovers from physical load (~$0.05–0.50 $/MWh, but it spikes during grid stress when gas/plants are strained). Published daily; stretched flat across each market day.
- Transmission + administration — Schedule 9 (NITS) and Schedules 10/17 admin fees. These sit on top of energy and are roughly flat across the day; they can’t be measured to the cent from public data, so this is a modeled estimate (~$5.50 $/MWh combined).
Data sources & timing
- energy + ancillary MISO anonymous final day-ahead LMP reports, Ameren Illinois load zone.
- ancillary clearing prices MISO day-ahead ancillary-market clearing ($/MWh for reg / spin / supplemental).
- capacity Hard-coded MISO Planning Resource Auction (PRA) results; updated by hand each April when MISO publishes auction outcomes.
- carbon-free % MISO public fuel-mix API (today + yesterday), anonymous.
- RSG uplift MISO daily Revenue Sufficiency Guarantee report (DA distribution rate), an XLSX read only for missing market days.
- transmission + admin Modeled estimate (Schedule 9 NITS ~$5/MWh combined with Schedule 10/17 admin); re-checked annually, not scraped.
MISO timestamps are in Eastern time and are converted to Central prevailing time for display. Market days run hour-ending, Central time.
Freshness
Data is refreshed automatically each hour (at :02 Central) — but only the pieces MISO says are missing. Tomorrow’s day-ahead hours publish around mid-afternoon and then fill in as they update. The meta line on each screen shows how many hours are shown and when coverage is incomplete.
What this does not include (and what to compare against)
The number here is the wholesale + ISO-recovery cost of the energy itself. It deliberately does not include your local distribution charge — the fee Ameren collects to run the wires from the grid to your meter. Distribution is a separate, roughly fixed-per-kWh line on your bill that we can’t see or measure here, so it is added on top of everything shown.
To use the display, compare each hour’s all-in number against what you actually pay for that energy:
- Your aggregator’s market rate — e.g. Carbondale’s preferred aggregator Homefield (which buys from MISO) posts a flat per-kWh market cost; that flat line is the reference shown on the chart. If an hour’s all-in comes in below Homefield’s flat rate, that hour is cheaper than your blended market cost.
- Ameren’s seasonal rates — the other comparison if you’re on a time-of-use or seasonal schedule.
So on a sunny morning when energy is ~2¢/kWh, remember your delivered cost is that plus distribution plus any delivery-related adders — which is exactly why the “run now vs. wait” question still matters even when the chart looks green.
Important disclaimers — read these before acting on the numbers
For informational purposes only. The information presented by SI Energy Timer is for general education and awareness. It does not constitute professional, financial, investment, legal, or energy-advisory advice, and should not be relied upon as such.
Not your actual bill. Your retailer, tariff, metering schedule, time-of-use rates, taxes, fees, or fixed components may differ substantially from what is shown here. The displayed “all-in” figure is derived from wholesale market data and may not match the price you are actually charged. Always compare against your own account and rate schedule before making decisions.
Data may be inaccurate, incomplete, or stale. While we make a good-faith effort to reflect MISO-published data, errors can occur in scraping, conversion (e.g. $/MWh → ¢/kWh), caching, or reporting. Prices shown are estimates and can lag the true clearing price by an hour or more; cached values on this device may be out of date if the network is unavailable. We make no representation or guarantee as to the accuracy, completeness, or timeliness of the data.
No liability. SI Energy Timer and its operators shall not be liable for any direct, indirect, incidental, consequential, or punitive damages — including financial loss or damage to property or appliances — arising from your use of, or reliance on, this information, even if advised of the possibility of such damage.
You are responsible for your own decisions. When in doubt, confirm against your official energy bill and a licensed professional.