Platform Guide · Utility Tariffs
Utility Tariffs in CogenS™: A Quick Walkthrough
How to get the right tariff into your study in a few minutes. Start from the built-in rates for your city, pull a US electricity tariff from OpenEI, or pull the current US or Canadian electric or gas tariff from RateAcuity. Then check it, adjust it and save it.
Why the Tariff Matters
CogenS™ bills every hour of the simulated year against your utility tariff, or every 15 minutes on a sub-hourly run. Energy rates, time-of-use periods, usage tiers, demand charges and fixed charges all count, so the tariff often decides whether a project pays back.
A battery saves money mostly by cutting demand charges. CHP pays off on the gap between electricity and gas prices. Thermal storage pays off on the gap between peak and off-peak rates. A flat average price hides all of that.
The built-in rates are a fast start for an early study. For a study a client will rely on, use the real tariff: from OpenEI for US electricity, from RateAcuity for current US and Canadian electric and gas, or typed in from the tariff sheet.
Tariff Sources at a Glance
Built-in rates
340 cities in 87 countries, in local currency. Electricity, natural gas and water, plus the grid CO₂ factor. Representative planning rates, on every plan.
OpenEI
US electricity tariffs from NREL's free Utility Rate Database, for utilities within 50 miles of your site. No extra cost.
RateAcuity
Current US and Canadian electric and natural gas tariffs, with riders, fees and taxes. $50/month add-on with 10 pulls included; needs a paid plan.
Manual entry
Up to 20 periods per section, each with up to 20 tiers. Weekday and weekend rates, hours and months, fixed charges, and demand billed per month, day, hour or 15 minutes.
Saved tariffs
A private library of your electricity, gas and water tariffs. Save once, then load into any project with one click. Reusing a saved RateAcuity tariff costs no extra pull.
What gets billed
Time-of-use energy, usage tiers, demand charges, fixed monthly charges, riders and taxes, for electricity, natural gas and water.
Not modeled
Holidays (schedules are weekday and weekend), minimum bills, and demand ratchets. A RateAcuity preview warns you when a tariff has a ratchet or similar charge.
Walkthrough: Set Up a Tariff
Eight steps, from a new project to a study billed on the real tariff, then reused on the next one.
Set your site
On Site Information, choose the country, city and building sector. This sets the weather, the currency and the built-in rates for that city.
Check the built-in rates
Open Utility Rates. The Electricity Energy, Electricity Demand, Natural Gas and Water sections already hold your city's built-in rates for your sector, so you can run a first study right away.
US electricity: pull a tariff from OpenEI
In the OpenEI Tariff Database section, click OpenEI Fetch. Pick a utility from the list of those within 50 miles of your site, then pick the tariff, using the sector, size range and dates to find the right one. Click Apply Tariff to Electricity Rates.
US or Canada, electric or gas: pull from RateAcuity
With the RateAcuity add-on, go to the RateAcuity Tariff Library section and click Find Electric Utilities or Find Gas Utilities for your state or province. Pick the utility and the rate schedule, then click Pull Full Tariff. Each new schedule uses one pull; the same schedule again the same day is free.
Check the preview, then apply
The preview lists every period with its months, weekday and weekend hours, rates and tiers, plus the fixed charge and any warnings. A breakdown shows each rate before and after riders and taxes. Download the Excel file to check it against the utility's tariff sheet, then click Apply Tariff to Project.
Adjust anything by hand
Every rate stays editable. Use Add Period and + Tier to change the structure, set the hours and months for each period, and choose how demand is billed. You can type a whole tariff in this way if it isn't in either database.
Save it to your library
In the Saved Tariffs section, type a name, choose Electricity, Natural Gas or Water, and click Save Current Tariff. RateAcuity pulls are saved for you, labelled with the utility, schedule and effective date. Then run the model: every step of the year is billed against the tariff you set.
Reuse it on your next project
Start a new project, open Utility Rates and click Apply next to the saved tariff. The rates load into the matching section, ready to edit. A saved RateAcuity tariff doesn't use another pull, and your library is private to your account.
Related Guides
Utility Tariff Features
Built-in rates, OpenEI and RateAcuity in detail, including a raw RateAcuity response and the inputs CogenS builds from it.
Tariff Billing Validation
174 of 174 tariff and net-metering scenarios match NREL's System Advisor Model.
Battery Energy Storage Guide
Where the tariff matters most: sizing a battery against demand charges and time-of-use rates.
Ready to run a real analysis?
Sign up free and run a complete technoeconomic analysis in your browser — pre-loaded weather, tariffs, equipment specs, and financials for 340+ cities.