Idaho Electricity Rates per kWh: What Snowpack Does to Your Bill

Idaho runs on rivers, so a dry year reaches your bill within months. It still has the third-lowest home power price in the US, but 2026 is the most expensive year it has ever recorded.

Third-cheapest in America, in its most expensive year

The 2010 Idaho average was just 7.99¢ per kWh. Prices jumped 10.1% in 2012 and 7.6% in 2013, then sat near 10¢ for most of a decade. That long flat stretch ended in 2023, with a 6.5% rise, and the price has climbed every year since.

The first eight months of 2026 averaged 13.01¢, up 11.7% from the same months of 2025 and above every full year on record. Over the latest 12 months the average was 12.77¢. Only North Dakota and Nebraska paid less, and Idaho has never been above the US price at any point in this data. The gap was 31% below the US in 2025, the same as in 2010, after narrowing to 22% in 2015.

All three big utilities changed their bills in 2026

No single decision explains 2026. Idaho homes took several separate changes, and they came from different places: a base rate case, an annual power cost update and an efficiency rider. All of these went through the Idaho Public Utilities Commission.

The January rise came out of a settlement. Idaho Power asked for $199.1 million, or 13.09%, and the commission approved $110 million. For a home using 900 kWh a month that added $12.13. The company wanted its $15 monthly service charge raised to $25, and it stayed at $15. Rocky Mountain Power’s June cut is the average for homes, worth $0.61 a month at 836 kWh, and its fixed charge rose the same day, as we explain below.

A dry year reaches your bill by 1 June

Hydro produced 9.7 of the 20.7 terawatt-hours generated in Idaho in 2025, according to the Idaho Department of Labor. That is down from nearly 80% of the state’s generation in 2005, but it is still the biggest source, and output swings with the water. When the rivers run low, utilities burn more gas or buy power, and that cost goes somewhere.

At Idaho Power it goes to a charge called the Power Cost Adjustment, reset each 1 June. Customers carry 95% of the gap between actual and expected power costs, and the company carries the other 5%. For June 2026 the company forecast 16% less hydro generation than the year before, which pushed the charge up by about $51.3 million, roughly 3% on bills. With the separate Fixed Cost Adjustment, commission staff put the June change at 3.30% overall.

The charge is now 0.5392¢ per kWh, or $4.85 a month at 900 kWh, on top of every price in your tariff. It can also fall: the mechanism works in both directions, so a wet year can cut it, and the commission told Idaho Power to file off-cycle if its forecast proves significantly wrong. The commission also notes that this money only recovers power supply costs and does not raise the company’s return.

Avista has a similar mechanism with a 90/10 split, and its reasons this year were different. Its 0.301¢ rebate ended and a 0.157¢ surcharge began on 1 October 2026, which adds $4.31 a month at 939 kWh. The commission listed lower market sales revenue and lower customer sales among the causes. It also ordered a review of the Palouse Wind contract at Avista’s next rate case, after staff calculated it cost about $13 million more than market power during the period.

Idaho Falls homes pay almost 4¢ less than Rocky Mountain customers

Idaho Power serves about six in ten Idaho homes, and in 2025 it averaged 11.78¢ per kWh. Avista, in the north, was close at 11.84¢. The widest gap in the state is in the east, where Rocky Mountain Power averaged 13.53¢ and the city-owned utility in Idaho Falls 9.60¢.

Idaho Falls Power says five hydropower plants supply about a third of the city’s electricity. You cannot simply opt in, though. Idaho law generally bars one electric supplier from serving another’s customers, which means your address decides your utility. The two do sometimes agree a transfer: the commission approved one customer’s move from Rocky Mountain Power to the city in August 2026.

Co-op homes use more power, so their bills run higher than their prices suggest. In 2025 an average home used 1,120 kWh a month at Kootenai Electric and 1,172 at Fall River, against about 900 at Idaho Power and Avista.

EIA-861 for 2025: each utility’s revenue from homes divided by the kWh they used, so monthly charges are spread into the price.

Five Idaho bills at 1,000 kWh

These five tariffs show why a single price tells you little in Idaho. They differ in the fixed charge, in the summer months and in where the higher tier begins. Each bill below includes the utility’s power cost charge.

Summer means June to September at Idaho Power and June to October at Rocky Mountain Power, which is why its year averages about $133 against about $129. Kootenai’s traditional rate is the same all year. Its higher tier starts only at 3,800 kWh, against 800 at Idaho Power.

The rows are not quite like for like. Avista’s bill is its full billed rate from 1 October 2026, including a 0.722¢ efficiency rider, an exchange credit and a small tax adjustment. At Avista’s own 939 kWh average that comes to about $132.50 a month. Idaho Power and Rocky Mountain Power leave out smaller riders, franchise fees and any exchange credit. Idaho Falls is the city’s fee schedule from 1 October 2026, which lists no power cost figure for homes. It raised the rate from $23 and 7.15¢ in the January 2025 schedule to $24.50 and 7.85¢, so a 1,000 kWh bill went from $94.50 to $103.00.

Rocky Mountain Power’s fixed charge rises every June

This one is already written into the tariff. Since 2025 Rocky Mountain Power’s Idaho customer charge has been stepping up on a set timetable, while its energy prices step down. A small user loses and a big user gains, even though the average home barely moves.

889 kWh was the average Rocky Mountain Power home in 2025. If you live in a small apartment or are away for part of the year, cutting your use will now save you less, because more of the bill does not depend on use.

June 2027 could bring the next Idaho Power rate case

Idaho Power did not file a general rate case in 2026. On its October earnings call, IDACORP said it had started running numbers on a possible June 2027 filing and that the chance of a filing next year had increased. It would give 60 days’ notice first, so the sign to watch is a notice of intent in spring. The last case was filed in mid-2025 and set rates from January 2026, so a June filing would not reach bills straight away.

• Avista: agreed no new general rate change before September 2027.
• Rocky Mountain Power: the $29.25 fixed charge begins 1 June 2027.
• Idaho Power: a new Power Cost Adjustment takes effect each 1 June, set by what the water and markets did.

Rate and power cost cases take written comments, and customers do use them: 12 people commented on this year’s Idaho Power power cost case. The Rocky Mountain step is already approved.

Meta, Micron and the question of who pays

Idaho Power expects a lot more demand. Its Q3 2026 call put annual sales near 19,000 GWh in 2027 and about 29,000 GWh by 2032, and it plans $1.3 billion to $1.5 billion of capital spending in 2026. A Meta data center south of Boise began operating in September 2026, and Micron is building in Boise.

The company says revenue from large contracts, $20.1 million of operating income so far in 2026, helped it avoid a rate case this year. One customer in the June case told the commission that costs were shifting away from large industrial users. Staff asked for clearer accounting of the company’s Clean Energy Your Way contracts in the power cost charge, and the commission ordered it. That is the argument to watch if a rate case arrives in 2027.

Idaho Power’s time-of-use plan has a $10 safety net

Idaho Power’s Time-of-Use Plan charges $15 a month like the Standard Plan, but the price depends on the hour. Sundays and holidays are off-peak all day, in both seasons.

On our figures at 1,000 kWh a month, the plan beats the Standard Plan in summer if about 15% or less of your use falls in the on-peak hours and about 20% in mid-peak. In other months the line is about 18% of use in the on-peak hours. Those are tight limits for a home that cooks and showers in the evening, but a timer on a dishwasher or car charger can move a lot.

If you are new to the plan since 1 January 2026, it costs little to test. Idaho Power compares your first 12 months with the Standard Plan and credits anything over $10 of extra energy charges. You must stay enrolled for the full 12 months and you only get this once at an address. If you leave the plan, you cannot return for a year.

Try your own kWh on an Idaho utility

Choose a utility and type in the kWh on your latest bill. The calculator works from that utility’s average 2025 price, so treat the answer as a guide and add the 2026 changes above.

January is the biggest month, and July the biggest bill

Idaho homes use the most power in winter. Over the past three years they averaged 1,249 kWh in January and 1,090 in July, against 729 in October. Yet July cost more over the latest 12 months, at about $153 against $143 in January, because Idaho Power and Rocky Mountain Power both charge more in summer. In October and May the bill was about $92. Over the 12 months July 2026 ($153) was the costliest month and October 2025 ($92) the cheapest.

So about one Idaho home in four heats with electricity, and those homes see a much sharper January than the state average. On Idaho Power’s tiers, winter use above 800 kWh costs only about half a cent more, while in summer the same step is more than a cent. Big winter bills there come mostly from the kWh, not the price.

Why Utah spends $138 less than Idaho at a higher price

Idaho has the lowest price of the 8 Mountain states. Bills tell a different story. Idaho’s $1,389 a year for 10,876 kWh is the 46th highest of 51, and Utah ($1,250), Wyoming ($1,374) and Montana ($1,381) all spent less despite paying more per kWh, at 13.26¢, 14.01¢ and 13.94¢. To the west, Washington and Oregon pay about $1,580 a year.

Across the border: Utah 13.26¢, Nevada 13.45¢, Montana 13.94¢, Wyoming 14.01¢, Washington 14.20¢, Oregon 15.53¢.

All 50 states and DC on one page, with a map.

Why June 2026 looks like a 16% jump

The chart shows 14.37¢ in June 2026, up 16.4% in a month. Bills did not rise 16%. Three things landed together: summer prices began at Idaho Power and Rocky Mountain Power, the new power cost charge began on 1 June, and this figure divides revenue by kWh, so it runs high whenever use is low and fixed charges spread over fewer kWh. A fair test is June against the June before.

Some older points are also odd. September 2011 shows 6.73¢, the lowest on record, and the price then rebounds 16.9% in a month, which looks like a timing effect in the reporting, not a real price. The newest months are preliminary, so the 11.7% rise may move when EIA revises them.

Figures to August 2026 (EIA marks recent months preliminary), utility figures for 2025, refreshed 3 November 2026. How every number in this series is made and checked.

• Idaho, every month since 2010 (CSV): price per kWh, kWh and bill per home, and the US price.
• Every state, DC and the US (CSV)
• Everything above with the utility and supplier figures (JSON)

EIA data is in the public domain: credit the U.S. Energy Information Administration. A link back is welcome.

Questions

Electricity rates in other states

Version history

• 1.2.1 (November 2026): wording and page heading tidied; no figures changed.
• 1.2 (5 November 2026): clearer headings for the calculator and neighbours sections. No figures changed.
• 1.0 (November 2026): first published.