Value of lost Load Calculator
Value of Lost Load (VoLL) puts a dollar figure on electricity that never arrives. Utilities, regulators and large energy buyers use it to decide how much reliability is worth paying for: if an outage destroys $62,500 in value, a $40,000 fix that prevents it is money well spent. This calculator prices an outage two ways, because the industry genuinely uses two definitions: unserved energy multiplied by its value per unit, and the premium you would pay to avoid a disruption at all.
Planning estimates only. Real VoLL studies use customer surveys and outage-duration models; treat results as indicative.
Quick Answer
An outage that leaves 12.5 MWh undelivered, valued at $5,000 per MWh, has a lost-load value of $62,500: 12.5 × 5,000. In the second mode, paying $200 now but being willing to pay $600 to avoid a disruption gives a VoLL of $400: 600 − 200. Both worked examples are pre-filled in the calculator above.
Key takeaways
- VoLL is a planning price for reliability, not a bill and not a compensation rate. It answers “what is an outage worth avoiding?”
- Two definitions share the name: energy not served × value per unit (the planner’s version), and avoidance price − current price (the economist’s version). This tool runs both.
- There is no single typical VoLL. Published studies disagree by orders of magnitude across customer class, country and outage duration, so this page reports what named studies actually found instead of tidy universal ranges.
- The decision rule is a comparison: a reliability fix is worth funding while it costs less than VoLL × the unserved energy it prevents.
- Quick Answer
- How to use the Value of Lost Load Calculator
- The two VoLL formulas
- Worked examples, checked against the tool
- What studies actually report for VoLL by customer class
- How planners use VoLL: EENS, SAIDI and the investment rule
- What competing calculators miss
- Frequently asked questions
- Add This Calculator to Your Website
- References
How to use the Value of Lost Load Calculator
Pick the tab that matches your question, enter two numbers, and calculate. Results stay hidden until you click, and switching tabs clears the previous result.
- Unserved energy mode: choose kWh or MWh, enter the energy the outage fails to deliver and the value of one unit of it. The pre-filled example is 12.5 MWh at $5,000 per MWh. Click Calculate Lost Value to get the total lost value plus a sentence restating your inputs.
- Willingness to pay mode: enter what you currently pay for the supply and the most you would pay to guarantee no disruption. Click Calculate VoLL to get the difference, floored at $0.00 as explained below.
- Copy or share the result from inside the results box. Copying before you calculate produces the message “Calculate first, then copy your results.”
Each mode rejects bad inputs with a plain message: blank or non-numeric entries (“Please enter the energy not served and the value per unit.” or “Please enter both prices.”), energy or value per unit at zero or below, and negative prices in the willingness-to-pay mode. One behaviour to know in advance: if your avoidance price is below your current price, the raw difference is negative, and the calculator reports $0.00 with the explanation that there is no lost-load value to insure against at those inputs. That clamp is deliberate. A negative VoLL would imply an outage benefits you, which is not a planning number anyone can use.
The two VoLL formulas
Both formulas are one line long. They differ in what they measure, which is why a page that offers only one of them answers only half the questions people bring to this term.
Willingness to pay: VoLL ($) = Price to Avoid Disruption − Current Price ($)
The first formula scales with the size of the outage. Double the unserved energy and you double the lost value, which is what a planner sizing a feeder upgrade or a battery needs. The unit choice is cosmetic but unforgiving: entering 12.5 with MWh selected and $5,000 per MWh gives $62,500, and entering 12,500 with kWh selected and $5.00 per kWh gives the same $62,500, but mixing the two scales (12.5 with a per-kWh value) understates the answer a thousandfold. If you are converting a bill into energy terms first, the cost per kWh calculator handles that division.
The second formula does not scale with energy at all. It measures one customer’s premium for certainty over a stated period, which is the number an economist uses to price reliability products, interruptible-rate discounts and backup-power offers. Keep the two periods identical when you enter the prices: a monthly current price against an annual avoidance price produces a meaningless difference.
Worked examples, checked against the tool
The unserved-energy example is a planning comparison. An outage threatens 12.5 MWh and the planner values lost load at $5,000 per MWh, so the outage carries $62,500 of lost value. Faster reclosers costing $40,000 would prevent it, leaving a net benefit of about $22,500. That comparison, not the $62,500 alone, is the usable output.
Every row below is a real run of the calculator above, so you can retype any row and get the same figures back.
| Mode and inputs | Result | Reading |
|---|---|---|
| Unserved energy: 12.5 MWh × $5,000 per MWh | $62,500.00 | The worked example; beats a $40,000 prevention cost |
| Unserved energy: 12,500 kWh × $5.00 per kWh | $62,500.00 | The same outage expressed in kWh; identical answer |
| Unserved energy: 1,000 kWh × $3.50 per kWh | $3,500.00 | A neighbourhood-scale outage at a household-grade value |
| Willingness to pay: $600 avoidance − $200 current | $400.00 | The premium this customer places on certainty |
| Willingness to pay: $200 avoidance − $600 current | $0.00 | Avoidance below current price; the result is clamped at zero |
| Willingness to pay: $0 current, $0 avoidance | $0.00 | Zero prices are accepted in this mode and return zero |
What studies actually report for VoLL by customer class
Studies agree that business customers lose far more per outage than households, and then disagree about almost everything else. Earlier versions of this page printed tidy ranges ($1 to $5 per kWh residential, $5 to $15 commercial, $10 to $50 industrial) as if they were settled planning constants. No single study supports those exact bands, so they are gone. What named research actually found is messier and more useful:
| Source | What it measured | Finding |
|---|---|---|
| Lawrence Berkeley National Laboratory customer damage functions (the research behind the ICE Calculator) | Cost per customer for a 1-hour summer afternoon outage | About $3 for a residential customer, about $1,200 for a small or medium commercial and industrial customer, and about $82,000 for a large commercial and industrial customer. Per-event figures, not per-kWh rates. |
| London Economics study for Ofgem (Great Britain) | A single system-wide VoLL for network planning | £16,940 per MWh (about £16.94 per kWh) as the combined “vanilla” value, with segment-level values varying widely around it, including far higher values for fuel-poor households and rural small businesses. |
| Residential survey research in Japan (Energies, 2025) | Household willingness to pay to prevent a 2-hour outage, converted to a per-kWh VoLL | Estimates moved four to eight times depending on how households not using electricity at the time were treated, with a cited residential VoLL near 560 yen per kWh. Method choices dominate the answer. |
| Sectoral load-shedding study of Germany (Energies, 2016) | VoLL across 51 economic sectors | Sector values ran from below €1 per kWh for rail services to roughly €47 per kWh for business services. “Industrial” and “commercial” are not single numbers in the data. |
Three lessons survive every method. First, duration changes everything: a one-minute interruption and an eight-hour one do not share a per-kWh value, because spoiled food, lost production runs and exhausted backup batteries all arrive with time. Second, customer mix changes the rest: a feeder serving a cold-storage warehouse and a feeder serving homes can lose the same energy and differ in lost value by a hundred times. Third, any VoLL quoted without a country, a customer class, a duration and a method is decoration, not data. Use the ranges from a study that matches your situation as the value-per-unit input, or use your own survey figure, and treat the output as an estimate with wide error bars. If your question is what the energy itself costs when it does flow, that is a different calculation: see the cost of energy calculator and the energy value calculator.
How planners use VoLL: EENS, SAIDI and the investment rule
VoLL rarely stands alone in a real study. It is multiplied by expected energy not served (EENS), the probability-weighted amount of energy a network is expected to fail to deliver over a period, to produce an expected outage cost in dollars per year. That product is the benefit side of every reliability business case: a project that cuts EENS by 10 MWh a year in an area valued at $5,000 per MWh avoids about $50,000 a year in lost value, and it earns its budget only while it costs less than that.
The frequency and duration side of the same picture comes from the reliability indices utilities report to the U.S. Energy Information Administration on Form EIA-861: SAIDI, the minutes of interruption the average customer experiences per year, and SAIFI, the number of interruptions the average customer experiences per year, both defined under the IEEE 1366 standard. SAIDI and SAIFI describe how often the lights go out and for how long; VoLL prices what that costs. Regulators use the combination to test whether a utility’s reliability spending is justified in rate cases, which is why the VoLL assumption in a filing gets argued over so hard: move it and every project’s benefit moves with it.
For site-level work in the United States, the reference tool is Lawrence Berkeley National Laboratory’s Interruption Cost Estimate (ICE) Calculator, rebuilt as ICE Calculator 2.0 from fresh customer surveys across 24 U.S. utility service territories, with residential costs modelled on willingness to pay and business costs modelled on direct losses such as spoiled production and idle labour. This page’s calculator is the transparent arithmetic core of that work, the two multiplications and subtractions, without the survey model behind it. Use it to test assumptions quickly, and use a damage-function tool when the answer will be filed with a regulator.
What competing calculators miss
The VoLL tools in this space each implement one definition and stop:
- Willingness-to-pay-only calculators (Calculator Ultra): the PAD − CP formula with a $200 − $150 = $50 example. Correct as far as it goes, but there is no energy quantity anywhere, so a planner with 12.5 MWh unserved gets nothing.
- Load-and-duration calculators (Savvy Calculator): build unserved energy from load size × duration × interruptions per year, which is a genuinely useful front end, then multiply by a rate. What is missing is the willingness-to-pay definition entirely, plus any sourcing for the rate you are told to type in.
- The survey models (Berkeley Lab ICE Calculator 2.0): the authoritative end of the market, with customer damage functions fitted to thousands of survey responses. The trade-off is opacity and effort: you get a modelled estimate for a territory, not a two-input check you can run against your own VoLL assumption in ten seconds.
- The gap this page fills: both definitions as working modes on one page, a kWh/MWh toggle so utility-scale and household-scale users stop converting by hand, study-sourced context for the value-per-unit input instead of invented ranges, and copy and share buttons on both results.
Frequently asked questions
Value of lost load (VoLL) is the economic value of electricity that is not delivered during an outage. It is measured either as unserved energy multiplied by its value per unit, or as the premium a customer would pay to avoid the disruption. Planners use it to price reliability: an outage with a VoLL of $62,500 justifies spending up to that amount to prevent it.
Because the literature uses two definitions with the same name. Planners multiply quantity by value per unit, which suits sizing an investment against an expected amount of unserved energy. Economists measure willingness to pay, the gap between the price to avoid a disruption and the current price, which suits pricing reliability products. The two modes answer different questions, so the calculator keeps them separate.
There is no single typical value, and any tidy universal range should be treated with suspicion. Berkeley Lab damage functions put a 1-hour outage at about $3 per residential customer but about $82,000 per large commercial and industrial customer, while the London Economics study for Ofgem used a single planning value of £16,940 per MWh for Great Britain. Country, customer class, duration and method move the answer by orders of magnitude.
Longer outages cost more per unit of unserved energy. A brief interruption may only reset clocks and stall a process for minutes, while an eight-hour outage spoils food and refrigerated stock, loses whole production runs and runs backup batteries flat. That is why serious studies report VoLL for a stated duration instead of one number for all outages.
EENS is expected energy not served: the probability-weighted amount of energy a network is expected to fail to deliver over a period. Multiply EENS by VoLL to get the expected outage cost, which is the benefit figure in a reliability business case. A project that cuts EENS by 10 MWh a year at a VoLL of $5,000 per MWh avoids about $50,000 a year in lost value.
SAIDI is the System Average Interruption Duration Index, the minutes of interruption the average customer experiences per year. SAIFI is the System Average Interruption Frequency Index, the number of interruptions the average customer experiences per year. U.S. utilities report both to the Energy Information Administration on Form EIA-861 under the IEEE 1366 standard. They describe how unreliable supply is; VoLL prices what that unreliability costs.
Because the calculator clamps the result at $0.00. If the most you would pay to avoid a disruption is below what you already pay, the raw difference is negative, and a negative VoLL would claim an outage benefits you. The calculator reports $0.00 instead and explains that there is no lost-load value to insure against at those inputs.
Utilities and grid operators use VoLL for reliability planning, regulators use it to judge reliability spending in rate cases, and large energy buyers use it when deciding on backup power, insurance or interruptible-rate contracts. It is a planning estimate, not a compensation rate: nobody is automatically owed the VoLL figure after an outage.
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References
- Sullivan, M. et al., Lawrence Berkeley National Laboratory. A Framework and Review of Customer Outage Costs: Integration and Analysis of Electric Utility Outage Cost Surveys (customer damage functions; 1-hour summer afternoon outage estimated at about $3 per residential customer, $1,200 per small-medium commercial and industrial customer, and $82,000 per large commercial and industrial customer). Accessed October 24, 2026.
- Electricity North West / London Economics. The Value of Lost Load: Summary Factsheet (the London Economics value of £16,940 per MWh used by Ofgem, with segment-level variation by customer type, affluence and location). Accessed October 24, 2026.
- Energies (MDPI). Investigation of Residential Value of Lost Load and the Importance of Electric Loads During Outages in Japan (household survey; per-kWh VoLL estimates vary four to eight times with the treatment of non-users, with a cited residential VoLL near 560 JPY per kWh). Accessed October 24, 2026.
- Energies (MDPI). The Value of Lost Load for Sectoral Load Shedding Measures: The German Case with 51 Sectors (sector-level VoLL results, from below €1 per kWh for rail services to roughly €47 per kWh for business services). Accessed October 24, 2026.
- Resource Innovations / Lawrence Berkeley National Laboratory. Interruption Cost Estimate (ICE) Calculator 2.0 (2025 release built on new customer surveys from 24 U.S. utility service territories; willingness-to-pay modelling for residential customers, direct-cost modelling for businesses). Accessed October 24, 2026.
- Lawrence Berkeley National Laboratory. ICE Calculator 2 Phase II Final Report (customer damage function variables and survey programme behind ICE Calculator 2.0 and its Phase II update to version 2.2, hosted by the U.S. Office of Scientific and Technical Information). Accessed October 24, 2026.
- U.S. Energy Information Administration. Electric Power Annual, Table 11.1: Reliability metrics (SAIDI, SAIFI and CAIDI definitions under IEEE 1366, from Form EIA-861 utility filings). Accessed October 24, 2026.
- Korea Energy Economics Institute. Estimation of the Value of Lost Load for Commercial and Public Sectors in Korea (stated-preference survey estimates by sector, including commercial and public sector VoLL of 2,080 KRW per kWh against 384 KRW per kWh for manufacturing). Accessed October 24, 2026.