How to Calculate Cost Per Kilowatt-hour of a Small Wind Power Install

January 5th, 2010 by Susan Kraemer

When I read about the training workshops for small wind power dealers for WePower, I found no information on the site to let you know how much their units will cost. But if you want to sell (or buy) their vertical axis revolving wind turbines, you’d want to know how cost-effective they are.

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Here is how you can calculate the cost per kilowatthour for (any given) small wind turbine install, once you know your wind speed range, the output, and how long you’d get power from it, plus the unit cost.

Once you know these numbers, you can do the math yourself. We have all the numbers we need to do the math, other than the cost per turbine. You can contact the manufacturer to get that.

First, check your utility bill to see how many kwh you use a month. You want a unit that makes that much monthly even in low wind conditions if you want to get 100% of your energy from renewable power.

For example, the WePower 12 KW Falcon (PDF), about 18 feet tall with the tower. On a site with 30 mile an hour winds 10%-40% of the time, their 12 KW Falcon turbine production of electricity monthly would range between 833 kwh/month and 3,500 kwh a month. So, worst case scenario is 833 kwh a month.

(While it is unlikely that you live in an area with 30 mile an hour winds 10-40% of the time, it is quite possible that an industrial park outside town, or a rural area has those kinds of wind speeds. )

Take the monthly kWh production. Multiply that by the number of months the turbine is expected to last, and divide the result into the cost of the turbine. The number you end up with is the cost per kWh over the lifetime of the turbine.

So if the WePower 12 KW system cost $10,000 (for example), and we know it makes – worst case scenario of decent wind only 10% of the time – 833 kwh a month for 20 years, then its making your electricity for 19 cents per kwh.

Because 833 kwh x 240 months = 199,920 kwh, divided by $10,000 = $0.19 per kilowatthour.

Not bad. If you check your energy bill, you can see what you are paying on average per kwh now for the filthy fossil fuel that your utility loves to send you now. In many states, this won’t be so different from what you pay now.

But that hypothetical $10,000 is before incentives, tax credits and local rebates. So, next, check out all the ways you can reduce this theoretical $10,000 cost. Find your new cost and do the math based on that.

Given that there are the 30% Federal tax credits, many business incentives, plus your own state’s incentives, that could put these turbines very competitively in your budget. The Department of Energy Renewable Energy site dsire lists all the nationwide and all the state by state incentives.

Now add in the costs; if any, of interest over however many years you’ll need to pay back the $10,000, if you are both borrowing and cannot deduct the interest. If you can deduct the interest next year on taxes, because you can deduct interest on a second mortgage, don’t add in the interest cost, obviously.

Image: WePOWER

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Tags: cost per kwh, cost/benefit, Falcon 12 KW, how to estimate wind, WePower

About the Author

Susan Kraemer writes at CleanTechnica, CSP-Today, PV-Insider , SmartGridUpdate, and GreenProphet. She has also been published at Ecoseed, NRDC OnEarth, MatterNetwork, Celsius, EnergyNow, and Scientific American. As a former serial entrepreneur in product design, Susan brings an innovator's perspective on inventing a carbon-constrained civilization: If necessity is the mother of invention, solving climate change is the mother of all necessities! As a lover of history and sci-fi, she enjoys chronicling the strange future we are creating in these interesting times. Follow Susan on Twitter @dotcommodity.

Gerard Vaughan

At last they are admitting – however tacitly – that wind-power “costs”. i.e. so many $ per kW-hr.

Cost = “carbon foorprint” = insustainable without oil or something-else to provide the energy to build it !! Currently it is simply more invasive “technology” but this time telling us that it is “green” – and therefore ok ?

Solar hot water undoubtedly has a Negative carbon foorprint in places such as here in Bulgaria , and quite possibly Solar photo-voltaic has too.

Wind energy, though, doesn’t Have to have a carbon footprint. Sailing ships and the Dutch polder pumps have demonstrated this, as I have – with a Turbine-Alternator device – TAD ? – which pays for itself in many locations after about 20 years, and in a good coastal location I would guess that maybe this would be reduced to 5 yrs. A “guilt-edged” investment by any standards. Meanwhile, the same people who talk of “Cost/kW-hr” (e.g. swea.co.uk) will tell us that the things pay several Hundred % of cost back PER ANNUM !!!
Gerard Vaughan

At last they are admitting – however tacitly – that wind-power “costs”. i.e. so many $ per kW-hr.

Cost = “carbon foorprint” = insustainable without oil or something-else to provide the energy to build it !! Currently it is simply more invasive “technology” but this time telling us that it is “green” – and therefore ok ?

Solar hot water undoubtedly has a Negative carbon foorprint in places such as here in Bulgaria , and quite possibly Solar photo-voltaic has too.

Wind energy, though, doesn’t Have to have a carbon footprint. Sailing ships and the Dutch polder pumps have demonstrated this, as I have – with a Turbine-Alternator device – TAD ? – which pays for itself in many locations after about 20 years, and in a good coastal location I would guess that maybe this would be reduced to 5 yrs. A “guilt-edged” investment by any standards. Meanwhile, the same people who talk of “Cost/kW-hr” (e.g. swea.co.uk) will tell us that the things pay several Hundred % of cost back PER ANNUM !!!
Bill Woods

“Because 833 kwh x 240 months = 199,920 kwh, divided by $10,000 = $0.19 per kilowatthour.”

Whoa. 199,920 kW·h / $10,000 = 20 kW·h/$ -> 0.05 $/kW·h.

The levelized cost is 2–3 times that, because the construction cost is up-front while the average kW·h isn’t generated for a decade.
Bill Woods

“Because 833 kwh x 240 months = 199,920 kwh, divided by $10,000 = $0.19 per kilowatthour.”

Whoa. 199,920 kW·h / $10,000 = 20 kW·h/$ -> 0.05 $/kW·h.

The levelized cost is 2–3 times that, because the construction cost is up-front while the average kW·h isn’t generated for a decade.
JJ

I like cleantechnica, gas2.0, treehugger less so, too.

I saw pictures on the wepower site of turbines on a building like in Times sq for advertising and another attached to the bill board itself. If they were out in the open they might even work to some degree, but tiny turbines really don’t produce cheap power, only feel good token power. Now the giants produce power at least avg 6W per sq m when you factor in land but its dual use so thats okay.

I don’t really have a preferred energy source, I’ll take what works so I can forget. For now while we have growing renewables and fossil fuels and nukes they can work together. The problem is the CO2 emissions and then the fossil fuels will eventually go away in my kids lifetime.
JJ

I like cleantechnica, gas2.0, treehugger less so, too.

I saw pictures on the wepower site of turbines on a building like in Times sq for advertising and another attached to the bill board itself. If they were out in the open they might even work to some degree, but tiny turbines really don’t produce cheap power, only feel good token power. Now the giants produce power at least avg 6W per sq m when you factor in land but its dual use so thats okay.

I don’t really have a preferred energy source, I’ll take what works so I can forget. For now while we have growing renewables and fossil fuels and nukes they can work together. The problem is the CO2 emissions and then the fossil fuels will eventually go away in my kids lifetime.
Bruce B

JJ maybe you should start a blog about your preferred energy. People read cleantechnica for renewable energy news. You don’t like that, fine. Go start a blog about nuke and oil and fossil power, how great it is.

Buildings use 40% of the nations electricity not 5. Plus these turbines can go in rural fields – what makes you think they are just for on houses.
Bruce B

JJ maybe you should start a blog about your preferred energy. People read cleantechnica for renewable energy news. You don’t like that, fine. Go start a blog about nuke and oil and fossil power, how great it is.

Buildings use 40% of the nations electricity not 5. Plus these turbines can go in rural fields – what makes you think they are just for on houses.
JJ

Trouble is nobody can get 100% of their energy from wind, solar or even a private nuclear battery because most people except maybe the Amish use up an order of magnitude more power than they ever knew about through the rest of the economies hidden energy structure.

If every single home in the UK or US and Timbuktoo had a $0 electric utility bill, it would take only 5% of the energy demand off the books, in other words it makes almost no difference unless you start working on the true energy bill of your lifestyle that is so out of site.
JJ

Trouble is nobody can get 100% of their energy from wind, solar or even a private nuclear battery because most people except maybe the Amish use up an order of magnitude more power than they ever knew about through the rest of the economies hidden energy structure.

If every single home in the UK or US and Timbuktoo had a $0 electric utility bill, it would take only 5% of the energy demand off the books, in other words it makes almost no difference unless you start working on the true energy bill of your lifestyle that is so out of site.