Wind turbine power output ratings

n3phi1im

I was inspired by the Free Solar Panels article to look into wind turbine as we are planning a move to Scotland in the next few years.

The turbines are all rated by wattage, but it is unclear what this means. Is it the amount of electricity produced per hour, per minute, per second, per day, per year (based on an average windspeed)?

A calculation on the energy saving trust website doesn't help clarify this either.

Recent monitoring of a range of small domestic wind systems has shown that a well sited 2.5kW turbine could generate around 4,000kWh per year

Can anyone clarify what the rating of these turbines actually means?

albyota

some interesting data here....http://www.segen.co.uk/eng/wind/gaia.htm
but you would have to spend a s*** load of money, but if the RHI goes ahead.....well!

spot the mistake above.... not RHI ......FIT

Cardew

n3phi1im wrote: »

I was inspired by the Free Solar Panels article to look into wind turbine as we are planning a move to Scotland in the next few years.

The turbines are all rated by wattage, but it is unclear what this means. Is it the amount of electricity produced per hour, per minute, per second, per day, per year (based on an average windspeed)?

A calculation on the energy saving trust website doesn't help clarify this either.


Can anyone clarify what the rating of these turbines actually means?

A wind turbine is rated by its output in kW at a certain wind speed - usually given in metres per second. For instance in the link given above the turbine is a Gaia 133 rated 11 kW @ 9.5m/s(approx 21 mph)

So if the wind blew at a steady 21mph for one hour it would produce 11kWh(i.e. 11 units of electricity on a domestic electricity meter)

Obviously the more exposed and windier locations will produce a higher annual output in kWh than those in more sheltered locations.

There is however far more to calculating output than simple maths - the location is critical and in urban environments the turbulence can render them useless.

The smaller turbines in general have been something of a disaster. This is from Which:

http://www.which.co.uk/news/2009/07/uks-largest-wind-turbine-trial-yields-poor-result-179850

The largest field test of domestic wind turbines in the UK has found that fewer locations are suitable for home installed wind turbines than previously predicted - with wind turbines in urban areas yielding particularly poor results.

None of the building or roof mounted wind turbines installed in urban or suburban areas generated more than 200kWh, or £26 of electricity a year during the test, and in some cases used more electricity than they produced.

In addition there are big problems with noise and vibration.

Cardew

albyota wrote: »

some interesting data here....http://www.segen.co.uk/eng/wind/gaia.htm
but you would have to spend a s*** load of money, but if the RHI goes ahead.....well!

RHI??

Wind turbines are covered by the current regulations for FITs on the generation of electricity. Same regulations as Solar PV but different FITs

albyota

Cardew wrote: »

RHI??

Wind turbines are covered by the current regulations for FITs on the generation of electricity. Same regulations as Solar PV but different FITs

I was obviously tired and ready for my nap, of couse it is the FIT, I have had my sleep now, and will pay more attention to the question.

newfoxnose

well. ie. if the annual average wind speed is 7m/s, the rated power at 7m/s is 800W, that means it can produce 0.8*24=19.2 kWh per day, and 19.2*365=7008 kWh per year.

Of cause this value is just for reference. Remeber wind is not guaranteed always.

Usually you can find the power at some wind speed from the wind speed againt power curve from factory, but there is a theoretical formula for calculating the power.

jd87

The thread is a month old, but I'm surprised nobody tried to explain what the difference is between a W and a Wh.

Cardew

jd87 wrote: »

The thread is a month old, but I'm surprised nobody tried to explain what the difference is between a W and a Wh.

I did in post #3 above:

A wind turbine is rated by its output in kW at a certain wind speed - usually given in metres per second. For instance in the link given above the turbine is a Gaia 133 rated 11 kW @ 9.5m/s(approx 21 mph)

So if the wind blew at a steady 21mph for one hour it would produce 11kWh(i.e. 11 units of electricity on a domestic electricity meter)

Cardew

newfoxnose wrote: »

well. ie. if the annual average wind speed is 7m/s, the rated power at 7m/s is 800W, that means it can produce 0.8*24=19.2 kWh per day, and 19.2*365=7008 kWh per year.

Although I understand the table you are using, your explanation above is incorrect.

Your figures would only apply if the wind blew at a steady speed of exactly 7m/s for 24hours or for 365 days.

The power output of a turbine is not linear. So taking the figures in your example, if the wind blew for 1 hour at 1m/s and 1 hour at 13m/s that would be an average of 7m/s but the output would not be 1.6kWh.