# Energy and power production units

1. Mar 26, 2013

### few

The decision has been made to install a wind farm with 2000MWe of generating capacity.

The rest of the question gives the

average wind speed (m/s)
air density (kg/m^2)
turbine efficiency (%)

all of which are used to calculate the power production of the turbine, in Watts (kgm2s-3)

I am confused by the time frame of the power production for the wind farm though. It says 2000MWe, basically MW of electricity, but is that referring to 2000MW are produced every year?? The reason I ask is that I can calculate the power generated by a single turbine to be 4MW, but does that mean to make 2000MWe total I would need 500 turbines??

Likewise, if I calculated that the wind-turbine produced 4MW, what is that referring to? The unit was in seconds (wind speed was meters per second), so if i want total production in a minute would I just multiply it by 60s/min??

Thanks for any help, this has been confusing me for a while.

2. Mar 26, 2013

### SteamKing

Staff Emeritus
Power is defined as the amount of work done per unit of time. A watt is an amount of work equal to one Joule (or N-m) done in one second.

If a wind turbine produces 4 MW, that is the power output of the unit. If you need to produce 2000 MW, then 500 wind turbines producing 4 MW each are required. That is why wind farms have many individual turbines: it takes so many to produce the amount of power required to replace a conventional generating plant.