Compute total energy made per year by one hundred 3-MW wind turbines operating at the wind speed of 15m/s. Its global efficiecy (turbine, gearbox and generator) is assumed to be 30%. Suppose that wind is available at nominal velocity during 15% of time (as is frequently case in Germany); during 25% of time. Suppose that there gas-fired plant backup in case where there is no wind evaluate amount of gas required and CO2 emissions assuming 50% efficiency.