Electricity demand is always going up and down - the grid operator’s job is to constantly match the electricity generation available to electricity demand. Wind energy’s variability is just one more variable in the mix.
Today, in Denmark, about 30% of electricity demand is already supplied by the wind, and is managed successfully by the Transmission System Operator. The Danish government aims to get 50% of its electricity from wind by 2020 and 100% of renewables by 2035. In South Australia 20% of electricity demand is met by wind, and in Iowa, US, 24.5% of electricity was supplied by wind in 2012.
According to GWEC projections (Global Wind Energy Outlook 2012) wind energy will supply between 8% and 12% of the world's electricity by 2020.
In a recent report, the International Energy Agency (IEA) points out that so-called “variable” energy sources such as wind can be managed with an intelligent, joined-up grid and a functioning electricity market.