Windy conditions [From the Editor]

I am pleased to offer this issue devoted to the integration of wind-generated power into the electric grid. This is our fourth look at this subject, each coming at two-year intervals. When we last looked, wind power constituted 1.5% of worldwide electricity usage (according to 2008 figures); that number has grown to 2.5% (per 2010 figures). Several countries have achieved relatively high levels of wind power generation, notably Denmark (21%), Portugal (18%), Spain (16%), Ireland (14%), and Germany (9%). During that same period (2008–2010) China has installed approximately 30 GW, a almost four-fold increase in wind generation.