A very high penetration of wind energy in the electric­ ity sector is assumed in the official Danish energy plan ENERGY 21. This will put issues of fitting a variable en­ ergy source into a stable supply system in focus. The pres­ ent study was performed for the Danish Energy Agency [1]. It investigates the role that collaboration with the hy­ dro-based Scandinavian countries can offer, and particu­ larly looks at the conditions for power exchange at the Nordic power pool, asking whether it will be possible to profitably trade wind power in such a pool system.