The study identifies short-term fluctuations, from zero to 15 minutes, as a key issue, since these are not easy to predict. As the proportion of wind on the Nordel system grows, more need for regulation may arise, necessitating a review of regulation and dispatch reserves. The report does not query the ability of the combined system to cope with large amounts of wind, but notes that transmission constraints may at times limit the ability of the regulating reserves (mainly in the north) to compensate for substantial wind power changes in the south (Denmark). One suggestion is that wind plant may be used to regulate supply and demand.
System operations are complicated in Scandinavia by around 9 GW of non-dispatchable CHP. But substantial hydro in the north helps with regulation, though there is little pumped storage. Nordel makes the point, however, that advances in technology may mean more storage is available by 2020, thus easing the assimilation of large amounts of wind.