Nevertheless, capacity credits remain low in the best of cases, usually in the 10% range or below. Furthermore, the capacity credit declines with increasing penetration of variable renewable resources, as stable 24 hour demand needs to be met and the system no longer can rely on the fortuitous matching of intermittent supply and peak demand. Their advantage, however, is that such outages are rarely correlated and can frequently be co-ordinated over time (see Chapter 3).