The countries you mention have neighbours with large and stable base power generation capacity, and a well-connected international power grid. In Denmark, for i

The countries you mention have neighbours with large and stable base power generation capacity, and a well-connected international power grid. In Denmark, for instance, a single one of the power lines goin up to Norway has 1700 MW capacity. Costa Rica isn't as fortunate; even though they are connected to their neighbours, the network is limited to just 300 MW total and the neighbours don't have the most stable grids either. From what I can see, Denmark net imports up to 15% of their annual electricity consumption, while Costa Rica gross imports around 2%.