Use of renewable energy sources is enforced by national and international regulations.
Drivers for such policies include mitigation of climate change due to emission of
greenhouse gasses and reducing dependency on fossil fuel reserves. Due to the
intermittent character of renewable energy sources such as photovoltaic or wind power,
integration of such sources creates a challenge in maintaining balance between demand
and supply. Indications of such challenges in countries with e.g. a high penetration of
wind power are already showing in prices on power exchanges reaching zero or negative
energy prices. In general, without mitigation measures, an increase in the use of
intermittent renewable energy sources leads to a diminished ability to guarantee security
of supply.