Answer:
Renewable.
Step-by-step explanation:
Renewable energy is also known as clean energy and it can be defined as a type of energy that are generated through natural sources or technology-based processes that are replenished constantly. Some examples of these natural sources are water (hydropower), wind (wind energy), sun (solar power), geothermal, biomass, waves etc.
Basically, a renewable energy source is sustainable and as such can not be exhausted.
In Switzerland, about 60% of its energy generation comes from hydropower (hydroelectricity) and comprises of over 550 hydropower stations.
Hence, Switzerland's most important source of renewable energy is hydropower.