Hydro, wind, solar and ocean energy are good examples of renewable sources. Fossil fuels — oil, coal and natural gas — are not renewable, because the deposits are not replenished as they are extracted. Biomass for burning, such as timber, counts as renewable if woodland is grown as fast as it is felled.
Geothermal is a renewable resource
Geothermal heat is internationally defined as a renewable energy source. It is estimated that only about 0.1% of it would be needed to meet humanity's entire present energy demand for some 10,000 years. Geothermal heat can nonetheless be used both sustainably and unsustainably.