Renewable energies include solar energy, wind energy, hydro energy, geothermal energy and biomass energy. Currently, about one fourth of the world’s energy is produced with renewables. Improving energy efficiency and recovering waste heat energy are important aspects along with the transition from fossil fuels to renewables.

The shift towards renewable energy is in the core of climate change mitigation. However, renewable energy also has its impacts and not all renewable solutions are sustainable. Often localized and small energy solutions are better than large-scale infrastructure projects. Both will become more common in the future.

Bioenergy is often considered as a replacement for fossil fuels. It might have its place in covering the heat demand during winters but as a replacement for all fossil energy, biomass fractions are not a sustainable solution in terms of climate or nature. In the transition to renewable energy, justice issues must be taken into account – this means that it needs to be ensured that people who have worked in fossil industry find new jobs and that the costs of the transition do not fall upon low income households.

Many developing countries such as China and India have made significant investments in renewable energy. India's goal is to be the third largest solar energy producer in the world. At the moment, India is building so many solar energy plants that when the sun is shining, the amount of electricity they produce is equivalent to hundred nuclear power plants. China, on the other hand, has become the world's biggest investor in renewable energy. The country has just suspended the construction of hundred large coal power plants, and the growth in carbon dioxide emissions has stagnated a few years ago.