Abstract
Projections are important tools for long-term planning and policy settings. Renewable energy sources that use indigenous resources have the potential to provide energy services with zero or almost zero emissions of both air pollutants and greenhouse gases. Currently, renewable energy sources supply 14% of the total world energy demand. Renewable energy is a promising alternative solution because it is clean and environmentally safe. Approximately half of the global energy supply will be from renewables in 2040. Photovoltaic systems and wind energy will be able to play an important role in the energy scenarios of the future. The most significant developments in renewable energy production are observed in photovoltaics (from 0.2 to 754 Mtoe) and wind energy (from 4.7 to 688 Mtoe) between 20014 and 2040. Biomass is the most used renewable energy source now and in the future. The potential of sustainable large hydro is quite limited to some regions in the world. The potential for small hydro (<10 MW) power is still significant and more significant in future. Photovoltaic systems and wind energy are technologies with annual growth rates of more than 30% during the last years. that will become more significant in the future. Geothermal and solar thermal sources are more important energy sources for the future. Photovoltaics will then be the largest renewable electricity source with a production of 25.1% of global power generation in 2040.