Energy Efficiency and Renewable Energy: the key factors for a sustainable future

within 1.5 to 2°C until 2050 have been taken. The resolution of COP21 in Paris to keep the temperature increase well below 2°C is signed already by 172 of 197 parties (http://unfccc.int/paris_agreement/items/9485.php).One very important step to reach these goals is to develop new ideas and implement existing technologies for energy efficiency and renewable energies in a broad range. This will also bring down the costs for the energy system transformation. The limitation of renewable energies in regions with high population density will lead, on the on the one hand, to large energy distribution networks causing new economic and political dependencies between countries, and, on the other hand, to more efficient technologies and systems like energy efficient buildings (for hot and cold climates), energy efficient transportation systems like more public transportation, smaller and electric (or hydrogen) driven cars, and more efficient industrial processes.Knowledge generation and distribution as done in the International Journal on Renewable Energy and Sustainable Development plays an important role for this further development.