Managing the transition to sustainable energy supplies is one of the greatest challenges we face in the 21st century. With its study "Vision for a 100 percent renewable energy system" Fraunhofer has demonstrated how reliable, cost-effective and robust energy supplies can be achieved in Germany by the year 2050 using only renewable resources. But what will the changeover cost us? True, stepping up the supply of energy from renewables will initially incur additional costs, with a projected maximum of around 17 billion euros – roughly eight percent of Germany‘s total expenditure on energy – being reached in 2015. But, after that, the costs are set to fall dramatically. Over the period from 2010 to 2050, total cost savings of 730 euros billion could be achieved in the electricity and heat production sectors alone.

A decentralized system of energy production from renewable sources requires the power grid to be structured differently than the one already in place. In future it will be necessary to coordinate a large number of solar, wind and biomass power plants and to calibrate their yield and load estimates sensibly. Gaps in supply arising from fluctuations in the availability of sun and wind must be compensated for with fast-acting temporary storage and balancing power plants.

A radical shift in energy production toward renewables is possible only if we simultaneously launch a revolution in energy efficiency. The best way to lower energy costs is to conserve resources and consume less energy. Getting more light, more heat and more power out of one liter of oil or one kilowatt-hour of electricity makes economic sense not only for individual households or businesses but also for the national economy as a whole. More efficient electronics, for instance, can help to reduce power consumption significantly. Simply by switching over to LED lighting, which consumes 80 percent less power, Europe could save more than 56 terawatt-hours in electricity. That equates to the output of almost six nuclear power plants. The Fraunhofer study entitled „Energy efficiency in the production environment" has demonstrated the huge potential gains to be made from enhancing efficiency. The most important result of the study is this: In the medium term, energy consumption in the industrial production sector can be reduced by as much as 30 percent.

Existing housing stocks currently present one of the major opportunities for achieving more sustainability. Over one-third of Germany‘s energy consumption goes toward heating and cooling the country‘s buildings. It is well worth taking a look at the energy efficiency of older buildings as they consume three to five times more heating energy than their modern counterparts. Here, proper insulation or more efficient heating and cooling could help to achieve energy savings of up to 80 percent. In the Research Union Economy – Science, Fraunhofer has teamed up with the German Federal Ministry of Education and Research to develop the "City of Tomorrow," our vision of a metropolis that emits virtually no CO₂ and where no fossil fuels are burnt in the city’s houses or its vehicles. Both electricity and heat are generated mainly from renewable energy sources, while transport and utilities are primarily electricity-based. Electric mobility has significantly reduced the burden of noise and exhaust emissions on the city’s inhabitants. The quality of life is higher, and energy supplies are more secure than in other regions. Money previously spent abroad to purchase oil and gas remains within the country.

Germany continues to enjoy a sound reputation for technical innovation and the quality of its products. Going forward, energy and resource efficiency will be the country’s new hallmark of quality. We need to build on the competitive advantage we already have in this field and translate it into economic success. In short, we need to become experts in efficiency.