European energy policy is facing major challenges. In order to tackle the climate crisis, a dramatic reduction in greenhouse gas emissions is essential. At the same time, security of supply and affordable energy for a competitive economy must be ensured. Many conventional power plants in the European Union are old and will need to be replaced or modernised in the coming years and decades. In the light of these challenges, economic and environmental goals sometimes appear to require opposite paths of action. This paper demonstrates, however, that an expansion of renewable energy sources is the only path to a secure, affordable and climate-friendly energy system until 2030 and beyond. Renewables not only drastically reduce emissions and other environmental and social burdens; they also reduce energy import dependency and hence increase energy security, strengthen local economies, and create jobs. While fossil fuels and nuclear power will become more expensive, renewable energy will become cheaper. This is even more true if the external costs are factored in. Together with a reduction of energy consumption by increasing energy efficiency, total energy costs for European industries and citizens could even fall. Choosing the renewable path thus pays off in the medium and long term.