If flexibility is the watchword in the new world of renewable energy sources and decarbonization of the global economy, then Demand Response is a key element, the factor that will make the transition to a greener future work. While electrical power is volatile because it cannot be stored, the amount generated also has to match demand. The increasing importance of renewables in the energy mix has boosted the variability of supply, an issue that is only going to become more pronounced. Many countries have some form of 100% renewable target and some are far more ambitious. Germany, for example, is aiming to get at least 80% of power from renewables by 2050, while Sweden and Spain are targeting 100% by 2040 and 2050, respectively.