Demand side flexibility is an integral part of the way in which modern electricity markets are set to ensure the ongoing operation and development of the electricity system. Creating demand side flexibility in retail electricity consumption has had a high priority in several EU-policies throughout a number of years. Regulators, the scientific community and the industry have furthermore considered demand side flexibility to be of great importance to the efficient use and limited expansion of electricity infrastructure as well as the continued integration of renewable energy sources. Despite the high political priority, many insights and large R&D-efforts, demand side flexibility in the form of price elastic retail electricity consumption is currently not a substantial part of the European electricity system nor the green transition. To address the discrepancy between the significant international ambitions and the actual progress being made, this years anthology on better regulation in the in the energy sector presents a collection of works that show the potential of demand side flexibility and the pathways through which it can be achieved. The contributions cover a vast terrain by funneling the possibilities and barriers associated with demand side flexibility from the larger principles of system governance to the concrete technicalities of tariff design.