I. Transitioning to a net zero energy system. Smart systems and flexibility plan. 89p. Appendix I: Electricity system flexibility modelling. 27p. Appendix II: Smart systems and flexibility plan - Monitoring framework. 31p. II. Digitalising our energy system for net zero. Strategy and Action Plan 2021. 44p. III. Call for evidence on facilitating the deployment of large-scale and long-duration electricity storage. 27p. IV. Call for evidence on the role of vehicle-to-X energy technologies in a net zero energy system. 22p.