The urgent need to combat climate change demands a complete overhaul of the energy system, as outlined in the Paris Agreement. Renewables, although growing rapidly, cannot be the sole solution. The World Energy Outlook 2024 report by the IEA shows positive signs with increasing renewable capacities and substantial investments in clean energy projects. Europe's ambitious European Green Deal aims for climate neutrality by 2050, emphasizing the necessity of an integrated energy system vision. This integrated vision involves a synergy between electrons (electricity) and molecules (gases) to address the energy trilemma of achieving net zero emissions, energy availability, and cost efficiency. By combining electricity and gases, the system can overcome the intermittency of renewables and cater to energy-intensive industries requiring high temperatures. Simulation and optimization models are crucial in designing a coherent energy system. Models like the North Sea Integration Model highlight the benefits of green hydrogen, biomethane, and carbon capture and storage in achieving carbon neutrality. Moreover, interconnections between countries are vital for energy transfer, with storage playing a key role in balancing energy systems. While simulation tools offer valuable insights, political will and decisive actions are essential. Industry leaders and policymakers must collaborate to implement the integrated energy system and address the challenges posed by climate change.