Abstract: A process and system for producing hydrocarbon compounds or fuels that recycle products of hydrocarbon compound combustion—carbon dioxide or carbon monoxide, or both, and water. The energy for recycling is electricity derived from preferably not fossil based fuels, like from nuclear fuels or from renewable energy. The process comprises electrolysing water, and then using hydrogen to reduce externally supplied carbon dioxide to carbon monoxide, then using so produced carbon monoxide together with any externally supplied carbon monoxide and hydrogen in Fischer-Tropsch reactors, with upstream upgrading to desired specification fuels—for example, gasoline, jet fuel, kerosene, diesel fuel, and others. Energy released in some of these processes is used by other processes. Using adiabatic temperature changes and isothermal pressure changes for gas processing and separation, large amounts of required energy are internally recycled using electric and heat distribution lines.