Compressed natural gas (cng) power system with c02 emissions capture and storage

CNG power system (1) comprising a storage tank, a fuel conversion system and an energy transfer system, wherein the storage tank is connected fluidically to the fuel conversion system via the energy transfer system, the fuel conversion system comprising a power unit using CNG as fuel and generating gas emissions comprising CO2, the fuel conversion system comprising a CO2 capture unit configured for separating out CO2 from the gas emissions, wherein the energy transfer system comprises a CNG expansion turbine mounted in a fuel circuit between the storage tank and fuel conversion system powered by expansion of the CNG flowing from the storage tank to the fuel conversion system, wherein the energy transfer system further comprises a CO2 compressor connected between the fuel conversion system and the storage tank along a CO2 circuit for compressing the CO2, wherein power for driving the CO2 compressor is supplied in part by power generated by the CNG expansion turbine.