Energy requirements in the separation-regeneration step in forward osmosis using TMA–CO2–H2O as the draw solution

•TMA–CO2–H2O forward osmosis requires 6.8–16.7kWh/m3 fresh water produced.•TMA–CO2–H2O forward osmosis energetically outperforms evaporative processes.•DDS carbonation degree does not affect the stripping energy requirements.•Strong relationship between DDS concentration and FO total energy requirements.