A system for separating carbon dioxide gas from internal combustion engine exhaust and an electricity generating heat exchanger for the system. The system includes a scrubber tank containing a carbon dioxide absorbent fluid and configured to bubble exhaust gas from the heat exchanger through the carbon dioxide absorbent fluid, whereby carbon dioxide gas is absorbed by the carbon dioxide absorbent fluid. A carbon dioxide storage means stores the carbon dioxide released in a heat exchanger. The heat exchanger cools the exhaust gas emitted by the internal combustion engine, and includes a thermal electric generator (TEG) configured to couple thermally the exhaust gas chamber to the absorber fluid chamber in a manner effective to heat the CO2 absorbent fluid by heat from the engine exhaust to release CO2 gas from the CO2 absorbent fluid and generate electricity in response to a temperature difference therebetween.