An apparatus includes a low temperature fuel cell, a high temperature fuel cell or a hydrocarbon reformer, a hydrocarbon fuel supply, an oxygen generator, and a molecular sieve. The oxygen generator separates air to provide oxygen enriched air to the fuel cells and the reformer. Hydrocarbon fuel is provided to the high temperature fuel cell or the reformer, and the exhaust gas thereof may be separated through the molecular sieve, to provide hydrogen enriched gas to the low temperature fuel cell, water, carbon monoxide, and carbon dioxide. The low temperature fuel cell outputs nitrogen gas and high purity water. The emitted carbon oxides and nitrogen oxides are catalytically converted to nitrogen and carbon dioxide being returned to the atmosphere. The process and apparatus are very efficient, produce high purity water and electrical energy, and are environmentally friendly.