In this paper, several novel polygeneration systems are presented which convert natural gas, coal, and a carbonless heat source such as high-temperature helium to gasoline and diesel. The carbonless heat source drives a natural gas reforming reaction to produce hydrogen rich syngas, which is mixed with coal-derived syngas to produce a syngas blend ideal for the Fischer-Tropsch reaction. Simulations and techno-economic analyses performed for 16 different process configurations under a variety of market conditions indicate significant economic and environmental benefits. Using a combination of coal, gas, and carbonless heat, it is possible to reduce CO2 emissions (both direct and indirect) by 79% compared to a traditional coal-to-liquids process, and even achieve nearly zero CO2 emissions when carbon capture and sequestration technology is employed. Using a carbonless heat source, the direct fossil fuel consumption can be reduced up to 22% and achieve a carbon efficiency up to 72%. Market considerations for this analysis include prices of coal, gas, high-temperature helium, gasoline, and CO2 emission tax rates. The results indicate that coal-only systems are never the most economical choice, unless natural gas is more than 5 $/MMBtu. (C) 2013 Elsevier Ltd. All rights reserved.