Electric Power Research Institute (EPRI) and the Institute of Natural Resource Sustainability at the University of Illinois at Urbana-Champaign (UIUC) have developed a patented technology for the on-site production of activated carbon (AC). This technology, the Sorbent Activation Process (SAP), is projected to reduce the cost of activated carbon for mercury control by >50%. SAP involves on-site production of AC from coal which is then injected directly into the flue gas upstream of a particulate control device, such as an existing ESP, to capture mercury in flue gas. The feedstock coal used can be the same coal burned by the utility. SAP can be used to prepare ACs with various surface areas, pore structures, and surface chemistry from bituminous, subbituminous, and lignite coals. The proof-of-concept of SAP was demonstrated at both a lab and prototype field scale. The laboratory SAP was used to produce 1 to 5 pounds AC per hour from different types of coals. The results from the laboratory SAP tests revealed that the ACs with properties comparable to those of the commercially available ACs for control of mercury emission from coal-fired power plants can be prepared. The process engineering data collected during the laboratory SAP tests were then used to design and fabricate a prototype field SAP unit capable of producing up to 50 pounds of AC per hour. The prototype field SAP was first tested at the Ameren's Meredosia power plant. The AC produced had mercury adsorption capacities that were comparable to that of the Darco Hg activated carbon. The SAP unit was then moved to a second test site, the 70 MWe, PRB fired, Hennepin Unit 1 Power Plant. The SAP produced AC was injected directly into the flue gas of Hennepin Unit 1 before the baghouse. Both Powder River Basin (PRB) and Illinois Bituminous coal were tested as the SAP feed coal for AC. The SAP AC produced from bituminous and PRB coals achieved mercury removal rates across the fabric filter of 80 to 90% at injection rates < 21b/MMacf.