New Technologies in Power Generation
While our generation portfolio has shifted over the last decade to include more natural gas-fired and renewable generation, we also completed construction of the country’s first ultra-supercritical coal-fired unit, the John W. Turk, Jr., Power Plant in Hempstead County, Ark., last year. The Turk Plant’s advanced thermal cycle ranks it among the highest efficiency coal plants in the world. This unit was designed to provide low-cost base load power to complement new gas generating resources that were built in recent years. This supports our intent to diversify our fuel mix.
The Turk Plant represents a new generation of plant design using a higher temperature and pressure steam cycle that requires less fuel to produce each megawatt-hour of electricity. This means that all emissions, including SO2, NOx, mercury and CO2, are lower than conventional coal-combustion processes per unit of electricity produced. Turk began commercial operation Dec. 20, 2012. The plant was dedicated in April 2013.
The 600-MW John W. Turk, Jr., Plant in southwestern Ark., is among the nation's cleanest, most efficient pulverized coal plants.
A noteworthy example of innovation in power generation that we are monitoring closely lies in the field of chemical looping technology. Chemical looping is not a carbon capture technology nor is it a combustion technology in the way we typically describe combustion today. In one application of chemical looping, coal undergoes a flameless chemical reaction with a metal oxide, known as an oxygen carrier. The oxide reacts with the carbon in the coal to produce a pure stream of CO2 and the chemical energy in the coal is then transferred to the oxygen-depleted, or reduced, metal. The CO2 can then be compressed and sequestered, or hopefully used for other purposes. The reduced metal is sent to an oxidation reactor where air is introduced to re-form the metal oxide, generating enough heat to produce steam to run a power generating turbine. The metal oxide is then “looped” back to react again with more coal, and the process starts over.
With success, this and other new revolutionary technologies will enable our next generation of power plants to use coal with extremely high efficiency, producing ultra-low emissions and a pure stream of CO2 with no added energy impact. Not only will these concepts revolutionize the power generation industry, they can open the vast, yet untapped, oil reserves in this country to enhanced oil recovery production by making enormous quantities of low-cost CO2 available to support oil extraction. The potential for chemical looping is significant and is the type of purposeful innovation we believe can sustain our company and our industry by leveraging existing infrastructure and finding new and better ways to use coal in the future.