A computing system comprising: at least one computing device having at least one controller, the at least one computing device configured to tune each gas turbine in a set of a plurality of gas turbines based upon an exhaust energy parameter and an emissions parameter, wherein the at least one computing device is configured to: command each gas turbine in the set of GTs to a respective base load level, based upon a respective measured ambient condition for each GT; command each GT in the set of GTs to adjust a respective actual value of the exhaust energy parameter of each gas turbine in the set to match a nominal value of the exhaust energy parameter of the set, and subsequently measure a respective actual value of the emissions parameter for each GT; and perform an adjustment to a respective operating parameter of each GT in the set of GTs based upon a difference between the respective actual value of the emissions parameter and a nominal value of the emissions parameter at the respective measured ambient condition for each gas turbine in the set, wherein the adjustment to the respective operating parameter of each gas turbine in the set aligns each gas turbine in the set onto a first line in a graphical space plotting the exhaust energy parameter versus the emissions parameter, wherein the adjustment is by a fixed fraction of a difference between the actual value of the exhaust energy parameter and the nominal value of the exhaust energy parameter, wherein the first line is orthogonal to a characteristic line in the graphical space, wherein the characteristic line is a mean characteristic line of all of the plurality of gas turbines in the set, at the respective base load level of each gas turbine in the set, plotting the exhaust energy parameter versus the emissions parameter. at least one computing device having at least one controller, the at least one computing device configured to tune each gas turbine in a set of a plurality of gas turbines based upon an exhaust energy parameter and an emissions parameter, wherein the at least one computing device is configured to: command each gas turbine in the set of GTs to a respective base load level, based upon a respective measured ambient condition for each GT; command each GT in the set of GTs to adjust a respective actual value of the exhaust energy parameter of each gas turbine in the set to match a nominal value of the exhaust energy parameter of the set, and subsequently measure a respective actual value of the emissions parameter for each GT; and perform an adjustment to a respective operating parameter of each GT in the set of GTs based upon a difference between the respective actual value of the emissions parameter and a nominal value of the emissions parameter at the respective measured ambient condition for each gas turbine in the set, command each gas turbine in the set of GTs to a respective base load level, based upon a respective measured ambient condition for each GT; command each GT in the set of GTs to adjust a respective actual value of the exhaust energy parameter of each gas turbine in the set to match a nominal value of the exhaust energy parameter of the set, and subsequently measure a respective actual value of the emissions parameter for each GT; and perform an adjustment to a respective operating parameter of each GT in the set of GTs based upon a difference between the respective actual value of the emissions parameter and a nominal value of the emissions parameter at the respective measured ambient condition for each gas turbine in the set, wherein the adjustment to the respective operating parameter of each gas turbine in the set aligns each gas turbine in the set onto a first line in a graphical space plotting the exhaust energy parameter versus the emissions parameter, wherein the adjustment is by a fixed fraction of a difference between the actual value of the exhaust energy parameter and the nominal value of the exhaust energy parameter, wherein the first line is orthogonal to a characteristic line in the graphical space, wherein the characteristic line is a mean characteristic line of all of the plurality of gas turbines in the set, at the respective base load level of each gas turbine in the set, plotting the exhaust energy parameter versus the emissions parameter.