estimates for each TD method will be referred to as the `delta dierence'. Figure displays the delta dierence for estimates from both TD methods. Supply chain sector of the facility: G&P = Gas Processing, T&S = Transmission and Storage The type of mover driving the compressor(s) at the facility: Recip = reciprocating (piston) engine, Turbine = combustion turbine * For facilities with reciprocating (piston) engines, code indicates the type of engine: 2SLB = two-stroke, leanburn, 4SLB = four-stroke, lean-burn, 4SRB = four stroke, rich-burn If there are two numbers that indicates the facility changed from state 1 to state 2 during the measurement period.