7. Appendices

7.1 Physical and economic constraints of a natural gas network

Electricity transmission and distribution are subject to Kirchhoff laws. Natural gas transmission and distribution are subject to Renouard-Panhandle laws. At one end of the network, the gas is injected under high pressure, and at the other, it is drawn off in the open air through a multitude of burners. If the flow is regular, the quantity withdrawn is equal to the quantity injected, but the outlet speed is higher than the inlet speed, because the pressure is lower at the outlet than at the inlet. The decrease in pressure and the increase in speed are continuous along the entire route, and the difference in pressure at two points in the network constitutes a "pressure drop". This pressure drop is due to the flow regime...