Quick Start

1. Install the most recent version of Julia
2. Install the package EnergyModelsBase and the time package TimeStruct, by running:

julia ] add TimeStruct EnergyModelsBase

These packages are required as we do not only use them internally, but also for building a model.

1. Install the package EnergyModelsGasNetworks

julia ] add EnergyModelsGasNetworks

1. Install the package JuMP by running:

julia ] add JuMP

1. Install a suitable solver

   Some constraints defined in EnergyModelsGasNetworks are nonlinear and nonconvex.

   • Pooling constraints. The pooling formulation introduces bilinear terms (non-convex quadratic), defining a nonconvex QCQP (and, if integer variables are present, a nonconvex MINLP).
   • Pressure-flow constraints for blended gases. The pressure-flow relation for blended gases is also nonlinear and nonconvex (adapted Weymouth equation for blended gases). However, within the physically operating region (i.e., inlet pressure >= outlet pressure, nonnegative flows and bounded pressures), the relation is smooth and monotonic. To obtain a MILP, we approximate the nonlinear surface using a piecewise-affine outer approximation built from tangent planes via PiecewiseAffineApprox.

   Consequently, when pooling and/or pressure-flow constraints are enabled, you need a solver capable of handling nonconvex MINLP problems. SCIP is the recommended open-source option; commercial alternatives such as Gurobi and Xpress also work.

julia ] add SCIP, HiGHS using JuMP, SCIP, HiGHS model = Model(SCIP.Optimizer)

When only DiscretizedPoolingNode and BlendingNode are used (no PoolingNode), the model is a pure MILP and HiGHS suffices:

julia model = Model(HiGHS.Optimizer)