A set of models for optimization of gas distribution networks: a study in Process and Systems Engineering

G5 Doctoral dissertation (article)

Internal Authors/Editors

Publication Details

List of Authors: Markéta Mikolajková-Alifov
Publisher: Åbo Akademi
Publication year: 2019
ISBN: 978-952-12-3824-6
eISBN: 978-952-12-3825-3


atural gas is a fossil fuel with a high potential to become the bridging
fuel in the transition towards a sustainable future because of its
lower share of carbon compared to oil and coal. A growing popularity of
LNG, biogas, CNG or SNG is expected to lead to an increase in the demand
and consumption. However, the distribution of the gas from the gas
sources to consumers at remote or stranded areas poses challenges for
the gas supply chain.

The main objective of this thesis is to study, formulate and apply
optimization models for minimizing the costs incurring during the
expansion and operation of a gas supply network. Such a network has to
satisfy demands from multiple customers and technical requirements. At
the same time, it has to be able to respond to the changes in the
conditions such as fluctuations in the fuel prices and in the supply and

Mathematical modelling and optimization are efficient tools to deal
with complex gas distribution problems. The optimal network structure
may be determined by formulating and solving an optimization problem,
using, e.g., non-linear programming (NLP), mixed-integer linear
programming (MILP) or mixed-integer non-linear programming (MILNP)
models. The specific features of gas pipeline distribution problems
require consideration of nonlinear expressions, while options whether to
connect a node to the network require binary variables. In the supply
chain, pipeline distribution can be augmented by truck supply from LNG
ports or CNG stations to the customers. This results in problem
formulations where the optimal pipeline connections, gas flows,
compression, storage size, the number of truck transports, etc., must be
determined. The thesis develops a set of models for optimization of gas
supply chains, and illustrates them by case studies considering the
optimal structure, extensions and operation of the existing Finnish
transmission network and of two small regional gas distribution networks
in Finland. The sensitivity of the optimal solutions to changes in the
conditions, e.g., fuel prices and investment costs, is also considered.
The advantages and limitations of each of the formulations developed,
such as the possibility to identify optimal extensions and network
operation, the model complexity, calculation time, etc., have to be
considered in the selection of an appropriate tool for optimizing the
gas distribution network. The models developed can be used in the design
of new supply chains, for analyzing existing ones with respect to
operation efficiency or to assess the feasibility of extensions or
modifications of the chains.

Last updated on 2019-05-12 at 03:04