  Goals to reduce carbon emissions and changing electricity prices due to
increasing penetrations of wind power generation affect the planning and
operation of district heating production systems. Through extensive
multivariate sensitivity analysis, this study estimates the robustness of
future cost-optimal heat production systems under changing electricity prices,
fuel cost and investment cost. Optimal production capacities are installed
choosing from a range of well-established production and storage technologies
including boilers, combined heat and power (CHP) units, power-to-heat
technologies and heat storages. The optimal heat production system is
characterized in three different electricity pricing scenarios: Historical,
wind power dominated and demand dominated. Coal CHP, large heat pumps and heat
storages dominate the optimal system if fossil fuels are allowed. Heat pumps
and storages take over if fossil fuels are excluded. The capacity allocation
between CHP and heat pumps is highly dependent on cost assumptions in the
fossil fuel scenario, but the optimal capacities become much more robust if
fossil fuels are not included. System cost becomes less robust in a fossil free
scenario. If the electricity pricing is dominated by wind power generation or
by the electricity demand, heat pumps become more favorable compared to
cogeneration units. The need for heat storage more than doubles, if fossil
fuels are not included, as the heating system becomes more closely coupled to
the electricity system.
