Optimal development of the future Danish energy system – insights from TIMES-DTU model

Abstract

After a long period of transition, Danish energy system is half-way towards completely renewable in 2050. Drastic changes happened in the last forty years – the imported oil has been replaced by a mix of coal and natural gas, energy efficiency and conservation have been improved by extensive use of CHP-based district heating and heat saving measures. In the same period Denmark became well-known by integration and export of wind turbines. In line with the changes in the past, Denmark currently has very ambitious renewable energy targets, most ambitious being the 100 % renewable energy system in 2050. To achieve this, it is obvious that the present energy system needs to change, but the open question is how this should be done. In order to answer this question, the present paper uses TIMES-DTU model. TIMES-DTU is technology-rich, bottom-up, optimisation model covering all sectors of the Danish energy system, assuming full foresight and perfect competition. It simultaneously optimises investments and operation across all sectors and all time periods. Three different scenarios have been described in the present paper: (i) Base scenario without any policy constraints imposed on the model, (ii) WLP with the constraint that 50 % of electricity production should come from wind starting from 2020, and (iii) WLP-NFE scenario with the constraint that power and heat sector should be fossil fuel-free starting from 2035 and Denmark should be 100 % renewable starting from 2050. In all scenarios, Denmark was constrained to be a net exporter of electricity. The results imply that heat demand in future Danish energy system will be significantly reduced as a result of significant heat saving measures within the building stock, especially in rural and sub-urban areas. In urban areas, large district heating networks will supply between 55 and 73 % of heat supply in the years close to 2050. Electricity demand will be largely increased mainly due to transition to large scale heat pumps in the district heating networks. More than 90 % of increased demand for electricity will be based on on-shore and off-shore wind energy. WLP scenario implies less than 1 % higher total system costs compared to Base scenario, while WLP-NFE scenario implies 5-6 % higher total system costs compared to Base scenario. An additional conclusion from the current study is that Denmark has sufficient resources to achieve self-sufficiency in energy supply.