IEA DHC Annex XIV project 04: RE-PEAK - How to cover peak heat loads in DH networks with renewables?

One challenge for the decarbonisation of many district heating networks (DH) is the provision of peak load. The objectives of the RE-PEAK project are: to gain a better understanding of the specific problems, to collect empirical data on the provision of peak load, to analyse the perception of district heating network operators with regard to the transition to climate-neutral peak load coverage, and to consolidate the results and derive recommendations.

Short Description

District heating networks (DHN) are still relying on fossil fuels, although the application of renewables is increasing. Today, many DHNs already use climate-neutral alternatives. However, these are often used to cover the base load. In most DHN, the challenge for full "decarbonization" is the supply of peak heat load.

Peak loads are about performance, not quantity. Peak heat load plants are only used for a few hours a year. The demand for high performance can most easily be covered by combustion technologies. That explains why today, natural gas or heating oil are the dominant energy sources for providing peak heat load.

Many technologies that are expected to provide carbon-neutral peak heat load are mature. Especially in winter, the "benchmark renewables" are green gas or green electricity, which need to be seasonally stored or imported. These high-exergy energy carriers are very expensive and scarce.

The first goal of RE-PEAK is to provide a better understanding of the current problems of fossil-based peak heat load supply in DHNs and the possible challenges in the transition towards a climate-neutral provision. Therefore, a taxonomy of peak heat load will be created and the term will be classified according to certain criteria (e.g., temperature level, network size, maximum load etc.).

The second goal is to obtain empirical data on the provision of the peak heat load through a comprehensive survey.

The third goal is to empirically analyze the perception of DHN operators regarding the transition to climate-neutral peak heat supply. The survey results will allow reflecting on the prevalent opinions on the various options and especially the "benchmark renewables".

The final goal of RE-PEAK is to merge the results and to derive recommendations. The aim is to prepare these in an application-oriented manner and make them usable: for DHN operators, we will develop a self-assessment tool. policymakers and branch organizations will benefit from an illustrative summary in a SWOT-like matrix that allows a direct comparison of the options and their strengths and weaknesses.

Thus, the transition of DHN must be supported by a better understanding of the challenges and options associated with peak heat loads.

Participants

Austria (lead), Estonia, Belgium

Contact Address

Project lead

Dr. Simon Moser
Energieinstitut an der Johannes Kepler Universität Linz (EI-JKU)
Altenberger Straße 69, 4040 Linz
Email: moser@energieinstitut-linz.at