Title:
Sensitivity of System Design on Heat Distribution Costs in Biomass Fired District Heating
Author(s):
Nussbaumer, T., Thalmann, S.
Document(s):
Paper
Abstract:
District heating (DH) induces costs and energy losses at the heat distribution. The present IEA project introduces a sensitivity analysis for a linear DH network with 1 MW heat output, a pipeline length of 1 km, and 2000 annual full-load hours corresponding to a linear heat density of 2 MWh per year and meter of pipeline length (MWh/m a). An economic assessment based on an annuity of 5.1 % p.a. (3.0 % p.a. for 30 years) reveals heat distri-bution costs of 2.16 c/kWh delivered heat for an optimised pipe diameter and the worst-case assumption of heat con-sumers at the final distance, while 1.99 c/kWh result for distributed heat consumers along the pipeline as typically found in practise. The costs are dominated by the capital costs representing 62% of the total, while the fuel costs at biomass for 4.0 c/kWh contribute with 25% and electricity costs at an electricity price of 16.5 c/kWh with 13%. Since the capital costs dominate the total costs, the main design approach to minimise the heat distribution costs in district heating networks of the investigated size range implies the use of the smallest, technically feasible pipe diameter without cavitation pitting. For the model network, an oversizing by one diameter results in 9% higher heat distribution costs while two diameters cause 30% higher costs. Besides the pipe diameter, it is essential to exhaust the maximum temperature difference. Finally, an evaluation of the connection load reveals that at constant linear heat density and identical network structure, the heat distribution costs increase with increasing network size. Due to this diseconomies of scale in the heat distribution, economies of scale in the heat production are necessary for large DH systems, which is typcially found for combined heat and power (CHP) production.
Keywords:
biomass, costs, district heating, economics, modelling
Topic:
Industry Sessions
Subtopic:
Power & Heat processes and systems
Event:
23rd European Biomass Conference and Exhibition
Session:
ICV.4.21
Pages:
1787 - 1791
ISBN:
978-88-89407-516
Paper DOI:
10.5071/23rdEUBCE2015-ICV.4.21
Price:
FREE
