Renewable energy sypply for waste water treatment plant aeration
A techno-economic analysis of different technology options
- authored by
- Levin Matz, Astrid Bensmann, Richard Hanke-Rauschenbach
- Abstract
This paper investigates the introduction of renewable electricity (RE) supply in waste water treatment plants (WWTP) aeration. WWTPs are significant energy consumers, constituting 1% of global electricity consumption. In Germany, WWTPs electricity demand was 3.4 TWh in 2017, corresponding to 0.75% of national electricity demand in that year. 50-90% of WWTPs electricity demand results from the aeration of the biological treatment, causing high operational costs. Conventionally, grid-supplied electricity powers blowers to blow air into the biological treatment to satisfy oxygen (O2) demand. This study advocates for a transition to RE supply to cover the energy demand within the aeration process. The present contribution examines three technology routes (TR) to introduce RE supply in WWTPs aeration. Each TR consists of RE supply by wind turbines and PV. RE is used either directly in the aeration blowers or indirectly via different energy conversion and storage options, provided by an electrical energy storage in TR 1, by an air compressor and storage in TR 2 and by an O2 storage with O2 produced as a byproduct in water electrolysis in TR 3. A case study is conducted on the example of a large-scale WWTP in Germany with an annual O2 demand of 10.6 million kg, resulting in 5.3 GWh/a of electricity demand for the conventional aeration processes, incurring energy costs of 1.38 million EUR/a. The techno-economic analysis employs linear optimization to minimize the system's total annual costs (TAC) under a predefined RE share constraint between 0% and 100%. The analysis reveals a substantial economic potential of introducing RE supply in WWTPs aeration. RE supply shares close to 80% are realized without using a storage, coming with a reduction in TAC of up to 50% for the considered economic parameters, if RE is supplied without additional charges. Considering additional charges, the potential TAC reduction diminishes to 17%. RE shares of up to 100% requires storage installation, reducing economic efficiency. At 100% RE supply, TAC increase by 41% in TR 1 using electrical energy storage and by 167% in TR 2 using compressed air storage, compared to TAC without RE supply. The economic efficiency of TR 3 depends on the revenues from hydrogen sales. If the revenues cover hydrogen production costs, TR 3 is the most economical, yielding TAC reductions of up to 65% even at RE shares of up to 100%.
- Organisation(s)
-
Institute of Electric Power Systems
- Type
- Conference contribution
- Volume
- 3
- Pages
- 1671-1682
- No. of pages
- 12
- Publication date
- 30.06.2024
- Publication status
- Published
- Peer reviewed
- Yes
- ASJC Scopus subject areas
- General Energy, General Engineering, General Environmental Science
- Sustainable Development Goals
- SDG 7 - Affordable and Clean Energy
- Electronic version(s)
-
https://doi.org/10.52202/077185-0143 (Access:
Closed)
