Demand response (DR) can compensate for imbalances in variable renewable energy supplies. This possibility is particularly interesting for electrochemical processes, due to their high energy intensity. To determine the technical feasibility and economic viability of DR, we chose the chlor-alkali process with subsequent polyvinyl chloride production, including intermediate storage for ethylene dichloride. We estimate the maximum possible cost savings of implementing load flexibility measures. A process model is set up to determine the system characteristic. Subsequent optimizations result in the facility's best possible dispatch depending on additional and minimum power load, storage volume, and cost of a load change. Real plant data are used to specify model parameters and validate the system characteristic and the plant dispatch. An economic evaluation reveals the economic advantages of efficiency and flexibility. The approach can be used to analyze the DR potential of other chlorine value chains or facilities with high electricity demand in general.

Renewable sources of energy supply an increasing share to the electricity mix although they show much more fluctuations than conventional energy sources. Hence, net stability and availability represent very large challenges. Demand response can positively contribute to the solution of this issue as large electricity consumers adapt their consumption to the available electricity. In the past, chloralkali electrolysis has been suggested as such a large consumer. Unfortunately, its main product, chlorine, cannot be easily stored in large amounts, so that downstream processes have to operate based on a fluctuating feed. This work reviews the processes within the chlorine value chain, determines the most promising ones for flexibilisation based on their chlorine consumption, and analyses these processes in more detail to assign them to one of four flexibility categories. It is shown that 45 % of the theoretical potential could be used for demand response right away. Highlights: • A novel approach to evaluate the flexibility of chemical processes is proposed. • The flexibility potential of the whole chlorine value chain is assessed. • The chlorine-consuming processes relevant for demand response are identified. • Subsequent processes limit demand response potential of chloralkali process. • The dichloroethane and the chloroacetic acid route have the highest potential.

Ein auf erneuerbare Energiequellen ausgerichtetes Versorgungssystem benötigt ein hohes Maß an Flexibilität, um Systemstabilität zu sichern. Lastmanagement kann einen großen Beitrag leisten und die chemische Industrie als einer der größten Verbraucher elektrischer Energie dabei eine wichtige Rolle spielen. Die Analyse der bisher hierzu durchgeführten Studien zeigt große Potenziale für den Chlor‐Alkali‐Prozess und die Luftverflüssigung. Die variablen Kosten sind mit anderen Flexibilisierungsoptionen vergleichbar. Zur Bestimmung der tatsächlich realisierbaren Potenziale bedarf es noch weiterer Untersuchungen.

Demand response is a viable concept to deal with and benefit from fluctuating electricity prices and is of growing interest to the electrochemical industry. To assess the flexibility potential of such processes, a generic, interdisciplinary methodology is required. We propose such a methodology, in which the electrochemical fundamentals and the theoretical potential are determined first by analyzing strengths, weaknesses, opportunities, and threats. Afterward, experiments are conducted to determine selectivity and yield under varying loads and to assess the additional long-term costs associated with flexible operation. An industrial-scale electrochemical process is assessed regarding its technical, economic, and practical potential. The required steps include a flow sheet analysis, the formulation and solution of a simplified model for operation scheduling under various business options, and a dynamic optimization based on rigorous, dynamic process models. We apply the methodology to three electrochemical processes of different technology readiness levelsthe syntheses of hydrogen peroxide, adiponitrile, and 1,2-dichloroethane via chloralkali electrolysisto illustrate the individual steps of the proposed methodology.

Demand response is a viable option to cope with the increasing demand for flexibility of an energy system based on renewables. Several studies have shown that the electricity-intensive chlor-alkali process has high potential. Previous research primarily focused on process engineering to determine technological flexibility potentials or optimal production scheduling. However, these potentials can only be realized if they are economically viable. This requires knowledge of the costs of a demand response, including their causes and dependencies, as well as an understanding of the necessary market conditions. Using a business management approach, we examine the economically viable demand response potentials. The cost is based on real data and the economic evaluation of marketing flexibility on a day-ahead market. The results lead to conclusions about relationships between costs and performed load change and the economic limit of demand response. Significant costs like accelerated membrane aging or anode degeneration depend on various load change parameters. These conclusions can be used to implement economic conditions in models for dispatch and scheduling or bidding strategies concerning the chlor-alkali process and similar electrochemical processes. We demonstrate that the chlor-alkali process with subsequent PVC manufacturing is economically viable under current market conditions.