Key uncertainties and scenarios for future energy systems Sector coupling in the energy transition Wolf-Peter Schill
Overview 1. Sector coupling: potential benefits and system impacts 2. Sector coupling: another source of uncertainty 3. Insights from own work 4. Conclusions
1 Sector coupling: potential benefits and system impacts Potential benefits of sector coupling Decarbonization of other sectors Flexibility for the integration of variable renewables Currently discussed sector coupling options Power-Heat Combined heat and power Power-to-heat: heat pumps, direct resisitve heating Electric mobility Battery-electric vehicles Overhead lines Power-to-x (various sectors and applications) Hydrogen Synthetic natural gas, synthetic liquid fuels Electrification of industrial processes
1 Sector coupling: potential benefits and system impacts Potential power system impacts of increased sector coupling Additional demand for renewable electricity Additional source of flexibility This has an impact on the optimal portfolio of (i) generators and (ii) flexibility options Particularly interesting: interaction with electricity storage
2 Sector coupling: another source of uncertainty But there are several sources of uncertainty How much? level of electrification in different sectors How flexible? realization of flexibility potentials Examples of uncertainties Power-Heat Decentral vs. centralized power-to-heat? Role of active and passive heat storage in buildings? Heat pumps vs. direct resisitve heating? Electric mobility Battery-electric vehicles: size of batteries, charging availability, V2G? Power-to-x A hydrogen economy? Synthetic fuels vs. battery-electric mobility?
2 Sector coupling: another source of uncertainty Bloess et al. (2018): Power-to-heat for renewable energy integration: A review of technologies, modeling approaches, and flexibility potentials. Applied Energy 212, 1611-1626. https://doi.org/10.1016/j.apenergy.2017.12.073 Different characteristics with respect to overall electricity demand and flexibility
3 Some insights from research at DIW Berlin: impact on electricity storage needs 3.1 Previous work: effect of various parameter assumptions 3.2 Impact of generic sector coupling 3.3 Comparative analysis of different sector coupling options
3.1 Previous work (without sector coupling): impact of various parameter assumptions on electrical storage needs Long-term simulation with 100% RES for Germany, but without sector coupling: Impact of different parameter assumptions on required storage power Sensitivities on storage costs, DSM, and reserves Sensitivities on renewable costs and availabilities Schill and Zerrahn (2018): Long-run power storage requirements for high shares of renewables: Results and sensitivities. RSER 83, 156-171. https://doi.org/10.1016/j.rser.2017.05.205
3.2 Now turning to sector coupling: Impacts of generic sector coupling on electricity storage needs Based on framework presented by Sinn (European Economic Review 2017) Sinn finds: increasing shares of variable RES require excessive storage needs Focus on Germany Using historic feed-in time series of onshore wind and PV Our answer: storage needs substantially decrease if Renewable curtailment is allowed Sector coupling is considered Open access article (just accepted at European Economic Review), based on simple open-source models: http://arxiv.org/abs/1802.07885, https://doi.org/10.5281/zenodo.1170554 Stylized illustration of a generic sector coupling option Additional, flexible demand: 50 GW with 2,000 full-load hours (i.e. 100 TWh) Perfectly flexible within theses limits Corresponding expansion of renewable generation capacity
3.2 Impacts of generic sector coupling on electricity storage needs Result: substantially lower storage needs and lower curtailment Zerrahn et al. (2018), http://arxiv.org/abs/1802.07885
3.2 Impacts of generic sector coupling on electricity storage needs Effects depend on parameterization: here, exemplarily for 70% vres Zerrahn et al. (2018), http://arxiv.org/abs/1802.07885
3.3 Comparative analysis of different sector coupling options Analysis with our open-source model DIETER Minimization of investment and hourly dispatch costs Extended model version developed and applied in LKD-EU context Work in progress Electric vehicles 28 profiles: twelve plug-in hybrids, 16 battery electric vehicles Hourly time series of electricity demand and charging availability Electrolysis PEM and alkaline electrolyzers Flat hourly hydrogen demand, option to build gas storage Electric heating
3.3 Comparative analysis of different sector coupling options Model perspective: ~2050 Loosely calibrated to Germany only Preliminary parameterization Variation of exogenous parameters Minimum renewables share (also for additional sector coupling) 70%, 75%, 100% Electric vehicles 0, 20, 40 million Hydrogen demand (power-to-x) 0, 100, 200 TWh
3.3 Electric vehicles: effects on generation portfolio Electric vehicles increase the need for wind and solar generators
3.3 Electric vehicles: effects on electrical storage capacities Electric vehicles substantially reduce the need for electrical storage Both for energy and power
3.3 Electrolysis: effectson generation portfolio Comparable effect as for electric vehicles
3.3 Electrolysis: effects on electrical storage capacities Effect on storage energy comparable to electric vehicles Smaller effect for storage power
3.3 Electrolysis: electrical vs. hydrogen storage Electrical storage substituted with hydrogen storage
3.3 Electric vehicles and electrolyserscombined: effects on storage capacities Electric vehicles have a stronger effect on storage power Electricity storage needs may remain moderate even in very high RES scenarios
3.3 Residual load duration curve: without sector coupling Electrical storage used to shift renewable surplus generation to periods of positive residual demand
3.3 Residual load duration curve: medium sector coupling scenario Electric vehicles and electrolysers reduce storage needs In particular for storage driven by right-hand side But also (somewhat) on left-hand side RES oversizing
4 Conclusions Different types of sector coupling play an important role in many future scenarios Decarbonization of other sectors Flexibility for renewable integration Important system implications, particularly for other flexibility options Electricity storage needs may remain moderate even in scenarios with very high renewable shares Under the assumption that additional demand is sufficiently flexible
4 Conclusions Sector coupling introduces new uncertainties Level of electrification Expansion limits for domestic renewables? Flexibility of electrification Over-optimistic modeling assumptions? Implications for modeling Take these uncertainties into account! (Preliminary) implications for policy Prepare for larger expansion of domestic renewables Focus on more energy-efficient sector coupling options Aim to provide incentives for flexible sector coupling
4 Epilogue We were asked: Content: How can we get to better scenario studies? Use: How can we make better use of scenario studies? Communication: How can the authors communicate better on their scenario studies? Part of the answer is: open source and open data Use open data LKD-EU: DIW Data Documentation 92, https://doi.org/10.5281/zenodo.1044463 http://open-power-system-data.org Provide model code and input data in suitable repositories E.g., www.diw.de/dieter Zenodo. GitHub etc.
Thank you for listening DIW Berlin Deutsches Institut für Wirtschaftsforschung e.v. Mohrenstraße 58, 10117 Berlin www.diw.de Contact Wolf-Peter Schill wschill@diw.de