The real substitution effect of renewable electricity: An empirical analysis for Germany
Introduction
The electricity sector in the European Union is one of the main contributors to the union’s greenhouse gas emissions. Currently, there are two policy levels targeted at decarbonizing the electricity sector. First, the supranational EU ETS, which covers power plants and industrial sites, requires regulated entities to surrender an allowance for every ton of CO2 they emit into the atmosphere. Second, as preferences for tackling climate change appear to be heterogeneous across the European Union (Marchiori et al., 2017, Cetkovic´ and Buzogány, 2019), some member states have implemented their own, additional policies, such as setting energy efficiency targets or subsidizing the generation of renewable electricity with the goal of achieving a climate-neutral electricity sector. This has contributed to renewables providing just over 50% of German electricity demand in the year 2020 (Fraunhofer, 2021), up from six percent in the year 2000 (BMWi, 2021). At the same time, about 17% of European emissions in the electricity sector were emitted from power plants located in Germany (DEHSt, 2020), making it a particularly interesting case to study.
The two policy layers overlap and there are interaction effects. Before the EU ETS was reformed in 2018 by implementing the Market Stability Reserve (MSR), unilateral policies such as renewable subsidies only shifted cumulative emissions in time and space but did not reduce them, because the supply of allowances was fixed. The MSR alters this picture by permanently deleting allowances depending on the amount of unused allowances in circulation (Perino, 2018). Unilateral policies can now reduce total emissions - but at least in principle, they can also increase them (Perino et al., 2020, Gerlagh et al., 2021).
In light of these issues, this paper answers the question of how effective renewable electricity in Germany is in abating greenhouse gas emissions in the EU. To that end, I construct a rich dataset of hourly plant-level emissions and cross-bordert rade. I estimate the amount of offset emissions in response to higher renewable production using a novel estimation technique based on Machine Learning algorithms. Together with a detailed analysis on emission leakage via cross-border flows, this gives deep insights into the mechanics of the German electricity system, including the climate impact of grid congestion. I merge these results with recent insights about the behavior of the MSR to estimate the long-term abatement effect of German renewable electricity.
Onshore and offshore wind are more effective in reducing emissions than electricity from solar panels. Redispatch measures have only a slight impact on this magnitude. Negative leakage effects (Baylis et al., 2014) within the EU are substantial, reinforcing the reduction in emissions demand. This result is in line with internal carbon leakage for demand side policies1 from Perino et al., 2020. The estimates range up to 91% for solar, meaning a domestic emission reduction is almost mirrored by Germany’s neighboring countries. A fraction of these emission cuts translate to long-term abatement under the EU ETS as a result of additional allowance cancellations. This portion approaches one with increasing duration of MSR storage for electricity produced before 2018, but decreases for later abatement.
It is well established in previous literature that the emission impacts of renewable electricity differs between conventional technologies.2 Generally, wind is more effective than solar in reducing emissions. I extend the literature by studying onshore and offshore wind separately. These two technologies are heterogeneous in terms of intermittency and generation peak within the day. Both technologies tend to reduce emissions by less than the system average in all considered settings.
The technical efficiency of power plants is found to be negatively affected by renewable supply as a result of increased cycling (Kaffine et al., 2013). I construct a detailed plant-specific emission series that adjusts the often used average emission rate when the turbine is running at part load.
Abrell et al. (2019) compare relatively isolated Spain and highly interconnected Germany to highlight the relevance of inter-zonal electricity trade on domestic emission reductions. A high capacity for trade allows for sizable leakage. I use detailed data on international electricity trade that allows for specific calculation of reduced emissions in neighboring countries and thereby leakage effects.
A complementary carbon price under the EU ETS and its effectiveness in reducing emissions is empirically investigated for the EU ETS by Gugler et al., (2021) and for Texas by Cullen and Mansur (2017). Aside from endogeneity issues, the aspect of overlapping policy and its impact on long-term emission abatement is overlooked3 in this strand of literature. I offer a new angle by analyzing the interplay between these two policy levels.
Section snippets
Data
In order to analyze the issues mentioned above, I construct a dataset that consists of 38 lignite, 56 coal and 41 gas generation units, each with a capacity of at least 100 MW. This data is made available from ENTSO-E (2020). Observations are recorded on an hourly basis for the years 2017, 2018 and 2019. Graf and Marcantonini (2017) motivate using panel data to be able to control for unit outages and maintenance. I merge data on scheduled maintenance and technical outages from the same data
Domestic emissions
I first estimate the amount of emissions from lignite, coal and gas units that is offset when generation from renewable sources in Germany is marginally increased. Fig. 1 shows how unit-level emissions, a nonlinear function of output, are determined. A generation unit adjusts its emissions based on marginal costs (gas_coal, eua), demand (load) and the amount of renewables (onshore, offshore, solar) fed into the grid in each respective hour. In addition, renewables can cause the electricity grid
International spillover effects
Renewable electricity,due to the short-run marginal cost being close to zero, has been shown to suppress the wholesale electricity price (Ketterer, 2014). This makes exporting electricity to neighboring countries more profitable or decreases the imports from neighboring countries. Lower net imports to Germany will decrease the amount of conventional production in the respective neighboring country. German renewable electricity can offset emissions in other countries as well.
I measure the net
Abated emissions
Up to this point in the analysis, I have estimated the short-term offsetting effect of renewable electricity. However, since the electricity sector in Europe is regulated under the EU ETS, a short-term emission reduction does not necessarily translate into a long-term emission saving. Perino et al. (2020) demonstrate that this long-term climate benefit depends on carbon leakage within the EU ETS and the waterbed effect.
The rate of internal carbon leakage is defined7
Conclusion
I estimate the short-term greenhouse gas emission replacement effect of renewable electricity in Germany using a rich dataset on fossil power plants. Both onshore and offshore wind reduce pollutants more than electricity from solar panels, confirming previous findings. This can be explained by timing of infeed and different export opportunities. These additional exports lead to substantial negative leakage effects, reducing emissions in neighboring countries. These emission reductions are
Funding
This work was supported by the German Federal Ministry of Economic Affairs and Energy under the grant number 03SIN432.
CrediT authorship contribution statement
Philip Schnaars: Conceptualization, Data curation, Formal analysis, Software, Validation, Writing-original draft, Writing-review & editing.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
The author holds a Bachelor and Masters degree in Economics from the University of Hamburg. During his PhD studies, he investigates various issues of the energy transformation, using extensive data from Germany. Alongside working at the faculty at the University of Hamburg, he has experience in consulting policy makers.
References (52)
- et al.
Carbon abatement with renewables: evaluating wind and solar subsidies in Germany and Spain
J. Public Econ.
(2019) Effects of wind power intermittency on generation and emissions
Electr. J.
(2019)- et al.
Renewable energy and its impact on thermal generation
Energy Econ.
(2017) - et al.
Effectiveness of climate policies: Carbon pricing vs. subsidizing renewables
J. Environ. Econ. Manag.
(2021) - et al.
Do renewable energy policies reduce carbon emissions? On caps and inter-industry leakage
J. Environ. Econ. Manag.
(2017) The impact of wind power generation on the electricity price in Germany
Energy Econ.
(2014)- et al.
Domestic politics and the formation of international environmental agreements
J. Environ. Econ. Manag.
(2017) - Agora , 2020. The German Power Market - State of Affairs in 2019. URL:...
- Athey, S., Imbens, G.W. , 2015. Machine Learning methods for estimating heterogeneous causal effects. Working Paper....
- et al.
Generalized random forests
Ann. Stat.
(2019)
Negative leakage
J. Assoc. Environ. Resour. Econ.
Random forests
Mach. Learn.
The political economy of EU climate and energy´ policies in central and Eastern Europe revisited: shifting coalitions and prospects for clean energy transitions
Polit. Govern.
Measuring the environmental benefits of wind-generated electricity
Am. Econ. J. Econ. Policy
Inferring carbon abatement costs in electricity markets: a revealed preference approach using the shale revolution
Am. Econ. J. Econ. Policy
How much does wind power reduce CO2 emissions? Evidence from the Irish single electricity market
Environ. Resour. Econ.
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The author holds a Bachelor and Masters degree in Economics from the University of Hamburg. During his PhD studies, he investigates various issues of the energy transformation, using extensive data from Germany. Alongside working at the faculty at the University of Hamburg, he has experience in consulting policy makers.