The Repowering Potential of German Onshore Wind Energy

The previous federal government, consisting of the SPD, Greens, and FDP, set the target of covering around 80 percent of gross electricity consumption with renewable energy by 2030. This target also applies to the current coalition.¹ A key pillar of this transformation is onshore wind energy. Already in 2024, with an installed capacity of around 63 gigawatts (GW), it accounted for over 25.9 percent of German electricity generation.²

To achieve the expansion target of 115 GW of onshore wind energy by 2030, continuous additions are required. However, this stalled from 2018 onwards. Although addition rates have been rising again since 2020, additions in 2024, at only 60 percent of the 2017 level, remained well below previous peaks.^{3 4}

Figure 1: Expansion of onshore wind energy in Germany and development of cumulative installed capacity since 2010 (Source: Germany in Figures | BWE e.V.)⁵

Challenges

The reasons for the current shortfall are varied. Available grid connection capacities are sometimes not used efficiently, and existing grids are reaching structural limits of their utilization. ⁶ Planning and approval procedures also continue to pose a challenge for project developers, despite interim legislative relief measures. Several years often pass between the application for construction of a facility and its commissioning. In addition, wind turbine operators frequently face considerable resistance from the public or environmental organizations. Criticism ranges from disruption of the landscape to impacts on protected species.

The Solution: Repowering?

Repowering represents a possible solution to many existing challenges. Old wind turbines are replaced by more modern and more powerful models. Through larger rotor diameters, higher hub heights, and more efficient generators, the rated capacity of newly erected turbines has increased significantly over the past 20 years—from an average of around 1 megawatt (MW) in 2000 to currently around 5 MW. In addition, electricity yield can be increased through the more stable wind speeds at higher wind layers and the higher capacity factors, i.e., the utilization of rated capacity over the year. A common rule of thumb is shown in Figure 2: Through repowering, with the same area and a reduction in the number of turbines by about half, a tripling or even quadrupling of electricity yield can be achieved.⁷

Figure 2: Rule of thumb for repowering: tripling of electricity yield with halving of the number of turbines

Furthermore, repowering reduces bureaucratic hurdles. The time-consuming acquisition of land is eliminated, as proven sites with existing grid infrastructure (which may need to be reinforced) are used. Resistance from the public is also expected to be lower, as the turbines are erected at familiar sites and no additional interventions in untouched natural areas are required. In addition, potential hazards to animal species are reduced, as the lower number and more modern design of the turbines can reduce disruptive influences.⁸

Repowering Potential in Germany

The impressive potential of repowering in Germany is shown by the model developed in Figure 3. It assumes that all wind turbines are replaced after 20 years of operation, all turbines erected before 2005 are repowered evenly by 2030, and today’s capacity can be increased threefold through repowering. In the diagram, the light green line represents the cumulative installed capacity of onshore wind energy up to 2024 and subsequently the required development necessary to achieve the federal government’s targets for 2030.

The gray bars show the annual additions in recent years. The dark green bars illustrate the possible contribution of repowering, and the blue bars show the necessary expansion of wind energy through the development of new sites. The scenario under consideration yields the following key findings:

• Only new areas for generating around 1 GW of onshore wind energy would need to be developed annually to achieve the targets for onshore wind energy expansion. The remaining demand could be met through repowering, i.e., through the use of existing wind energy sites.
• Around 15,000 existing turbine sites with a current capacity of around 21.5 GW could be increased to 64.5 GW through repowering, thereby covering a large part of future demand.
• The scenario assumes a tripling of capacity through repowering. In fact, the targets for onshore wind energy could be achieved through repowering alone with a yield increase by a factor of 3.4, and current studies show that such a factor is not inconceivable.⁹ The repowered turbines would reach a total capacity of 73.1 GW, and the development of new sites would no longer be necessary.

Figure 3: Potential of repowering for achieving the target of 115 GW of onshore wind energy by 2030 (Source: based on data from the Marktstammdatenregister)¹⁰

Continued Operation or Repowering?

For wind farm operators, repowering represents a strategic investment decision. It is necessary to weigh whether an investment in repowering and the resulting revenues from electricity generation exceed the economic benefit of continued operation of existing old turbines. This question is closely linked to the framework conditions set by the Renewable Energy Sources Act (EEG). Since 2017, the promotion of electricity from renewable energy has no longer been provided through a fixed feed-in tariff, but through auctions with limited volume. The winners of the auction receive a reference value for 20 years equal to their bid. For example, the average reference value at the bidding date on May 1, 2025, was 6.83 cents per kilowatt-hour (kWh). ¹¹ In addition, a correction factor was introduced in the EEG in 2021 to continue the promotion of low-wind sites, whereby their reference value is increased by up to 4.56 percent (EEG 2021). ¹²

After 20 years of operation, a wind farm therefore has two options: continued operation with sales at low and volatile wholesale electricity prices, or repowering, which (still) enables a fixed reference value within the framework of the market premium model for another 20 years. What is significant for profitability is that the operator wins the auction with their bid, while at the same time ensuring that this bid enables a positive profit.

A study by Fuchs et al. concludes for a fictitious example that continued operation of the old wind farm only makes sense if approval of the new wind turbines is rejected and positive margins from electricity generation can continue to be achieved. The latter is not self-evident (even without further depreciation), as low revenues at the level of the wholesale electricity price meet high maintenance and repair costs.

Due to the significantly higher feed-in of modern wind turbines, existing grid connections generally need to be reviewed and frequently adjusted, as the requirements for voltage, reactive power, and short-circuit behavior also change. In practice, this usually includes the reinforcement of transformers, lines, and protection technology, as well as the implementation of current grid connection rules (e.g., VDE-AR-N 4120), to ensure safe and stable integration of the increased feed-in capacity. ^{13 14}

Operating and decommissioning costs have only a minor influence, as the profitability of the repowering project depends 95 percent on the feed-in tariff achieved.¹⁵

Legislative Direction

The legal framework conditions are crucial for the feasibility of repowering projects, and in recent months they have experienced significant relief, particularly with regard to repowering possibilities. For example, extensive adjustments were made by the Act to Improve Climate Change Mitigation in Emission Control, to Accelerate Emission Control Approval Procedures, and to Implement EU Law, which was published in the Federal Law Gazette on July 8, 2024, and entered into force one day later. With this article law, described in coalition circles as the largest amendment to the Federal Emission Control Act (BImschG), emission control approval procedures were accelerated to contribute to achieving the net greenhouse gas neutrality set out in the Federal Climate Change Mitigation Act for 2045.

In addition to shortened approval deadlines and greater digitalization and streamlining of approval procedures, the legislature made extensive adjustments to the regulations on repowering. Thus, § 16a para. 2 sentence 1 BImSchG clarified that the classification of an action as repowering is to be made independently of the extent of structural size differences, capacity increase, or change in the number of turbines in relation to the existing turbine. Furthermore, the scope of application of repowering was significantly expanded. For example, the period to be observed between the decommissioning of the existing turbine and the erection of the new turbine was doubled from 24 to 48 months, and the distance to be maintained between the existing turbine and the new turbine was increased to five times the total height of the new turbine (previously twice the total height was the distance to be maintained), § 16b para. 2 sentence 2 BImSchG. As a result, project developers are considerably more flexible in their planning without having to forgo the relief measures for repowering projects.

If the site of a turbine is changed by no more than eight meters, the total height is increased by no more than 20 meters, and the rotor sweep is reduced by no more than eight meters, only the structural stability and the harmful environmental impacts from noise and adverse effects from turbulence need to be examined, § 16b para. 7 sentence 3 BImSchG.

In the case of only minor changes within the meaning of § 16 para. 7 sentence 3 BImSchG and in cases where the capacity or yield of an onshore wind turbine is increased without structural changes or without the replacement of parts and without a change in the approved operating times, an approval fiction applies after six weeks if the authority has not previously decided on the application or an oral hearing has been requested, § 16b para. 9 sentence 1 BImSchG. Finally, repowering does not require operator identity between the operator of the existing turbine and the project developer. The operator of the existing turbine only needs to have consented to the project developer’s application by the time of the official decision, § 16b para. 10 sentence 1 BImSchG.

With the Act to Implement Requirements of Directive (EU) 2023/2413 for Approval Procedures under the Federal Emission Control Act and the Water Resources Act, as well as for Planning Procedures under the Building Code and the Spatial Planning Act, to Amend the Federal Waterways Act, and to Amend the Wind Energy Area Requirement Act of August 12, 2025, which was published in the Federal Law Gazette on August 15, 2025, the regulations were revised again. For projects with minor changes within the meaning of § 16b para. 7 sentence 3 BImSchG, the compatibility of the changes with military and aviation interests must now also be examined, § 16b para. 7 sentence 3 BImSchG (new). If no decision is made on the application within three months of receipt of the application documents by the authorities responsible for military and aviation interests and there is no application for an oral hearing, the approval is deemed granted upon expiration of the approval period (approval fiction), § 16b para. 8a BImSchG (new).

Furthermore, repowering projects cannot be opposed by the exclusion effect of § 35 para. 3 sentence 3 BauGB, which results from existing concentration area planning, § 245e para. 3 BauGB. Rejection of the project is only possible if, exceptionally, the basic principles of the planning are affected. This only applies differently in Natura 2000 areas and nature reserves.

Success Stories in Practice

The fact that repowering is not a new invention is demonstrated by the North Frisian municipality of Galmsbüll. Here, a repowering project was implemented as a community wind farm between 2005 and 2007. In addition to individual operator companies, citizens participated in one-third of the total costs, with demand significantly exceeding supply. Through the project, 38 wind turbines with a total capacity of 12.4 MW were replaced by 21 turbines with a total capacity of 60 MW.¹⁶

Another successful example is the project completed this year by the VSB Group at the Elster wind farm in Saxony-Anhalt. Through the repowering project, the wind farm now uses one-third less area and can supply approximately 150,000 people with electricity.¹⁷ With an investment of 200 million euros, 50 old turbines were replaced by 16 state-of-the-art turbines, so that in the future a sixfold increase in annual electricity production to 235 GWh is possible.^{18 19}

Conclusion

For wind farm operators, repowering is a powerful lever to simultaneously increase yield, planning certainty, and acceptance. If the wind farm is located in one’s own grid or distribution area (insofar as also an energy supplier), then there are further advantageous circumstances that facilitate the project: existing sites with available grid connection supplemented by direct access to the customer side. Strategically, repowering is clearly preferable to continued operation, at the latest after the expiration of the fixed feed-in tariff. From around the 15th year of operation, wind farm operators such as municipal utilities should therefore address the following points:

1. Comprehensive screening of existing sites for wind resources, distance regulations, species protection, etc., to determine optimal sites with low conflict potential and maximum yield increase.
2. Apply for approvals early to shorten lead times.
3. Develop a competitive and economical auction strategy for the feed-in tariff.
4. Consider regional policies such as citizen participation to increase acceptance.
5. Early analysis of grid connection capacities to identify possible reinforcement or new construction requirements.

Especially as long as the fixed market premium under the EEG still exists, a careful analysis of these points is essential, as otherwise the economically optimal time window for repowering can hardly be determined. In addition, municipal utilities should also examine the targeted acquisition of old wind farms in their own grid and supply area. Examples such as Statkraft show that the market for such business models has long been established. The group invested around 413 million euros in the purchase of 35 old wind farms in Germany. This enables municipal utilities to secure sites, unlock repowering potential, and at the same time strengthen regional value creation, competitiveness, and security of supply in the long term. ²⁰

From the newsletter “E|nEws: Renewable Energy”

Sources:

¹ Bundesverband WindEnergie e.V., Wind as a Key Contributor to the Energy Transition Confirmed – Unnecessary Blockades Must Now Be Removed, https://www.wind-energie.de/presse/pressemitteilungen/detail/wind-als-leistungstraeger-der-energiewende-bestaetigt-unnoetige-blockaden-jetzt-aus-dem-weg-raeumen/.
² Fachagentur Wind und Solar e.V., Status of Onshore Wind Energy Expansion in Germany in 2024, https://www.wind-energie.de/fileadmin/redaktion/dokumente/publikationen-oeffentlich/themen/06-zahlen-und-fakten/20250115_Status_des_Windenergieausbaus_an_Land_Jahr_2024.pdf.
³Federal Government (Germany), Clear Path for Wind Energy – Build Onshore Wind Turbines Faster, https://www.bundesregierung.de/breg-de/service/archiv-bundesregierung/erster-windgipfel-habeck-2172994.
⁴ Bundesverband WindEnergie e.V., Germany in Figures, https://www.wind-energie.de/themen/zahlen-und-fakten/deutschland/.
⁵ Bundesverband WindEnergie e.V., Germany in Figures, https://www.wind-energie.de/themen/zahlen-und-fakten/deutschland/.
⁶ Bundesverband WindEnergie e.V., Rapid Increase in New Approvals – Reduce Implementation Hurdles, https://www.wind-energie.de/presse/pressemitteilungen/detail/rasanter-anstieg-von-neugenehmigungen-umsetzungshuerden-senken/.
⁷ EnBW Energie Baden‑Württemberg AG, Out with the Old, In with the New: What Does Repowering Bring?, https://www.enbw.com/unternehmen/themen/windkraft/was-bringt-repowering.html.
⁸ Bundesverband WindEnergie e.V., Repowering – More Capacity on Less Area, https://www.wind-energie.de/themen/anlagentechnik/repowering/.
⁹ EnBW Energie Baden‑Württemberg AG, Out with the Old, In with the New: What Does Repowering Bring?, https://www.enbw.com/unternehmen/themen/windkraft/was-bringt-repowering.html.
¹⁰ Marktstammdatenregister (MaStR), https://www.marktstammdatenregister.de/MaStR.
¹¹ Bundesverband Energie‑ und Wasserwirtschaft (BDEW), May Auction for Onshore Wind Turbines 2025, https://www.bdew.de/energie/maiausschreibung-fuer-windenergieanlagen-an-land-2025/.
¹² Rödl, EEG 2021 – Innovations in the Wind Sector.
¹³ Deutsche Kommission Elektrotechnik Elektronik Informationstechnik e.V. (DKE), VDE-AR-N 4120 (VDE -AR-N 4120):2015-01, https://www.dke.de/de/normen-standards/dokument?id=7023752&type=dke%7Cdokument.
¹⁴ Bundesnetzagentur, Grid Connection for Renewable Energy Plants, https://www.bundesnetzagentur.de/DE/Fachthemen/ElektrizitaetundGas/ErneuerbareEnergien/Netzanschluss/start.html.
¹⁵ Current State and Future Prospective of Repowering Wind Turbines: An Economic Analysis, https://www.mdpi.com/1996-1073/13/12/3048
¹⁶ Bundesverband WindEnergie e.V., Repowering of Wind Turbines, https://www.wind-energie.de/fileadmin/redaktion/dokumente/publikationen-oeffentlich/themen/04-politische-arbeit/04-weiterbetrieb-repowering/repoweringbroschuere_2012_web.pdf.
¹⁷ VSB Gruppe, Repowering of the Elster Wind Farm, https://www.vsb.energy/de/de/projekte/windpark-elster-repowering/.
¹⁸ Energate Messenger, August 14, 2025.
¹⁹ MDR, The White Giants from Elster, https://www.mdr.de/nachrichten/sachsen-anhalt/dessau/wittenberg/xxl-windpark-elster-elster-groessten-repowering-projekte-europas-100.html.
²⁰ Handelsblatt, Repowering: How Upgrading Old Wind Farms Becomes a Business Model, https://www.handelsblatt.com/unternehmen/energie/repowering-so-wird-das-aufruesten-alter-windparks-zum-geschaeftsmodell/29361490.html.