Spain’s Renewable Energy Backlash: How National Policy Shifts Triggered International Arbitration Storms

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Over the past decade, Spain’s foray into the renewable energy market has been hailed as a triumph for the industry; nonetheless, it has been marked by dizzying, costly missteps, culminating in several international arbitration disputes as Spain briefly aimed to cut back on renewable investment.

 In the early 2000s and 2010s, Spain was praised for its proactivity in developing wind and solar energy. The Spanish government offered considerable tax incentives and feed-in tariffs to encourage sector development. However, due to Spain’s limited grid capacity, renewable energy faced severe congestion, limiting the profitability of bigger projects. Even in 2024, Spain still faced this issue, with 88% of distribution grid nodes at capacity, which slows renewable deployment. Inadequate power grid capacity in the midst of renewable energy transitions have faced many countries, including China. Following the 2008 financial crisis and European austerity measures, Spanish politicians began advocating a rollback of ongoing infrastructure projects. This precipitated international arbitration cases brought by investors, which have dragged on to the present day. With the shift towards conservatism in the Spanish elections of 2012, rollbacks of renewable energy policies increased dramatically. Changes in 2013, specifically Royal Decree Law 9/2013 and Law 24/2013 abolished the fixed feed-in tariff system entirely and replaced it with a new framework, which reduced investor returns. Although these rollbacks eventually gave way to the growing renewable energy industry, Spain is still dealing with the legal consequences of the era, with more than 40 arbitrations filed over this issue.

Foreign investors challenged the rollback, citing claims under the Energy Charter Treaty (ECT) for international arbitration. The ECT emphasizes the state’s requirement to “create stable, equitable, favourable, and transparent conditions” for investors. For example, the International Centre for Settlement of Investment Disputes (ICSID), which handles foreign-investor/state disputes, ruled in late 2025 that Spain owed 260 million euros to Eiser, a prominent Dutch investment firm, and its Luxembourg energy subsidiary, Energia Solar. Investors argued that Spain’s sudden policy changes impeded upon favourable conditions that were present at the time of ‘investment’. In 2019, it was similarly decided that Spain must pay NextEra €290.6 million as part of a settlement of its arbitration claim against Spain. NextEra was involved in the construction of two solar power plants in Spain. In another landmark loss, the ICSID tribunal awarded EUR 64.5 million to an Emirati-based fund, Masdar Solar. Other recent prominent rulings include a case involving an American investor company, in which a federal judge ruled that Spain must pay a $70 million arbitration award stemming from a dispute over revoked incentives in 2013 and 2014. 

These losses have reframed the scope of ECT jurisprudence; investors have begun to expect certain commitments from states in regard to general legislation around the energy market without explicit stabilization agreements from states. For example, these international tribunals, including those of the ICSID, have found that, while Spain has sovereignty over its regulatory laws, certain limitations must be respected. However, critics argue that this greatly limits states' capacity to respond to changing economic and environmental conditions and imperatives. These investment tribunals have adopted different analytical approaches to balance these factors. Some tribunals focus on investor expectations, while others consider states’ regulatory demands fundamental but argue that states’ changes must be within reason to avoid obstructing the essence of “stability” as defined in the ECT. 

Investment arbitration within the European Union has recently seen some growing resistance because of tensions with the case law of the Court of Justice of the European Union (CJEU). The EU and Spain’s withdrawal from the ECT (effective 28 June 2025) has intensified uncertainty about the future of energy investor protections and ECT-based arbitration in Europe. The newly amended Article 47 of the ECT now includes a 20-year “sunset clause” to preserve investor protections after a state’s withdrawal. Article 47 specifically states, “The provisions of this Treaty shall continue to apply to Investments” for all parties for a “period of 20 years” from the state’s withdrawal date. However, its applicability within the EU is now strongly disputed. In its 2021 Komstroy v Moldova judgment, the Court of Justice of the European Union held that Article 26 of the Energy Charter Treaty cannot be used for arbitration between EU investors and EU member states. As a result, even though Article 47 contains a “sunset clause” that extends treaty protections after withdrawal, it is uncertain whether investors can still rely on that clause to bring intra-EU arbitration claims. To reinforce this position, the EU adopted the Komstroy Declaration and an inter se agreement which confirmed that Article 26 and the sunset clause cannot be relied upon for intra-EU arbitration, in line with earlier rulings such as Achmea.

Despite this wave of cuts to renewable energy, Spain remains a leader in the European Union, with the majority of its energy use coming from renewables. Solar and wind investment has been soaring in recent years despite prolonged international arbitration cases from the early 2010s. While the future of solar and wind energy infrastructure projects is steadier in Spain, the government seems more focused on grid upgrades and optimization to facilitate future projects. 

The arbitration saga in Spain hints at a deeper legal and diplomatic lesson that influences how states may move forward with clean energy transitions. Such arbitration cases have also affected other EU member states, including the Czech Republic, Romania, Italy, Germany, Ukraine, and Bulgaria. These disputes refer to similar national policy measures that have upset investors including: “repeal of income tax exemptions for renewable energy producers”, “reduction of ‘green certificates” and “adjustments to methods calculate renumerations“. This issue highlights the need to incentivize investors while also providing some economic flexibility, possibly through requiring specific contractual stabilization clauses and clearer sunset laws, in order to provide state accountability and avoid costly litigation.

Elina Coutlakis is a sophomore at Brown University studying International and Public Affairs and Economics. She is a staff writer for the Brown Undergraduate Law Review and can be contacted at elina_coutlakis-hixson@brown.edu.

Priyanka Nambiar is a pre-law sophomore at Brown University studying Cognitive Neuroscience. She is a staff editor for the Brown Undergraduate Law Review and can be contacted at priyanka_nambiar@brown.edu.