UK and EU Agree in Principle to Link Carbon Emissions Trading Systems
<p>The UK and European Union have reportedly finished negotiations to connect their emissions trading systems. This would mark one of the most substantial areas of regulatory cooperation since Brexit and could remove significant carbon-related trade costs for UK manufacturers exporting to the EU.</p><p>Both sides made a political commitment to link the schemes at their bilateral summit on 19 May 2025. However, the agreement is not yet legally binding. Implementation depends on publishing formal legal texts, securing ratification and passing the necessary domestic legislation in both jurisdictions.</p><p>For UK businesses in sectors such as steel, cement, aluminium and fertilisers, the consequences are potentially significant. Without a linked system, UK exporters could face carbon border charges when selling into the EU market. Energy UK has estimated these costs could reach £800 million a year by 2030, though the actual figure would depend on carbon prices, trade volumes and the emissions intensity of individual products.</p><p>The agreement addresses a growing problem. As both the UK and EU introduce carbon border adjustment mechanisms, manufacturers face the prospect of paying twice for the same emissions. Once under their domestic carbon pricing system, and again at the border when exporting. Linking the two emissions trading systems could eliminate this double burden for compliant businesses.</p><h2>How the UK and EU carbon markets separated</h2><p>Before Brexit, UK installations operated within the EU Emissions Trading System. This framework put a price on greenhouse gas emissions by setting a declining cap on total emissions and allowing companies to trade allowances within that limit.</p><p>The UK established its own independent system in 2021 after leaving the EU scheme. Both systems work on similar principles. They cover large industrial emitters and power generators, require participants to surrender allowances equal to their verified emissions, and reduce the total supply of allowances over time to drive down emissions.</p><p>Consequently, the two markets now operate separately. An allowance purchased in the UK system cannot be used for compliance in the EU system, and vice versa. This separation matters because it creates regulatory divergence in how carbon costs are applied to goods traded between the two markets.</p><p>The Trade and Cooperation Agreement signed after Brexit included a commitment for both sides to "seriously consider" linking their carbon markets. Nevertheless, negotiations did not begin immediately. The issue gained urgency only as both jurisdictions moved forward with their respective carbon border adjustment mechanisms.</p><h2>Carbon border charges create pressure for alignment</h2><p>The EU's carbon border adjustment mechanism places a carbon cost on imports in emissions-intensive sectors. This prevents producers in countries with weaker climate policies from gaining a competitive advantage over European manufacturers who face carbon costs under the EU system.</p><p>The mechanism covers cement, iron and steel, aluminium, fertilisers, hydrogen and electricity. Its definitive phase is scheduled to begin in January 2026. Importers will need to purchase CBAM certificates corresponding to the embedded emissions in covered goods, minus any carbon price already paid in the country of origin.</p><p>The UK is preparing its own border adjustment mechanism, scheduled to start on 1 January 2027. The initial UK mechanism will cover aluminium, cement, fertiliser, hydrogen, and iron and steel. Indirect emissions will be excluded until at least 2029 under current government plans.</p><p>Therefore, UK exporters selling covered goods to the EU could face carbon charges at the border even though they already pay for emissions under the UK system. Similarly, EU exporters could face equivalent charges when selling into the UK market once the UK mechanism takes effect.</p><p>The UK government has stated that linking the two emissions trading systems could create conditions for mutual exemptions from the respective border mechanisms. This would apply to goods originating in the UK and EU, provided they comply with relevant legislation in both jurisdictions.</p><h2>What manufacturers and heavy industry should understand</h2><p>The most immediate impact would fall on companies in internationally competitive sectors that produce emissions-intensive goods. Steel producers, aluminium smelters, cement manufacturers, fertiliser plants and chemical facilities would be among those most affected by carbon border charges.</p><p>For these businesses, the current situation creates planning uncertainty. A steel manufacturer in the UK already pays for carbon allowances under the UK system. Without a linkage agreement, that same company could face additional carbon costs when exporting steel products to EU customers. This effectively means paying twice for the same emissions.</p><p>Furthermore, the scale of potential costs is not trivial. Industry estimates suggest UK businesses could face payments approaching £800 million annually by 2030 in the absence of linked systems. The actual figure would vary depending on several factors, including the carbon price in each system, the volume of trade in covered sectors and the emissions intensity of specific products.</p><p>A linked market would provide greater certainty for investment decisions. Companies planning industrial decarbonisation projects need to understand future carbon costs over timeframes of ten to twenty years. Similarly, businesses negotiating long-term electricity or fuel contracts need clarity on regulatory frameworks that affect pricing.</p><p>Market liquidity would also improve under a linked system. A larger combined market reduces the likelihood of sharp price divergences between the two systems and provides more opportunities for companies to manage their carbon positions through trading.</p><h2>Technical requirements for connecting the two systems</h2><p>Linking two emissions trading systems involves more than simply agreeing in principle. The UK and EU will need to establish detailed rules governing how the combined market operates.</p><p>Mutual recognition of allowances forms the core of any linkage. An allowance issued in the UK system must be accepted for compliance in the EU system, and vice versa. This requires agreement on monitoring, reporting and verification standards to ensure emissions are measured consistently in both jurisdictions.</p><p>Both systems include market stability mechanisms that adjust the supply of allowances to prevent extreme price volatility. These mechanisms would need to be coordinated under a linked system. Otherwise, interventions in one market could create unintended consequences in the other.</p><p>The agreement would also need to address how changes to either system are managed. For example, if the EU decides to extend its system to cover new sectors, or if the UK adjusts its emissions cap, procedures must exist to maintain compatibility without requiring constant renegotiation.</p><p>Climate ambition presents another consideration. Both systems are designed to reduce emissions over time through declining caps on total allowances. A linkage requires that both sides maintain sufficiently ambitious reduction trajectories. If one system becomes significantly weaker than the other, it could undermine the environmental integrity of the combined market.</p><p>The EU and Switzerland provide a working precedent. Their emissions trading systems were linked in 2020, demonstrating that the EU can connect its carbon market with a non-member country while preserving separate institutional structures. That agreement required Switzerland to align closely with EU rules in areas covered by the linkage while maintaining its own climate policy framework.</p><h2>Key facts about the reported agreement</h2><ul><li>The UK operated within the EU Emissions Trading System before Brexit and launched an independent system in 2021.</li><li>Both sides agreed to work toward linking their carbon markets at a bilateral summit on 19 May 2025.</li><li>The EU's carbon border adjustment mechanism enters its definitive phase in January 2026, covering cement, steel, aluminium, fertilisers, hydrogen and electricity.</li><li>The UK plans to introduce its own border mechanism on 1 January 2027, initially covering aluminium, cement, fertiliser, hydrogen and iron and steel.</li><li>UK exporters could face carbon border costs of up to £800 million annually by 2030 without a linkage agreement, according to industry estimates.</li><li>Linking the systems could create conditions for mutual exemptions from carbon border charges for compliant goods traded between the UK and EU.</li><li>The agreement is not yet legally binding and requires publication of formal texts, ratification and implementing legislation before taking effect.</li></ul><h2>Implications for Northern Ireland and electricity markets</h2><p>Northern Ireland's position adds complexity to the linkage question. The region participates in the all-island energy market with the Republic of Ireland, which remains part of the EU system. This creates potential regulatory friction for electricity trading and industrial activity connected to both jurisdictions.</p><p>The UK Parliament's European Affairs Committee previously concluded that linking the UK and EU schemes would be the most realistic route to avoiding carbon border exposure for UK businesses. The committee noted that the case for linkage was strengthened by the EU's carbon border proposals.</p><p>Electricity trading presents specific challenges under separate systems. Power generators and electricity suppliers operating across the Irish Sea face uncertainty about how carbon costs and border mechanisms will apply to cross-border electricity flows. A linked system could reduce this regulatory friction and support more predictable trading arrangements.</p><p>Nevertheless, the precise impact will depend on how the final agreement treats Northern Ireland and whether special provisions are needed to accommodate the region's unique circumstances under the Protocol on Ireland and Northern Ireland.</p><h2>Steps still required before implementation</h2><p>Reports that negotiations have concluded do not mean the linkage is already operational. Several formal steps remain before the two markets can be connected.</p><p>The legal text must be published and made available for scrutiny. This will reveal important details about scope, timing, governance and how the agreement addresses potential conflicts between the two systems.</p><p>Approval by relevant institutions in both jurisdictions comes next. In the EU, this typically involves the European Commission, the European Parliament and the Council. In the UK, Parliament would need to pass implementing legislation.</p><p>Technical preparations for market integration would follow. This includes establishing systems for allowance transfers between jurisdictions, coordinating registry functions and ensuring that monitoring and reporting systems are compatible.</p><p>Timing remains uncertain. The UK government has said mutual exemptions from carbon border mechanisms would be subject to provisions of UK and EU law. This means that an announcement alone does not automatically eliminate all reporting or compliance obligations for businesses.</p><p>Questions about sectoral coverage also need answers. Will the linkage apply to all sectors covered by both systems, or only to certain categories? Will transitional arrangements be required, and if so, how long will they last?</p><h2>Broader significance for UK-EU relations</h2><p>The reported agreement represents one of the clearest examples of practical cooperation being rebuilt after Brexit. It would reconnect a significant part of the two economies while allowing both sides to retain separate climate policy institutions.</p><p>This matters beyond carbon markets. The agreement could establish a model for future cooperation in which the UK remains outside the EU but aligns closely with selected regulatory systems where cross-border trade and environmental objectives make separation costly.</p><p>For businesses, the potential benefits are clear. A larger, more closely aligned carbon market strengthens the price signal for reducing emissions. It reduces incentives to relocate production to less-regulated jurisdictions and encourages investment in cleaner industrial technologies.</p><p>However, the UK would need to accept ongoing alignment with EU rules in areas covered by the linkage. Analysts at the Institute for European Environmental Policy have noted that the UK would retain its own climate policy framework, but its emissions cap and reduction trajectory would need to remain sufficiently ambitious to support compatibility with the EU system.</p><p>This creates an ongoing commitment. If the EU strengthens its climate ambition, the UK would face pressure to follow. If the UK's carbon pricing becomes significantly weaker than the EU's, the linkage could come under strain.</p><h2>What businesses should consider now</h2><p>Companies in affected sectors should not wait for final legal texts before reviewing their position. Several actions merit consideration even while details remain unclear.</p><p>Assess your exposure to carbon border mechanisms under current rules. Calculate potential costs based on your export volumes to the EU, the emissions intensity of your products and reasonable assumptions about future carbon prices. This provides a baseline for understanding the potential value of a linkage agreement.</p><p>Review your carbon reporting and verification processes. A linked system will require consistent monitoring and reporting across both jurisdictions. Companies that already maintain robust emissions accounting will be better positioned to demonstrate compliance when the agreement takes effect.</p><p>Consider how a linked market might affect your decarbonisation plans. If carbon border charges are reduced or eliminated, the financial case for certain emissions reduction projects may change. Conversely, if carbon prices converge between the two systems, the value of <a href="https://sbs.eco/net-zero-program/">carbon reduction investments may become more predictable</a>.</p><p>Supply chain implications also deserve attention. If you source materials or components from EU suppliers, or if your customers are in the EU, a linked system could affect pricing, contract terms and competitive dynamics in your sector.</p><p>Public sector suppliers should pay particular attention. Government procurement increasingly includes <a href="https://sbs.eco/compliance/">carbon reporting requirements</a>, and understanding how cross-border carbon costs affect your supply chain could become relevant for tender responses.</p><p>We work with manufacturers and industrial businesses to understand their carbon reporting obligations, assess exposure to carbon pricing mechanisms and develop responses that meet both compliance requirements and commercial objectives. The interaction between domestic emissions trading, border adjustments and supply chain requirements creates complexity that benefits from structured analysis rather than reactive responses.</p><h2>Where to find authoritative information</h2><p>The UK government's Department for Energy Security and Net Zero publishes information about <a href="https://www.gov.uk/government/organisations/department-for-energy-security-and-net-zero">UK climate policy and the UK Emissions Trading Scheme</a>. This includes guidance on compliance obligations and updates on policy developments.</p><p>For information about the EU system, the European Commission maintains <a href="https://climate.ec.europa.eu/eu-action/eu-emissions-trading-system-eu-ets_en">detailed resources on the EU Emissions Trading System</a>, including rules, market data and policy documents.</p><p>The European Commission also provides <a href="https://taxation-customs.ec.europa.eu/carbon-border-adjustment-mechanism_en">guidance on the EU's carbon border adjustment mechanism</a>, including which sectors are covered, how charges are calculated and compliance requirements for importers.</p><p>Industry bodies such as <a href="https://www.energy-uk.org.uk/">Energy UK</a> publish analysis and commentary on UK carbon pricing policy and its implications for different sectors. These resources can help businesses understand how policy developments affect their specific circumstances.</p><p>As formal legal texts become available, they will provide the definitive source for understanding rights, obligations and implementation timelines. Until then, businesses should monitor official government sources for announcements and consult with advisers who can help translate policy developments into practical implications for their operations.</p>
