2020 ESG Report Letter from the CEO As we publish our 2020 Environmental, Social and Governance (ESG) report there is an ever- growing focus on the importance of renewable energy in the global energy mix and the increasing relevance of ESG and climate-change commitments for companies to reduce their GHG emissions. Our strategy focuses on climate change solutions in the power and water sectors. We intend to continue to play an important role in the solution to climate change and our long-term strategy reflects this. Following a thorough analysis in 2021, the Board of Directors approved a new ambitious GHG emissions target, setting out to achieve a 70% reduction in Atlantica's emission rate per unit of energy generated by 2035 versus the 2020 base year. This is a particularly aggressive target for a company like Atlantica, where renewable energy production – an activity which already has a very low rate of emissions per unit of energy produced and is well below the average power production activities in traditional utilities – accounts for approximately 75% of our business. In 2020, our activities allowed us to avoid over 5 million tons of CO2 emissions, and as part of our commitment to sustainability, we implemented a new GHG emissions offset mechanism that reduced our Scope 1 GHG emissions by 12%. We are also committed to ensuring that over 80% of our adjusted EBITDA, including unconsolidated affiliates, continue to be generated from low-carbon footprint assets such as renewable energy, storage, transmission infrastructure and water assets. We also have an ambitious plan to continue growing our renewable energy business. In 2020, we invested approximately $300 million in clean energy assets, and in 2021 we have already agreed acquisitions and investments amounting to more than $350 million – including a renewable energy asset in California and a 49% stake in a portfolio of wind assets in the United States. However, climate change and the environment is not our only area of focus. At Atlantica, safety remains at the forefront of everything we do – and this year is no exception. With this in mind, in February 2020, the company established a COVID-19 Committee aimed at monitoring the situation at each of our locations in order to ensure all necessary action was taken to minimize the risks affecting our employees, operations and stakeholders. We held 142 COVID-19 Committee meetings and implemented extensive health and safety measures at all our assets. In 2020, we also saw how the crisis caused by the COVID-19 pandemic took the digitalization of society to the next level, highlighting the dependence on a reliable energy supply. Throughout the pandemic, all our assets remained operational and provided a reliable service across all the geographies where we operate, with no disruptions in availability or production due to COVID- 19. In terms of the Social dimension, last year we improved our key health and safety indicators for a sixth consecutive year, achieving “Lost Time Injury” and “Total-Record Incident” rates well below the average across all our geographies. Additionally, considering that some communities where we operate are suffering and will continue to suffer the consequences of COVID-19, we donated PPE and basic supplies to these local communities. In 2020, we also launched an employee climate survey designed to actively listen to our employees. Participation was high and the general engagement with the Company was 77%, above the average for similar companies. In terms of Governance, our Board has reviewed and approved all our ESG policies. In addition, as of December 31, 2020, all Board Committees only comprise independent members, two of 2 four Board Committees are chaired by women, and 25% of ethnic minorities are represented at Board level. The good progress we have made in terms of our ESG commitments has been reflected by ESG rating entities. In February 2021, Atlantica was rated by Sustainalytics on its ESG Risk Rating assessment as having the lowest ESG risk within both the renewable power production and the broader utilities industry. Based on its score, Atlantica sits in the top 1% of companies in Sustainalytics' global ratings universe. In January 2021, we were also rated with an “A-” by CDP. January 2021 also saw us included in the Global 100 Most Sustainable Companies Index by Corporate Knights, where we were ranked 12th (2nd in the power sector). Finally, Atlantica was listed in the Bloomberg Gender-Equality Index for the first time. Last, but not least, we are happy to report that over the past twelve months we have been able to leverage our positioning in ESG by closing over $1 billion in new Green Financing. This includes project and corporate debt – from the banking sector and capital markets – that complies with all Green Bond and Loan Principles. We are pleased to see that the financial industry is actively promoting ESG development by allocating credits to sustainable projects and companies. In summary, sustainability is a core part of our DNA and we are confident that we will keep on leading the transition to a sustainable, resilient and low-carbon economy, while continuing to protect our employees in the current COVID-19 pandemic. Santiago Seage Chief Executive Officer 3 Index Message from the CEO 1. Overview 2. Environment 1.1 Atlantica in Two Minutes 5 2.1 Environment 24 1.2 About This Report 7 2.2 Task Force on Climate Related 26 1.3 Our Business Model and 11 Financial Disclosures (TCFD) Strategy 2.3 Greenhouse Gas Emissions 35 1.4 Key Business Highlights 18 2.4 Water Management 40 U.N. Global Compact 20 2.5 Waste Management 46 2.6 Biodiversity 49 4. Governance 3. Social 3.1 Our Principles 58 4.1 Business Ethics 89 3.2 Asset-Management 60 4.2 Sustainability Governance 96 3.3 Supply Chain Management 62 4.3 Capital Structure 99 3.4 Human Capital 66 4.4 Board of Directors 100 3.5 Occupational Health and Safety 76 4.5 Incentivized Pay 121 3.6 Local Communities 82 4.6 Digital Transformation and 139 Data Security 4.7 Shareholder Engagement 142 www.atlantica.com 4 1. Overview 1.1. Atlantica in Two Minutes Our Sustainable Infrastructure Businesses Portfolio breakdown1 Renewable • Renewable energy energy • Other sustainable infrastructure assets including storage, 76% natural gas, transmission lines and water assets 1 2 31 Assets 16 Years ~$10 Billion >$1 Billion 100% contracted or Weighted average years Total Assets Revenue 2 3 regulated revenue contracted life remaining Core Geographies: North America, South America and certain EMEA regions Our Purpose Our purpose is to support the transition towards a more sustainable world by investing in and managing sustainable infrastructure, while creating long-term value for our shareholders, employees, suppliers, customers, business partners, local communities and debt investors. 2020 Selected Key Financial and Operational Metrics Financial Performance Operational Performance $1,013 Million $796 Million 3,244 GWh produced6 ▲0.2% vs 2019 ▼3.1% vs 2019 ▲0.2% vs 2019 Revenue Adjusted EBITDA inc. 1 Renewable energy unc. Aff. $201 Million $1.67 ≥100% Availability (%)7 ▲5.5% vs 2019 ▲6.4% vs 2019 Cash available for Dividends per share Other sustainable infrastructure assets distribution4 paid (in $)5 34567 1 Portfolio breakdown calculated based on the average Adjusted EBITDA including unconsolidated affiliates for the years ended December 31, 2020, 2019 and 2018. Adjusted EBITDA including unconsolidated affiliates is calculated as profit/(loss) for the period attributable to the parent company, after adding back loss/(profit) attributable to non- controlling interest from continued operations, income tax, share of profit/(loss) of associates carried under the equity method, finance expense net, depreciation, amortization and impairment charges of entities included in the Annual Consolidated Financial Statements and the Consolidated Condensed Interim Financial Statements. 2 Regulated in the case of the Spanish solar assets and Chile TL3 and non-contracted nor regulated in the case of Chile PV 1. 3 Represents weighted average years remaining as of March 31, 2021 including announced acquisitions some of which have not closed yet. 4 Cash Available for Distribution (CAFD): refer to cash distribution received by Atlantica Sustainable Infrastructure plc from its subsidiaries minus cash expenses of the Company, including debt service and general and administrative expenses. 5 Sum of the dividends per share paid to shareholders in each quarter of the year. 6 Includes curtailment in wind assets for which we receive compensation. 7 Availability refers to the time during which the asset was available to our client totally or partially, divided by contracted or budgeted availability, as applicable. 5 Environment GHG Emissions NEW Climate change target : Reduce our GHG 400 emission rate per unit of energy generated by - Verified 100% of Scope 1, CAGR 4% 300 2 and 3 70% by 2035 (vs. 2020 base) /KWh 200 - Increased CO2 emissions CO2e g 100 avoided vs. 2019 ▲15% ✓ Reduced hazardous waste vs. 2019 ▼75% 0 - Implemented GHG offset 8 Scope 1 and 2 ✓ Reused or recycled hazardous waste vs 2019▲16% 2018 2019 2020 mechanism rd ✓ 3 consecutive year withdrawing 50% or less of Climate change commitment: Maintain- over 80% of our water available under existing permits adjusted EBITDA including unconsolidated affiliates generated from low-carbon footprint assets8 ✓ Carbon pricing to evaluate investments Social Our Employees Health and Safety Metrics 9 Men 73% 456 27% Women LTIR CAGR 21% TRIR10 CAGR 19% 0.5 2.0 333 men ▲5% vs. 2019 ▲7% vs. 2019 123 women ▲13% vs. 2019 1.0 - 24% of women at the management level vs 21% in 2019 0.0 - Employee voluntary turnover rate ▼ 1% vs 2019 0.0 2018 2019 2020 2018 2019 2020 Other ✓ Community investments to mitigate COVID- 19 pandemic consequences Key ✓ Supply Chain Management verification Commitment: maintain a zero-accident culture Facts 100% internally, and >51% externally ✓ 6th consecutive year improving key health and safety indicators 910 Governance Only one class of shares.