Filed Pursuant to Rule 424(b)(3)
Registration No. 333-259706

SUPPLEMENT NO. 2

(to Prospectus dated October 5, 2021)

ReNew Energy Global Plc

PRIMARY OFFERING OF

20,226,773 CLASS A ORDINARY SHARES

SECONDARY OFFERING OF

271,479,759 CLASS A ORDINARY SHARES,

118,363,766 CLASS C ORDINARY SHARES,

7,026,807 WARRANTS TO PURCHASE CLASS A ORDINARY SHARES, AND

7,671,581 CLASS A ORDINARY SHARES UNDERLYING WARRANTS

This prospectus supplement updates, amends and supplements the prospectus dated October 5, 2021 (as supplemented or amended from time to time, the “Prospectus”) (Registration No. 333-259706) , covering the issuance from time to time by ReNew Energy Global plc, a public limited company organized under the laws of England & Wales, or “we”, “our”, the “Company”, of up to 20,226,773 Class A Ordinary Shares, nominal value of $0.0001, or the “Class A Ordinary Shares,” including 7,026,807 Class A Ordinary Shares issuable upon the exercise of Warrants that are held by RMG Sponsor II, LLC, or “RMG Sponsor II”, or “Private Warrants” and 11,499,966 Class A Ordinary Shares issuable upon the exercise of Warrants held by the public warrant holders, or “Public Warrants”. The Prospectus also relates to the resale, from time to time, by the selling securityholders named therein, or the “Selling Securityholders”, or their pledgees, donees, transferees, or other successors in interest, of (a) up to 271,479,759 Class A Ordinary Shares, (b) up to 7,026,807 Private Warrants; (c) up to 118,363,766 class C ordinary shares having a nominal value of $0.0001 per share, or “Class C Ordinary Shares”, and (d) up to 7,671,581 Class A Ordinary Shares issuable upon exercises of the Private Warrants.

This supplement is not complete without the Prospectus. You should read this supplement in conjunction with the Prospectus. This supplement is not complete without, and may not be utilized except in connection with, the Prospectus, including any amendments or supplements thereto.

This prospectus supplement is being filed to update, amend and supplement the information and key operating metrics included in the Prospectus with information on our six months ended and three months ended September 30, 2021 financial results, which is set forth below.

Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 7 of the Prospectus and other risk factors contained in the documents incorporated by reference therein for a discussion of information that should be considered in connection with an investment in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is November 19, 2021.

Key Operating Metrics:

As of September 30, 2021, our portfolio consisted of 10,217 MWs compared to 9,958 MWs on September 30, 2020. As of September 30, 2021, commissioned capacity was 6,315 MW of which 3,653 MWs were wind, 2,563 MWs were solar and 99 MWs were hydro. We commissioned 63 MWs of wind and 451 MWs of solar capacity during Q2 FY22 against 0 MWs of wind and 10 MWs of solar in Q2 FY21. We commissioned 63 MWs of wind and 556 MWs of solar capacity during the H1 FY22 against 0 MWs of wind and 10 MWs of solar in H1 FY21.

Electricity sold

Total electricity sold for H1 FY22 was 7,558 million kWh, an increase of 1,385 million kWh, or 22.4%, over H1 FY21. Total electricity sold for Q2 FY22 was 4,003 million kWh, an increase of 969 million kWh or 31.9%, over Q2 FY21.

Electricity sold for H1 FY22 for wind assets was 5,304 million kWh, an increase of 1,317 million kWh, or 33.0%, over H1 FY21. Electricity sold for H1 FY22 for solar assets was 2,184 million kWh, a decrease of 2 million kWh or 0.1%, over H1 FY21 due to lower radiation levels than the prior year. Electricity sold for H1 FY22 for hydro assets was 70 million kWh. The hydro assets were acquired in the month of August 2021.

Electricity sold for Q2 FY22 for wind assets was 2,888 million kWh, an increase of 846 million kWh or 41.5%, over Q2 FY21. Electricity sold for Q2 FY22 for solar assets was 1,045 million kWh, an increase of 53 million kWh or 5.3%, over Q2 FY21. Electricity sold for Q2 FY22 for hydro assets was 70 million kWh. The hydro assets were acquired in the month of August 2021.

Plant Load Factor

Our weighted average Plant Load Factor (“PLF”) for H1 FY22 for wind assets was 33.6%, compared to 27.8%, for H1 FY21 due to an improvement in wind resource. The PLF for solar assets H1 FY22 was 22.6% compared to 22.8% for H1 FY21.

Our weighted average PLF for Q2 FY22 for wind assets was 36.3%, compared to 28.1% for Q2 FY21. The PLF for solar assets for Q2 FY22 was 20.4% compared to 20.6% for Q2 FY21.

ESG

We released our first sustainability report on September 15, 2021 which reflects on our ESG performance for FY21. The report was prepared in line with the Global Reporting Initiative’s (GRI) sustainability reporting standards and was assured by DNV GL Business Assurance India Private Limited. By generating power through clean energy, we believe that we have helped the power sector avoid 1.1% of its greenhouse gases emissions. Our avoided emissions were more than 200 times that of its scope 1 & 2 emissions for the financial year 2020-21. We have been critically monitoring our water footprint and has saved over 66,000 kilolitres of water by deploying robotic dry cleaning of solar panels.

We have received the Great Place to Work recognition twice and has been recognized among the best employers in India in the category this past year by Great Place to Work. FORBES. Financial contributions towards energy access, water conservation, COVID-19 relief, women empowerment, and community development helped over 400,000 people across 200+ villages in nine states.

Acquisitions

We completed the acquisition of 99 MWs of hydro assets on August 30, 2021 and the acquisition of 260 MWs of solar assets in the state of Telangana on November 4, 2021.

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Interim Financial Information

RENEW ENERGY GLOBAL PLC

INTERIM CONDENSED CONSOLIDATED STATEMENT OF FINANCIAL POSITION

(INR and US$ amounts in millions, except share and par value data)

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RENEW ENERGY GLOBAL PLC

INTERIM CONDENSED CONSOLIDATED STATEMENT OF PROFIT OR LOSS

(INR and US$ amounts in millions, except share and par value data)

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RENEW ENERGY GLOBAL PLC

INTERIM CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(INR and US$ amounts in millions)

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Non-IFRS Measures

Adjusted EBITDA

Adjusted EBITDA is a non- IFRS financial measure. We present Adjusted EBITDA as a supplemental measure of its performance. This measurement is not recognized in accordance with IFRS and should not be viewed as an alternative to IFRS measures of performance. The presentation of Adjusted EBITDA should not be construed as an inference that our future results will be unaffected by unusual or non-recurring items.

We define Adjusted EBITDA as loss (income) plus (a) income tax expense, (b) finance costs, (c) depreciation and amortization, (d) share in loss of jointly controlled entities, (e) charges and impairments, such as listing expenses share based payment expense and others related to listing, less (f) finance income. We believe Adjusted EBITDA is useful to investors in assessing our ongoing financial performance and provides improved comparability on a like to like basis between periods through the exclusion of certain items that management believes are not indicative of our operational profitability and that may obscure underlying business results and trends. However, this measure should not be considered in isolation or viewed as a substitute for net income or other measures of performance determined in accordance with IFRS. Moreover, Adjusted EBITDA as used herein is not necessarily comparable to other similarly titled measures of other companies due to potential inconsistencies in the methods of calculation.

Our management believes this measure is useful to compare general operating performance from period to period and to make certain related management decisions. Adjusted EBITDA is also used by securities analysts, lenders and others in their evaluation of different companies because it excludes certain items that can vary widely across different industries or among companies within the same industry. For example, interest expense can be highly dependent on our capital structure, debt levels and credit ratings. Therefore, the impact of interest expense on earnings can vary significantly among companies. In addition, the tax positions of companies can vary because of their differing abilities to take advantage of tax benefits and because of the tax policies of the various jurisdictions in which they operate. As a result, effective tax rates and tax expense can vary considerably among companies.

Adjusted EBITDA has limitations as an analytical tool, and you should not consider it in isolation or as a substitute for analysis of our results as reported under IFRS. Some of these limitations include:

Investors are encouraged to evaluate each adjustment and the reasons we consider it appropriate for supplemental analysis.

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Reconciliation of Net Loss to Adjusted EBITDA for the periods indicated:

Cash flows to equity (cfe):

CFe is a Non-IFRS financial measure. We present CFe as a supplemental measure of our performance. This measurement is not recognized in accordance with IFRS and should not be viewed as an alternative to IFRS measures of performance. The presentation of CFe should not be construed as an inference that our future results will be unaffected by unusual or non-recurring items.

We define CFe as EBITDA add non cash expense, less interest expense paid, tax paid/(refund) and normalized loan repayments. Normalized loan repayments are repayment of scheduled payments as per the loan agreement. Adhoc payments and refinancing are not included in normalized loan repayments. The definition also excludes changes in net working capital and investing activities.

We believe IFRS metrics, such as net income (loss) and cash from operating activities, do not provide the same level of visibility into the performance and prospects of our operating business as a result of the long term capital-intensive nature of our businesses, non-cash depreciation and amortization, cash used for debt servicing as well as investments and costs related to the growth of our business.

Our business owns high-value, long-lived assets capable of generating substantial Cash Flows to Equity over time.

We believe that external consumers of our financial statements, including investors and research analysts, use CFe both to assess ReNew Power’s performance and as an indicator of its success in generating an attractive risk-adjusted total return, assess the value of the business and the platform. This has been a widely used metric by analysts to value our business, and hence we believe this will better help potential investors in analysing the cash generation from our operating assets.

We have disclosed CFe for our operational assets on a consolidated basis, which is not our cash from operations on a consolidated basis. We believe CFe supplements IFRS results to provide a more complete understanding of the financial and operating performance of our businesses than would not otherwise be achieved using IFRS results alone. CFe should be used as a supplemental measure and not in lieu of our financial results reported under IFRS.

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Reconciliation of Net Loss to CFe for the periods indicated:

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