v3.26.1
Cover Page - shares
 3 Months Ended
Mar. 31, 2026
May 07, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
Document Transition Report false  
Entity File Number 001-40272  
Entity Registrant Name OPAL FUELS INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 98-1578357  
Entity Address, Address Line One One North Lexington Avenue  
Entity Address, Address Line Two Suite 1450  
Entity Address, City or Town White Plains  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10601  
City Area Code 914  
Local Phone Number 705-4000  
Title of 12(b) Security Class A Common Stock, par value $0.0001 per share  
Trading Symbol OPAL  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Central Index Key 0001842279  
Amendment Flag false  
Document FY Focus 2026  
Document Fiscal Period Focus Q1  
Current Fiscal Year End Date --12-31  
Common Class A    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   30,357,544
Common Class B    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   121,500,000
Common Class D    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   22,899,037