SolarSquare, an Indian rooftop solar startup that helps households and housing societies adopt solar power, is in advanced talks to raise fresh capital after securing India’s largest solar venture investment in December 2024, TechCrunch has learned.

B Capital and Lightspeed Venture Partners are set to co-lead the Series C round, which could value SolarSquare at between $450 million and $500 million and bring in $55 million to $60 million in new investment, according to multiple people familiar with the matter. That would represent more than a doubling of SolarSquare’s valuation in roughly 18 months — a sign of how rapidly investor conviction is building around India’s residential solar market.

Lightspeed Venture Partners previously led SolarSquare’s $40 million Series B round at around a $200 million post-money valuation in December 2024. This time, according to a source, it’s investing through its growth fund, which has backed names such as Razorpay — India’s leading digital payments platform — and Zepto, the fast-delivery startup.

Existing investor Elevation Capital is also expected to participate in the deal, which is currently in advanced stages and is expected to close next month. The terms could still change as the financing has not yet been finalized. SolarSquare has raised $61.1 million in equity financing to date, per the startup data platform Tracxn.

India has set a target of achieving 500 gigawatts of renewable energy capacity by 2030, with solar expected to contribute more than half of that total. The country became the world’s third-largest solar power producer in 2025, trailing only China and the U.S. Its cumulative installed solar capacity has surged from about 3 GW in 2014 to more than 150 GW in 2026, aided partly by government incentives and subsidy schemes aimed at accelerating rooftop solar adoption.

Mumbai-headquartered SolarSquare, founded in 2015, is positioning itself as a full-stack residential solar platform in a market that remains highly fragmented, dominated by small local installers and dealer networks tied to component manufacturers such as Tata Power, Waaree Energies, Luminous Power Technologies, and Exide Industries. The startup designs, installs, and maintains rooftop solar systems for homes, housing societies (the apartment complexes and gated communities common across urban India), and enterprises, and has installed more than 150 megawatts of solar capacity with a presence across 29 cities in nine states, per its website.

SolarSquare has powered nearly 50,000 homes and around 400 housing societies, according to a source. The startup has also deployed rooftop solar systems for large enterprises including Swiggy, Zepto, and iD Fresh Food.

Residential customers and housing societies now account for a majority of SolarSquare’s business, according to people familiar with the startup’s operations, as the startup has increasingly scaled back lower-margin industrial rooftop solar projects in recent years.

The startup has crossed an annualized revenue run rate of more than ₹10 billion (around $104 million) across homes and housing societies combined, according to a source familiar with the matter. It also aims to reach 200 megawatts in its residential solar portfolio this year, the source added.

SolarSquare declined to comment. B Capital, Lightspeed Venture Partners, and Elevation Capital did not respond to requests for comment.