The refinancing of GSSG Solar and Voltaiyo’s 104 MW Jupiter Portfolio comes at a time when Japan’s first-generation feed-in-tariff (FIT) projects are nearing the end of guaranteed rates, forcing owners to reassess their revenue strategies in a changing post-FIT market.
Japan’s maturing solar sector is entering a decisive post-FIT phase as GSSG Solar and Voltaiyo KK secure the refinancing of a 104 MW portfolio of existing FIT projects with SBI Shinsei Bank – a deal that underlines lenders’ confidence in well-managed assets even as guaranteed rates begin to expire.
The 104 MW portfolio consists of eight operational projects spread across four grid areas on the islands of Honshu and Kyushu. Colorado-based GSSG Solar is the transaction sponsor; Voltaiyo KK is the Tokyo-based operating partner. The deal marks the sixth time that GSSG Solar has acted as a sponsor for a loan from SBI Shinsei Bank.
Adrian Archambault, valuation partner at GSSG Solar, says lenders’ underwriting approach to FIT assets approaching maturity has not fundamentally changed, but operational track record now carries more weight. “Operational projects have the opportunity to benefit from actual production data and operational execution,” he said pv magazine.
GSSG Solar CEO Tomakin Archambault said the refinancing marks “an important milestone” for the partnership, reflecting common interests and approaches to investing in the decarbonization of Japan’s energy sector.
Industry estimates based on IEA-PVPS data indicate that Japan will reach approximately 100 GW of cumulative solar capacity by the end of 2024. Fiscal year 2026 is the last year of auction-based support for ground-mounted commercial solar above 250 kW, and no further auctions are planned from fiscal year 2027, according to summaries coordinated with Japan’s Ministry of Economy, Trade and Industry (METI). As guaranteed rates expire, projects face a significant revenue gap relative to wholesale market prices.
Repowering is emerging as an option for owners of first-generation FIT power plants. Masaya Ishida, director of the Tokyo-based Renewable Energy Institute (REI), said most of the modules installed under Japan’s early FIT program are designed for 20 years of operation and typically generate sufficient revenue without replacement. He said repowering can be cost-efficient for all project sizes because developers can reuse existing land, mounting structures and network connections with new, cheaper modules. Ishida described the opportunity to generate new energy as “a big market,” driven in part by growing corporate demand for new renewable energy supplies.
Adrian Archambault said the Japanese market is shifting in ways that will support asset values post-FIT, pointing to rising energy costs due to Japan’s dependence on imported fuel and growing corporate and trader demand for solar power. GSSG maintains the opportunity for monetization on the Jupiter Portfolio, which takes into account merchant exposure, participation in feed-in incentives and corporate energy purchase agreements.
GSSG Solar Japan Asset Management currently manages 223 MW of solar energy in Japan, outside the Jupiter Portfolio. The company said the refinancing model is relationship-driven and applicable to the broader fleet.
Voltaiyo, which recently rebranded as a standalone company under the Obton umbrella and entered into a capital relationship with ICG, said the transaction reflects its origination capabilities and international capital relationships. Voltaiyo CEO Mikkel Berthelsen said the deal reflects “the origination capabilities of the Voltaiyo team” and its deep international capital relationships.
Japan’s FIT program has been central to GSSG Solar’s Japanese strategy since the company completed its first Shinsei Bank financing for a 47 MW solar project in Suwa, Nagano Prefecture in May 2016. The refinancing of the Jupiter Portfolio marks the sixth transaction the two institutions have completed together.
According to RTS Corp. estimates. Japan added between 5.8 GW and 6 GW of solar in 2025, pushing cumulative capacity past 100 GW – a market that was largely built on FIT-era investments and is now facing a structural revenue transition as guaranteed rates give way to merchant and corporate PPA exposure.
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