Residential solar power is no longer all Chinese-made – don’t be afraid to accelerate rooftop installations

Global Sustainability Standards Board (GSSB) Board Member
GHG Protocol Technical Working Group (TWG) Members

Zeroboard Research Institute Director Tomoo Machiba

As I proceed with renovating an old house I purchased, I am considering installing solar power generation in order to become as Energy self-sufficient as possible.However, when I started to consider which solar panels to use, I was surprised to find that there were quite a few manufacturers.

Regarding solar power generation, in addition to concerns about disasters and landscape destruction, such as landslides caused by panels installed on slopes, criticism of China has recently increased, with comments such as, "The renewable energy surcharge will increase the burden on the public while benefiting China" *1 and "Connecting Chinese-made equipment to the power grid will increase the likelihood of it becoming a target for cyber attacks" * 2, and even opposition parties have begun to express caution about the expansion of renewable energy. *3 Indeed, Chinese manufacturers, including Jinko, JA, Trina, LONGi, and Tongwei, monopolize 8 of the top 9 global panel shipments (as of the first half of 2024) *4 .

However, when we look only at domestic residential use, the AI ​​generator (Google Gemini) answers, "Even for residential solar panels, the proportion of Chinese-made panels is thought to be very high," but in reality, this does not seem to be the case. The residential panel market is said to be centered around two companies, Choshu Industry and Hanwha Japan, with domestic and foreign manufacturers competing fiercely.

Choshu Industry, based in Sanyo-Onoda City, Yamaguchi Prefecture, started out as a water heater manufacturer. In 1998, it entered the solar power generation business, working as an OEM for Panasonic Corporation(then Sanyo Electric)'s high-performance HIT panels. It now operates its own domestic factories, with an integrated production system for everything from wafers, the raw material for solar cells, to modules. The company's ability to comply with domestic subsidies and its ability to offer small, square, and trapezoidal panels, maximizing installation capacity even on narrow, complex urban roofs, has led to increased sales. According to the contract sales figures of Solar Partners' installation dealer network, Choshu Sangyo boasts an overwhelming two-thirds share of Industry, particularly in Tokyo, when installing systems in combination with storage batteries (Figure 1). It appears that this domestic manufacturer is greatly benefiting from the city's solar power subsidies. * 5

Figure 1: Share of solar panels installed in homes in Tokyo by manufacturer (2024)
Source: Solar Partners, "Solar Power Generation Panel Manufacturer Comparison Ranking by Category: 2025 Residential Solar Panel Popularity Share Ranking (Tokyo)," published June 17, 2025 * 6

Hanwha Japan is the Japanese subsidiary of a South Korean conglomerate, which acquired Germany's Q Cells to enter the solar power generation business and entered the Japanese market in 2012, selling more than 15 homes to date. It offers its original brand, Re.RISE®, for the Japanese market, including residential modules that have high solar-to-electricity conversion efficiency and can be mounted on narrow, complex roofs * 7 . Following this is Canadian Solar, the only company outside of China to rank among the world's top panel shipments. It entered the domestic market in 2009 and boasts high performance yet low prices thanks to its overwhelming production volume and R&D costs * 8 .

Sharp, Panasonic Corporation , Kyocera, and other major companies that once dominated the global market, as well as Solar Solar Frontier K.K., a subsidiary of Showa Shell Sekiyu (now Idemitsu Kosan) and the only Japanese Manufacturing of non-silicon thin-film panels, are still active today. Kyocera has reportedly withdrawn from its own factory in China and is now producing residential panels in Yasu City, Shiga Prefecture * 9 . Panasonic Corporation, after withdrawing from in-house production in 2021, continues to sell panels through OEM supplies from Canadian Solar * 10 . Other companies in the market include Japanese companies such as Exsol, Next Energy, the emerging DMM Energy, and Looop, as well as the US-based Maxeon. In other words, if you are installing solar power generation through a local home builder, power Company, or construction company (unless you import them yourself via the internet, for example), it is unlikely that you will encounter Chinese solar panels (Figure 2).

Figure 2: Proportion of solar panels installed in homes by manufacturer (sales results of Solar Partners' construction dealer network; black outline indicates proportion of Japanese manufacturers) * 11
Source: Solar Partners, "Should you avoid Chinese-made solar panels in 2025? Explaining the performance and price differences between domestically produced and overseas solar panels. Domestically produced panels account for 5% of the Japanese residential solar panel market," published June 10, 2025

A power conditioner (PSU) is essential for installing solar panels to convert direct current (DC) to alternating current (AC). There have been reports of suspicions that Chinese-made inverters contain communications equipment that allows for remote Action* 12 , but with the exception of Germany's SMA and China's Huawei, domestic manufacturers appear to be the mainstream * 13 . Even when installing storage batteries to provide power during rainy days, nights, or disasters when power generation is not possible, with the exception of Tesla, Canadian Solar, and Huawei, many domestic manufacturers' products are used * 14 .

It's true that even domestic manufacturers often source their components and Manufacturing overseas, particularly in China. According to the latest statistics from the Japan Photovoltaic Energy Association, 86% of Japanese companies' domestic shipments of solar modules, including those for Industry and mega-solar projects, are produced overseas * 15 . The International Energy Agency (IEA) has recommended diversifying production countries, citing China's expected share of the main Manufacturing stage of solar panels as exceeding 8% by 2022, creating an imbalance in the supply chain. In particular, as of 21, China accounts for 79% of the world's production capacity for polysilicon, a key material, with 42% of that production located in the Xinjiang Uyghur Autonomous Region, where human rights violations, including the oppression of the Uighur ethnic group, are feared * 16 .

However, we must not forget that there are various options, as shown above. Some products are produced in Japan or overseas, other than China, and it may be possible to request disclosure of the country of production and thorough due diligence from Japanese, Western, or other manufacturers. When I actually looked into it this time, I realized that I too had been misled by the skeptical information about renewable energy that was flooding the Internet.

Currently, only 6.3% of households nationwide (11.7% for detached houses) use solar power generation. * 17 The 7 Strategic Energy Plan calls for renewable energy to account for 5% of the power generation mix by fiscal year 2040, with solar power in particular reaching 22% .* 18 To achieve this, significant expansion of solar panel installations on existing flat surfaces, such as rooftops, farmland, abandoned farmland, former factory sites, and waterfront areas, is essential. While the price of solar power generated under the Feed-in Tariff (FIT) system continues to decline year after year, * 19 focusing on self-consumption, such as by installing an Ohisama EcoCute, offers significant economic benefits. Those who haven't yet done so should not hesitate to do so. * 20 Starting in April 2025, installation of solar panels on newly constructed buildings will be mandatory in Tokyo and Kawasaki City. * 21 We hope to see measures to expand this practice in other regions.