How much does solar cost in Japan in 2026?

Residential solar in Japan costs approximately ¥200,000–400,000 per kWp installed in 2026. A typical 4kWp system costs ¥800,000–1,600,000. Home battery storage adds ¥800,000–1,500,000 before subsidies. Tokyo's ¥37,000/kWh battery subsidy reduces this significantly. Total payback for a 5kWp grid-tied system is typically 8–12 years.

What is the Tokyo solar ordinance?

From April 2025, Tokyo requires solar panels on new residential buildings under 2,000m² built by registered developers. The mandate covers approximately 50% of new Tokyo construction and requires 2–4kWp minimum depending on floor area. Tokyo offers additional subsidies to offset compliance costs and a ¥37,000/kWh battery storage subsidy.

🇯🇵 Solar Calculator Japan

Enter your monthly electricity bill and city — get solar system size, panel count, FIT income at ¥16/kWh, self-consumption savings at ¥30/kWh, battery subsidy, and payback period.

Your electricity details

Monthly electricity bill?

¥JPY

City?

Roof area?

m²

Building type?

Incentive mode?

Add home battery?

Recommended solar system — Japan

4.5 kWp system — 12 × 400W panels

Monthly kWh usage400 kWh/mo

Annual solar production4,868 kWh/yr

Self-consumption savings¥102,236/yr

FIT export income (¥16/kWh)¥23,368/yr

Total annual benefit¥125,604/yr

System cost estimate¥900,000 – ¥1,800,000

Total installed cost¥1,350,000

Payback period10.7 years

25-year net savings¥1,790,099

Link copied to clipboard

How to Use This Calculator

Enter your monthly bill and city

Enter your average monthly electricity bill in Japanese Yen (JPY). The calculator uses a blended retail rate of ¥30/kWh to estimate your monthly consumption. Select your city — Okinawa gets the most solar radiation (4.8 PSH) while Sapporo gets the least (3.5 PSH). Tokyo and Osaka fall in the mid range at 3.8–4.0 PSH.

Set roof area and building type

Enter your south-facing or usable roof area in m². The calculator uses 65% as the installable fraction to account for setbacks, obstructions, and non-south-facing sections. If your home is a new build in Tokyo subject to the 2025 solar ordinance, select "New build (Tokyo mandate)" — this flags the mandatory requirement for homes under 2,000m² built by registered builders.

Choose incentive mode and battery

Japan offers two main strategies: self-consumption priority maximizes savings against the ¥30/kWh retail tariff; FIT mode earns ¥16/kWh for exported electricity under the Feed-in Tariff scheme (for systems ≤10kWp). Enabling the battery toggle adds home battery storage — Tokyo's subsidy of ¥37,000/kWh significantly reduces battery cost.

The Formula

Monthly kWh = Monthly Bill ÷ ¥30/kWh (blended retail rate) Daily kWh = Monthly kWh ÷ 30 System kWp (from consumption) = Daily kWh ÷ (PSH × 0.78 efficiency) System kWp (from roof) = Roof m² × 0.65 × 400W ÷ 1000 Usable kWp = min(consumption limit, roof limit) Annual production = kWp × PSH × 365 × 0.78 Self-consumption savings = Annual kWh × 70% × ¥30/kWh FIT income = Annual kWh × 30% × ¥16/kWh Battery subsidy = Battery kWh × ¥37,000 (Tokyo) Payback = Total cost ÷ Annual benefit

The 78% system efficiency accounts for inverter losses (~4%), cable losses (~2%), soiling (~3%), and temperature derating (~3%). Japan's climate — especially typhoon regions in Okinawa and snowfall in Sapporo — requires robust mounting hardware that affects installed cost per kWp. The FIT rate of ¥16/kWh applies to new applications for systems ≤10kWp in fiscal year 2026.

Example

Keiko — Osaka home, 5kWp, FIT mode

Keiko pays ¥18,000/month and has a 35m² south-facing roof in Osaka. She installs a 5kWp system and signs up for FIT to export surplus electricity.

Monthly bill¥18,000

City / PSHOsaka, 4.0 PSH

Roof area35 m²

ModeFIT export

Result

System size5.0 kWp

Panels13 × 400W

Annual production~5,694 kWh/yr

Self-consumption savings~¥119,574/yr

FIT income~¥27,331/yr

System cost~¥1,500,000

Payback~10.2 years

25-year net savings~¥2,170,000

Japan's relatively moderate electricity prices compared to its solar resource mean payback periods of 8–12 years are typical for grid-tied systems. Self-consumption mode is increasingly preferred as retail rates exceed ¥30/kWh while FIT rates decline. Adding battery storage shortens the self-consumption payback by capturing evening demand.

FAQ

Is solar worth it in Japan? ▼

Yes, especially in high-sunshine regions like Okinawa, Nagoya, and Osaka. Japan's retail electricity prices (¥26–35/kWh) create strong self-consumption savings. Typical residential 4–6kWp systems pay back in 8–12 years with 25-year system life. The Tokyo solar ordinance for new builds means solar is increasingly standard in new construction. Combined with battery storage and Tokyo's ¥37,000/kWh subsidy, net-zero homes are financially viable.

What is the FIT rate in Japan for 2026? ▼

Japan's Feed-in Tariff (FIT) for residential solar systems ≤10kWp is ¥16/kWh for new applications in fiscal year 2026, paid for 10 years. This rate has declined steadily from ¥48/kWh in 2012 as solar costs fell. After the 10-year FIT period, surplus electricity is sold to the grid at spot market rates (typically ¥7–10/kWh). Self-consumption has become more financially attractive than FIT export as retail electricity prices exceed ¥30/kWh.

What is the Tokyo solar panel mandate? ▼

From April 2025, Tokyo's solar ordinance requires solar panels on new residential buildings under 2,000m² constructed by housing developers with annual sales of 2 billion yen or more. It covers roughly 50% of new construction. The mandate requires minimum system sizes based on building floor area: approximately 2–4kWp for detached homes. Builders must also meet insulation standards. Tokyo provides additional subsidies to support compliance costs.

Does Tokyo subsidize home batteries? ▼

Yes. Tokyo Metropolitan Government offers a subsidy of ¥37,000/kWh for home battery storage systems, up to specified capacity limits. This subsidy significantly reduces battery payback periods. Additional subsidies exist at the national level and from some utility companies. A 10kWh home battery with Tokyo subsidy receives ¥370,000 off the purchase price, reducing effective battery cost from ~¥1,200,000 to ~¥830,000. Other prefectures offer similar programs.

Which city in Japan gets the most solar energy? ▼

Okinawa (4.8 PSH) receives the most solar radiation in Japan — roughly 37% more than Sapporo. Nagoya (4.2 PSH) and Osaka/Fukuoka (4.0 PSH) are strong mainland performers. Tokyo (3.8 PSH) is slightly below the mainland average. Sapporo (3.5 PSH) has the lowest irradiance due to high latitude and significant snowfall that can cover panels in winter. Despite lower irradiance, all Japanese cities produce viable solar economics when self-consumption rates are maximized.

Related Calculators

Embed This Calculator

Free to embed on your website. Just copy this code:

<iframe src="https://solarsizecalculator.com/jp/solar-calculator-japan"
  width="100%" height="700" frameborder="0"
  title="Japan Solar Calculator"></iframe>