🇰🇷 Solar Calculator South Korea
Enter your monthly electricity bill and city — get solar system size, government subsidy (up to 85% low-interest loan), SMP+REC income, KEPCO net metering savings, and payback period.
How to Use the South Korea Solar Calculator
Enter your monthly electricity bill in Korean Won (KRW), select your city, choose a system size in kWp, and optionally apply the government low-interest loan subsidy. Results update instantly with SMP income, REC income, net metering savings, payback, and 25-year projections.
Solar in South Korea — Key Numbers 2026
- Peak sun hours: 3.5 PSH (Seoul) to 4.3 PSH (Jeju) — Korea has moderate but consistent solar irradiance
- System cost: ₩2,000,000–₩3,000,000 per kWp (including installation)
- KEPCO electricity rate: ~₩150/kWh average residential (progressive tariff)
- SMP rate: ~₩80/kWh (System Marginal Price for exported energy)
- REC value: ~₩60/kWh equivalent (Renewable Energy Certificate income)
- Government subsidy: Up to 85% low-interest loan at 1% for 15 years
SMP + REC Income Explained
Korea's solar income has two components for exported electricity:
- SMP (System Marginal Price): The wholesale electricity price KEPCO pays for solar energy fed to the grid — typically ₩75–85/kWh. Fixed monthly by KEPCO based on market conditions.
- REC (Renewable Energy Certificates): Solar producers earn 1 REC per 1 MWh generated. RECs are sold to electricity suppliers meeting their RPS (Renewable Portfolio Standard) obligations. Small residential systems (≤100 kW) receive a weight multiplier of 1.2–1.5, increasing effective value.
Combined SMP + REC income provides ₩140/kWh equivalent for exported energy — close to the retail rate — making grid injection economically viable.
Government Subsidy Programs
Korea's Ministry of Trade, Industry and Energy (MOTIE) and KEA (Korea Energy Agency) run several programs:
- Low-interest solar loans: Up to 85% of system cost at 1% annual interest, repayable over 15 years. Available through participating banks and credit unions.
- Saemaeul Solar (새마을 태양광): Local government matching grants for community solar installations.
- RE100 corporate programs: Businesses can access additional incentives through Korea's RE100 voluntary program.
- Apartment complex solar: Apartment management associations can apply for collective solar installation subsidies covering up to 50% of costs.
Calculation Formula
Annual production (kWh) = System kWp × PSH × 365 × 0.80 (system efficiency) Self-consumed kWh = Annual production × 40% (net metering offset) Exported kWh = Annual production × 60% Annual benefit = Self-consumed × ₩150 + Exported × (₩80 SMP + ₩60 REC) System cost = kWp × ₩2,000,000–3,000,000 With subsidy: Upfront = 15% of cost; Annual loan = 85% × cost × 1%/15yr Payback = Upfront cost ÷ (Annual benefit − Annual loan payment)
Worked Example — Busan 5 kWp
Busan: 4.0 PSH. System: 5 kWp at ₩2,500,000/kWp = ₩12,500,000 total.
- Annual production: 5 × 4.0 × 365 × 0.80 = 5,840 kWh/yr
- Self-consumed (40%): 2,336 kWh → ₩350,400/yr saved
- Exported (60%): 3,504 kWh × ₩140 = ₩490,560/yr
- Total benefit: ₩840,960/yr
- With 85% loan: Upfront = ₩1,875,000; Annual loan = ~₩709,000/yr
- Net annual benefit: ₩840,960 − ₩709,000 = ₩131,960/yr
- Payback on cash outlay: ₩1,875,000 ÷ ₩131,960 = 14.2 years
- Without subsidy: ₩12,500,000 ÷ ₩840,960 = 14.9 years
- 25-year savings: ₩840,960 × 25 − ₩12,500,000 = ₩8,524,000
FAQ
Is solar worth it in South Korea?
Yes, especially in southern cities like Busan, Daegu, and Jeju. Korea's progressive electricity tariff (heavy users pay ₩200+/kWh) makes solar highly valuable for high-consumption households. With government low-interest loans, upfront costs are minimal. Typical payback: 10–15 years, with 25-year savings of ₩5–20 million.
Can apartments install solar panels in Korea?
Individual apartment units typically can't install rooftop solar due to shared roof ownership. However, apartment complexes can install collective solar systems through the management association, applying for KEA subsidies covering up to 50% of costs. Balcony solar (베란다 태양광) for small panels is also growing, though output is limited.
What is the KEPCO net metering process in Korea?
KEPCO's net metering (상계거래) allows residential solar owners to offset their electricity bill with solar production. Surplus exported to the grid is credited at SMP rates. You need to sign a net metering agreement (상계거래 계약) with KEPCO before installation. The process takes 4–8 weeks and requires an RPS-certified installer.
Are there tax benefits for solar in Korea?
Korea provides VAT exemption on solar panels and installation equipment. Additionally, corporate solar investments qualify for accelerated depreciation and investment tax credits under the Restriction of Special Taxation Act. Residential homeowners don't receive direct income tax benefits, but the subsidized loan programs are effectively equivalent to grants.
How does Korea's REC system work for small solar?
Systems under 100 kW earn RECs at a weight of 1.2 (general) to 1.5 (building-integrated). One REC = 1 MWh × weight factor. For a 5 kWp system producing 5,840 kWh/year with 1.2 weight: you earn ~7 RECs/year. RECs are sold monthly through the KPX (Korea Power Exchange) at market prices ranging ₩40,000–80,000 per REC.
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