Korean solar industry urges higher module-to-inverter ratio for PV
The Korean renewable energy industry urges revising solar PV installation standards, specifically the 105% DC module capacity limit relative to AC inverter output. This proposal, discussed on September 30th, aims to boost generation during low sunlight without increasing grid connection capacity.
Our take
How could Korea's solar PV installation rules change to boost generation efficiency?
The proposed revision to Korea's 'New and Renewable Energy Equipment Support Guidelines' would decouple solar PV module capacity from inverter output for grid connection, potentially allowing developers to install up to 150% DC module capacity per AC inverter without increasing grid burden.
Currently, the 105% DC module-to-AC inverter limit underutilizes inverter capacity during periods of weak sunlight, as modules produce less power. Increasing this ratio would allow for greater energy capture during these times, boosting overall annual generation. Since inverters automatically cap output at their rated AC capacity, the maximum power injected into the grid remains unchanged, thereby avoiding additional grid reinforcement costs.
What the source says
- The renewable energy industry proposes distinguishing DC module capacity from AC inverter output for management purposes.
- The industry advocates for managing grid connection capacity based on the inverter's AC output, rather than the module's DC capacity.
- The current 105% module-to-inverter ratio limit prevents increasing generation during weak sunlight, even when inverter capacity is underutilized.
- solar industry official A solar industry official stated that if module output exceeds the inverter's AC processing limit, the inverter automatically limits output, ensuring the AC output to the grid remains within its allowed range.
- solar expert A solar expert stated that increasing the module-to-inverter ratio would not burden grid reinforcement, improve inverter utilization, increase annual generation, boost Korea's overall solar generation share, and lower solar generation costs.
- Modifying module capacity under current regulations requires changing the entire power business permit.
- Overseas markets, including the United States, Germany, and Japan, maintain more flexible module-to-inverter ratio standards for large-scale solar power plants compared to Korea's current limit.
- Discussions on improving the current system have not progressed due to cautious views regarding the potential impact of module expansion on grid operations.
For investors — If adopted, investors and operators could increase annual energy yield from existing solar PV sites by deploying more modules per inverter, optimizing asset utilization without incurring additional grid connection costs or requiring new permits.
Watch: Progress on the Korean government's review of solar PV installation standards and capacity calculation methods, particularly regarding the module-to-inverter ratio.
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