Optimizing PV Solar Deployment on Hilly Terrain: Techno-Economic Analysis of Grading and Dynamic Mismatch Losses

After the 2011 Fukushima disaster, which led Japan to take all 54 of its nuclear plants offline for safety checks, the country made a strategic shift towards renewable energy. By the end of 2023, the total installed Photovoltaic (PV) solar capacity approached 87 GWp. PV installations peaked above 10 GW in 2014-2015, followed by a decline in the annual installation pace, stabilizing around 5 GW per year after 2017. Meanwhile, the kWh tariff decreased from 40 JPY under the Feed-In Tariff (FIT) in 2012 to 9.2 JPY in the 2024 Feed-In Premium (FIP) auction. This tariff pressure is pushing solar developers to reduce development and construction costs. One significant cost factor in Japan is civil work grading. While reducing this cost benefits the project capital expenditure (CAPEX), it introduces new technical challenges, including dynamic mismatch losses. In this paper, we will demonstrate how reducing civil work costs leads to dynamic mismatch losses, impacting the energy yield of a PV plant. Subsequently, we will propose a method to mitigate these dynamic mismatch losses with minimal impact on project finances.