Study on Mitigating Power Fluctuation of Variable Renewable Energy toward Reducing CO₂ Emission in Hokkaido

Abstract

Wind and solar power generation is gathering attention as the solutions of global warming, but not being introduced in large scale because of its unstable output. This paper analyzes the mitigating power fluctuation of these variable renewable energy toward reducing CO₂ emission in Hokkaido. The analysis takes into account wind and solar data in one-hour interval for a year, and calculates annual total cost by linear programming. Conventional analysis specified renewable energy share of annual total electric power demand, and new analysis method defines CO₂ reduction rate. The result shows that it is possible to reduce 60% CO₂ Emission from actual value in 2013 without so large increase in total cost. However, surplus power and total cost increase due to power fluctuation of renewable energy in case of reducing more than 70%. There is difference between conventional and new analysis methods, and it indicates needing extra cost on the assumption of expanding renewable energy share compared with optimal composition with same CO₂ reduction rate. Considering the situation with charging electric vehicles from power grid, we found that the electric vehicles are effective for usage of surplus power.