The Duck Curve Normalized: How Solar Power Is Reshaping JEPX Intraday Price Structure

What Is the Duck Curve?

The "duck curve" describes the shape of net load (total demand minus solar generation) plotted over a 24-hour period. As solar generation peaks around midday, net load drops sharply, forming the "belly" of the duck. When the sun sets and demand rebounds rapidly, the steep ramp creates the "neck."

Trading Opportunities and Challenges

The normalization of the duck curve creates significant arbitrage opportunities but also introduces new risk management challenges. For traders with battery energy storage systems (BESS) or pumped hydro assets, intraday spread arbitrage — buying cheap at midday and selling into the evening peak — is the most direct profit strategy.

"In Japan's electricity market, understanding and predicting the depth of the duck curve has become one of the most essential competencies for power traders."