Is the Belgian Duck Curve Growing Deeper in 2024?

Over the past few years, Belgium has significantly reduced emissions within the electricity sector by expanding its solar and wind energy capacities. However, with these advances comes the well-known challenge of managing intermittent energy sources—power generated only when the sun shines or the wind blows. This intermittency has led to the emergence of the "Duck Curve," a graphical representation of energy demand on a typical sunny day, highlighting the increasing discrepancy between demand and supply from solar generation. This curve shows how, during mid-day hours, solar power generation causes a dip in the grid’s net demand—the power that must be met by traditional power plants. The curve earned its name due to its distinctive shape, which resembles a duck, with the "belly" representing the lowest demand during peak solar production.

2024 Update: A Deeper “Duck Belly”

In August 2024, Belgium experienced an unusually sunny month, which accentuated this duck effect even more. Solar generation was at its peak, driving the mid-day demand from the grid to some of the lowest levels recorded in recent years. The "duck belly" has become deeper, demonstrating an even greater dip around noon. This intensifies the challenge for grid operators, who must balance these midday lows with early morning and evening peaks as the sun sets, causing demand to surge again.

Figure 1: Average daily Belgian grid load in August. Data from Elia.

With this deeper curve, the grid faces heightened risks of imbalance. The “duck belly” represents not just a visual shape but a real operational challenge, where excess solar energy production can lead to power curtailment, and, without adequate storage or flexible generation, may even result in grid instability.

Flexibility and Storage Solutions: Meeting the 2024 Challenges

Belgian grid operators are actively seeking solutions to manage the deepening “duck belly” effect. With the expanding EV market, electric vehicles offer a promising buffer for these fluctuations. When parked and connected to the grid, EVs can help absorb midday solar surpluses and release energy during peak demand hours, adding needed flexibility to smooth out load variations.

Another relevant development is the recent announcement of results from Belgium's CRM (Capacity Remuneration Mechanism) auctioning process, which has become a regular feature around this time each year. Last week’s release highlighted the projects selected to receive subsidies under the CRM mechanism, specifically aimed at managing the large load swings caused by the pronounced duck curve. These CRM-backed storage and flexible generation projects are essential to balance the grid and maintain stability as solar power deepens the midday demand dip.

The intensified duck curve of 2024 underscores the importance of adaptive energy solutions. Through CRM-backed projects and the integration of EVs, Belgium is equipping itself to handle the challenges posed by renewable energy. Continued investment in these flexibility solutions ensures that Belgium can pursue its low-carbon goals while preserving grid reliability.