Key metrics for wind and solar in Belgium and Germany over the past five years
In this post, I present a series of graphs illustrating key metrics related to wind and solar production, along with relevant economic indicators. I begin with Belgium and then provide the same analysis for Germany, focusing on the past five years. The data used for this analysis is sourced from here (based on ENTSO-E).
Installed capacity and total production (Belgium)
Installed capacity (in GW) for offshore wind has remained largely stable since 2021, while onshore wind has seen moderate growth. In contrast, solar capacity has more than doubled over the same period. These figures reflect year-end values. As we will discuss later, the most significant changes in economic indicators have occurred in the solar sector.
Regarding total electricity production, we have observed a significant increase in solar generation over the years, which has now surpassed 10 TWh for the first time. You can find more detailed information about recent electricity generation in Belgium here.
Capacity factor (Belgium)
The capacity factor measures how much electricity a source actually produces over a period compared to its maximum possible output. It is calculated by dividing the actual energy produced by the plant by the energy it would have generated if it operated at full capacity the entire time.
For solar energy, the capture rate is slightly underestimated because capacity is measured at the end of December each year. Since solar capacity tends to increase significantly throughout the year—unlike wind—this approach doesn’t fully reflect actual growth.
Interestingly, onshore wind capacity factors show quite large year-to-year variability, whereas offshore wind remains relatively stable. Additionally, Belgium’s capacity factors are notably lower than international benchmarks1.
Capture prices and capture rates (Belgium)
Capture prices2 represent the average market price that renewable energy producers would receive if they sold all of their electricity on the day-ahead market. This is calculated as the average electricity price, weighted by the hourly production from each technology. Capture rates express the ratio of this capture price to the overall average market price for the same period.
As shown, capture prices were relatively similar across all technologies until 2024, when solar’s capture price dropped significantly compared to wind. It’s also worth noting that 2022 was an exceptional year, with much higher summer prices caused by the energy crisis, which contributed to particularly strong performance for solar.
As expected, solar capture rates have been the most impacted, particularly from 2024 onwards. For wind, capture rates have generally remained stable, with the exception of a dip in 2022. The year 2022 was particular due to the extremely high prices in summer.
Revenues per kW installed (Belgium)
Combining the consideration on capacity factors and capture prices, we can derive a revenue per kW installed. As we can see, the revenue per kW for solar is currently around 6 times lower than for offshore wind and around 3 times for onshore wind. Of course, offshore wind is sensibly more expensive than onshore wind, and even more than solar.
The following section, under paywall, will present the data for Germany and include a comparison with and without negative prices. If you find my work valuable, please consider becoming a paid subscriber. In any case, thanks for reading.