Production profile of variable renewable energy

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Traditional power generation facilities such as coal and oil-fired power plants can adjust their electricity output based on demand. In contrast, renewable energy sources like solar and wind power plants lack this inherent capability, as the availability of solar radiation or wind speed is not adjustable.

Solar production profiles

The orientation of solar panels within a plant has a strong impact on the production profile.

A simulation was carried out by Synertics for a location in the south of Spain in which fixed solar systems with different orientations and a tracker system were analysed. As seen in Graph 1, the production profiles of the fixed systems varied greatly according to their orientation.

Trackers generally outperform fixed systems in terms of generation yields by moving with the sun throughout the day.

Wind output profiles

Wind production profiles vary strongly according to individual site locations and characteristics, as presented in the simulated average hourly production profiles of a wind turbine in Cadiz and Bilbao (Graph 2).

The overall generation is slightly higher in Bilbao. However, Cadiz's generation usually overcomes Bilbao’s in the afternoon after 14:00h and in the night until 03:00h, where higher electricity prices can generally be captured.

Impact on revenues

Energy prices fluctuate throughout the day, with higher costs in the early morning and late afternoon (Graph 3). Modifying solar panel layouts or wind plant locations can capitalise on these price trends.

Comparing the 3 fixed solar layouts, the south orientation does not provide the best capture prices. Trackers, despite the higher generations and capture prices, require bigger investments for their construction, so the better results shown do not necessarily guarantee better returns on investments (Table 1). 

Regarding the wind simulations, although having a lower generation than Bilbao, Cadiz achieved better capture prices and higher revenues (Table 2). 
 

Conclusion

When developing a wind or solar PV plant, it's essential to consider the hourly production profile to optimise the plant’s revenue stream by leveraging higher electricity prices.

A solar PV plant oriented to the south performed the best in terms of revenues when considering fixed mounting systems in the south of Spain in 2023.
 
For wind development in 2023, Cadiz turned out to be a better site when compared to Bilbao, as confirmed by its achieved capture price which allowed higher revenue streams, even with an inferior generation yield.

While capture prices are one of the most important factors when considering different layouts and sites for achieving the best revenues, it's worth noting that they often must be able to compensate for the inferior generation of a given production profile.