Energy Generation by Technology in Spain

Daylight boosts Solar, night favours Eolic, and Nuclear stays steady—Spain’s rhythmic energy dance.


In a world shifting towards sustainable energy sources, it’s essential to understand how different energy technologies contribute to generating the electricity that reaches your house.

This article explores the intricacies of Spain’s energy generation, breaking down the hourly contributions of various technologies over a year.


Each row of the following dataset represents the energy (electricity) that different technologies, such as Hydroelectric, Combined Cycle, and Nuclear, generate per hour in one year.

The data is provided by Red Eléctrica de España (REE), Spain’s Grid Operator, via ESIOS API. Learn how to download the data automatically with this video.

Figure 1. Dataset with hourly generation Spain during one year


  • Which technology makes more energy in one year?
  • Which month-hour requires more energy?
  • How do the technologies behave during the day?
  • How much energy does solar power produce during summer vs. winter?

Learn how to produce the data analysis report of this article.



Eolic is the technology that generates more energy in a year because it has a greater power capacity than the rest, with almost 30GWh.

Why is Nuclear energy the second-highest technology? Nuclear power generates energy continuously, without stopping. Each Nuclear plant generates 1,000 MWh. Since Spain has 7 nuclear plants, approximately 7,000 MWh are guaranteed.

Nuclear plants sometimes stop during the year for maintenance operations.

On the other hand, Eolic energy won’t work if there is no wind, nor Solar energy if there is no sun during the hour.

A considerable amount of energy (almost 20 TWh) is exported to other countries, such as France.

Figure 2. Energy generation by technology in Spain | Interactive Chart

Technology per Hour

What is the average energy generated per technology per hour on any given day?

  • Photovoltaic solar energy generates more energy during sunlight hours (10-17).
  • Eolic achieves higher generation at night when the wind is more potent. During the day, it remains slightly consistent.
  • Nuclear energy is almost perfectly consistent at each hour.
  • The Combined Cycle presents a variance among the top technologies, not explained by climatological reasons but by economic ones: their plants generate energy from gas, whose storage ability plays a crucial role because you can fill up the required power that the climate cannot give (no sun, nor wind). The market agents will carefully optimize the gas because geopolitical tensions can cause shortages.
  • Hydraulic energy works as a battery because you can let the water go down to produce power when the market demands more.

The hour range is reduced from 7 to 23 for simplicity.

Figure 3. Average energy generation (MWh) by technology-hour


During January, most of the hours are breaking records. Why?

  • January is one of the coldest months. Therefore, we need more energy to warm our houses during the whole day. At 20:00h, 1,138 GW of energy was generated, the time frame with the highest mark.
  • July and August (months 7 and 8) also show higher generation during the most intense sunlight hours; we need more energy to power the air conditioning.
Figure 4. Total energy generation (TWh) by month-hour

Winter vs. Summer

How does the climate affect the energy generation?

Eolic energy generates more energy during the winter and less during the summer months, while photovoltaic solar works the other way around.

Figure 5. Comparing Eolic and Photovoltaic Solar energy generation by month | Interactive Chart


Spain’s diverse energy landscape showcases a harmonious blend of traditional and renewable sources. With the varying contributions of Nuclear, Eolic, Solar, and more, the country adeptly meets its power needs while adapting to challenges from nature and geopolitics. As we further explore the Spanish electricity market, we recognize Spain’s stride towards a balanced and sustainable energy future.

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Jesús López

Statistics, cloud and data programmer @datons

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