Going to a renewable energy generation

If we look at the energy generation of the city Leiden, there is only a little use of renewable energy generation. The percentage of the renewable energy generation in Leiden is far below the average of the Netherlands. There is just a little increase in the use of renewable energy which is to low for Leiden, a city of knowledge, innovation and development. Leiden must be one of the leading cities in sustainability of the world.

The county council of Leiden made a ‘Duurzaamheidsagenda’. The ‘Duurzaamheidsagenda’ is a report which contains the main goals to become a sustainable city. One goal is about the amount of renewable energy which must be 20% by 2020. There are four obvious ways of renewable energy generation, namely solar energy, thermal storage, geothermal and wind energy.

I compare the four obvious ways of renewable energy generation and investigate the possibilities for Leiden.

Thermal storage:

Heated water is stored in a buffer or tank. The heated water in the buffer or tank will be converted to energy by a heat exchange.  Thermal storage is based on this concept.  The municipality has already got some thermal storage, but this method is only successful in new buildings.


IF Technology investigated the possibilities for geothermal energy in the city Leiden. There is a geophysical potential, but the temperature which will be gained is very low (60 degrees). The current heating network is based on higher temperatures. So, geothermal energy can’t be used in Leiden.

Wind energy:

Wind energy isn’t an alternative energy source anymore because it already delivers 3% of the electricity in the world. Wind energy is an effective way of energy generation, but is it realistic in Leiden? Windmills aren’t beautiful and make a lot of noise, nobody would like to have a windmill in his backyard. Windmills need a lot of wind which doesn’t exist in a city. There are two available places for wind energy in Leiden, the Oostvlietpolder and the A44. The Oostvlietpolder is a nature reserve which isn’t a suitable place.

Solar Energy:

The technology of solar energy is developing and the costs for solar panels are decreasing. The solar panels transform sunlight into electricity. Electricity will also be produced on a cloudy day. Solar panels can be placed on the houses in the city Leiden.

Solar energy might be the best option for  a renewable energy generation. The video shows how a city uses only solar energy as energy source.

The efficiency of the solar panels is increasing. The panels can lie on the roofs of the buildings in Leiden, so they doesn’t bother the citizens of Leiden. However is it possible, in such a short period, to reach an increase of almost 18,5% renewable energy generation of the total energy generation by only using solar panels? And is it possible to become energy neutral? The technology is innovating which might be the solution. What will the new technologies bring? Is energy based on movements the future, or will it be bio-energy in our future? At last we have to remember: Leiden is a city of knowledge, innovation and development!



Noortje van Wanrooij


7 thoughts on “Going to a renewable energy generation”

  1. Leiden seems pretty stuck in terms of options for renewable energy, which is a bummer! Do you think it’s better to try solar power or is it still not enough and would it be better to find an altogether new alternative for green energy in Leiden?


    1. Yes, unfortunately Leiden has got less options for renewable energy. I think it’s better to develop only one option. Technology for solar energy is already developing and it can offer a lot more to coming years. As show in the graphic (figure 1 in the link) new kind of solar panels are in developing very fast and on a more efficient way which is great! Alternative green energy will need a lot of work because it is still in its infancy,



  2. The example of Dasmar city, completely running on solar power, is really cool. However, in Leiden the intensity of the sun will be less than in the Emirates. I don’t think Leiden can run on 100% solar energy, but implementing solar panels throughout the city is a step towards more renewable energy. However, a large part of the buildings (especially in the old city centre) have a high cultural, monumental status. Do you think solar panels should be placed on their roofs? Right now we view our aesthetic as more important than the generation of renewable energy. How can you change this view? For example by campaigns or subsidy maybe?
    Furthermore, renewable energy is not the only challenge right now, the city also has to become climate adapted. Do you know a way to combine these two measures (climate adaption & energy generation)?
    I know you can place solar panels on green roofs, but are there other combinations you can think of?


    1. Thank you for your comment on my blog. There are different factors which determine the efficiency of a solar panel. For example, when the temperature is higher, the efficiency of the solar panel decreases. The solar panels are black and the temperature can easily increase to 65 degrees or higher. This might be a bigger problem for places in the Emirates. However, the factor which you mentioned: The intensity of the sun, is a limiting factor. This will lead to more solar panels in Leiden for the same amount of energy in Dasmar.
      https://www.zonnepanelen-info.nl/zonnepanelen/rendement-zonnepanelen/ (sorry, it is in Dutch)

      Another problem which you mentioned was the view of the city Leiden. Tesla is developing solar panels which have the same look as a normal roof. This panels doesn’t change the authentic view of Leiden which is very important for an old city.

      The technology is developing, but it is unclear how the efficiency of green roofs and solar panels on roofs will be. There are only a few places were solar panels, which have a high effect can be placed in the city Leiden. You can see it as a visual circle: If we need more energy (less solar roofs), there have to be renewable energy generation (more solar panels). Another option might be the use of a heating solar panel. This will reduce the use of gas.


      1. Thank you for your answer! The solar panels of Tesla look really promising. Well, I found out that solar panels have a higher efficiency when they are placed on a green roof. Solar panels work best around a temperature of 25°C, but the temperature of a normal roof in summer can lead to a solar panel which has to perform at 80°C (which decreased the efficiency). Green roofs have a cooling effect, so the temperature of such a roof will rise to a maximum of 35°C! So, solar panels are more efficient when they are placed on a green roof. The combination of them thus offers multiple benefits: more renewable energy, coll houses and surroundings, and they can retain water!


  3. Of course every municipality in the Netherlands should strive to be self sufficient. However for most urban municipalities this only a utopie. The whole region Rijnland Holland have barely the potential to generate its own energy on a renewable way let alone the city of Leiden. But is that a bad thing? If it is easier to generate the energy somewhere else on a more renewable way the city of Leiden can be used for other purposes. In my opinion sustainability in the Netherlands is not a race between municipalities but a challenge we have to solve altogether.

    Regarding the geothermal heat it is true that the city of Leiden has less potential than for example the Rotterdam area. But still if you drill to a depth of 3 km in Leiden you still end up with heat of a temperature of 90 degrees Celsius. If you even drill deeper to the ultra deep geothermal heat the water you pump in even returns in the form of steam which even can be used for industrial purposes. The key element for geothermal heat is more about the flow of water through the porous medium than the geothermal gradient but of course the geothermal gradient will help a lot.


  4. Thank you for your comment, Huub. To be exactly, an energy neutral city is a city where the municipality, the consumers and the companies produce the energy which they use them self. If the energy is coming from the South of Rotterdam, the Netherlands is going to be energy neutral instead of Leiden. One of the main goals of the city Leiden is to become energy neutral (as a city). The potential of Leiden is discovered by IF technology as mentioned in my post. TNO also investigated the potential of the Netherlands. In the map is shown that Leiden doesn’t have less than 30% chance for geothermal energy.

    http://www.nlog.nl/geothermie-0 (First document under informatiebladen geothermie)

    The heat must be 120 degrees to generate energy.It will be unlikely that a temperature of 120 degrees can be reached, because the heating isn’t there. A temperate of 90 degrees can be used for heating the buildings, but the city Leiden used a heating system were this heat can’t be used.



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