Leiden’s canals charging your phone

Everybody is familiar with the beautiful scenery of canals in old Dutch cities like Leiden. But below their surface, the key to a green Leiden is hiding. Those beautiful canals contain a huge amount of silt.
The silt from those famous canals might launch a huge transition in energy generation in Leiden, and make Leiden an example to all other cities with water flowing through them.

Silt contributes to the overarching term biomass, that is composed of vegetable, garden and fruit-waste, vegetable oil, wood, fertilizer and plant-rests from agriculture. Biomass can be used in many ways to increase sustainability. Biomass is capable of lowering relative CO2 levels emitted by power plants. When a part of the power plant’s ‘fuel’ (mostly coal) is replaced by biomass, it lowers the usage of fossil fuels and thus reduces the relative CO2 emission. Furthermore biomass on its own can be used to produce electricity, when it is burnt down, steam is produced that will enter a turbine in order to generate electricity. Another way of using biomass is by fermenting it, in this way biogas is produced. Biogas is composed of methane and carbon dioxide. After fermentation a wet digestate is left. The methane that is formed by fermentation can be burned in power plants and create green energy.
Biomass can also be gassed. This means; burned down under certain conditions (low oxygen level). This generates biosyngas, that is composed of mostly carbon monoxide and hydrogen. Hydrogen can be used to generate energy in a hydrogen fuel cell.

All these techniques need to have a huge biomass input. Luckily enough, in the Netherlands we’ve got a big amount of biomass available. Of course the silt which was named already. Furthermore waste from people’s homes, restaurants and supermarkets can be used. Especially when accurate advertising is done, a lot of people will join and collect their organic waste. Leiden is near to the Westland, which means a huge amount of greenhouses. In these greenhouses there is a lot of organic waste, because only the fruits/vegetables of the plants are being used. The rest of the plant is perfect for creating green energy. Almost the same counts for ‘Het groene Hart’, where a lot of farming is done. Not everything that grows on the land, is being used.

For turning silt into energy, fermentation to biogas seems to be the most appropriate technique. For cities like Leiden to kick-off such a project, investments will have to be made. A fermenter needs to be installed and a power plant that can transfer biogas (methane) into electricity  as well. This is a huge investment, however, cities can work together and share their resources.

Leiden to kick-start the transition!








8 thoughts on “Leiden’s canals charging your phone”

  1. Sounds like a great plan to generate a lot of energy! At first it seems like there are no cons for this plan. Therefore the point where you said “huge investments must be made” disappointed me a lot! Do you know in what quantities of money we have to think to realise a working biomass energy generator? Or are those calculations that still need to be done?


  2. I personally never thought about using silt for biomass energy and think t’s an idea with much potential. However, I’m not sure I fully understand the process of getting to the silt in order to use it. Is shoveling the silt out of the channels something that is being done regularly anyways? If not how would you make that happen on a large scale and what would be the consequences for the channels when there is less silt in them, also from a biodiversity perspective?


    1. Very interesting piece! Like Lieuwe, I would also like to find out how much money is needed for such developments and especially how much this is compared to the total life cycle of fossil fuels (extraction, transport, combustion, infrastructure, and so forth). If we would quantify the environmental and health damage done by using fossil fuels, I think biogas from silt would be a much stronger competitor of fossil fuels than expected at first glance. I would like to know whether such calculations are already done. Otherwise, I’ll wait patiently until new research on this topic comes out!


    2. Good point! I would think that the process of dredging the silt from the canals increases turbidity. I found a site with information on the effects of turbidity increase, you might want to take a look: http://www.fondriest.com/environmental-measurements/parameters/water-quality/turbidity-total-suspended-solids-water-clarity/#Turbid4
      Also, the possible turbidity increase might make it harder for fish and other animals in the water to see, and find, food… But I’m not sure!


  3. Sounds like a great idea! It really is something I wouldn’t have thought of. I think a few pictures could have helped me understand the processes you describe a little better.
    There is something I am still curious about. Do you know what kind of effects using the silt of the canals have on biodiversity inside and around the canals? How long will Leiden be able to use the silt from the canals?


  4. Your plan sounds very interesting! Although I had the same question in my mind as @evaold asked. How exactly do you get the silt out of the canals in order to use it? I know the last time they extensively dredged the canals was in 2014 – for the first time in seventy years (!). The whole operation cost thirty million euros. But what’s even more interesting is the amount of trash in the silt. In 2014 they found three million kilo’s of trash in the canals… including hundreds of bicycles and even a car. And I know for a fact – from a reliable source – they will find a construction trolley the next time they dredge ;). But my point being, do you think there’s an affordable way to separate the trash and the polluted silt in order to use it?


  5. Can the silt, available in the canals, already be used for the process of biomass and how much will the whole operation (fermenter and power plant) costs?
    A question about the biomass part. Currently there are no strict guidelines or any regulations about the emission requirements, in what portion will the silt account for that? Also, one of your sources mentions that biomass ‘could threat the biodiversity and food production’ and that bothers me a lot. Not only that, but it can also produce harmful air pollution, consume large amounts of water and produce net greenhouse emissions.


Comments are closed.