All posts by gijsvannes

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!