Tag Archives: Leiden

This is what a energy-neutral Leiden look like.

Nowadays it’s a trend for every country, company, organisation and municipality to set as ambitious goals on sustainability as possible. Most of the time however, those goals are put on the back burner. The methods to reach the goals are kept vague and the goals are often not reached in time. The municipality of Leiden seems to be going down a different path.

Leiden also set some ambitious goals on sustainability. One important goal is to realise a netto energy-neutral Leiden by 2050. But, directly after setting this goal, the municipality of Leiden and the Dutch ministry of infrastructure and environment commissioned several companies and organisations to join hands and to develop an energy transition map of Leiden and its surroundings. This map shows a scenario of what Leiden would look like if this goal indeed would be reached by 2050. You can check out the map below.

map-leidenFor a bigger version of this map click here

This map clearly shows that the transition to an energy-neutral Leiden requires quite some rigorous changes. I’ll discuss the two most comprehensive ones here:

1. Complete new heating infrastructure

To reach the goal set for 2050, Leiden and its surroundings will need to get rid of fossil gas used for heating. Instead, there’s a need for a completely new heating infrastructure, fuelled by geothermal heat ánd waste heat from the Rotterdam industrial area. Realising this infrastructure will take an enormous effort. However, Leiden and some partners have already started the realisation of this network in a big project. Check out the video below to learn more about this project (in Dutch).

2. Placing hundreds of wind turbines

To generate enough energy to make Leiden energy neutral, a huge amount of energy needs to be generated inside the area. To achieve this, there need to be placed hundreds of wind turbines. In the scenario presented in the map, the wind turbines will create a thick belt through the area, ‘separating’ the urban area from the nature area. Some other wind turbines will be placed in the dunes, a almost sacred place for a lot of citizens. To convince people of the urgency of those placements as well as to fund this expensive project will probably be a tough task for the involved parties.


So to conclude, the municipality of Leiden took a bold step by developing this map which shows how radical the transition towards 2050 will need to be. This transition brings great challenges and I’m really curious on how Leiden will take these on.
What do you think? Will Leiden be able to reach their ambitious goal, based on the map that is presented? Can you find any underexposed solutions on the map? Feel free to let me know.


Cycling through a sustainable Leiden

The city council of Leiden is working on a liveable and promising city through the years.
At the moment they set up a plan for 2016 until 2020 to focus on a more sustainable city even more. The idea seems really nice, but the big question is: Will it be  achieved?

To realise such an achievement, you will need the contribution of the citizens.
Because they are the biggest player in the sustainable game. To make them act towards the sustainable plan of the council, you will first have to show them that it is really possible to do something for a more sustainable city.
And people in the city are allready on the right track actually!
I would like to give you a short preview on how citizens make Leiden more sustainable starting with a small contribution.

Everything in Leiden is very close to each other, this makes it very attractive for people to take the bike instead of their car. Actually almost fifty percent of the people takes their bike to go to work or school.
And that school part is very important in Leiden, because there are a lot of students living in the city. Almost every student has one bike (or more). But you would be a fool to buy the most beautiful bike you can afford, because the chance that it will be stolen is very high.

But a lot of students on crappy bikes also means a lot of bikes which break down. Those bikes will often not be repaired, because its easier to buy a cheap new bike.
Bikes that broke down will stay where they are, which most of the time means next to a canal (and after an amount of time end up in the canal)
Those bikes have a large impact on the environment because they release iron while rusting. Once a year these bikes have to be dragged out of the water, which costs a lot of money.

Two students in Leiden thought that something should be done about this problem.
They wanted to offer a very quick bike fixing service and also to stop waisting old bikes which aren’t used anymore. A new company arose at that moment, EasyFiets.
They started to collect old bikes through the city which owners could address themselves. Those bikes were repaired and put back on the market again for leasing, or renting for a day. You can easily recognise them on the red handles and saddle. 

Remarkable red saddle and handles (EasyFiets)

This is an example of a small start to contribute to a circular economy.
Ofcourse not all the old bikes will be collected by the company and re-used. But still, once you know about the concept you see the remarkable bikes everywhere you go.And every time you see one, you will be remembered about the easy way to contribute to a more sustainble city.

It’s only one example of a contribution by citizens, but ofcourse there is more. This example is just to show that people are willing to change and work with the council to make the city of Leiden more liveable and promising.


The city as goldmine of both materials and knowledge

What’s wrong?

Today, production and consumption of goods in all corners around the world is more extensive than any time before.1 The problem is that our global economy has always been a linear system. We extract raw materials, transform it into something useable and then, after a relatively short lifetime, turn it into waste. But what if I told you that we no longer have to extract raw materials from Mother Earth and have the opportunity to turn our waste into a resource? Intrigued yet?

That sounds better!

Fortunately, businesses are innovating a new industrial paradigm: closing loops. The driving force behind this? Our economy is approaching a tipping point where the old take-make-waste business model is a dead end. Finished, finito and no longer lucrative. Businesses are forced to rethink their products, as the global population is growing and urbanizing and resources are not infinite.

What do cities have to do with this?

Taking into account that cities accommodate a vast amount of the people that design, create and use these products that are eventually thrown away, I argue that cities cover a great part of the solution to make these products available for reuse. Half a century ago, urbanist Jane Jacobs already exclaimed that “cities are the mines of the future”. This approach of urban mining is seen as a way to recycle metals from city waste like buildings, infrastructure and devices.2 The resource stock that has been mined from underground into the human society now has a chance of circularity. Let’s see what’s in this for Leiden!

“As a city of knowledge and innovation, Leiden should be a frontrunner when it comes to sustainability” – Leiden Duurzaam 2030

Abuse the city’s students!

Life in Leiden is highly influenced by the relatively large number of students, as most of them live and study in de city.3 I have always believed that students can offer great help in society’s contemporary problems when it’s in their field of expertise. Because, as cheesy as it may sound, today’s students are tomorrow’s future. And other than that, it is both cost effective and awesome for municipalities or companies to collaborate with a university or a particular group of students.  When you ask students to get the job done you don’t have to hire an over-priced consultant and you are guaranteed that quality will be delivered, as these students will be advised by the country’s best-educated people: their professors.

Can you get back to the point?

Linking the latter story to urban mining in Leiden, there are a couple of things that can be done. Since students are the future’s leaders, scientists, inventors, entrepreneurs and engineers, it’s clever to get them to work together from a systems perspective. We are still counting on technological advancements, pollution-control technologies and public awareness when it comes to determining what forms of urban stocks exist, when these urban stocks will become available for reuse and how these can be reused.

N.B. I would like to remind the municipality and/or companies not to forget to reward these students with an excessive amount of ECTS.


1 J. Li (2015) Wastes Could be Resources and Cities Could be Mines. 

2 P. Brunner (2011) Urban Mining A Contribution to Reindustrializing the City.

3 http://www.prospectivestudents.leiden.edu/studying-in-holland/university-town-leiden.html

Climate proof Leiden: simplicity is key

Overwhelmed by new initiatives for tackling the effects of climate change nearly weekly, I got lost within this stream of ideas a long time ago. Each time I get confronted with technically complex product designs, my initial thought about creating new techniques and designs pops up. Why do we constantly have to come up with advanced and innovative ideas, when we can achieve so much with already existing ideas and products?

Take for instance Leiden. This Dutch city, also known as Sleutelstad (Key City), is a densely built-up city and municipality in the Netherlands. The inhabitants of Leiden are quite familiar with the abundance of water in the streets after high amounts of rainfall, which is getting worse year by year because of climate change. Especially the northern districts of the city have difficulty coping with high amounts of rainwater regularly, mainly because of the low-lying area the districts are located in and the further subsidence of the houses over the years. Adaptation is therefore highly essential to adjust to the short-term effects of climate change.

Flooding in Leiden due to heavy rainfall. Source: leidennoord.nl

A wonderful and simple invention that can easily contribute to tackling this problem is the rain barrel, a product we already use for centuries to collect rainwater. As stated by WWF, not only is the usage of rain barrels a great way to conserve scarce freshwater, it is also a simple and cheap step to reduce flooding as a result of heavy rainfall. Different sizes and materials are available when purchasing a rain barrel, but the overall rule is that it should not take any effort to connect the barrel to the downspout. Taking into account that watering your garden can account for a high percentage of domestic water consumption and that you can easily use rainwater for flushing your toilet, installing a rain barrel could possibly save you quite some money and prevent you from using much more water than necessary.

Example of a rain barrel connected to the downspout. Source: extension.usu.edu

The municipality of Leiden has tried to encourage the usage of rain barrels in 2009 by offering free rain barrels to the inhabitants of district Groenoord-Zuid. Despite the fact that 60 households were interested in participating in this project, the municipality has not actively continued encouraging the usage. Therefore it is time for action.

Major repairs and renovations within the city will not be enough to fully adapt Leiden to the rainy effects of climate change. Collaboration and participation of the inhabitants is also required to prevent everyone from having wet feet. In fact, to prevent flood damage, more and more municipalities obligate their inhabitants to collect rainwater from their downspouts with rain barrels. An active attempt like this would suit Leiden, especially because of their past experience with the abundance of water in the streets.

The solution for the water problem in Leiden does not necessarily have to be completely technically complex. Maybe by looking for straightforward measures as the key for adaptation, a climate proof Leiden is achievable sooner than we might think.

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

From leftover to luscious meal

Leiden: the city of students, which are the future of our planet. Leiden is also a possible frontrunner in sustainability. These two aspects are opportunities to make Leiden a sustainable city, like the municipality wishes for by 2030. In a city with an abundance of students, loads of food is eaten. Because without food, there won’t be any nutrition for the brain to study. And let a diet just be where there is a lot is to gain in sustainability.








Of all the food produced, the percentage of food that is thrown away is estimated between one-third and one-half. That just makes your stomach turn, right? Certainly when you think of it this way: most of the food that is thrown away is still good and edible. It is lost in production, during transport or in our own houses. A movement towards a circular economy would be a more efficient way to use food. In a circular economy, raw materials are optimally used. Reduce, reuse and recycling are keywords for this system: reduce the amount of needed raw materials; reuse products instead of buying new ones; and recycle as much as possible. A circular economy can for example include the use of leftovers.

In Utrecht, Amsterdam and The Hague special pop-up restaurants have popped up for leftover food, called Instock. Leftover doesn’t sound very delicious, but it really can be. Products with today’s date from supermarkets cannot be sold anymore, but can still be very tasty. Other examples of thrown away food are ‘ugly’ vegetables.

‘Ugly’ vegetables

Producers think the products need to look good for the consumers, but when the food is on your plate, you will not taste the difference between a round pepper and one with a bump on it. In the United States of America is even a business in ugly vegetables! And when an apple is beginning to bruise, they can still make apple pie out of it. But, the stores cannot use products out of date, because that’s not in line with the law.

Of course, this is not a fully circular economy. It will not be feasible to create a complete full circle of the food web, because there will always be a percentage of produced food that’s simply not tasty anymore. You also have products that do not expire quickly that always needs to be bought in pop-up stores like these. In Instock, it’s about 20 % of the dinner that must be bought, like oil and dairy. The leftovers of the leftovers – products out of date or bruised – can be used as fuel (bio-gas) or fed to the animals in the petting zoo. In this way, even these leftovers can be used well. It is a good start into sustainability.

For Leiden, a pop-up store like Instock can be an opportunity. As a student, I like to eat out. In this restaurant, you will get a prepared three-course meal for little money. There are enough supermarkets to provide the restaurants in their needs and enough students as customers. I would definitely eat there!

Sustainability in Leiden, yes we can!

If you are looking for innovative circular concepts in the Netherlands you cannot miss the industrial park ‘De Ceuvel’ in Amsterdam North. De Ceuvel is a circular office park located on a former shipyard. It is a platform for innovation and creativity, related to sustainability issues. The entrepreneurs and artist working on the Ceuvel have a heart for sustainability and all helped building their working place. At the shipyard old houseboats have been placed on heavily polluted soil, around these boats you can find phyoto-remediating plants working to clean the soil. All the workplaces in the park use clean technologies and are connected by a winding jetty. De Ceuvel can be called one of the most sustainable and renewing experiments in Europe.

A short movie about De Ceuvel: https://vimeo.com/98671834

Overview of circular office park ‘De Ceuvel’

One of the initiatives on De Ceuvel is called ‘Café de Ceuvel’. The people that founded Café de Ceuvel want to make a difference in the world and they do that by working as sustainable as possible in the café. This goes further then just using products with a label that says ‘organic’ or ‘biologic’. They want to make sure that every meal or drink has a positive impact somewhere else. To realize that they use their own made soda, grow their own vegetables and make bitterballen from coffee leftovers of LaPlace (restaurant). The people from Café de Ceuvel also take action with closing loops to become more circular, this happens in different ways. They win phosphate out of urine, have a hot-house on the roof and a floating garden with vegetables. Moreover, Café de Ceuvel is building world’s first biogasboat on which organic waste is fermented into methane which can be used to cook in the restaurant. In this way, the biogas boat closes the loop of organic matter.

The concept of this sustainable café illustrates that the founders are aware of the fact that the world’s food system is one of the biggest causes of climate change and that they really want to make a change in this system. A restaurant like Café de Ceuvel can help raising awareness for sustainability and circularity, it can change the food people eat and the way it is produced which helps in the battle against climate change.

Café de Ceuvel in Amsterdam

The city where I currently live in, Leiden, would be the perfect place to combine two of the initiatives from Café de Ceuvel; a sustainable café including a biogas boat. The reason why this would fit so well in Leiden is because Leiden is already known for it’s unique flooding terrace boats in the city centre. A sustainable café with a biogas boat, including a terrace on it, would therefore fit perfectly next to the other boats in the canal at the Nieuwe Rijn. The café would have a central location, which has several advantages. First, the central location would help attracting attention to the café and second, it could inspire the surrounding restaurants towards using more sustainable products. Furthermore, if the café has a biogas boat it has the possibility to occasionally move the boat around in the cannels of Leiden and locate it to spots with a lot of people. You can think of the big student associations (which are located by canals) in the annual student introduction week. On these locations organic waste can then be collected to transfer into gass and show the students what is possible with waste.

Terrace boats at Nieuwe Rijn, Leiden

To conclude, the concept of Café de Ceuvel in Amsterdam can function as an inspiration for Leiden to raise awareness for sustainability and circularity among inhabitants. Placing the sustainable café at de nieuwe Rijn with a biogas boat makes the concept even more attractive because it fits into the unique surroundings of floating terraces in the city centre and has the possibility to displace to different locations.