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.


Energy Transitions past and future

As we begin to come to terms with the serious effects of climate change, it is now more than ever that we must look back into the past to ensure mistakes made in previous generations are not repeated in our current transition period. One such mistake that seems immediately obvious is an over investment in one pathway for transition. For example, while not exactly an energy transition (but nonetheless relevant to sustainability), the change from open sewage system to underground sewage removal in modern cities was a transition that has left us with no easy way to again adapt to changes. In the future if our sewage systems should prove incapable of dealing with novel problems we can of course try to alter it to overcome these challenges, however the heavy investment in infrastructure during the transition period was done in a way that has left us locked into the current sewage system with little possibility of a radical overhaul. While we may not yet be in a position where the sewage system requires a radical overhaul, the same cannot be said for our energy production and unfortunately, the same “lock-in” effect seems so have taken effect. When society transitioned to a fossil fuel economy little care was taken to ensure the new system was adaptable and versatile. Huge investments were made without pausing to thing about how a complete reliance on fossil fuels could hinder us in the future. Of course, people back then had no idea that the carbon dioxide given off would cause the environmental issues we see today, but the problem I want to highlight is not that they were unaware of future problems but that they did not appear to even consider the possibility of future problems arising.

So, what does this mean for our current energy transition? I think these lessons from the past show us the importance of investing in multiple different energy alternatives and not relying on one single source such as solar or wind to solve our problems. We see in ecological and biological systems alike that diversity increases resilience. With a large array of renewable energy sources powering our future societies, we will be less vulnerable to unforeseen problems. If years later we find out wind turbines are having damaging effects on the Earths air circulation it will not be nearly as challenging if we have a vast array of alternative energy sources ready to fill the energy deficit while we transition once again. Furthermore, transitions in the past show us that while we should design our future energy production systems to survive well into the future we should design them with the knowledge that one day they will change once more. Whether this be changes to make the systems more efficient or changes that ultimately see them dismantled, we need to thing not just about the life of the infrastructure but also its death. Technology is constantly evolving and if something is not made obsolete by technological advancements making it function redundant, then it will soon be superseded by a more advanced and more efficient version of itself.

In the real world there is no silver bullet. A successful energy transition for the future will require innovative and new sources of energy designed to exploit the different environments in which they operate. We should take heed of the mistakes made in the past and never slip into thinking that the solutions for today’s problems will be the solution for the problems in the future.

District Heating: Not a hottie, but I’d still do it

When it comes to the energy transition of Leiden, it is vital to explore new ways to heat the city without gas, the good old gas that has been something oh so convenient, but also deceptive. It has betrayed Leiden, and many others. Now it tries to explain things for the better: “Come on, carbon capture and storage will fix this. And how about condensing boilers?! Hey, at least I am not as bad as oil and coal!”

But Leiden has started to realise that it needs to look for a new source of warmth. Now it seems that the best bet for Leiden is to opt for―no matter how unsexy it sounds―an extensive district heating network. Others, like many cities in Denmark, have already fallen in love with it.

Simply put, in a district heating system heat is distributed in the form of water or steam from the site(s) of production to a wide range of users. The system, like any other, has its pros and cons. A top-down imposed centralized system might raise objection, and the initial changes needed in the infrastructure will be costly. Nonetheless, a district heating system would offer substantial long-term benefits for Leiden.

District heating systems are energy efficient and highly flexible as they can utilize various sources of heat for optimal energy use.

To start with, surplus or waste heat from different processes could be pumped in the network. For instance, cogeneration plants that produce both electricity and heat (for a network) are significantly more energy efficient than conventional thermal power plants that merely waste the by-produced heat. Surplus heat can be connected to the district heating network from various local, or more distant sources, such as the Rotterdam harbour. Using waste or surplus heat would result in significant total energy savings, which is positive for the environment, and perhaps even for the wallets of the Leidenaars.

Apart from waste heat sources, the system can be fed by almost any current (and likely future) heat production forms. Some of the renewable examples are geothermal heating, biomass, central solar heating, and various types of heat pumps that can harvest heat from air, ground and water. In Duindorp, for instance, the district heating is fed by warmth harvested from seawater.

District heating system’s flexibility and compatibility with different forms of heat production makes sure that Leiden will not be dependent on only specific sources of energy. This, in turn, provides energy security. In order to make the district heating system even more flexible, it is recommended to pair it with (seasonal) thermal energy storages that act as a buffer and solve the intermittency problem of certain renewable energy sources. The storages can also help to optimize the energy efficiency of the system and its financial returns.

In short, it is time for Leiden to leave its smelly old gas system and move on. District heating—even if it remains unsexy—is a perfect fit for Leiden in its longevity and adaptability. It will open endless possibilities to keep the city warm and cosy—now, and in the future.


Photo: Bill Ebbesen

Sources and further reading:

State of Green: New White Paper on District Energy

The Guardian: Lessons from Denmark: How District Heating Could Improve Energy Security

Sustainable Cities Collective: The Heat is On for Sustainable District Heating and Cooling

UNEP: District Energy in Cities

The Energy Collective: Holland: Pioneering Sustainable District Heating Innovations

Review of District Heating and Cooling Systems for a Sustainable Future

Towards Next-Generation District Heating in Finland

The ADE: What is District Heating?


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!



Leiden: Leading in sharing

Modern problematic

Living in a modern world we, as human beings, have exceeded our potential of connecting to (and sharing with) one another by the means of internet, smartphones and most of all an intensive use of social media. Despite its underlying philosophy of bringing people together and creating a sense of community, people still are feeling lonelier than ever and feel more unsafe than they did in earlier times. Even though the latter might be true looking purely from an environmental perspective, one could say we live in prosperous times in which the world is safer than it ever was before. To kill two birds with one stone, moving towards a sharing economy can contribute to a sustainable future while recovering our sense of community and feelings of safety.

How a sharing city works

Basically, a sharing economy works according to the principle of sharing products or services through the concepts of peer-to-peer or peer-to-business-to-peer sharing or renting (such as Airbnb). In doing so, it can reduce the demand for new products and therefore reduce a populations resource consumption. Furthermore, the sharing or temporarily trading of a product or service with ones close by neighbors would result in more communal solidarity. When implented on a large scale in a city, we can speak of a sharing city. As a leading example, Seoul is currently the front-runner on becoming a sharing city. They have implemented interesting ideas such as:

  • Using “sharing libraries” where people could deposit and borrow tools or books for free.
  • Car Sharing
  • ShareHub: a place to find all that can be shared.

The transition towards a sharing economy isn’t only happening in South Korea, but also here in the Netherlands in both Nijmegen and Amsterdam. One could argue that if Amsterdam could implement innovative ideas towards becoming a sharing city, Leiden could most certainly succeed just as well. As Leiden is a lot smaller and less, the possibilities are endless to make the transition.

Leiden towards becoming a sharing city

To make the transition towards becoming a sharing city one could think of several applications in the city of Leiden. For starters, Leiden has a lot of empty buildings that could function as sharing hubs or as headquarters for startup companies that could work on the transition. For instance, the old V&D building on the Nieuwe Rijn/Breestraat which is now being used for pop-up stores could be the new center of sharing. By dividing this massive building into separate supervised corners which all have an own product category (e.g. tools, clothes, electronics), you create an accessible and fundamental place for sharing.

Another way of making it possible for Leiden to become a sharing city is by developing an overarching website or app which includes all categories of products and services which could possibly be shared among the city’s citizens. By including as much companies and students in the development of this application as possible, and by sharing the service throughout the city’s universities, popular visited locations and through the inhabitants mailboxes, this application might result an a success.

To make the transition towards a sharing economy lot of extra services will need to be implemented to make it a succes. For instance, a workforce that examines the products for any damages to a persons product needs to be implemented. Next to that, people would want to be sure that their product always returns to their rightful owner, meaning that people would have to register to be able to share or borrow a product. Of course the transition towards a sharing economy isn’t something that happens overnight and takes time and effort (meaning job opportunities!) to make it all possible. Nevertheless, a sharing economy is an interesting concept that could change our end of life economy  to a more communal and sustainable way of living.

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.