Tag Archives: Leiden

Two ways to find out how sustainable you live in your house

On 12 December 2015, 171 political leader signed an international climate policy in Paris, the Paris Agreement. This agreement also meant a reversion for Leiden in the field of CO2- emissions: a reduction of 49% in 2030 compared to 1990. In order to achieve this, the trias energetica was included in the policy plan of the municipality. The trias energetica is based on the following: ‘First, we need to reduce the demand for energy. Second, we need to use sustainable sources in stead of fossil fuels. Third, we need to produce and use fossil energy as efficient as possible.’ Despite the fact that the trias energetica is included in the policy plan, there are two issues, which make the target more difficult to achieve:

  1. The mandatory energy label (Dutch: Energielabel plicht)
  2. The green certificates from abroad (GOs = Guarantees of Origin)

1. The mandatory energy label 

monumentaalpand leiden.png

An energy label is a label that indicates how many measures for energy- savings have been applied to a house. Houses can no longer be sold without a label because of the mandatory energy label. This measure aims to reduce the demand for energy. With this measure, the government has set a step in the right direction. However, this obligation does not apply to all houses. Protected monuments* do not need to have a label, while protected monuments form a significant share in the housing market in Leiden. It is possible that Leiden is not going to achieve its target for 2030 because of this legislation. If you do not live in a protected monument, see if your house contributes to achieving the climate agreement. Below, you can find out what your label is. Label A is the best and G the worst.

*According to the Heritage act (Dutch: Erfgoedwet) or in the provincial or municipal regulation (Dutch: verordening)

Step 1. The website: https://www.rijksoverheid.nl/onderwerpen/energielabel-woningen-en-gebouwen/vraag-en-antwoord/hoe-kom-ik-aan-een-energielabel-voor-mijn-woning

2. The green certificates from abroad 

The next step requires an explanation about green certificates from abroad. What are green certificates anyway? The video below gives a good explanation. A green certificate  proofs that 1 MWh of renewable energy has been generated from sources such as solar panels and windmills. The green certificate is sold to the energy provider and therefore  the energy provider can provide the consumer with green energy. This is done, because it ensures the consumer that he or she contributes to the production of green energy on the general energy network.  Since the general energy network also contains energy from fossil fuels, such as coal-fired plants. There is often no direct connection between the source of the renewable energy and the consumer, for example between a windmill and a specific building. This direct connection is only made on paper because of the green certificates. The purpose of the certificates is to use more and more renewable energy and less fossil fuels.

It is therefore regrettable that some energy providers have found a way to use green certificates, but on the other hand do not contribute to the energy transition. This is due to purchased green certificates from abroad, for example from Norway and Iceland. Inhabitants of Norway and Iceland are sure that they receive green energy from the hydropower plants. They do not necessary need a green certificate to believe that they are receiving energy from renewable resources. On top of that, these countries can sell  green certificates to other countries, because they have enough certificates to reach the climate targets. Therefore, the green certificates from Norway and Iceland can be sold to countries such as the Netherlands. Inhabitants of the Netherlands also want to contribute to a more sustainable world, but because we do not automatically purchase electricity from renewable resources, we buy green energy with the green certificates. The behavior of some energy providers is misleading. It is cheaper for them to buy green certificates from abroad than actually produce renewable energy themselves. The hydropower plants in Norway have been running there for decades. Unfortunately, this does therefore not contribute to the energy transition. So see if your energy provider also participates in this. You can see this below.

Step 2. The website: https://wisenederland.nl/energievergelijker



Local initiatives will lead to a climate proof Leiden

I have been living in the city of Leiden for three years now and fell in love with the canals, the old streets and buildings and the little parks here and there. This beautiful scenery will however not last very long. The streets are subsiding, the city centre is heating up and water related problems are occuring. And these problems will only become more intense since the climate is changing due to global warming. There will be more tropical days, meaning that the heatstress problem will become dangerous to weaker people, such as small children and the elderly. Next to more tropical days, there will also be more heavy rainfall. Currently, with all the stone and little green in cities the amounts of water get to large and streets and buildings will flood, giving large damage costs. So, it is necessary that Leiden becomes climate adaptive.

This climate adaptation can be done by the munincipality who will force rules on the citizens to change. That however will be very hard and will not make the munincipality popular amongst their citizens. It is probably a better idea to have the initiatives come from the locals themselves. The munincipality can then help the citizens with expertise and subsidies.

There are already some local initiaves in the Netherlands that show great effort from within the local community. One of them is Amsterdam Rainproof, an initiative to decrease the water problems due to heavy rain in the city centre of Amsterdam.  For instance, people can put rain barrels in their garden to collect the water. And the project encourages the citizens to add more green to their gardens so the ground and the plants can hold on to the water longer. More information can be found on their website. https://www.rainproof.nl/

Another local initiative is Operatie Steenbreek, it literally tries to break the stones in the city of Leiden. So, replacing stones by plants, the same kind of idea as Amsterdam Rainproof. Because, plants don’t only hold water but also lower the temperature of an area. This is important since we will have more tropical days and the heatstress will cause great problems. In the current situation, people still have a lot of stone in the gardens or balconies. If everyone would more their houses and direct environment greener, then the water and heat problems will drastically decrease.

This video below explains Operatie Steenbreek.

These are just two examples of local initiatives in communities to battle the problems that arise because of climate change. It shows that little changes can eventually solve a large problem. These kind of bottom up actions lead to more awareness amongst the citizen. This is a very important aspect in climate adaptation. The more people that think and act on possible solutions the faster we can solve the big issues. Because heatstress and water issues are serious problems that must be solved before they become a threat to our health.

Climate Adaption from the Past


From the Last Glacial Maximum at the end of the Palaeolithic (10.000 years ago) to the warmer periods in the Bronze Age (4.000 years ago), humankind has always adapted their way of living to a changing environment. Actually, archaeology shows a long history of climate adaption in every possible population. As Dr Joe Flatman of UCL Archaeology mentions in his mini-lecture: we can learn about how to manage climate change by looking into the past.
True, a lot of adapting consisted out of moving away, but regarding our present situation, this is not a viable solution. The lesson we can learn should be about the positive and negative results of adaption of multiple communities. This can form a framework for modern societies.

Take as an example the city of Leiden. Based in a temperate region, the danger of extreme heat is not the first risk you will think of regarding the consequences of climate change. Nevertheless, heat stress has become a great threat to the less healthy inhabitant of the city.  Atlas Natuurlijk Kapitaal provided a map with the ‘Urban Heat Island Effect’ of the Netherlands. Due to the old, densely build centre of Leiden, the heat island effect causes almost a 2⁰ Celsius increase in this area. We, humans, are capable of adapting rather well to hot conditions gradually, but it is a sudden increase in temperature which poses the greatest risk.

One of the simple ways to reduce the heating in the city is installing ‘green roofs’ on top of the buildings. Studies in different places all over the world have found some way of reducing the heat by using natural material. In the Neolithic times (13.000 years ago), when humans became dependent on agriculture and lived sedentary lives, permanent housing became more important. Many materials were too heavy or not heavy enough to function as a roof. Due to their internal cohesion, it was turf or sod that was used for the roofing of their homes. Not only did it protect them from wind and water, but it also reduced the intrusion of the heat in summertime and escape of the heat in the colder periods.

A worker mowed the grass roof of a government building near Torshavn, the capital of the Faroe Islands, August 2009. (Bob Strong/Reuters)



Thinking of houses with a sod roof, you will probably imagine a lonely farmhouse build in the last century, but sod roofs can be applied to modern housing as well!

Green roofing can not only be applied on the houses in the city centre of Leiden as a way to reduce the effects of the Urban Heat Islands’, but can also be of value for reducing your energy use. Another plus is the increasing biodiversity in the city, another objective of the municipality.
The example above is not the most original idea regarding heat stress reduction, but still a very effective one. And it shows how much we can learn from our ancestors to tackle such an important threat as climate change. We have always adapted to our environment and we will continue to do so. How? That is up to us.

Waste or Energy – What do we find in local restaurants’ waste bins?

For more than 5 years now, I’ve seen the hospitality industry and many of its facets. From high-class hotels and fancy restaurants to cafeterias in zoos and museums, one thing strikes me time and time again: how can such a big industry be so unsustainable? As a student interested in sustainability, the unsustainability of the industry kept bothering me. The Dutch Circular Economy week (16 to 24th of January 2018) and Leiden’s 2020 goal to have a 50% waste separation, and ambition to be completely circular by 2050 are an inspiration to rethink our use of waste. From my point of view, it is time to tackle one of the main distributors if it comes to waste, namely: the hospitality industry.

In a Circular Economy, waste does not exist because all resources can be reused. This video from the Ellen MacArthur Foundation briefly explains the concept of the Circular Economy. A way to reuse stuff is through recycling. Especially the recycling of organic waste can be interesting for the municipality of Leiden. There are approximately 162 restaurants and cafeterias in Leiden, including big chains as for instance McDonald’s. A small change in the recycling policy of organic waste in such a restaurant can already provide a big amount of material that can be reused in a profitable way. Hence, there is plenty of potentials to recycle organic waste in Leiden’s local restaurants.


A short illustration of how the Circular Economy works, with on the left side the recycling of organic waste

In the hospitality and restaurant scene, food remainings are already scraped from the plate into a bin. Then, the plates and cutlery are put into separate places, waiting for the washing machine. Therefore, with the introduction of garbage bins for organic waste, it is only a small effort to recycle the food remainings. A short explanation of how organic waste is recycled and can be reused in various ways is shown in this video20161208_foodwaste_news_featuredFirst of all, organic waste can serve as a cheap fertilizer for the farmland surrounding Leiden. Moreover, the remaining organic waste can be transformed into food for livestock. Hereby, Leiden can reach its goal of 50% waste separation by 2020. Secondly, recycling food waste produces biogas, which can Leiden help to achieve its ambition of Circular Energy by 2050.

For sure, neither Leiden nor the Netherlands is the only place where the issue of organic waste separation in the hospitality industry occurs. Best practice case studies in other countries, such as the United States, illustrate how to reuse organic waste from this industry. In San Francisco, it is forbidden by law to not separate organic waste. Instead, the waste is collected and transformed into profitable fertilizer. Moreover, in New York around 300 restaurants and hotels are already obliged to separate its organic waste in order to recycle and reuse it. A local example is at the University of Leiden – Campus Den Haag (Wijnhaven), where organic waste is already separated.

A cook throws away leftovers in the 'Auf da Muehle' restaurant in Soell636372896323838453-636366774865832683-uscpcent02-6uf4nti61x1100qtirj-original

Examples of organic waste separation in restaurants

Next week, the Circular Economy week in the Netherlands starts. Maybe it is an idea to be inspired by those examples and make the circle round in Leiden. Other cities are showing us how to cope with waste in a sustainable way. Let’s not waste the potential to profit from the food thrown away in the hospitality industry. It is a win-win situation for all parties. So, it is about time to start acting on this opportunity.


Sustainable Leiden & The Hague Jan 2018

A new year, a more sustainable city?! Students of this year’s final course of the Minor Sustainable Development, provided by the Institute of Environmental Sciences (CML) at Leiden University, will again be working with the Leiden City Council to help them further develop their Sustainability ambitions. Half the class will this year also contribute to a further development of the Sustainability goals of the City Council of The Hague. In groups they will act as consultancy agencies and work with the councils as their client on current and relevant sustainability challenges.

As part of this course, students will be investigating the opportunities for the cities of Leiden and The Hague with respect to energy transition, circular economy and climate adaptation. In groups (acting as consultancy agencies, with the Council as their client), they will investigate current hot-topic questions of the council within these themes. They will present their results at the end of January. As part of the course, the students will also be writing posts to this blog detailing ideas and initiatives from elsewhere as inspiration for what may be done in Leiden/The Hague within their themes.

We look forward to reading some exciting ideas over the next few weeks!

Map by FABRICations

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.