Tag Archives: renewable energy

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.

Generating energy; what other sustainable options are there besides solar and wind energy?

When we think about generating energy in a sustainable way –thus no use of fossil fuels- most people think about solar panels and large (ugly) windmills. Of course not without a reason, because both options have already been proven to be very efficient and have become cheaper and better every year. But to generate energy there are so many other nice possibilities that each have their own set of extra benefits. It would be a shame to neglect these options.

What about all the people that work there asses off in the local gym? Why is the power generated by all their hard work not being used to burn our lights yet? About 20 % of the population in the Netherlands over 15 years has a gym membership.That’s about 3.2 million people if they all run say, one hour per week on a treadmill. That would already be 3.2 million*52 hours= 166.4 million hours on a treadmill. One hour on a treadmill gains you about 400 watts. So that’s 166.4 million *400 watt. That can be used. The bonus here of course is that people also get healthier!

Honey, I’d like to charge my phone tonight, could you please go on the treadmill this time?

Another idea could be to take an advantage out of our ageing problem. We have more and more elderly people with failing body’s like for example incontinence. In Japan diapers of elderly people are being used to recycle the paper and plastic from the diaper, but they have found a system which can separate the faeces in the diaper and use the methane to heat the roads or to heat greenhouses.

Japans system of diaper energy

Or what about energy generating speed bumps? We have tons off them in the Netherlands so why not implement an energy generating system out of those annoying car wreckers.  In England they have already started installing ‘’electro-kinetic road ramps’’ as they are romantically called. The bump contains some kind of a metal plate. Whenever a car drives over the bump an internal generator will be powered. Of course it depends on the weight of the car and the passenger (do they generate energy as well in the gym or not?) how much kilo watt the bump generates, but it can go up to 50 KwH per vehicle! All this energy could be used by traffic lights for examples of LED road signs

As my last example of multi-beneficial sustainable energy generating I would like to give some attention to a quite simple implementation that Sweden did. They use confiscated alcohol, which would normally be poured down the drain, as a way of generating energy. How amazing is that! In the Netherlands we have a lot of festivals every year, where people bring their own booze. And although I am sure that many people actually can smuggle their alcohol into the venue, there are also enough that get caught. In Sweden the alcohol they confiscate (700.000 litres last year) is converted to biogas and will subsequently be used for trucks, buses and trains.

And there are so many other bizarre ways of generating energy that could be used. In a sense everything that moves, contains energy. In my opinion it would be a waste to not use all these options that are already there anyway. We just need to make some slight adaptions. And most importantly we need to keep thinking out of that box!




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

Fossil to turbine, turbine to kite


Planete energies defines energy transition as “the shift from current energy production and consumption systems, which rely primarily on non-renewable sources such as oil, natural gas and coal, to a more efficient, lower-carbon energy mix.1” This is a lot easier said than done, especially with lots of discrepancy amongst scientists on various approaches and unforeseen problems. However, they do agree on one concept known as the energy trilemma:



The energy trilemma looks at how policies made need to balance three different aspects: security, sustainability, and affordability. The easiest way for change to be made is for innovative technological breakthroughs. These would hopefully raise energy efficiency, lower the cost, and not harm the environment, thus solving the trilemma.

One particular solution was a concept brought up many years ago but never fully took off. Saul Griffith talks in his short Ted talk about the efficiency and usefulness of kites to capture wind energy. Griffith explained how turbines are limited in how much taller they can be, however kites can go significantly higher, which is where more wind is.3


You can watch his 5 minute Ted talk here

Griffiths isn’t the only one who is advocating for kite energy. Several other companies around the world are hopping on this bandwagon:

Kitenrg, an Italian company, is working on making kites that reach up into the troposphere where there is significantly more wind, thus creating more energy. It is harnessed to the ground with two cables as well as an electric generator.5


Kite Power Systems of the UK explain the added benefits of low cost that government subsidies won’t be needed and that unlike windturbines, these can go places the turbines can’t. They have already set up a small station in Essex as well as a 500-killowatt system near Stranraer in Scotland.6

Makani, a company bought by Google, focuses on making wind energy more affordable and efficient which will ultimately eliminate fossil fuels. This kite is slightly different than the previous two examples. The kite is launched from a station on the ground and reaches heights of 800 feet with the help of rotors acting as helicopter blades. Power is generated by flying in circles higher up in the air.7


As shown above, wind kites come in a variety of shapes and sizes with several different companies from around the world trying to propel this solution everywhere. Kites could be a key concept to help Leiden transition from a city of fossil fuels to a city of renewables. This is relatively cheaper and simpler than current wind turbines. Additionally, since it is not feasible for Leiden to rely heavily on wind turbines as an option for renewable energy, this could be a key solution.

Wind kites have the potential to be the technological breakthrough that solves the energy trilemma for renewable energy.





  1. http://www.planete-energies.com/en/medias/close/challenges-energy-transition
  2. Picture: http://www.arup.com/low_carbon_energy_the_future_is_now
  3. http://www.ted.com/talks/saul_griffith_on_kites_as_the_future_of_renewable_energy/transcript?language=en
  4. Picture: https://www.faulhaber.com/global/markets/environmental-safety/energy-kites/
  5. Picture and Website: http://www.kitenergy.net/technology-2/key-points/
  6. http://www.independent.co.uk/environment/kite-power-station-scotland-wind-turbine-plant-electricity-a7348576.html
  7. Picture and Website: http://www.alternative-energy-news.info/makani-energy-kite/

Accomodating energy neutrality: Living on top of a parking lot!

Leiden: the ‘city of knowledge’ and one of the most densely built cities of the Netherlands. This fact goes hand in hand with many challenges, including a need for parking areas and housing, especially for students who account for at least 10% of the Leiden population! And now Leiden is facing another challenge as well: getting carbon neutral with a 40% energy reduction by 2020, as stated in the Duurzaamheidsagenda. However, it still proves to be a huge task to make this transition to other forms of energy and to establish a society in which saving energy is the norm… Public support is required in order to reach those goals. Therefore it is crucial to create public awareness of the necessity, options, and even advantages of the transition!

Three themes are highlighted here: a lack of space, a necessity for the transition to other forms and ways of using energy, and the need for a public awareness and support for this transition. Would it not be perfect if all those issues could be combined in one single project?

Maybe the ZED Pods  from the Zero Energy Development (ZED) Factory could offer such a multi-functional solution. ZED Pods are literally small sized, pre-fabricated pop up houses with a general gross internal floor area of 22.4 m2. This makes them cheap and easy to erect, as well as to relocate if necessary. In their design they are placed on top of parking lots or other unused spaces, thereby combining different functions. ZED Pods are supposed to be completely energy neutral due to a combination of very good insulation, efficient energy use, and a roof fully covered with solar panels. About 70% of the time the solar panels provide the houses in all the electricity they need, plus that of the charging points for electric vehicles which are located on the parking lot underneath. The lion share of the electricity for necessary heating is used to provide hot water, which gets heated and distributed by a small electric heat pump.

Composition of the insulation

In addition to their huge advantage of being energy neutral, the ZED Pods are cheap and easy to erect as well as to relocate if necessary. This makes them highly suitable for spaces which do not yet have a fixed destination plan. The Pods which are meant for couples have an estimated rent of €750 which makes them suitable for student housing too. Therefore the implementation of those Pods could potentially decrease the shortage of student housing which Leiden is facing at. Additionally, the ZED Pods could be an incentive for people to make the transition towards electric vehicles. At the same time they could raise awareness among the (young) residents and their surroundings. This awareness might spread even further when combined with a more wide-spread promotion of the project.

ZED Pods for students

Altogether this means that the implementation of ZED Pods could provide the city of Leiden with a unique opportunity: creating cheap housing in line with the goals of a carbon neutral Leiden, while responding to the challenges of a limited space capacity of the city, a need for (student) housing, and a need for public support and awareness of the energy transition. Embracing this opportunity would thus enrich the city, its inhabitants, and the environment as a whole!