People as Energy Source

Wouldn’t it be amazing if we could create energy by just performing our everyday activities? This is not a mere dream, it is already possible. In 2009 the idea was presented for the first time: an energy generating tile. Pavegen creates just that, energy generating tiles, producing energy every time someone steps on it. Even though the tiles only produce 5 watts per step, I believe this new form of renewable energy can play a vital role in future energy generation and save our Earth.

These energy generating tiles can be used everywhere people walk. Areas bustling with life are great sources of energy, think about office buildings, train stations, airports, schools, restaurants and sports grounds. People spend many hours a day walking around, travelling from A to B. There is no need for them to change their behavior. For an idea on how the tiles produce energy, please watch this video. The tiles have other capabilities as well. For example, they can gather data on how people move in a certain area. The data gathering possibilities is interesting for many companies interested in behavior. The tiles are relatively new, so there is still a lot of room for improving their energy producing capabilities. If the tiles are improved and placed with many in a lively area I am sure they can become an acknowledged energy source. Saving on your energy bill by just playing soccer, that’s killing two birds with one stone.


Shell soccer pitch, Nigeria, using energy generating tiles

This sounds very nice, but there are a few downsides. The tiles don’t produce much energy yet. Financially placing the tiles is also a tough decision to make, as a single tile still costs £600 per square meter. However, the producer aims to sell the tiles at almost the same price as regular tiles in the future.

The municipality of Leiden, the Netherlands, wants to be 100% energy neutral by the year 2040. Meaning the want to produce as much energy as they use within their own borders. This is an admirable goal and a tough challenge. There is only so much that can be done within the boundaries of the municipality. There is not enough room to start very big projects within a city. Perhaps the energy generating tiles will not be very profitable at this point, but I would advise the municipality of Leiden to keep an eye on this renewable energy source. For now I hope they can get as far as possible with reaching their goal by using existing renewables. Hopefully a part of Leiden’s need for energy can be covered by the movements of its own population in the future.

Whenever we think of renewable energy, we often think about wind turbines and solar panels first. However, I don’t think we can become energy neutral by just using those two methods. We need other methods like geothermal energy and hydropower. I hope people will come up with more innovative ideas, such as the energy generating tiles. In this new age where climate change is a huge threat to mankind, it is of great importance to switch to renewable energy as fast as possible. We need to protect our Earth and our future, but we only have limited time.



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!

Solar power, answer for Leiden’s renewable energy source?

Our primary energy generation still relays on fossil fuels. Approximately 80% of the world’s energy supply comes from fossil fuels. However, fossil fuels will soon or later depleted. Therefore, energy generation by non-fossil fuels should be implemented on large scale. Solar energy has a large potential to generate a considerable amount of energy in the world. The potential of solar energy can be seen in figure 1.

Figure 1. Solar energy potential in the world.

Energy generation still also relays primarily on fossil fuels in The Netherlands. In 2014 only 5.5% comes from renewable sources. The government has set a target of 20% renewable energy sources in 2020. In the next coming years we have to increase our renewable sources by 14.5% of our total energy generation. Currently, biomass and wind energy accounts for the majority of renewable energy in the Netherlands. Solar power has relatively a small share in comparison to biomass and wind energy. This can be seen in figure 2.

Figure 2. Shares of renewable energy sources in the Netherlands.

However, in recent years the use of solar power has significantly increased from 88 MW in 2010 to 1405 MW in 2015. Solar power will contribute a significant amount of renewable energy. In order to reach the target of 20% renewable energy sources in 2020, solar energy has to expand in The Netherlands. Solar power has potential to generate energy as can be seen in figure 3.

Figure 3. Solar power potential by annual sun hours.

The potential is not that high as in countries with more sun hours per annum e.g Australia. However, Germany installed an enormous number of solar power systems. In 2015 the installed capacity was 40782 MW.[i] This accounts for approximately 7% of the total energy generation in Germany. The amount of solar energy generation is almost neglectable. Germany has a similar sun energy potential as in the Netherlands; we have a similar climate and sun hours per annum. Therefore, it is likely to implement similar solar systems in the Netherlands as in Germany to increase the share of renewable energy sources.

Solar energy has a small share in renewable energy in the Netherlands. However, let’s zoom further in local municipalities in the Netherlands. The city of Leiden has an ambitious target to reduce CO2 emissions by 40% compared to 1990 in 2030. They also want to increase the use of renewable energy sources. The percentage of renewable energy was 6.1% in 2014 in Leiden according to klimaatmonitor. The share of renewable energy usage is slightly higher than the national average. However, Leiden has less solar polar per inhabitant than the national average. This can be seen in figure 4.

Figure 4. Comparison Leiden-the Netherlands solar power per inhabitant

This suggests the city does not invest enough in solar systems. According to figure 3 Leiden has a higher solar potential than other cities in the Netherlands. Moreover, Lots of roofs are suitable for installing solar panels. In order for Leiden and the Netherlands to reach its targets, solar energy could attribute significantly more to renewable energy sources than our currently capacity of solar energy.


Energy Producing Flooring: a steppingstone for Sustainability

Step by step by step by step we move forward. Each and every one of us makes thousands of steps every single day. Be it frantically running around the bedroom to find that last clean shirt or walking down to the shops to get a cold beer you earned for putting so much effort into finding a clean shirt. In total a person walks up to 150 million steps in their lifetime. Whether you live in Sweden, Zimbabwe or Guatemala: walking  is unarguably the most common way of transport.

So what if I told you that each and every single one of those steps has the potential to generate sustainable energy; that we can move away from fossil fuel-based energy simply by walking?


 Making this vision reality is exactly what Laurence Kemball-Cook, the founder of Pavegen is trying to achieve. In 2009 he engineered a flooring tile that can transform the kinetic energy that is released through a step into energy and save this energy in a battery. This battery can then be utilized to power street lighting, advertisements or charge phones for example. A big asset of this kind of energy is that it is off-grid and, not like solar or wind energy, independent from weather developments.

As Kemball-Cook explains in a TEDx talk in Rio, first trials were successfully made in a school, and public awareness rose rapidly.  Newspapers started writing and politicians and celebrities stated their support for the idea. With this positive response the start-up started growing. By 2012 they had built a football field in Brazil  lighting is now powered by the movement of people playing or walking on it. Today several big places such as train stations, airports and commercial sites are already equipped with the floor, producing energy every day. Moreover, similar firms such as energy-floors are already developing which is an indicator for the economic viability of the idea for producers but also for consumers

The exact cost information is currently not released to the media but in an interview with Forbes  Cook claims that “ a standard square meter of decent flooring that would be used in a building such as a train station would cost around 1000 pounds and Pavegen will be sold for around that price”. Furthermore, even if the cost still is slightly higher it will be compensated for by the energy saved while it is in use. In the long run the tiles are expected to become even more affordable for several reasons. The production is going to be less pricy when done on a larger scale and the batteries, a crucial component, will become cheaper with the help of Tesla’s gigafactory. Seeing these developments, there is reason to be optimistic about the future of energy-producing flooring.

Pavegen secured his market position by releasing a new tile: V3. The V3 produces 200 times more energy than its predecessor and also collects data about the steps made on it. This double function makes the flooring even more attractive for the interconnected, data driven city of the future. However, in addition to green energy and data collection the tile might be able to fulfill a third very important function: spreading awareness and involving people in sustainability on a personal level.

Harvesting human power as an energy source has the potential to show that every individual can contribute. The flooring can make this connection visible in a way that only few other solutions can. Be it by charging your own phone by dancing at a festival or lighting your own way when walking home.

e65cef9812e64fe5f0eb5247a629afe3The immediate response to your own action is an empowering and motivating experience. It basically sais: you can make a change. Since we all walk and all use public spaces such as train stations, clubs, shopping streets or airports this will permeate every level of society and hopefully give a more accessible image to the sustainability debate. Because for you it might only be a small step but if we all make it, it is one giant leap for mankind.


How a cute blouse with little birds changed my worldview

For a long time, I told myself there was nothing wrong with shopping at Primark stores. When I was ‘grown up’ and had a real money paying job, there would be enough time for conscious consuming and more expensive stores. Fashion, shopping and expressing my identity through the clothes I wear is one of my biggest hobbies. So I wasn’t willing to compromise in that area. “And so what,” I told my grandmother, if the clothes were worn out after a year? There was a big change I wouldn’t wear them by then anyway.

But my views changed drastically this fall. It all started with a nice, cute Primark-blouse with little birds all over it. I was in heaven and named the piece my new interview blouse. Nevertheless, the fairy-tale wouldn’t last long. After one wash, the blouse shrunk to size extra small… The only duty left for the blouse was hanging outside my wardrobe being pretty. But then it struck me: my best friend has a more petite anatomy, perhaps I could do her a favour.

“But the wastefulness of consuming bad fabricated clothes is just as shameful”

The situation got me thinking. I was always silently apologizing to the little children who presumably made my Primark-clothes. But the wastefulness of consuming bad fabricated clothes, which only last one season before falling apart, is just as shameful. I always praised myself as a conscious consumer for buying less meat than average. But those clothes are also made of energy. Energy that should last longer than one wash. And if the clothes do not stay with me, because I grow bored of them, at least I should give them to a new owner. In this way, the way I consumed over the past four years, I was a big supporter of the linear economy. Most of the time, I didn’t even try to donate my torn clothes to charity. All my Primark clothes ended up at the waste disposal. This ought to change, I want to participate in a more circular economy.

Apart from an old army bag, I never really bought any second-hand or vintage clothes. Sometimes I swapped clothes with my sister, sure, but that’s it. Even though those stores are all the rage nowadays. So after the blouse-incident, I explored the options Leiden had to offer. I was surprised. For example, Hartendief, a new vintage store in the famous characteristic Breestraat, became one of my favourite stores – they even have a jar full of ‘lost’ Scrabble stones! But in Modejacht and Olive Oyl’s Rusty Zipper I also found some nice pieces. Last month I even visited the famous Vintage per Kilo-sales in Rotterdam, which travels through the Netherlands. How nice would it be if the next one was in Leiden?

“The only thing that could improve, is a pick-up service for old clothes in the way they pick up trash”

Fortunately, the municipality of Leiden understood the importance of circularity somewhat sooner than I did. They constructed a complete information brochure summarizing all ways to donate, sell or dispose your old clothes. They explicitly mention the thrift store Het Warenhuis – almost as nice as an IKEA – which also gets all the bikes, to patch up and sell, the municipality takes away in the citycentre. How wonderful is that! I’m grateful to live in a city that stimulates a longer lifespan and new purpose for ‘old’ clothes. The only thing that possibly could improve, is a pick-up service for old clothes in the way they pick up trash. Maybe this is some nice idea for the future? Although I still would have given the cute blouse to my friend!

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:

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:

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