Geothermal Heat for Greenhouses

Geothermal Heat for Greenhouses

The greenhouses in The Netherlands are a major user of natural gas. The Trias Westland project is exploring the possibility to use geothermal heat as an alternative source for heating these greenhouses.

How does the harvesting of geothermal heat work?

Earth’s temperature rises with depth from the surface to the core. This gradual change in temperature is known as the geothermal gradient. In most parts of the world, the geothermal gradient is about 25° C per 1 kilometre of depth (1° F per 77 feet of depth).

Almost anywhere in the world, geothermal heat can be accessed and used immediately as a source of heat. The heat (energy) is stored in water which is present in the rock pores. When a well is drilled to this reservoir you can produce the brine. In some cases the water comes out of the ground automatically and in others you need a pump. In the Netherlands submersible pumps are required. After producing the warm water, the heat can be transferred to a heat network by heat exchangers.

Low-temperature geothermal energy can be used for heating greenhouses, homes, fisheries, and industrial processes. Low-temperature energy is most efficient when used for heating, although it can sometimes be used to generate electricity. High temperature flows can be used for electricity generation.

In the Westland area, how many MegaJoules of energy is currently used for heating greenhouses?

Currently, the Westland area uses 39 petajoules (PJ) per year of energy of which Greenhouses account for 31 PJ/year.

What are the main sources of this energy?

Total energy usage 31 petajoules per year. Of which 27 PJ comes from gas and 4 PJ from electricity.

How much of this can potentially be replaced with geothermal

The potential for sustainable use of geothermal energy is 38 PJ/jr.

Which layer do you want to research with the test boreholes?

The layer being researched here is referred to as the Trias layer. It was deposited between 252,2 till 201,3 million years ago. The name Trias refers to it being a three layered sequence; Buntsanstein, Muschelchalk and Keuper. In the Netherlands the Buntsantstein is the best reservoir for geothermal which consists of three sub-formations, the Hardegsen, Detfurth and Volpriehausen.

What are the characteristics that make a layer suitable for geothermal energy?

Good porosity and permeability as well as good layer thickness.

Before the drilling of the test borehole started, have you performed other tests of the geology and what were the results?

A lot of information about the Trias in the area is known from oil and gas drilling. Also seismic data is available.

Have there been similar drills in the area already?

Not till this depth. The deepest wells in the area are around 3500m. However, in the Netherlands there are multiple wells deeper than 5000 meter, so drilling technology is sufficient.

Once the borehole reaches a layer, how do you test the geothermal potential?

We hang in a submersible pump and produce the water to surface.

What is the timeline for the project?

Well tests will be performed in January for the first well. In case this is a success, we will drill another well. If not, we will open the well in a shallower layer.

Can the test borehole eventually be used for the production of geothermal energy?

Yes, if the Triaslayer is viable then a second borehole will be made. One from water production and the other for injection.

How long does a borehole stay productive?

The reservoir models predict a lifetime of at least 30 years, but probably more in the range of 50-70 years before the production well produces cold water. Another problem can be the wellbore integrity. Trias Westland has many corrosion and scaling mitigations in place, but there is always a risk that the well encounters problems during production.

How many MegaJoule does a borehole have to produce per year to be economically feasible at current energy prices?

The production capacity of Trias Westland will be approximately 25-45 MWth. Which saves about 25-40 million m3 of gas.

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Grow Smarter Stockholm

Grow Smarter Stockholm

The GrowSmarter project brings together cities and industry to integrate and demonstrate 12 smart city solutions in energy, infrastructure and transport, to provide other cities with valuable insights on how they work in practice and opportunities for replication. We interviewed Gustaf Landahl, the coordinator for GrowSmarter in Stockholm.

What are the goals that Stockholm uses when it comes to sustainability?

We have a city vision that comprises 4 main areas: ecological, social, economic and democratic sustainability. In our environmental programme we have 6 main goals and 30 sub-goals in the areas of:

  1. Sustainable energy use
  2. Environmentally friendly transport
  3. Sustainable land and water use
  4. Resource-efficient recycling
  5. A non-toxic Stockholm
  6. A healthy indoor environment

And what is your current position regarding these goals?

The city asseses the goals annually through the integrated management system. The environmental goals are monitored the same way as all other progress and the budget for each administration in the city. Last year’s assessment showed that we are doing fine.

My role for the process was setting up the programme for the City administrative board  I was temporarily detached to the city hall a couple of years ago to produce this programme and also the Climate strategy to be fossil fuel free by 2040.

Around the world we see a trend where cities are more ambitious than national governments when it comes to climate change and pollution. Does that also apply for Stockholm?

In many ways I can agree on that. We have for example reduced the climate gas emissions in Stockholm per capita, from all activities both private and public, within the municipal border by 50 % between the years 1995 and 2015. Although we also need to mention that the Swedish national carbon tax introduced in the 1990’s has been of great help supporting this work.

The GrowSmarter project combines measures in the areas of energy, mobility and infrastructure. What is the advantage of this approach?

When I applied for the project my main aim was to go further with our climate work using smart solutions to reach further than we can do by just picking the low-hanging fruits. The smart measures include more behaviour change among the citizens with other modes of mobility and also changing habits for the use of energy for hot-water and electricity. As we only build passive houses we need active tenants to reach further.

Can you name some successful measures that Stockholm is implementing in the area of low energy buildings?

In the GrowSmarter project we focus on retrofitting buildings. In Stockholm especially those built during the “million unit programme” in 1960’s and 1970’s.

We are retrofitting 6 buildings from that period. We are including energy efficiency measures that reduce the energy use by 60 %. This includes measures like quadruple glazed window, but where the mobile-phones can transmit without interferences. Thermal insulation of façades. Heat recovery of ventilation air. Better control systems of heat but also of electricity with smart home systems and metering.

When it comes to energy efficient buildings there is often the effect that the owner of the building is not inclined to invest because the energy savings don’t accrue to him but to the renter of the house. How does Stockholm try to tackle this incentive problem?

In Sweden heat and hot water is included in the rent you pay for your apartment. So all measures that reduce the energy use can give savings to the building owner.

What are the measures in the area of smart mobility?

Several. Both building logistics at the retrofitting site saving transports and moving around goods at the site thus making working conditions better as well as saving money and emissions.

Delivery rooms in the retrofitted buildings so that good bought on the internet can be delivered to the buildings instead of to some other store or delivery point thus improving the quality of life for the tenants but also saving emission from transport.

Electrical vehicle car pools are built into the area as well as charging facilities for these and also bike-pools.

Do you also use environmental zones in the city and what is your experience with the effects of this?

We have environmental zone setting requirements on vehicles weighing more than 3.5 ton. These vehicles  must be of  EURO Class 5 or later to be permitted in the zone. The zone comprised the inner-city area of Stockholm. The legislation sets up the rules but it is up to the municipality to designate a certain area an environmental zone.

The national government is now also considering passing new legislation making environmental zones for cars also possible. This will have an effect on especially diesel cars.

The cities that participate in the GrowSmarter project have different starting points and infrastructures. Do you still feel that you can learn from each other’s successes and failures?

We can absolutely learn from each other and we do. Both between the Lighthouse cities of Stockholm, Cologne and Barcelona, but especially with our five follower cities: Cork, Porto, Valetta, Graz and Suceava.

The whole idea of GrowSmarter is to help create a market for our 12 smart solutions thus helping other cities to reduce their emissions, Help create new jobs among the 20 industrial partners in the project and finally to help improve the quality of life for our citizens.

They say that energy efficiency is the first fuel. Would you agree with this?

To reach the climate goals we need to save energy but also change fuel from fossil to renewable. We need both!

What inspires you to work on a transition project like GrowSmarter?

I set up the project to reach further in our climate work. By demonstrating and showing new solutions we can inspire others to follow these examples. We can also help induce change in our own cities. That is why I chose to apply and that is what I hope we can do to help Europe grow smarter!

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Photo’s: courtesy of Grow Smarter Stockholm

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Growing mushrooms under solar

Growing mushrooms under solar

The use of agricultural land for solar panels can create a conflict between food production and energy production. In a unique project in Japan mushrooms are grown under the solar panels. We interviewed Minami Kikuchi from the Startup company Sustainergy in Tokyo Japan.

What is the potential for solar energy in Japan?

The potential of PV is approximately 566 GW except for rooftops of buildings and 381 GW of the number is for abandoned farmland, according to New Energy and Industrial Development Organization (NEDO).

Is shortage of land for placing solar panels a problem in Japan?

Yes, it is difficult to find a suitable site for solar power generation. Even if we could find a good site, probably we have to develop the land with many costs, or trees around the site might block off the sunlight. In Japan approximately 70% of the land is covered by forest, therefore flat and large sites are rare.

In your project you grow mushrooms under the solar panels. What type of mushrooms are grown and why did you choose this type?

We grow “wood ear mushrooms” which are frequently used for Chinese cuisine. To begin with, mushrooms do not contain chlorophyll so do not require direct sunlight to grow. Among them, we chose “wood ear mushrooms” because this type of mushrooms is relatively easy to grow compared to other mushrooms and possible to cultivate on the shelves which means you don’t have to worry about appropriate soil for cultivating.

Furthermore, although the current situation in Japan is that more than 90% of total wood ear mushroom consumption is made in China, suppliers want to convert to domestic products from the perspective of food safety, so we could expect some demands in the market.

Can you place less solar panels per acre when you combine them with mushroom growing?

As stated previously, mushrooms do not require the sunlight to grow so we do not have to reduce the number of solar panels per acre. Thus, we would rather add panels than reduce so as to get darker.

Did you need to make special adjustments in the solar installation to make mushroom growing possible?

We install shelves and sprinkling tubes to cultivate, but these are not special equipment.

What is the expected production yield of the mushrooms per acre?

The production yield per acre may change depending on how many mushroom beds are put on a shelf so I would say that the expected production of the whole area is 20,000kg for about 5 acres.

And how much additional income will this generate for the farmer per acre?

The financial management between power generation and agriculture is separated so basically there is no additional income for the farmer from power generation income.

However, since the upfront investment for agricultural equipment was borne by the energy utility, farmers did not make a large investment, which means that they can try to cultivate new agricultural products without risk, and eventually their income is expected to increase.

What is the business case for the solar panels? Are they paid for by the farmer or by an energy utility?

Solar panels were installed by a finance lease, and it is to be repaid by the energy utility over 15 years.

Does the government of Japan stimulate dual use of farmland for farming and solar energy?

In Japan, there are a number of farmlands abandoned for many years, where farmers can no longer continue agriculture due to ageing etc, but they can not even divert the land to some other purposes because the farmland has been subsidized for field improvement in the past. This kind of out-of-date system is one of the serious causes of local decline, and prevents locals from flourishing.

To make improvements in this situation, the government had introduced the new institution of dual use of solar energy and farmland for farming in 2013. We think the “government” itself stimulates, but the local departments at a field level are not likely to promote positively because apparently they do not want to increase their own tasks and loads. Many companies expect to install solar power plants with agriculture, but it is not easy for them to enter into the market because of those local negative attitudes (depending on the area).

What have been the biggest challenges in the project?

In Japan, using farmland is very restricted by the government and when someone tries to install a solar power plant to a farm they must make an application to the agricultural committee in each town. This application process made our project more challenging because the agricultural committee of this town had never received this kind of application and examined until ours. Furthermore, we had trouble adapting our plans to suit the standard released by MAFF (Ministry of Agriculture, Forestry and Fisheries of Japan), which describes a lot of terms to construct a solar farm.

What has been the response from the farmers so far?

The farmers cultivate wood ear mushrooms for the first time so they have tried and errored from the beginning. Although it is said that management of the wood ear mushroom is easier than other mushrooms, they had many troubles as they did not even know how to grow wood ear mushrooms. In fact, however, many local people got employed and this project can revitalize the local area as a new industry, so farmers are working with pride.

If this project is successful, how much potential for this type of dual-use do you expect in Japan?

We cannot assert the number of the potential, but we have already had many inquiries that request our advices after our news released so we think there are many seeds. However, the price of selling electricity from solar power has been gradually decreasing year by year so we think the number of this type of solar farm will not increase exponentially.

Do you also want to do similar projects in other countries?

If we get a chance, of course, we want to challenge. The farm products or the type of equipment should be different in each country thus it would be interesting for us.

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Photo’s : courtesy of Sustainergy

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Swiss Solar Decathlon Team

Swiss Solar Decathlon Team

The Solar Decathlon competition for 2017 will be held in October in Denver Colorado. In this international competition student teams are challenged to design, build and operate solar powered, energy efficient, sustainable and attractive houses. We interviewed the Swiss team that will participate in the competition.

How would you describe the Swiss design for the Solar Decathlon in one sentence?

Thanks to our NeighborHub experience, you can reach a whole neighbourhood and learn in a community spirit about sustainable ways of life.

Which schools and universities participate in the team?

The Swiss Team is made up by students from the Ecole Polytechnique Fédérale de Lausanne (EPFL), the School of Engineering and Architecture of Fribourg (HEIA-FR), the Geneva University of Art and Design (HEAD) and the University of Fribourg (UNIFR).

How did you organize the design process with such a large number of participants and specialities?

Team members were organized in seven working groups, named work packages, with a student manager for each group: Architecture, Engineering, Project Communication, Branding Communication, Partnership Development, Prototype Realization, Management. The work package Management had to ensure the general team coordination, information exchanges, budget tracking and work in close relation with the Solar Decathlon’s organisers. Everyone was aware of the challenge of being such a big team and gave his/her best.

The Solar Decathlon consists of 10 contests: architecture, health and comfort, market potential, appliances, engineering, home life, communications, water, innovation and energy. Which are the three aspects where your design scores exceptionally well?

We worked hard to perform well in the Communication and Architecture contests. Indeed, the NeighborHub has to adapt to a multitude of activities: a Repair space, urban gardening, eco-responsible cooking classes… More than a solar-powered house designed for a family, the project seeks to promote community spirit by offering a neighbourhood house where citizens can learn how to share more and use fewer resources. To sum up, our challenge was to build a house that would become our best communication tool, raise awareness and have an impact far beyond its surface.

About the Energy Contest, we took a bet : the NeighborHub has 29 solar panels that are all installed on its façades only, With this choice, the team demonstrates that it has now become feasible to rely entirely on wall-mounted solar panels. The building produces more than enough energy, even considering the risk of shade in urban environments. We believe that our strategy of concentrating power production on the façades makes us stands out starkly from our competitors.

The closed water cycle is one of the NeighborHub’s strong suits in the competition. We believe our “Every raindrop counts” strategy will help us win the Water Contest. The water used in the NeighborHub can be separated out into various types like for waste recycling. The rainwater collected on the roof is used for some domestic appliances. The waste waste water from these appliances, as well as from showers and sinks, gets used as grey water, which is treated using an on-site phyto-purification process: the water is filtered and purified using a reed bed with different layers of gravel. There is no “black water” from conventional toilets in the NeighborHub, as the building is instead equipped with dry toilets.

What have been the challenges in building the design?

There are several points that have strongly influenced our choice:

US security rules: the PV solar panels had to be UL certified; the integration of residential sprinklers (which are not used for residential building); the operating temperatures (of the fridge for instance that has to stay far colder than in Switzerland); the emergency exits that have to be different than in Switzerland, etc.

The transportation: the module’s dimensions had to enter in containers and the transportation’s extreme conditions, especially when crossing the Atlantic Ocean (humidity, temperatures, violent and perpetual movements, rust…), had a strong impact on the design. The competition rules have influenced the dimensions of the house (height, heated space or not heated space…)

All these challenges have pushed us to go further.

The built design has to be transportable because of the location of the Solar Decathlon in the USA. Did this requirement conflict with your other design goals?

Not really because it was integrated as a key point from the beginning of the design development. We integrated directly the notion of modular construction in order to have a transportable and quickly-assembled house.

Where are the biggest differences between the performance of your design and the current Swiss building requirements?

The fundamental difference is the concept of the NeighborHub itself. Current Swiss building requirements go in the direction of consuming less energy and producing renewable energy on-site. However, our NeighborHub goes further by presenting tools and alternatives about seven driving themes: energy of course but also water management, waste management, mobility food, materials and biodiversity.

What will the design be used for after its return to Switzerland?

The NeighborHub will return to Fribourg at the place where it has been built. It will contribute to the development of this new innovation square in the middle of Fribourg city. The NeighborHub will act there as either an initiator of changes or a space that brings people together to experiment sustainable solutions.

What do you consider the biggest inspiration that the team members get from participating in a project like this?

The team spirit: the collaboration, communication, discussions, development together towards the same objective. Each team member is important and helps reaching our common goal. This team spirit is like a proof for us that together we can build a better future.

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Photo’s: courtesy of Alain Herzog Swiss living challenge

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Science & Technology Today wishes all teams good luck in this exciting competition.


Dutch Solar Decathlon Team

Dutch Solar Decathlon Team

The Solar Decathlon competition for 2017 will be held in October in Denver Colorado. In this international competition student teams are challenged to design, build and operate solar powered, energy efficient, sustainable and attractive houses. We interviewed the Dutch team that will participate in the competition.

Can you tell us something about the team for your Solar Decathlon project?

Selficient started as a small project of five students majoring in engineering at the University of applied Sciences Utrecht. They submitted their concept into the Solar Decathlon and as the only University of Applied sciences, amongst higher level universities, they reached the finale. From then on, Selficient began to grow with students from all kinds of majors, not only from engineering, but also from Legal to Communications. The multidisciplinary team has various specialities at different fields, but physically building the Selficient house is what connects them.

How would you describe your design in one sentence?

We develop a self-sufficient house by using modern technologies and building accordingly to the principles of the circular economy and cradle-to-cradle philosophies.

Your design is based on life course adaptation. Can you explain what this means?

Every part of the house is possible to change, because Selficient is fully modular on different levels (e.g. adding or removing volumes, windows and facade cladding). With such kind of flexible building method, we provide the customer with choices that gives the necessary freedom to design a unique house. That is why Selficient is for everyone, no matter the situation. For example, if a first time buyer (couple) buys the house with one bedroom, do they need to move to a bigger house if they are expecting a child? This is a usual practice but not necessary with Selficient. Due to the modular structure they can easily add one more room to the house and keep living in their own home. Selficient adapts according to life situations. That is the future of housing.

How did you incorporate this goal into your design?

We made it possible in our design, by implementing modularity within the concept. It means every part of the house can be easily resized and (re)placed. Due to materials and components that are reusable, recyclable and, where possible, bio-based, nothing of the house will be to waste when you change your Selficient house.

Your design is also based on the circular economy and cradle to cradle. Were all the components you needed available in this standard?

Almost every component was available like we wanted. We had new technology from Schneider to implement in our house, we had help from Bsmart for installing the electrical wires and because of the beautiful framework of Suteki, it was a piece of cake to set the house up. For the wooden panels, we had Maatchalets customize it for us. In overall, the most components were there, but to make it work, we collaborated with various partners.

What were the lessons learned in the integration of all the different components?

The first time, we had to try different things. The integration process can be compared to LEGO: you have to puzzle and play with the blocks until they connect. That takes up a lot of time. Eventually, you will find a way to connect a compartment to another designated compartment. By trial-and-error, we developed a quicker way to build, which we will use in Denver at the Solar Decathlon site.

One of the features in your design is the greenhouse and the orientation towards the sun. How important are these features in regards to the goal of self-sufficiency?

The Greenhouse is a beautiful piece of our design, but it is not important for the goal of self-sufficiency. For the competition itself, we chose to leave the greenhouse out of the equation. Partly because of the little time that we have to prepare it, but also because it was not necessary.

Did you find that the goals of life course adaptation, circular economy and self sufficiency were opposing or reinforcing each other?

Well, with our concept, we think it reinforces our goals within self sufficiency. By changing the game from take, make and dispose (the linear approach), we go to a cyclical approach, where we will fully use the resources.

And how about affordability and the other goals?

Our prototype is not affordable for Everyman yet, but when you think about how easy it is to build a Selficient house, you can see the benefits. Not only are the materials prefab, you can also construct in such little amount of time and reuse and recycle all the materials when needed. It is not necessary to buy a whole new house, when a part is broken, you can replace it easily. In other words, it is a long-term investment and you can even make a profit via the energy you store. We believe that our greatest goal,  sustainable and affordable living for Everyman, will be in the best interest for all the next generations.

Will your design be the future building standard?

If we want to comply to the Paris Agreements and have a better future for the next generations, than the building standard has to change. Hopefully our design will make a difference.

What is the key thing you personally learned from participating in this project?

The most important thing we have learned from participating in this project is working together as a multidisciplinary team. We had to keep a healthy balance between our personal lives, school, work and Selficient team.

We all developed in a professional matter and felt the pride and support from our school, Utrecht University of Applied Sciences. We took our wins and losses as a team. But we are not there yet. We are ready to take the next step and develop our professional skills abroad. We are going to Denver with one team full of bright minds, created by other angles and perceptions of each individual.

We are thankful for this project, the experiences from it and for each teammate that made Selficient possible.

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Photo’s: courtesy of Selficient.

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Science & Technology Today wishes all teams good luck in this exciting competition.