Sust(r)ainable® Energy and Food
Authors: R.H.A. de Bruijn
Date: 11 september 2013
Humanity is facing difficult challenges. As the world population will increase to approximately 11 billion by the end of this century, the most obvious problems will be food and water related. Especially because this growth will be in areas that are not suitable for agriculture. At this point in time the process of growing crops and creating clean water is generating lots of carbon dioxide causing global warming resulting in a variety of other challenges. At this moment we are destroying our valuable rainforests to create the fertile grounds to grow the crops necessary to feed the growing population. Continuing this policy will prove to be disastrous. Therefore alternatives must be engineered.
This paper describes an alternative to break out of the vicious circle we are in. An idea that is environmentally friendly and yet will generate precisely the ingredients we need; energy, food and water.
The idea for this innovation originates from 1986 when we saw a solartower near Madrid that was built by a German consortium. We called the idea “Rainman” at the time where we would use the solartowers to produce clouds and rain and prevent global warming.
We presented that idea to the Dutch KNMI and their models calculated the influence of these towers. That they would produce clouds, was certain. At the time, it was however uncertain at what time these clouds would produce rain. We converted this idea into a solution where we don’t need rain to collect the water. Being gliding pilots, we always wondered why we don’t take more advantage of nature’s forces and possibilities. And that is exactly what we did here.
To explain the idea of Sust(r)ainable® Energy it is necessary to understand a law of physics; warm air can contain more water than cool air. So, if we can create an environment with enough supply of warm air, then in this environment it is possible to saturate this air and then cool it down. While cooling down, water will condensate and can be collected. This is distilled water.
This whole idea can be executed, using nature’s forces without adding any energy. Therefore, it is a carbon neutral process.
Solar Towers 2.0
By building a solar tower as shown in figure 1, a natural draft is created that will create a strong wind of air that is saturated by the nearby sea. Under a glass surface the air is heated and directed to the tower where it will ascend. While ascending it drives a wind turbine thus producing sustainable energy.
A side-effect in this constellation is that under the glass surface a variety of plants can be grown. Enough water is available for irrigation. In this solution it is possible to create:
- Sustainable energy
- Clean water
- Pure sea salt
Another possibility is to use the principles as explained above to create greenhouses in which enormous quantities of crops can be grown. By using a condenser instead of a Solar tower the same principles can be applied.
Dutch greenhouse technology is very advanced. In appendix Y some examples of this technology are explained. We are able to grow 50-60 kg of paprika per m2 per year. In the dutch climate lots of (fossil) energy is needed to generate the desired climate in the greenhouses and while labour is very expensive in Holland we are still able to export 90% of the crops grown in the greenhouses. Holland is feeding 70 million people with it’s greenhouse technology. Imagine what ha ppens when we bring these greenhouses to areas where the climate is better and labour is cheaper.
The beauty of this idea is that it can be applied in areas that normally aren’t suitable for agriculture. Desert areas like the middle-east or the semi-deserts in South Africa where only one sheep per hectare can live. Because of the absence of water, these areas are now unsuitable but by using the Sust(r)ainable ® solution they’ll be perfect. Though these areas are normally to hot to build Greenhouses, in our setup we can use the cooled air (from the drinkingwater extraction process) to cool the Greenhouses to the desired 22 degrees Celcius. Therefore no additional energy is needed to heat or cool the Greenhouses which is very cost-efficient.
The basic idea is to use a condensor. In this case the situation will be as shown in Figure 2. The water temperature at 180 metres depth is approximately 4 degrees. This cold water will be used to cool the warm saturated air and thus providing clean water and pure sea salt.
Some sustainable energy can be collected in this model but that energy is needed to pump the cold water from the sea.
By combining Sust(r)ainable®Energy and Greenhouses, one constellation can generate Energy, Food and Water. The optimum is location dependent. Every location has it’s own properties that define the optimum.
The water for Greenhouse use is in fact residual to the creation of drinking water. When creating drinking water, only 50% of the water is extracted. The remaining water can be used in the Greenhouses. Food prices vary but show an upward trend (supply and demand!) and the demand for energy and clean energy in particular is also increasing rapidly.
Therefore Sust(r)ainable® Energy and Food provides the solution for the main challenges of humanity!
Appendix A Statistics
As shown in Figure 3 this plan contains multiple condenser-units. Each unit is able to produce between 48.000 and 120.000 liters of clean water per day.
Food or oil
The Greenhouse is a perfect environment to grow crops. Jatropha can be grown in the area behind the greenhouse to provide Biofuel. Jatropha will generate approximately 2000 liter per hectare.
The combination of the height of the solar tower and the diameter determines the amount of energy that is generated. For instance, 500 meter high chimney can produce approximately 10 MW.
Pure Sea salt
Pure sea salt is a valuable mineral. Each condenser produces approximately 40 tons of pure sea salt per year
Appendix B Calculation Example Water
The saturation unit is 10m x 12x x 2,3m and the Condenser-unit is 40m x 12m x 2,3m.
The saturation unit can evaporate between 5000 and 20.000 liters of seawater per hour. See table 1.
The condenser-unit has a return of 50% and can deliver between 2.500 and 18.750 liters of distilled water per hour. See table 1. The other 50% is used condition the Greenhouse.
Using this information, table 2 shows how much distilled water is generated per period.
The largest part of the investment is needed for the cooling water. Therefore a minimum constellation should exist of 100 units. The investment for the cooling water-installation is approximately $ 2.000.000. Per unit an investment of $ 200.000 is needed. Total investment is $ 22.000.000.
The units produce approximately 4.000.000 m3 distilled water per year and 4.000 metric tons of pure sea salt. Assuming that the water can be sold at $ 1,50 per m3 and the sea-salt at $ 250 per ton this constellation will generate $ 7.000.000 per year. Another possibility is to bottle the water and sell the water per liter. This will increase the production costs but revenues will be dramatically higher.
Dependant on the location in the world, this idea is expandable in a combination with greenhouses (for food production) and a chimney (for energy-production). Greenhouses are profitable at a yield of approximately $ 15,- per m2. Whether a chimney for energy-production is profitable, is dependent on local energy prices.
Appendix C Calculation Example Food
75% of the greenhouse area can be used to grow crops. The other 25% is needed for paths, technical areas en construction. Therefore in an greenhouse of 100 hectares, 750,000 m2 is available to grow crops.
In the example of paprika’s, 50 kilograms per m2 can be grown. This greenhouse will generate 37,500,000 kilograms (750,000 x 50) of paprika’s per year. At $ 2,- per kilogram that is $ 75,000,000 per year.
Approximately the same figures apply to tomatoes, cucumbers and lettuce.
Appendix D Greenhouse technology
Waterefficiency, higher substrate resilience and the intelligent use of peat were the targetpoints of GroSci2013, an international symposium, organized by Wageningen University. Over 225 researchers from over 40 countries attended.
15 times more waterefficient
“Using more intelligent irrigations systems in controlled cultivation circumstances, results in substantial savings in water” says Cecilia Stanghilini of Wageningen University in her opening speech. “A more efficient water transport from the source, a more accurate irrigationsystem and covered cultivation leads to a good quality for instance tomatoes using far less water. Research showed a reduction from 60 to only 4 liters of water to grow 1 kilogram tomatoes. In areas where water is scarce, modern techniques can help cultivating quality products.”
Oxygen in the root area
Prof. Jean Caron of Université Laval, Canada gave a presentation on oxygen transport in the root area. He told that model calculations and experiments showed that not the amount of oxygen in the watery solution is important but the transport speed. “The plant doesn’t mind a low oxygen level as long as sufficiently fast oxygene is supplied to the roothair area”.
There’s a global interest in increasing substrate resiliance. Researcher Sammar Khalil of the Swedish University of Agricultural Sciences showed an overview of the possibilities to stimulate existing microlife in the rootzone by use of additions and rooting media. By stimulating the growth of bacteria and fungi, harmful organisms have less opportunities.
Treatment of bad water
Researcher Nikolaos Katsoulos of Thessaly University, Greece discussed new techniques to recycle bad water for use in extensive cultivation. He showed some modern pre-treatment- and recirculationtechniques that enables areas where water is scarce to cultivate quality products.
Peat- and lome substitutes
Johannes Welsch of the german Industrieverband Gartenbau told that there’s enough loam for the years to come but that a lot of effort is put into the development of peat substitutes.
In 2015 the symposium for Rooting Media will be held in Vienna, Austria and the symposium for Hydroponics in ‘the Gold Coast’, Australia.
Appendix E Projects
- Ennoblement- Better Plants:
- Breeding for abiotic stress tolerance
- A genetic analysis pipeline for polyploids
- Sequencing van het genoom
- Breeding for improved combined stresses
- Innovatieprogramma zaaizaadtechnologie
- A chemical genomics approach for improved plant propagation
- Sustainable Production:
- Waterproof Greenhouses
- Energy en Biobased:
- Energy & CO2
- Valorisation champost for more sustainable soil management, more robust cultivation systems and more efficient use of phosphate in outdoor horticulture.
- Space and logistics:
- Sustainable floriculture chain, GreenCHAINge