Team:TU Darmstadt/PolicyandPractices/ApplicationScenario




The evaluation of unwanted effects of our product was the central aspect of our product innovation process. The first step was the development of an application scenario that tries to examine the usage of our product as realistically as possible. We created an outline of our project with the help of various experts (e. g. Prof. Dr. Michael Grätzel and Solaronix) and our Synenergene supervisors at the Athena Institute in Amsterdam.

Our application scenario involves the production of Grätzel cells (DSCs) with anthocyanidins used as the dye. Those cells should be used to stimulate economy and welfare in rural areas with no electricity access. During the development process of our application scenario we have realized that a different biosynthesis product would be more suitable for a successful downstream processing and adopted our pathway.



The Problem

The availability of electrical power is very limited in many African countries. The population and the economy suffer from frequent power blackouts. In poor rural areas there is even less to no access to the electrical power grid. It is known that access to electricity has massive impacts on the population [1]. Additional lighting leads to increased time of children spent studying, because they are able to read in the evening. Electrically powered machines increase productivity and thus the net income gain per household. Furthermore the use of agricultural machines and cooking on electric stoves instead of fires has positive health benefits.

Nevertheless, central governments aren’t able to finance a wide-spread power grid and stay reluctant when financing off-the-grid solutions. First of all they fear the misuse of funds. Secondly investing the available money in the cities usually has a bigger benefit for the economy. Same counts for the maintenance of the power supply system in rural areas. So actually a power supply for economically weak regions is often not profitable enough for governments.

An off-the-grid solution with small upkeep-costs would be the solution to this problem. Some NGOs are trying to achieve this by installing small wind power plants [2]. This works well in areas with the required wind available. But in other areas this approach alone wouldn’t be suitable. And there’s another problem which has to be mentioned: The wind power plant is in fact off the main grid but it generates a small local grid. Therefore the same problems still exist in a smaller scale. Large villages get access but farmers and people living outside the center still don’t have access to electricity. In the end a solution independent of local conditions and population density would be most preferable.


Model region: Senegal

Senegal is a Presidential Republic in West Africa and is located close to the equator and possesses a semi-arid climate. About 60 % of the working population is employed in the agricultural sector, although its production accounts for less than 20% of the national GDP. Senegal’s most important agricultural product is the groundnut and most of the groundnut production is controlled by Islamic Sufi orders and brotherhoods, but desertification and crop failures endanger agricultural production. At the same time unemployment rates are high (> 50 %) and almost half of the population live below the poverty level. Illiteracy is at about 50% and particularly high amongst women. Child labor is prevalent because less than half of the child population between 5 and 14 years attend school and the public schools are not able to educate all children. Rural population's poverty leads to a rising exodus towards the cities and urbanization.

While Senegal struggles with its economic and educational problems, its political system is relatively stable and many NGOs are experienced with development projects in the region. Due to these preconditions our approach could be particularly promising for Senegal.

Figure 1: Graphic representation of the problem

The Solution

Our solution envisions the biotechnological production of anthocyanidins (flower pigments) in microorganisms. These anthocyanines will be used as dyes for dye-sensitized solar cells (DYSC or Grätzel cells). DYSCs are capable of producing energy under difficult circumstances like sandstorms or cloudy sky. Therefore they can be installed directly at the location of energy usage and do not even need a small scale grid. Financed by microcredits, locals get their own solar panel and machines for their usage and they are responsible for operating them. Thus the customers of this project only need the will to build up an off-grid solar system. The usage is simple, so everybody will be able to install and operate the panels on their own after brief instruction.

Grätzel cells

DSCs have significant differences to classical solar cells. They can effectively utilize scattered light and are therefore perfect for subequatorial regions with cloudy skies. Their efficiency is lower as normal solar cells, but that is compensated by a lower loss caused by high temperatures, which makes them a suitabel alternative in hot regions. DSCs are operating two-sided, which means light can be absorbed at their frontside and on their backside. In regions with a sharp angle of entry (at and nearby the equator), DSC panels can be installed upright for absorbing light in the most efficient way. For all these reasons DSCs are the solar cell of choice in equatorial and subequatorial areas.

Figure 2: Grätzel cells can utilize diffuse light and don't need a special angle to fully utilize the light.


The solar cells will be produced in cooperation with classical solar companies. These companies already exist (e.g. Solaronix). Our project only adds the application of biotechnology for cheaper and more efficient versions of DSCs. So the solar cells only need to be ordered and bought. Local partners and NGOs shall train the village population.

Both, the DSCs as well as required machines, will be financed by microcredits which are lend from one of the established microcredit organization in Senegal. The microcredits will only be given to women in groups of five or six, because experiences have shown that groups of women tend to be more reliable debtors. Another desirable side effect is women empowerment by a more steady income for the female population.

Figure 3: Organigram about the project's funding


In our project we develop the large-scale production of organic pigments. The original source of anthocyanidins would be pigment-containing flowers, harvested from large plantations, and subsequent extraction. This form of cultivation needs large agricultural spaces and huge amounts of pesticides. With our implementation of pigment synthesis in bacteria, the dyes can be produced in a fermenter similar to a brewery. This is cheaper, better for the environment and does not need agricultural space which can be used for food production.

This application scenario caused an adoption of our biosynthetic pathway. Since we've realized that our product will be only applied in relatively small niche and our dyes will have to be produced at a different place than where they will be used (see also Production below), we've decided to produce anthocyanidins instead of anthocyanins and remove one enzyme of our metabolic pathway.


High-tech mass productions of Grätzel cells would decrease the overall costs. Since rural areas lack the infrastructure and know-how to operate E. coli fermenters or production plants for solar cells, the production of both has to be based in industrial countries. Then the already assembled DSCs have to be transported to the location of interest. Their light and compact design gives them a transportation advantage compared to wind turbines.


Since we intend to use the Grätzel cells under potentially harsh conditions, the product's life cycle is a big issue. In order to reach a life cycle of 20-30 years several measures have to be applied. Different coatings protect the cell from UV radiation and the use of different anthocyanines can increase the heat stability. But since normal solar cells lose 20-30% of their efficiency in the first year and DSCs do not, they are the best option for sustainability even without optimization. The liquid inside the panel consists of organic pigments and an iodine solution. Therefore it does not pose a hazard for humans and the environment.


The costs to connect rural villages to the power grid are immense, so the only alternatives are other off-grid solutions. Classical solar cells are not only more expensive than DSCs, they also have some drawbacks when used in hot regions. But their main problem is the inefficient utilization of diffuse light. Another practical solution would be the installation of wind power plants. The advantage of wind power is the independence of sunshine. The disadvantage is the dependency on wind. Combinations of both (DSCs and wind turbines) can provide stable access to electricity in rural areas. But again that is only a solution for rather big villages and right now it is only financed by development aid budget.