Problem description

One of the biggest current problems of today's society is the transport and storage of electricity. It is tried to cover a high amount of required energy through regenerative sources like solar, photovoltaic, wind or geothermal energy. The problem of these sources is the fluctuating availability. To stay safe and maintain the electrical supply network the most needed energy is still covered through traditional energy sources. This means that surplus of energy mainly consist of regenerative energy. The surplus of energy cannot be stored efficiently so that it is wasted. A further problem is that a part of the energy will be lost during the transport. For example the rotor of wind power stations is moved by the wind which converts wind energy into mechanical energy. This mechanical energy will be converted into electricity. The conversion of energy leads to a loss of energy. Only 45% of the original energy will get to the electrical network as mentioned in Figure 1.
The percentage of regenerative energy as an electricity source has been increased in Germany over the last years continuously as shown in Figure 2. Wind power is one third of this.
This leads to the fact that the new sources through regenerative energy cannot be used as effective as they might be able to.

Possible applications

With our project we engage these named problems. We aim to store the surplus of energy by generating a product which can be combusted to produce energy again.
Our system relies on a fermenter in which bacteria grow by using electricity and carbon dioxide. The growth should be enhanced through the gain of reduction equivalents.
One application type we think of is the stationary application. With stationary application the size of the fermenter can be increased and the volume of generated product increases too. It makes sense to use sites where a surplus of energy arises. For example we are thinking of an application at wind power stations. Some of the produced energy could be used directly to produce more energy by the wind power station. It makes sense to hold the fermenter in operating state the whole time because there are some moments when the amount of surplus is very high. The problem is that the produced electrical energy has a voltage of 10-30kV, a local energy supply company,Stadtwerke Bielefeld, mentioned. To reduce the voltage transistors has to be built for each fermenter. Therefor the costs of this project will be too high for an economic application. A further development of this idea is to place our fermenter at electric power transformation substations. The needed transistors are already installed. The incoming regenerative energy would be used as the energy for the fermenter. A problem here is that we need continuous current for the fermentation process. This is produced at the wind power engine but immediately transformed into alternating current.
The availability of energy through regenerative sources varies. The energy from regenerative sources in Bielefeld is never down regulated while regulation at coast regions is more common. We got insights into the load profile of a wind power engine of Bielefeld by SWB Netz GmbH.

The load profile showed a high variance throughout a day, a month, a season or a year. For a better understanding we got in contact with the BMWI to talk about feed-in management. This led to the idea to use small wind energy power engines. This application come up through lively discussions with a local energy supply company, Stadtwerke Bielefeld. The power engines have a height of 15-30 meters which results in a high sound annoyance. Until now they lack in a real application. Maybe they are a plausible base for our fermentation system.

A second application scenario is to install our fermenter at anybody’s home. Many houses already produce regenerative energy through photovoltaic panels on the roof. The problem of this production is that the whole amount of produced energy cannot be used by the occupants itself. Most of the energy will be delivered to electric power transformation substations. It would make sense to store the energy at home where it is produced. Therefore the fermenter would be placed in the cellar. The produced isobutanol could be extracted and stored. Applications for the isobutanol at home could be various. For example it could be added to machines like lawn-movers or used as an addition for the fuel of the car as shown in Figure 5. Additionally isobutanol might be used as a heating substance.

The third scenario for stationary application would be at industrial production sites where isobutanol is needed. The fermenter would be placed directly on the premises. Photovoltaics would feed the bacteria in the fermenter which generate isobutanol for the productions of the company. An example production site would be a varnish producer. We got in contact with the Eckart GmbH, a member of Altana. They told us that they do not use isobutanol for production of pigments and others but the similar substance butanol is an often mentioned theme for discussion.

Consideration

An application at home seems plausible for users of photovoltaics. The problem might be the implementation of the whole system. The heating system has to be adapted to isobutanol. This leads to a dependency on the fermenter. If a problem leads to cell death of the culture in the fermenter the heating system fails.
The application for industrial production sites sounds very inefficient at this stage of development. Presumably the isobutanol is much cheaper to buy for the company than to build up a large fermenter which makes the company dependent.
The application at wind engines for the wind power station looks the most feasible one. If the system is installed at electric power transformation substations, unused energy could be taken for production. A large amount of regenerative energy is surplus. If there is a problem with the culture in the fermenter which leads to the cell death no isobutanol can be produced. In the first application, the problem can be solved because not the total volume of isobutanol is directly needed. It would be a surplus product to use.
Wind power for example is a seminal regenerative energy source. The number of wind power stations has increased throughout the last years in Germany as shown in Figure 7.

It has to be noted that the typical location of wind power stations shifted because of the technology development in higher efficiency as shown in Figure 8.
The increasing number of wind power stations and the increasing capacities result in a huge gain of capacity in megawatt (Figure 9, 10 and 11).

For the future several plans were made to invest more time and money in wind power stations. The building of offshore wind parks will increase in the next years which results in an increase of available energy. For this purpose we talked with a big constructer of offshore windparks, BARD Engineering GmbH.
In addition the development of the different states shows that more wind power stations will be built throughout the next years.

Problem description

The increasing atmospheric concentration of carbon dioxide is one reason for global warming. Beside natural carbon dioxide sources there is a huge contribution from humans (Figure 12). There are many attempts to reduce the emission of greenhouse gases like carbon dioxide. An alternative strategy could be the fixation of this particular gas from the air.

Possible applications

Figure 13: Scenario for CCS technology

Figure 14: Scenario for industry

Our modified bacterium uses carbon dioxide for its growth and the product synthesis. It could be able to convert the atmospheric carbon dioxide to oxygen and an organic carbon molecule. Important for this process is a high carbon dioxide concentration in the environment of our bacterium. Possible sources of concentrated carbon dioxide are depots which are currently filled for carbon capture and storage. This Carbon Capture & Storage technology was developed to reduce emission of carbon dioxide by pumping it into the ground. There are many fears of leaky storages (Spiegel). Our system could be applied to empty such critical storages and store the carbon in another form as shown in Figure 13.




Another application is the use of emission gases from industrial plants. Instead of pumping carbon dioxide under the ground it could be used (Figure 14) as growth substrate for our bacterium. Of course this is only useful if the carbon dioxide creating process is not used for electricity production.

The bacterium needs electric power for the carbon dioxide fixation process. The above mentioned application requires a renewable form of electricity generation to provide plenty of electric power. This could be achieved either by increased use of solar and wind energy or by future technologies like nuclear fusion.

Consideration

The problem of increasing CO₂ amounts could be engaged by the Carbon Capture & Storage (CCS) technology. The advantage of this technology is that it is a cost effective option to reduce carbon dioxide. The development of this technology leads to an application for our project in different sectors.

The plan to develop the CCS technology is taken into account by different countries. They aim to improve the technology and apply it at industrial sites. CCS could reduce emission by 4 Gt annually by 2050 if 20 - 40 percent of the facilities were equipped with CCS (Figure 15 and 16).

These statistics show that the CCS technology seem to be a feasible development throughout the next years. By adding our fermentation system, bound carbon dioxide could by efficiently used by converting it to isobutanol. The advantage is that this kind of carbon source will not deplete in the next years, because the amount of emitted carbon dioxide is high. The most feasible application would be CSS, because CSS will be heavily used in the next years to tackle the CO₂ emission

Problem description

Crude oil is the most important energy source worldwide; among other things, it is required for the production of gasoline and diesel. However, the increasing scarcity is not caused solely by the finiteness of this raw material. On the one hand, political unrest and security problems in the oil-producing countries compromise the security of supply and on the other hand, the price of oil rises by growing demand and speculative markets. Therefore, it is very important to reduce the dependence of the mobility of crude oil in the future. In Germany, there is a decline in sales of crude oil because of the EU targets. Political parameters demand a CO2-reduction of 95 g CO2/km for cars in 2020. This assumes a remarkable increase in efficiency of the applied energy in combination with innovative technologies.

Possible applications

We want to rectify these problems with our project. We intend to produce a substance which can be used as a biofuel. We have chosen isobutanol because it can easily be used as a fuel additive. In contrast to the commonly used gasoline supplement ethanol, the energy density of isobutanol is higher. Theoretically, this means a smaller quantity of this fuel is needed to operate a vehicle. For this reason, our project can be applied for mobility applications.

Figure 17: Scenario for car design

Figure 18: Scenario for ships

Figure 19: Scenario for a space station

First, we think of an implementation in the design of cars (Figure 17). Our idea is, that isobutanol is produced during the ride and the fuel in the tank gets diluted with isobutanol. The bacteria are in a fermenter in the car. The required carbon dioxide is received from the exhaust fumes of the car, while the required electricity is obtained from the self-loading battery or additional photovoltaic panels on top of the car. This idea works until the gasoline supplement reaches the 15 volume percent, which is the norm in Germany and the EU. Gero Storjohann of the German Bundestag told us per e-mail that there are several norms which we have to take into account. The limit is set by the total oxygen in the fuel (DIN EN 228). A large automotive firm from southern Germany confirmed that isobutanol is a possible alternative to ethanol as a fuel additive. Another large automotive firm told us that there are no clear advantages for the use of isobutanol referring to the octane rating. Several working groups are doing basic research in this field as mentioned on the Homepage of the "Bundesministerium für Bildung und Forschung (BMBF)".

A second idea for an application is the installation of our fermenter in the in-cabin room of a ship (Figure 18). Here the carbon dioxide is obtained from the exhaust fumes and the electricity is received from the affixed photovoltaic panels on the ship. This idea is similar to the application on cars. On the ship it is also thinkable to gain the electricity from small wind engines which are also affixed on the ship. We discussed our idea with a big German shipyard. They stated that until now mainly fat oil is used to fuel ships and other alternatives are rare and not implemented yet. Our project looks more plausible by thinking of the waste recovery system, which is already performed through a fermenter running on wildtype bacteria on ships. This means that the infrastructure for a fermenter is available.



Until now all of our ideas are mobility applications with association to the earth. But what about locomotion in space? Space stations have big photovoltaic panels and their generated electricity is not used completely. This electricity and the carbon dioxide available from human breathing means that a production system in a space station is possible. The NASA already sends bacteria in a small fermentation size into space to do some experiments. Here the exchangeability of our production system would be of great benefit. The astronauts might not need isobutanol but they might need biological plastics, antibiotics or feed additives which could be produced instead of isobutanol via pathway adaption.

Consideration

We did research about all three application ideas. It looks feasible to construct a fermenter for a space station. Sadly enough we could not get any further information, because we got no answers from any big stakeholder in this field. Combining our technology with a ship sounds feasible because constructs of the size of a fermenter are already used on several ships as well as container vessels to recover waste. This means that there already is experience with bacteria on board. This includes service, repair and control. A problem for this application is that ships usually use fat oil which cannot be diluted with isobutanol to increase the cruising range of the ship. The exchangeability of our production system could be used here for different needed products.
The preparation of a car to use a fermenter seems complex. But other advantages for using our system are already mentioned above. For example isobutanol is a proper alternative to ethanol. It has better energy density in comparison to ethanol, but has a lower octane rating. This means if there is the possibility to purchase isobutanol for a lower amount of money than ethanol, it could be used as an alternative dilution factor. A large automotive firm of southern Germany is already testing a fuel with an ethanol dilution of 20%. This means that the development of diluted fuels will advance throughout the next years. This could be positive for our project, because the limitation of gasoline supplement is increased and the produced isobutanol can be supplied longer. Another development for cars is the mounting of photovoltaic panels on the roof of the car. When you think about it, at first it sounds futuristic, but this construct has already been built, as the following picture shows.

This so called "Solar Powered Ventilation System" was designed by Toyota. It uses the self-produced electricity to power an electric fan to draw outside air into, through, and out of the cabin. It lowers the cabin temperature near to the outside temperature, once the inside temperature of the car reaches 9°C. Although the photovoltaic panels on top of the car were originally build for electric cars, the system could be used to power the bacteria in our fermentation system.
During discussions with a large German automotive firm we talked about problems of crash-safety, mobile technology and the available space in the car for our fermentation system. We came to the conclusion, that a new car design is required for our idea. Currently available cars cannot be upgraded with our project and a further development of this idea is necessary.
The table below (Spring 2014) shows that the range and the hours to recharge are not optimal at the moment for several users. This fact shows that there is still a long way to go for our system to be applied. The effectivity of an electric car is not as high that it can oust a gasoline car. After the discussion with the automotive firms it became clear that there will be an equation between both types of cars.

Electric vs. Gasoline
No tailpipe emissions	Greenhouse gases/pollution
100 +/- mile range	300+ mile range
Hours to recharge	Minutes to refuel
2 cents per mile	12+ cents per mile

Table 1: Comparison of electric and gasoline vehicles