Problem description

The main problem 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, photovoltaics, wind or geothermal energy. The problem of this source is fluctuating availability. To stay safe the most part is 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.
The percentage of regenerative energy as an electricity source increases in Germany over the last years continuously. 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 it might be able to.

Possible applications

With our project we engage these 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. 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 an 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 energy has a voltage of 10-30kV. To reduce the voltage transistors has to be built for each fermenter. The costs of this project will exceed each limit. 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 therefor is that we need continuous current for fermentation which 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. This led to the idea to use small wind energy power engines. They 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 roofs. 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. Therefor 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 electric machines like lawn-movers or used as an addition for the fuel of the car. Additionally isobutanol might be used as a heating substance.

The third application 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.

Conclusion

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 changed 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 first application 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.
Wind power for example is a seminal regenerative energy source. The number of wind power stations has increased throughout the last years.

It has to be noted that the typical location of wind power stations shifted because of the technology development.
The increasing number of wind power stations and the increasing capacities result in a huge gain of capacity in megawatt.

For the future several plans were made to invest more time and money in wind power stations. The building of offshore wind parks will hardly increase in the next years which results in an increase of available energy.
In addition the development of the different states shows that more wind power stations will be build throughout the next years.

Problem description

The increasing atmospheric concentration of carbon dioxide is one reason for the global warming. Beside natural carbon dioxide sources there is a huge contribution from humans. 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

fig. 2: Scenario for CCS technology

fig. 2: 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 while applying carbon capture and storage. This technology was developed to reduce emission of carbon dioxide by pumping it into the ground. There are many fears of leaky storages. Our system could be applied to empty such critical storages and store the carbon in another form.




Another application is the use of emission gases from industrial plants. Instead of pumping carbon dioxide under the ground it could be used 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.

Conclusion