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Bioenergy

Bioenergy is renewable energy derived from biomass. Biomass is organic material that was produced by living organisms. Each type of biomass was once converted into chemical energy using sunlight and then stored.

Since biomass is stored chemical energy, it can be burned directly. Biofuels can be produced from biomass in solid, liquid or gaseous form. Bio-electricity is both the direct use of biomass and the conversion of biomass into oils, biogas or other fuels for power generation.

Wood that is burned to make fire is another example of biomass. Wood is the world’s most widely used biofuel. Ethanol is also a popular biofuel. It is produced by fermentation of sugars. The process is the same as in alcoholic fermentation for the production of beer or wine. Usually, yeasts carry out fermentation, but other microorganisms, such as clostridia are capable of producing alcohols and other volatile organics as well.

While combustion of biomass produces about the same amount of CO2 as fossil fuels, biofuels are produced in the present day and their combustion does not release additional CO2 into the atmosphere. Biofuels can also be used as fuel additives to reduce carbon emissions from gasoline prices. But there are also vehicles that are powered mainly by biofuels. Bioethanol is widespread in the United States and Brazil, while more biodiesel is produced in the European Union.

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Nanomaterials in bio-electrical systems could improve performance

Since Professor Potter’s discovery of the ability of microbes to turn organic molecules into electricity using microbial fuel cells (MFC) more than a century ago (Potter MC, 1911, Proc Roy Soc Lond Ser B 84:260–276), much research was done to improve the performance. Unfortunately, this did not not produce an economically viable technology. MFCs never made it out of the professors’ class rooms. This may change now that we have advanced nanomaterials available.

The testing of nanomaterials in bio-electrical systems has experienced a Cambrian explosion. The focus usually was on electrodes, membranes, and in the electrolyte with infinite possibilities to find high performing composites. The benefits of such materials include a large surface area, cost savings, and scalability. All are required to successfully commercialize bio-electrical systems. The large-scale commercial application could be wastewater treatment. In our recently published literature survey we discovered that there is no common benchmark for performance, as it is usual in photovoltaics or for batteries. To normalize our findings, we used dollar per peak power capacity as ($/Wp) as it is standard in photovoltaics. The median cost for air cathodes of MFCs is $4,700 /Wp ($2,800 /m²). Platinum on carbon (Pt/C) and carbon nanofibers are the best performing materials with $500 /Wp (Pt/C $2,800 /m²; nanofibers $2,000 /m²).

We found that carbon-based nanomaterials often deliver performance comparable to Pt/C. While MFCs are still far away from being profitable, microbial electrolysis cells already are. With these new carbon-based nanomaterials, MFCs however, are moving closer to become an economic reality. Graphene and carbon nanotubes are promising materials when they are combined with minerals such as manganese or iron oxides. However, the price of graphene is still too expensive to let MFCs become an economic reality in wastewater treatment. The costs of microbial electrolysis, however, are already so low that it is a serious alternative to traditional wastewater treatment as we show in the featured image above. For high strength wastewater, a treatment plant can in fact turn into a power plant with excess power being offered to surrounding neighborhoods. Reducing the costs of microbial electrolysis is accomplished by using a combination of cheap steel and graphite.

Relationship between MEC reactor capacity and total electrode cost including anode and cathode. Errors are standard deviations of four different tubular reactor designs. Anodes are graphite granules and cathodes are steel pipes

 

Graphite, in turn, is the precursor of graphene, a promising material for MFC electrodes. When graphite flakes are reduced to a few graphene layers, some of the most technologically important properties of the material are greatly improved. These include the overall surface and the elasticity. Graphene is therefore a very thin graphite. Many manufacturers of graphene use this to sell a material that is really just cheap graphite. In the journal Advanced Materials Kauling and colleagues published a systematic study of graphene from sixty manufacturers and find that many high-priced graphene products consist mainly of graphite powder. The study found that less than 10% of the material in most products was graphene. None of the tested products contained more than 50% graphene. Many were heavily contaminated, most likely with chemicals used in the production process. This can often lead to a material having catalytic properties which would not have been observed without contamination, as reported by Wang and Pumera.

There are many methods of producing graphene. One of the simplest is the deposition on a metallic surface, as we describe it in our latest publication:

Single-layer graphene (SLG) and multilayer graphene (MLG) are synthesized by chemical vapor deposition (CVD) from a carbon precursor on catalytic metal surfaces. In a surface-mediated CVD process, the carbon precursor, e.g. Isopropyl alcohol (IPA) is decomposed on the metal surface, e.g. Cu or Ni. In order to control the number of graphene layers formed, the solubility of the carbon precursor on the metal catalyst surface must be taken into account. Due to the low solubility of the precursor in Cu, SLG can be formed. It is difficult to grow SLG on the surface of a metal with a high affinity for the precursor.

Protocol:
The protocol is a cheap, safe and simple method for the synthesis of MLG films by CVD in 30-45 minutes in a chemistry lab. A nickel foil is submersed in acetic acid for etching and then transferred to an airtight quartz tube. The same protects the system from ambient oxygen and water vapor. Nitrogen gas is bubbled through the IPA and the resulting IPA saturated gas is passed through the closed system. The exhaust gases are washed in a beaker with a water or a gas wash bottle. The stream is purged for 5 minutes at a rate of about 50 cc/min. As soon as the flame reaches a Meker burner 575-625 °C, it is positioned under the nickel foil, so that sufficient energy for the formation of graphene is available. The flame is extinguished after 5-10 minutes to stop the reaction and to cool the system for 5 minutes. The graphene-coated Ni foil is obtained.

But how thin must graphite flakes be to behave as graphene? A common idea supported by the International Organization for Standardization (ISO) is that flakes with more than ten graphene layers consist essentially of graphite. Thermodynamics say that each atomic layer in a flake with ten or fewer layers at room temperature behaves as a single graphene crystal. In addition, the stiffness of the graphite flakes increases with the layer thickness, which means that thin graphene flakes are orders of magnitude more elastic than thicker graphite flakes.

Unfortunately, to actually use graphene in bioelectric reactors, you still have to make it yourself. The ingredients can be found in our DIY Shop.

 
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A Short Introduction to Bioenergy

Bioenergy is renewable energy derived from biomass. Biomass is organic material that was produced by living organisms. Each type of biomass was once converted into chemical energy using sunlight and then stored.

Since biomass is stored chemical energy, it can be burned directly. Biofuels can be produced from biomass in solid, liquid or gaseous form. Bio-electricity is both the direct use of biomass and the conversion of biomass into oils, biogas or other fuels for power generation.

Wood that is burned to make fire is another example of biomass. Wood is the world’s most widely used biofuel. Ethanol is also a popular biofuel. It is produced by fermentation of sugars. The process is the same as in alcoholic fermentation for the production of beer or wine. Usually, yeasts carry out fermentation, but other microorganisms, such as clostridia are capable of producing alcohols and other volatile organics as well.

While combustion of biomass produces about the same amount of CO2 as fossil fuels, biofuels are produced in the present day and their combustion does not release additional CO2 into the atmosphere. Biofuels can also be used as fuel additives to reduce carbon emissions from gasoline prices. But there are also vehicles that are powered mainly by biofuels. Bioethanol is widespread in the United States and Brazil, while more biodiesel is produced in the European Union.

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What is bio energy? Why do we need bio fuels for energy production?

Bioenergy is the form of energy that is stored in the biological matter or ‘biomasses. It is available in abundance in our world and it is the world’s most important source of renewable energy. Biomass is a versatile source of energy that is used for the production of heat, power, and transport fuels. Biofuels also have the potential to significantly mitigate global warming, also known as climate change. Bioenergy and biofuels encompass energy products derived from plants or animals or organic materials.

Biodiesel, for example, does not only have a positive impact on the environment, it also improves economic activity. As part of our energy mix, biodiesel is not meant to replace fossil fuel but contributes to energy security and benefits local communities.

Good reasons to use biodiesel:

The ease of use

One of the main reasons to use biofuels is that it can be used in combustion engines of vehicles and that it integrates well into existing infrastructures without the need to make changes. It is the fuel that can be stored, burned and pumped the same way as petroleum diesel fuel. It can also be used in pure forms.

The form of energy is providing security

 Energy security of supply as well as affordability rank highest among consumers, as well as in the industry. The economic risks for the biofuel industry are, as for all commodities, energy price hikes, which can disrupt the supply of fossil fuels as fuel becomes an overall limited resource.

Economic development is possible via the use of biofuels

The increase in investment in biofuels will result boosts economic growth, especially for local markets involved in its production and processing. It means that there will be more job opportunities and the developing countries realizing this market opportunity will benefit hugely from the economic growth resulting from global energy demand

Greenhouse gas and emission reduction

Appropriate methods of biofuel production can mitigate significant amounts of greenhouse gases which are currently produced from fossil fuels. It leads to the potential of addressing the important challenges regarding fuel quality and emission. Biodiesel is also the successful alternative to compete with the rigorous emission.

It helps in energy balance

The energy balance refers to the ratio of how much energy is required to produce, manufacture, and distribute of fuel compared to the amount of energy that is released when fuel is burned. Biofuels generally improve the energy security and the energy balance through domestic energy crops.

It is recyclable and biodegradable

Biofuel is less toxic as its attributes make it less likely to harm the environment and cost less damage. It is safer to handle than petroleum fuel due to its low volatility. The recycled oils create multiple benefits to a thriving market and benefit hugely to the growing economies.

But the use of biomass faces criticism due to its costs, both economically and in terms of its energy carbon balance. It is expensive compared to other forms of low carbon energy, for example, natural gas. It drives up the cost of wood in other markets, for example in manufacturing and construction. Finally, it sometimes fails to deliver greenhouse gas savings over meaningful timescales relevant to the climate change targets. When managed sustainably, biomass is an essential part of the portfolio of renewable energy technologies, delivering low-cost carbon heat and power.

Some of the environmental benefits of bioenergy

  • It helps the reduction of pressure on finite natural resources
  • The release of greenhouse emissions gets reduced significantly with the use as fossil fuel addition or even substitution
  • The removal of the need for specialist food crops
  • Reduction of landfill waste and associated issues
  • Provision to thermal, electrical, and mechanical energy services
  • The handling of contaminated wastes
  • The removal of carbon from wastes
  • The increase of reservoirs and terrestrial carbon sinks
  • The reduction of dryland salinity and protection of ground water supplies
  • The maintenance of logging sites
  • The return of land into production with enhanced biodiversity

There are also other forms of energy that are being considered sources of energy for future use. For example, hydro-electric energy is used for peak and base-load power production, while nuclear power can deliver base-load power. Each of the technologies faces planning and cost barriers that are likely to stunt the future growth. Biomass is already an affordable form of energy that will meet the energy demands of the future.

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Starting up Power-to-Gas Reactors

In their paper “Effect of Start-Up Strategies and Electrode Materials on Carbon Dioxide Reduction on Biocathodes“, which was recently published in Applied and Environmental Microbiology, Saheb-Alam et al. teach us how to start-up bio-electrical systems for CO2 conversion to methane gas. They compared pre-acclimated with pristine electrodes and found that there is no difference in start-up time. Their findings stand in contrast to previous observations where pre-acclimation has indeed helped to improve reactor performance. For example, LaBarge et al. found that electrodes acclimated with methane-forming microbes, called Methanobacterium, do reduce start-up time.