Cow Dung can be an Excellent Source of Biofuel

I still have some childhood memories in my mind, when I travelled the rural areas of Pakistan, I could see the number of cow dung cakes pasted on the walls all around the village. Lots of questions came in to my mind, why the people of villages do so?  Is it beneficial or is it unhealthy? Later I came to know the amazing properties of cow dung as a biofuel. So, I choose this topic to discus here. Globally the demand of fuel in terms of transportation and power generation is increasing day by day. These have so far been met largely from the stock of fossil fuel such as crude oil, which is finite in nature. Fossil fuels are not environmentally friendly and are also expensive. The use of alternative and more environmentally-friendly energy sources such as biogas has been advocated.

Cow dung is considered as an excellent biomass for second generation biofuel. Each year, Dairy farms around the world generate billions of tonnes of dung. Cow dung can be used for both electricity and fuel. In both applications, the concept behind energy production is the collection of methane gas that is a product of manure. Because methane is the primary gas that is turned into energy when burning natural gas, there is a huge potential for collecting methane gas from cow manure. In the process of production of biogas, anaerobic digestion takes place with anaerobic bacteria (or) fermentation of biodegradable materials in the absence of oxygen. It primarily consists of carbon dioxide methane and small amounts of hydrogen sulphide, siloxanes,and moistures. The gases methane, carbon monoxideand hydrogen can be oxidized with oxygen. This energy which is released allows biogas to be used as a fuel, purpose of heating and also can be used in a gas engine for the purpose of converting the energy into electricity and heat. (Muthu et al., 2017).

Cow manure as energy not only interests dairy farms, but the idea has also interested car company Toyota. The company has plans to build a power plant that turns the methane from cow manure into hydrogen and power for electricity. The hydrogen in particular could be used to fuel Toyota’s fuel cell hydrogen cars. The plant will also produce enough power to sustain over 2000 homes and fuel for 1500 cars (Howard., 2017).

Fig 1: Carbon dioxide closed cycle for biogas (Noor et al., 2014)

Biofuel produced by cow dung has many advantages. It reduces greenhouse gas emissions, and is therefore climate friendly. It allows us to manage animal waste. Produce a stabilized residue that can be used as a fertilizer, thus it can slash our import bill for LPG and chemical fertilizer. (Korbag et al., 2020)

Besides having the various advantages, biofuel produced by cow dung have some limatitations and disadvantages as well. An unfortunate disadvantage is the lack of efficient system for the production of biogas. There is a need to develop new technologies that can simplify the process so that biogas is available at low cost and in abundance. Biogas contains impurities even after refinement and compression. If the generated bio-fuel was utilized to power automobiles, it can corrode the metal parts of the engine. This corrosion would lead to increased maintenance costs. Weather is another factor that can affect the production of biogas. Bacteria need an optimum temperature of 37°C to digest the waste material. In winter seasons, heat energy is required to maintain the temperature of a digester that leads to an additional maintains cost. Biogas generation by using cow dung depends on the availability of raw material that is plentiful in rural and suburban areas only (Khayal., 2019).

Muthu, D., Venkatasubramanian, C., Ramakrishnan, K., & Sasidhar, J. (2017, July). Production of biogas from wastes blended with cowdung for electricity generation-a case study. In IOP Conf. Series, Earth Environ. Sci, 80(1), p 012055. https://iopscience.iop.org/article/10.1088/1755-1315/80/1/012055/pdf

P. W. Howard, “Toyota to Build Power Plant to Convert Cattle Manure into Electricity, Hydrogen,” USA Today, 30 Nov 17. http://large.stanford.edu/courses/2017/ph240/xiao-m2/

Noor, M. M., Wandel, A. P., & Yusaf, T. (2014). MILD combustion: the future for lean and clean combustion technology. International Review of Mechanical Engineering, 8(1), 251-257. https://www.researchgate.net/publication/261173547_MILD_Combustion_the_Future_for_Lean_and_Clean_Combustion_Technology

Korbag, I., Omer, S. M. S., Boghazala, H., & Abusasiyah, M. A. A. (2020). Recent Advances of Biogas Production and Future Perspective. In Biogas. IntechOpen.93231  https://www.intechopen.com/online-first/recent-advances-of-biogas-production-and-future-perspective

Khayal, O. M. E. S. 2019. Advantages and limitations of biogas technologies.  https://www.researchgate.net/publication/336414255_ADVANTAGES_AND_LIMITATIONS_OF_BIOGAS_TECHNOLOGIES

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Municipal Organic Waste: back to the future?

“My dear, there is no such thing as waste in this world”.

My grandfather is putting away wooden skewers, with which he will build a small house to add to the nativity scene next Christmas. Being born in a peasant family in southern Italy almost a century ago, he is still proudly attached to a culture of saving, reusing, and living by what you have.

“When I was a child, people would throw their trash out of the window; that would essentially be dead leaves, vegetable peels and fish scraps. Other children and I would rush out every morning to take up as much as possible, so that it could be used on our gardens for having bigger vegetables and a bigger harvest. It was so much better back then, compared to our messy world nowadays! Clean streets and happy farmers. Why can’t we go back to that way of life?”.

Talking with always gives much to think.

I can agree on the fact that the way our society works is messy. Nutrient flows, which used to be circular in that rural society, are now separated: waste from the urban areas is generally not recycled, especially the organic fraction, and it is generally incinerated or dispersed in wastewaters, being wasted or causing eutrophication. On the other side, soil erosion and degradation are growing problems, especially in a context of climate change, and synthetic fertilizers are a nonrenewable resource.

I can agree on the fact that what we see as waste today can and must be seen as a resource. Not only durable materials like plastics and glass keep their value after being dumped: organic matter, too, has a high potential for reuse for different applications. Composting is only one possibility, and not the most efficient [1].

I can also agree on the fact that we need to be more creative in finding new ways to reuse what we have.

However, I cannot agree on the fact that our maximum aspiration is to go back to that old lifestyle. The world is different, the challenges are different, therefore the solution cannot be to go back to the past models of production and consumption. We need to be ready for the future!

A smart way to valorize waste and bring it back to the productive chain is to use is for energy production. The organic fraction of Municipal Solid Waste (MSW) could be utilized for the production of so called second generation biofuels, in particular biogas, bioethanol and renewable diesel [2]. The use of this resource would allow us to avoid the incineration of this resource, which is highly inefficient if compared to materials like plastics, and its disposal in landfills. The latter triggers anaerobic decomposition with production of methane, a greenhouse gas that is 25 times more potent than CO₂ over a 100-year period [3]. On the other hand, the use of organic waste for energy would not incentivize the reduction of food waste at the source or, similarly, such reduction would negatively affect our energy availability. In the picture it is shown the food recovery hierarchy drawn by the US Environmental Protection Agency (EPA), where “industrial uses” such as rendering and fuel conversion are four steps away from the most preferred option, and right before composting and landfill/incineration.

To sum up: the top three options in the hierarchy are the ones which would create most benefit for the environment, society, and economy. When it is not possible to reduce waste at the source or use it as animal feed, then the conversion of this kind of waste into biofuels is the most efficient and appealing alternative.

“So many difficult words, you know I couldn’t go to school”

“I said that instead of burning food waste or putting it into discharges we could use it to produce something to burn instead of gasoline! It is possible today with modern technologies”

“Oh, seriously? The more you know… But I will just keep using my potato peels to grow my tomatoes”

“That’s fantastic, nonno”

____________________________________________________________________________

References

[1] EPA, “United States Environmental Protection Agency,” [Online]. Available: https://www.epa.gov/sustainable-management-food/food-recovery-hierarchy. [Accessed 20 09 2020].

[2] Pöyry Management Consulting Oy , “Food Waste to Biofuels,” 2019.

[3] IPCC, “Climate Change 2007: The Physical Science Basis – Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.,” Cambridge University Press, Cambridge, United Kingdom, 2007.

Forest residues to reuse

Limbs, sawdust and treetops are some of the components so called forest residues. Unwanted by products from wood processing industries and forest harvesting have in my opinion a large potential in the field of bioenergy.

The largest biomass potential on the earth calculated per unit area are from forests, which covers approximately one third of the earth´s surface (Biomassa, 2020). Woody biomass in general is today the most common used biomass, and using the forest as material and energy source is not something new. But the increasing problem with deforestation is critical and contribute to loss of biodiversity and decreased carbon uptake capacity (FAO & UNEP, 2020).

I think that we must become better at taking care of the unwanted by products that arise along the process chain in a more sustainable way. Felling in the form of thinning is something that is needed to maintain the forests and ensure that all other vegetation thrives and can be used as biomass in conversion to energy (FAO & UNEP, 2020). There is a potential to increase harvest of biomass without increasing the harvest area by using forest residues. In Figure 1 below the energy use from residues 2015 and an estimation of potential energy use from residues are shown. In the high case the estimation is based on a sustainable enhanced residue collection, without compromising ecosystems (IRENA, 2019).  

 
Figure 1. Actual and enhanced residue collection in Sweden 2015.

Forest residues is categorized as a second generation biomass as well as an second generation biofuel (Cheng, 2017). The residues can either be processed towards an end-product as biofuel in forms of biodiesel or electricity/heat generation as pellets or biogas. The advantages of using forest residues in energy conversion are the use and optimization of residues along process chains that operate regardless and the potential in supply is large. Slash, stumps and treetops are used instead of rotten in the forest. However, forest residues have a few disadvantages that is important to keep in mind (Cambero, Sowlati, Marinescu & Röser, 2015). The residues have a low energy density and heating values, there is high costs in the supply chain mostly regarding transport. Mixed characteristics in the forest residues is also a disadvantage when it comes to the technical conversion process in energy recovery (Belyakov, 2020).

Sources
Biomassa.(2020, September 17). In Nationalencyklopedin. Retrieved September 17, 2020, from  http://www.ne.se/uppslagsverk/encyklopedi/lång/biomassa 

Belyakov, N. (2020). Sustainable Power Generation – Current Status, Future Challenges, and Perspectives. (1. ed.) Elsevier Inc. DOI:10.1016/c2018-0-01215-3.

Cheng, Jay (2017). North Carolina State University: Biomass to renewable energy processes (2. ed) Taylor & Francis Inc.

Cambero, C., Sowlati, T., Marinescu, M., & Röser, D. (2015).
Strategic optimization of forest residues to bioenergy and biofuel supply chain. INTERNATIONAL JOURNAL OF ENERGY RESEARCH Int. J. Energy Res. Wiley Online Library, 39, 439–452. DOI: 10.1002/er.3233

FAO and UNEP. (2020). The State of the World’s Forests 2020. Forests, biodiversity and people. Rome. https://doi.org/10.4060/ca8642en

IRENA (2019), Bioenergy from boreal forests: Swedish approach to sustainable wood use, International Renewable Energy Agency, Abu Dhabi.

raking the floors of the forest

In Sweden, the forestry industry is an important part of our exports and is one of the base industries. The trend is that the demand for wood-based raw materials is increasing, wood as a building material, in addition to the production of paper for writing (newspapers, books, office printouts) is decreasing, the demand for liquid cardboard and paper packaging and paper bags is increasing, especially now that plastic products are being phased out.

In Sweden, the majority of second-generation biofuels (made from non-food biomass) are produced from the forest, based on thinning residues, forest waste and energy forest. These biofuels are mainly used in the industry for the production of electricity and heat for district heating networks. The largest consumer of the biofuel is the paper and pulp industry, which uses by-products from its process for incineration. From the 1920s, the timber stock in Sweden has increased sharply, from 1720 million m³sk (m³sk = forest cubic meters – the timber volume including bark, excluding branches and roots) to todays amount 3549 million m³sk, an increase of >100% (Forest data 2020). When forestry was industrialized in the 19th century, the forests were cleared without any thought of regrowth, short-term profit interests reigned, and Sweden’s forest stock decreased sharply. Today, we are on a deforestation that is in balance with regrowth, despite the fact that fellable productive forest land has decreased when large forest areas are biodiversity protected.

Climate change with higher temperatures and more CO2 means that forest growth has increased, at the same time the higher temperature – especially the milder winters – means that certain pests can attack our forest, the current problem is spruce bark beetle infestation and forest fires during hot and dry summer months.

Sweden has large areas of mires that can be drained to expand usable arable land, but with the digging of mires, problems are created with large emissions of greenhouse gases, but with research there may be a solution to this if the need for larger forest areas arises.

Biomass from three steps of the wood supply chain, IRENA (2019):

• primary biomass, from harvesting and thinning residues and discarded and low-value wood.

• secondary biomass fuels from sawmills, pulpmills and the wood-working industry, like bark, sawdust, chips, black liquor and tall oil.

• tertiary post-consumer biomass, like paper in municipal household waste, recovered wood and sewage sludge.

Biomass and energy flows from Swedish forest. Source:Svebio analysis of data from Statistics Sweden (SCB), Swedish Energy Agency (SEA), Swedish Forest Industries (Skogsindustrierna), Swedish Forest Inventory, SLU, Swedish Pellets Council (Pelletsförbundet) and others (2018)

As shown in the picture above, stumps, roots and slash are left in the forest after harvest (energy content of
138 TWh). They will eventually decompose and release CO2 into the atmosphere. A larger share of
the fellings could be collected, improving carbon balances so “raking the floor” is not so stupid.

It feels like we are only at the beginning of using all the possibilities of the wood raw material. If there is the political will, Sweden can replace the mixing of fuels with ethanol or perhaps even better with methanol that can be extracted from the forest raw material and is an excellent fuel mixer instead of importing ethanol based on food crops.

References
Forest statistics 2020, Official Statistics of Sweden, Swedish University of Agricultural Sciences Umeå 2020, ISSN 0280-0543 https://www.slu.se/globalassets/ew/org/centrb/rt/dokument/skogsdata/skogsdata_2020_webb.pdf
 
IRENA (2019), Bioenergy from boreal forests: Swedish approach to sustainable wood use, International Renewable Energy Agency, Abu Dhabi. https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Mar/IRENA_Swedish_forest_bioenergy_2019.pdf

A renewable, competitive alternative transporation fuel?

There is no doubt that the energy potential of biomass on earth is enormous, estimations from 2014 suggests that the global annual production of biomass is approximately 100 billion tons per year (Wang et al., 2017). A promising biomass with huge theoretical potential is lignocellulosic biomass which comprises mainly forestry and agricultural waste which is nonedible second-generation biomass. An exceptional energy source in the form of lignocellulosic biomass are energy crops, which can be harvested on annual basis making their carbon cycle short. Energy crops can be processed by thermochemical conversion to further produce biofuels which can be used as fuel for transportation. In 2017 only 7.4 % of the energy utilized by the transportation sector in the EU was from renewable sources and as of 2050 the goal is to achieve net zero greenhouse gas emissions. The International Energy Agency (IEA) believes that biofuels can replace up to 27 % of the world’s transportation fuels by 2050 (International Energy Agency, 2011). However, to utilize biomass as transportation fuel, thermochemical processes are applied to extract bio oil which further can be upgraded to second generation biofuels (Mortensen et al., 2011). The most extensively used process for this is fast/flash pyrolysis where the biomass is heated at high heating rates with short residence times which favours a high liquid production. The produced bio oil has a higher heating value (HHV) of approximately 40 % of crude oil. Hence it requires complicated methods for upgrading before it can serve as an alternative for crude oil. The three major components of lignocellulosic biomass are cellulose, hemicellulose and lignin. Depending on the type of biomass the distribution of these main components varies quite a lot. Also, the structure of the components has a high correlation with how it reacts during pyrolysis hence also influencing the outcome of the end products from pyrolysis (Wang et al., 2017). Apart from the liquid product (bio oil), pyrolysis also produces char (solid) and a gaseous product, in a bio oil producing facility the char and gas can be combusted to supply the required heat for the pyrolysis process.

Figure 1 pathway from biomass to upgraded biofuels (Wang et al., 2017).

Processing biomass into biofuels is energy demanding but has a huge potential considering that end products that can be obtained. Further it can be classified as a net zero producer of CO2 emissions if annual crops are utilized. That this would entirely replace conventional fuels in the transportation sector is a longshot. If crude oil is to be replaced the production of bio oil needs technical advancements, more understanding needs to be obtained regarding the reaction mechanisms of both pyrolysis and the upgrading methods to able to design and operate large scale production of bio fuels. Positively, biomass pyrolysis has gotten a lot more attention, 800 % more journal papers was published on the subject in 2016 compared to 2005 (Wang et al., 2017). Hopefully increasing research will lead to a future breakthrough and large-scale biofuel production can present in a large reduction of CO2 emission from the transportation sector.

International Energy Agency. (2011). Technology Roadmap (p. 56). https://www.ieabioenergy.com/wp-content/uploads/2013/10/IEA-Biofuel-Roadmap.pdf

Mortensen, P. M., Grunwaldt, J.-D., Jensen, P. A., Knudsen, K. G., & Jensen, A. D. (2011). A review of catalytic upgrading of bio-oil to engine fuels. Applied Catalysis A: General, 407(1), 1–19. https://doi.org/10.1016/j.apcata.2011.08.046

Wang, S., Dai, G., Yang, H., & Luo, Z. (2017). Lignocellulosic biomass pyrolysis mechanism: A state-of-the-art review. Progress in Energy and Combustion Science, 62, 33–86. https://doi.org/10.1016/j.pecs.2017.05.004

The utilization of woody biomass

Already 300,000 to 400,000 years ago, humans started to use wood as an energy source. Until today, this has not changed much. More than two billion people worldwide depend on wood as their primary energy source and use woody biomass for cooking and/or heating, especially in developing countries (Kaltschmitt, Hartmann, & Hofbauer, 2016). This blog will discuss solid biofuels, some advantages/disadvantages, end-products as well as social and environmental challenges using this biomass resource.

Wood is the classical solid biofuel and a second-generation resource, used for thousands of years especially wood from forests. In most countries firewood is used as an energy carrier and it is a product from forestry management (e.g. timber for construction purposes). In addition to forest wood, woody biomass can also be grown on agricultural land. To maximize the average yield and minimize the needs for fertile land, tree plantations are harvested after a few years. Furthermore, wood as fuel can derive from production and consumption of wood and wood products as a residue, a by-product, or a waste material along the supply chain of wood as a raw material as well as pulp and paper products (see Figure 1). Thinning wood and forest residues are produced as a by-product during the production of stem wood as a raw material, for example case goods and furniture production. Industrial residual wood, bark, and wood dust are by-products or waste materials resulting from the production of timber and the manufacturing of wood constructions or wood products. At the end of the lifetime and after recycling some wood fractions, partly contaminated woody material and waste wood remain, which can be used as fuel too (Kaltschmitt, 2019) & (Ahurso, Medina, & Constantí, 2018).

Figure 1: Material flow of wood within the overall economy (Kaltschmitt, 2019)

Within the total range of energy carriers from biomass, the solid biofuels dominate the global picture. The main reasons for this are the relatively low costs and the mostly easy access to solid biofuels especially for the poorer parts of the population. Additionally, solid biomass can be used to provide solid, liquid, and/or gaseous biofuels as well as used for heat provision and electricity production. This sustainable provision and production of biofuels have the advantage of being climatically neutral and environmentally friendly compared with other sources of fossil fuel energies. In comparison to other renewable sources of energy, biomass can be used in very different sectors of the overall energy system. The market for heat, for electricity, and for transportation fuels can be fed by energy carriers made of solid biomass. Within all these markets, biomass already plays a certain and increasing role within the global energy system. This development already accelerates due to the policy actions such as the reduction of greenhouse gas emissions to achieve political goals. (Christ, Scherzinger, Neuling, & Kaltschmitt, 2019) & (Kaltschmitt, 2019).

Different conversion techniques developed in the past and are available on the global energy markets. Beside the provision of heat and/or electricity it is possible to produce secondary solid, liquid, and/or gaseous energy carriers characterized by different fuel-related properties. The conversion of solid biomass into these secondary energy carriers utilizes thermochemical processes. This thermochemical conversion proceeds through different conversion phases. Each phase delivers various products. End-products are synthetic natural gases (SNG) like biomethane, hydrogen or other gases (e.g. DME), solid charcoal, or liquids such as bio-crude oil, Fischer-Tropsch diesel and methanol (Kaltschmitt, 2019).

The utilization of woody biomass can be disadvantageous because of impacts on the environment. A biomass plantation depletes nutrients from soil, promote aesthetic degradation and increase the loss of biodiversity. A further negative aspect is the degradability of solid biomass caused by large distances transport activities as well as long-time storage. Disadvantageous is also that agro-forestry residues may have lower quality and contaminated with heavy metals. Furthermore, the low energy density and bulk volume of fresh woody biomass affect storage costs and transportation efficiency. The loss of biodiversity can be avoided through a careful forest management.  This contributes the conservation of biodiversity as well as the water regulation, carbon sequestration and leads to recreational benefits in natural or planted forests. Another solution can be the production of agropellets for example, which avoid degradation and transportation issues. Additionally, the biomass energy density enhances, and the moisture content reduced, therefore the transport efficiency increase. The blending of different biomass feedstocks arranges suitable average composition and reduces pollutant loads (Domac, Verwijst, Richardsen, & Schlamadinger, 2003) & (European Biomass Industry Association, 2020).

References:

Ahurso, R., Medina, F., & Constantí, M. (2018). Energies. Significance and Challenges of Biomass as a Suitable Feedstock for Bioenergy and Biochemcial Production: A Review. doi:https://doi.org/10.3390/en11123366

Christ, D., Scherzinger, M., Neuling, U., & Kaltschmitt, M. (2019). Thermochemical Conversion of Solid Biofuels: Processes and Techniques. In M. Kaltschmitt (Ed.), Energy from Organic Materials (Biomass) A Volume in the Encyclopedia of Sustainability Science and Technology, Second Edition (pp. 393-413). New York: Springer Science+Business Media, LLC. doi:https://doi.org/10.1007/978-1-4939-7813-7

Domac, J., Verwijst, T., Richardsen, J., & Schlamadinger, B. (2003). Sustainable Production of Woody Biomass for Energy. New Zealand. Retrieved from https://www.ieabioenergy.com/wp-content/uploads/2013/10/25_PositionPaper-SustainableProductionofWoodyBiomassforEnergy.pdf

European Biomass Industry Association. (2020). Challenges related to biomass. Retrieved 2020 September 19 from https://www.eubia.org/cms/wiki-biomass/biomass-resources/challenges-related-to-biomass/

Kaltschmitt, M. (2019). Biomass as Renewable Source of Energy: Possible Convertion Routes. In M. Kaltschmitt (Ed.), Energy from Organic Materials (Biomass) A Volume in the Encyclopedia of Sustainability Science and Technology, Second Edition (pp. 353-389). New York: Springer Science+Business Media, LLC. doi:https://doi.org/10.1007/978-1-4939-7813-7

Kaltschmitt, M., Hartmann, H., & Hofbauer, H. (2016). Energie aus Biomasse Grundlagen, Techniken und Verfahren (3., aktualisierte und erweiterte Auflage). Berlin, Heidelberg: Springer Vieweg. doi:https://doi.org/10.1007/978-3-662-47438-9

Can Biohydrogen be our saviour?

Biomass as an energy source – that’s a phrase which everyone reading this post has read at least once in a life. For those who hasn’t, we can imagine biomass as everything living, doesn’t matter if it’s a cow or algae under the sea. By using it as an energy source we mean the various ways of conversion, some we’ve known throughout the centuries (like burning wood) some are more advanced and sophisticated. And that’s the topic of this post, well not entirely, because more than on the means (which I will also mention) I’m focusing on the product. The product is BIOHYDROGEN.

Biohydrogen as the name suggests is hydrogen gas made by renewable means which are mostly fermentation processes. There are also thermochemical ways of generating hydrogen but they are more energy demanding and we’re focusing on using waste as a feedstock. Waste, either domestic, industrial or wastewater from water treatment plants is considered a second generation biomass resource. The definition of second generation biofuels is following: ‘The resource base for the production of second-generation biofuel are non-edible lignocellulosic biomass resources (such as leaves, stem and husk) which do not compete with food resources.’ [1] The other principle to turn biomass into H2 is based on biochemical processes. There are two main ways, which are only differentiated by the type of bacteria and by conditions they need to do their ‘work’. Those two are called dark fermentation and photofermentation[2]. Like the names suggest those two processes need either sunlight or darkness. In both of those the bacteria consume various complicated carbohydrates and turns them into alcohols, acetone and small amounts of H2 and CO2 [3].

The dark fermentation is mainly anaerobic (conditions where no oxygen is present) process. The advantage of this process is as you think that it doesn’t rely on sunlight so it can work in day or night. The restrictions of this process are that the bacteria is highly dependent on the acidity of its surroundings and also on the fact that hydrogen pressure can’t build up too much as it lowers additional production [3].

The dark fermentation process chain [3]

If the dark fermentation bacteria are night owls then photofermentation bacteria are early birds, because only sunlight gives them energy to get up and work (quite literally!). Other then that they need some organic acids, some water and voilà there is H2 (also with some CO2 we can’t escape that really). The efficiency is better the with dark fermentation but there are a few drawbacks. The bacteria need a pre-treatment because the waste waters may contain toxic compounds also the need organic acids for them to work which can be a difficulty which we’re facing when utilizing this process [3]

The photofermentation process chain [3]

Now when we’ve described main biochemical means of biohydrogen production there is an important question: Why all this? Can biohydrogen save us all from global warming, can it solve all our energy demand issues? Well, probably not. What hydrogen can offer that other fuels don’t and why should we care? It is undoubtedly a good question. For the most part it has highest energy density of any fuel! And when burned or used in fuel cells it only produces water vapour and no CO2 like other fuels [3]. Also the worldwide demand for hydrogen was 73,9 Mt worldwide and about three quarters of it were made from natural gas and only small fraction of it was made renewable way according to IEA [4]. The vital step to ensure sustainability is to move away from the utilization of fossil fuels even in this field and getting rid of our waste in doing so offer all the benefits. The main drawbacks are still it’s costs which can’t compete with generation of hydrogen the unsustainable way. If we look away from hydrogen that is currently mostly used in industry there are concepts of whole hydrogen ecosystem where the hydrogen is proposed to be used as energy carrier for electricity storage, because as we know the problem with renewable energy is mostly that we can’t efficiently store electrical energy for longer periods of time. Until long term storage technologies are developed our economies will still have to rely on fossil fuels and hydrogen could be the one that changes the path we’re currently on.

References:
[1] KAMAL, Talha Akbar. Resource Base for Second-Generation Biofuels [online]. 14.2.2020 [cit. 2020-09-15]. Available from: https://www.bioenergyconsult.com/second-generation-biofuels/
[2] Biohydrogen. Etip Bioenergy [online]. [cit. 2020-09-15]. Available from: https://www.etipbioenergy.eu/value-chains/products-end-use/products/biohydrogen
[3] NIKOLAIDIS, Pavlos a Andreas POULLIKKAS. A comparative overview
of hydrogen production processes. Renewable and Sustainable Energy Reviews
[online]. 2017, 67, 597-611 [cit. 2019-02-01]. DOI: 10.1016/j.rser.2016.09.044.
ISSN 13640321. Available from: https://linkinghub.elsevier.com/retrieve/pii/S1364032116305366
[4] The Future of Hydrogen [online]. 7.2019n. l. [cit. 2020-09-15]. Available from: https://www.iea.org/reports/the-future-of-hydrogen

A sustainable future with forestry

Sustainability is a word that is widely used nowadays in politics, when purchasing cloths, buying food, industry related topics and more. Know fact among the public masses is that the temperature is increasing globally, creating large problems e.g. a rising sea level. One factor that is greatly contributing to this phenomena is human activity when carbon that have been buried in the earth’s crust is used as an energy source it releases the carbon into the atmosphere creating a surplus of carbon dioxide.

Renewable energy resources is a way to reduce (hopefully lower one day) the carbon dioxide levels in the atmosphere. I’m a strong believer that the future lives within the forest in many different ways, manufacturing products, use as a energy resource, carbon capture and storage (CCS). In this short blog post I will be discussing the use of wood as an energy resource, advantages, disadvantages, end-product and social/environmental challenges.

Wood is a second generation energy resource meaning it is not suitable for human consumption. The biomass is available as an energy resource in different states. energy forest and forest biomass. Röser, Asikainen, Stupak and Pasanen (2008) illustrates the usage of wood as a energy source into two primary groups of wood based fuels, energy forest and forest biomass, as illustrated in Figure 1.

Figure 1. Illustration of wood based fuels (Röser, Asikainen, Stupak & Pasanen, 2008)

One advantage with forest biomass, as can be observed with the illustration in Figure 1, is that it is mainly residues from the general forestry industry. If these residues is used instead disposed that would help with creating a circular society as well as lowering the need of fossil fuels. As wood have a low energy density it is of great importance that as much the biomass is used in order to make it as economical as possible (Hakkila & Parikka, n.d.). This is a disadvantage, that biomass from forestry often have low energy density, this brings costs for e.g. transportation making it harder do use it in a profitable sense.

End-products of forestry residues could be packaging material, bio fuels, green chemicals and more as Lantmännen Agroetanol (n.d.) is currently working with. They’re are adding a process stream that will use cellulose from forestry (and agriculture) and turn it into these products. This shows that it is a profitable concept, economically and environmentally, a way to achieve circular economy.

That sounds lovely, doesn’t it? Well, unfortunately everything has its bright sides along with its dark sides. Most of the people seem to think that the green way is the way to go and want to go there quickly but there are challenges with implementing these kind of processes. Overusing the forest can have grave impacts on the environment and habitats for different terrestrial animals as the Rainforest Alliance (2016) sums up in their article. It is not suitable to stop everything, cut down all the trees and use it for bio fuels so we can stop using fossil fuels. If the trees are cut down they can’t capture the carbon dioxide which we release into the atmosphere when using the trees we cut down, really counter proactive. The habitats for a lot of species would disappear and a lot of species could go extinct (as what is happening to the rain forests right now), lowering the biodiversity. It have to happen in a rate that is manageable, where we continue to research new ways to use biomass more efficiently, where we ultimately release less carbon than that is captured.

With that said I think that forestry will play an important role in our strive to become sustainable. To lower the use of fossil fuels, capture the carbon dioxide in the atmosphere, finding alternative uses of the residues. But it will have to happen in the right pace, we are not able to stop using fossil fuels right here and now. The technique to use bio masses is not yet implemented to that level where our energy requirements would be met. One day, hopefully not too late, we will be able to lower the levels of carbon dioxide in the atmosphere.

References

Hakkila, P., & Parikka, M.. (n.d.). Fuel Resources from the Forest (pp. 19–48). http://doi.org/10.1007/0-306-47519-7_2

Lantmännen Agroetanol. (n.d.). Solutions for the transition to a sustainable society. Retrieved 14-09-2020 from https://www.lantmannenagroetanol.se/en/

Rainforest Alliance. (2016). What is Sustainable Forestry?.Retrieved 14-09-2020 from https://www.rainforest-alliance.org/articles/what-is-sustainable-forestry#:~:text=Sustainable%20forestry%20focuses%20on%20keeping,even%20apply%20for%20FSC%20certification.

Röser, D., Asikainen, A., Stupak, I., & Pasanen, K.. (2008). Forest Energy Resources And Potentials. In Managing Forest Ecosystems: The Challenge of Climate Change (pp. 9–28). Managing Forest Ecosystems: The Challenge of Climate Change. http://doi.org/10.1007/978-1-4020-5054-1_2

Co-fire us in to the 21st century

Guest blog by Kevin Daun, MTK311, HT19

Europe is in many aspects doing a great job with green initiative policies being implemented throughout the union, and in doing so keeping and greenhouse gas emission to minimalistic levels. Last year we had the lowest recorded levels as of yet! However, South Eastern Europe (SEE) beingthe highest emitters of and GHG (greenhouse gas) – within Europe – are still heavily dependent on fossil fuels, where coal, gas and heavy fuel dominate the regions as primary sources of energy. Seven of the ten most polluting coal-fired power stations is located within SEE, and similar stations areon their way to be implemented by 2030 due to foreign investors (Climate Action Network Europe, 2018). So what could be done to improve the current climate?

A good option that I recently came across is that of a so calledco-firing process within already existing thermal plants. With large thermal units already being used on a daily basisdomestically, there is a major possibility to dramatically improve emissions by integrating co-fire operations with biomass in to these systems. A recent model of a co-fire operation using coal and biomass – which is the most common combination – showed a boiler efficiency of 92% (Rusinowskiet.al, 2012) which is similar to what a “normal” combustion process achieves using only fossil fuels. The good news about this is that most units already have the ability to operate on a co-firing basis, thus incrementally decreasing the need for heavy emitters, while simultaneously keeping production costs extremely low since no new technology i.e. boiler needs producing in order to start this process. Boiler efficiency is a large factor when deciding on power production methods,which makes this is a discovery of great importance to further the cause.

To me it seems as clear cut of a solution as anything. Gaining some energy independence by simply decreasing the amountof imported products by using domestic resources, while simultaneously benefiting by fewer harmful emissions. It is difficult to see why this has not caught on, but a major reason seems to be the “cheap” production cost of power using coal compared to biomass. If all current boilers within the SEE would substitute 20% of their current fuel to biomass, you would correspondingly decrease the need for fossil fuels. 

There are also large quantities of biomass available, ready to be integrated in to these processes, mainly wood residues (e.g. sawdust, branches etc.) from the wood factories. Large portions of biomass can be obtained from annual tree branch trimming (Iliadis, 2009) that could make the process self-sustaining.

If EU want to reach their target of 27% of energy consumption from renewable resources by 2030 (European Commission, 2016), some actions towards the biggest polluters must be taken. Success on a global scale is heavily related to many small improvements at the location with the largest room for improvement. This integration of biomass in to an already existing process could really help improve the climate as a whole since it is cheap and already available, and we all know that availability is a huge factor in large scale decision making.

REFERENCES

H.Rusinkowski, M.Szega, A.Milejski. “Mathematical model of the CFB boiler co-fired with coal and biomass”. International Carpathian Control conference, 2012 Web 10 Okt. 2019

N.A.Iliadis. “Biomass development and potential in south east europe”. IEEE Power & Energy Society General meeting, 2009 Web 10 Okt. 2019

Climate Action Network Europe. 2018. South East Europe. [ONLINE]. Available at: http://www.caneurope.org/energy/south-east-europe [Visited 10 Okt 2019]

European Comission. 2016. Clean Energy for All Europeans. [ONLINE]. Available at: https://ec.europa.eu/energy/en/topics/energy-strategy-and-energy-union/clean-energy-all-europeans [Visited 10 Okt 2019]

Algae, biofuels of the future?

Guest blog by Daniel Israelsson, MTK311 HT19

The time we live in is marked by discussions about how to solve the problem of switching to biofuels, but at the same time not using our cultivable arable land or adversely affecting animals and nature.

But our seas then? The earth consists of over 70% water, where there is great potential, even at our latitudes according to Lorenza Ferro, a researcher at Umeå University, who in a study (Ekman, 2019) shows that algae can cope with our harsh climate. In combination with Susanne Ekendahl’s research (Ekendahl, 2009) that highlights the potential of algae, they can be the next big step in a fossil-free future. The potentials that have been demonstrated include that they can produce incredibly large harvests, where laboratory tests yield volumes of 22,000 liters of oil per hectare and year with corresponding figures for maize and sunflowers are 23 and 155 liters respectively, which is superior even under sub-optimal conditions.

It sounds absolutely incredible to my ears, but it must be something holding it back because this has not yet broken through? One of the reasons turns out to be price competitiveness, which is not a surprise. Even though it is our future, the future of the planet that is at stake it is always about money. So far, profitability seems a bit off e.g. it requires “24,000 liters of water, nutrients, equipment, personnel and about two weeks to generate around one gallon (3.79 liters) of finished fuel. The price for the same amount crude oil is 1:90 dollars (15:50 SEK)” according to Schonna Manning, a researcher at Agrilife on the south coast of Texas (Brusewitz, 2018), but at the same time the whole algae is not used for fuel, which means that if you use all parts there is hope of approaching the price of crude oil. Crude oil is also a finite resource which will eventually increase the price of it, and in line with the progress made with algae I think we will reach a breaking point where there is no longer any incentive to choose crude oil over algae.

If you look at the other benefits that algae have, in addition to the ones already mentioned, they can be grown in virtually anywhere; in deserts, in the sea, on unproductive land, etc. (Brusewitz, 2018) and with the large number of species the direction of cultivation can be controlled for algae such as e.g. ones that are rich in fats that can become biodiesel or others that are rich in carbohydrates that can become ethanol and biogas (Ekendahl, 2009). They efficiently absorb carbon dioxide and can withstand concentrations up to 12-13% and also purify water from phosphorus and nitrogen, which means that industrial emissions can be directed directly to cultivation, resulting in that the harmful greenhouse gases are purified immediately after production. (Ekendahl, 2009) (SP Sveriges Tekniska Forskningsinstitut, 2019).

Our ability to use the earth’s resources and to develop technology that optimizes this has led to great progress for us, but at the same time it has cost us and as it looks right now it will cost us our future. But the ability and innovativeness that brought us here will also take us out of it, if we just can get everyone to understand this. At least by my opinion.

References

Brusewitz, M. (den 20 April 2018). Alger som flygbränsle – hajp eller hopp? Sveriges Natur nr 2-2018 .

Ekendahl, S. (den 19 10 2009). RI.se. Hämtat från Odlade alger – framtidens energikälla?: https://www.sp.se/sv/press/news/Sidor/20091019.aspx

Ekman, J. (den 14 Mars 2019). Miljö&Utveckling. Hämtat från Svenska mikroalger bäst i test: https://miljo-utveckling.se/svenska-mikroalger-bast-i-test/

EnergyFactor by ExxonMobil. (den 02 Augusti 2019). From petri dish to pond: Algae farming, in pictures. Hämtat från https://energyfactor.exxonmobil.com/science-technology/algae-farming-pictures/

SP Sveriges Tekniska Forskningsinstitut. (den 13 10 2019). Algodling för biobränsleproduktion. Hämtat från RI.se: https://www.sp.se/sv/index/research/algae_cultivation/sidor/default.aspx