CO2 Blog – Page 2 – Frontis Energy

Posted on March 17, 2019October 12, 2019 by admin

Producing liquid bio-electrically engineered fuels from CO₂

At Frontis Energy we have spent much thought on how to recycle CO₂. While high value products such as polymers for medical applications are more profitable, customer demand for such products is too low to recycle CO₂ in volumes required to decarbonize our atmosphere to pre-industrial levels. Biofuel, for example from field crops or algae has long been thought to be the solution. Unfortunately, they require too much arable land. On top of their land use, biochemical pathways are too complex to understand by the human brain. Therefore, we propose a different way to quickly reach the target of decarbonizing our planet. The procedure begins with a desired target fuel and suggests a microbial consortium to produce this fuel. In a second step, the consortium will be examined in a bio-electrical system (BES).

CO₂ can be used for liquid fuel production via multiple pathways. The end product, long-chain alcohols, can be used either directly as fuel or reduced to hydrocarbons. Shown are examples of high level BEEF pathways using CO₂ and electricity as input and methane, acetate, or butanol as output. Subsequent processes are 1, aerobic methane oxidation, 2, direct use of methane, 3 heterotrophic phototrophs, 4, acetone-butanol fermentation, 5, heterotrophs, 6, butanol direct use, 7, further processing by yeasts

Today’s atmospheric CO₂ imbalance is a consequence of fossil carbon combustion. This reality requires quick and pragmatic solutions if further CO₂ accumulation is to be prevented. Direct air capture of CO₂ is moving closer to economic feasibility, avoiding the use of arable land to grow fuel crops. Producing combustible fuel from CO₂ is the most promising intermediate solution because such fuel integrates seamlessly into existing urban infrastructure. Biofuels have been explored intensively in recent years, in particular within the emerging field of synthetic biology. However tempting the application of genetically modified organisms (GMOs) appears, non-GMO technology is easier and faster to implement as the required microbial strains already exist. Avoiding GMOs, CO₂ can be used in BES to produce C₁ fuels like methane and precursors like formic acid or syngas, as well as C₁₊ compounds like acetate, 2-oxybutyrate, butyrate, ethanol, and butanol. At the same time, BES integrate well into urban infrastructure without the need for arable land. However, except for methane, none of these fuels are readily combustible in their pure form. While electromethane is a commercially available alternative to fossil natural gas, its volumetric energy density of 40-80 MJ/m³ is lower than that of gasoline with 35-45 GJ/m³. This, the necessary technical modifications, and the psychological barrier of tanking a gaseous fuel make methane hard to sell to automobilists. To produce liquid fuel, carbon chains need to be elongated with alcohols or better, hydrocarbons as final products. To this end, syngas (CO + H₂) is theoretically a viable option in the Fischer-Tropsch process. In reality, syngas precursors are either fossil fuels (e.g. coal, natural gas, methanol) or biomass. While the former is obviously not CO₂-neutral, the latter competes for arable land. The direct conversion of CO₂ and electrolytic H₂ to C₁₊ fuels, in turn, is catalyzed out by electroactive microbes in the dark (see title figure), avoiding food crop competition for sun-lit land. Unfortunately, little research has been undertaken beyond proof of concept of few electroactive strains. In stark contrast, a plethora of metabolic studies in non-BES is available. These studies often propose the use of GMOs or complex organic substrates as precursors. We propose to systematically identify metabolic strategies for liquid bio-electrically engineered fuel (BEEF) production. The fastest approach should start by screening metabolic databases using established methods of metabolic modeling, followed by high throughput hypothesis testing in BES. Since H₂ is the intermediate in bio-electrosynthesis, the most efficient strategy is to focus on CO₂ and H₂ as direct precursors with as few intermediate steps as possible. Scalability and energy efficiency, economic feasibility that is, are pivotal elements.

First, an electrotrophic acetogen produces acetate, which then used by heterotrophic algae in a consecutive step.

The biggest obstacle for BEEF production is lacking knowledge about pathways that use CO₂ and electrolytic H₂. This gap exists despite metabolic databases like KEGG and more recently KBase, making metabolic design and adequate BEEF strain selection a guessing game rather than an educated approach. Nonetheless, metabolic tools were used to model fuel production in single cell yeasts and various prokaryotes. In spite of their shortcomings, metabolic databases were also employed to model species interactions, for example in a photo-heterotroph consortium using software like ModelSEED / KBase (http://modelseed.org/), RAVEN / KEGG and COBRA. A first systematic attempt for BEEF cultures producing acetate demonstrated the usability of KBase for BES. This research was a bottom-up study which mapped existing genomes onto existing BEEF consortia. The same tool can also be employed in a top-down approach, starting with the desired fuel to find the required organisms. Some possible BEEF organisms are the following.

Possible pathways for BEEF production involving Clostridium, 3, or heterotrophic phototrophs, 7, further processing by yeasts

Yeasts are among the microorganisms with the greatest potential for liquid biofuel production. Baker’s yeast, (Saccharomyces cerevisiae) is the most prominent example. While known for ethanol fermentation, yeasts also produce fusel oils such as butane, phenyl, and amyl derivate aldehydes and alcohols. Unlike ethanol, which is formed via sugar fermentation, fusel oil is synthesized in branched-off amino acid pathways followed by aldehyde reduction. Many enzymes involved in the reduction of aldehydes have been identified, with alcohol dehydrogenases being the most commonly observed. The corresponding reduction reactions require reduced NADH⁠ but it is not known whether H₂ produced on cathodes of BES can be involved.
Clostridia, for example Clostridium acetobutylicum and C. carboxidivorans, can produce alcohols like butanol, isopropanol, hexanol, and ketones like acetone from complex substrates (starch, whey, cellulose, etc. ) or from syngas. Clostridial metabolism has been clarified some time ago and is different from yeast. It does not necessarily require complex precursors for NAD⁺ reduction and it was shown that H₂, CO, and cathodes can donate electrons for alcohol production. CO₂ and H₂ were used in a GMO clostridium to produce high titers of isobutanol. Typical representatives for acetate production from CO₂ and H₂ are C. ljungdahlii, C. aceticum, and Butyribacterium methylotrophicum. Sporomusa sphaeroides produces acetate in BES. Clostridia also dominated mixed culture BESs converting CO₂ to butyrate. They are therefore prime targets for low cost biofuel production. Alcohols in clostridia are produced from acetyl-CoA. This reaction is reversible, allowing acetate to serve as substrate for biofuel production with extracellular energy supply. Then, energy conservation, ATP synthesis that is, can be achieved from ethanol electron bifurcation or H₂ oxidation via respiration. While possible in anaerobic clostridia, it is hitherto unknown whether electron bifurcation or respiration are linked to alcohols or ketone synthesis.
Phototrophs like Botryococcus produce C₁₊ biofuels as well. They synthesize a number of different hydrocarbons including high value alkanes and alkenes as well as terpenes. However, high titers were achieved by only means of genetic engineering, which is economically not feasible in many countries due to regulatory constrains. Moreover, aldehyde dehydration/deformylation to alkanes or alkenes requires molecular oxygen to be present. Also the olefin pathway of Synechococcus depends on molecular oxygen with the cytochrome P₄₅₀ involved in fatty acid decarboxylation. The presence of molecular oxygen affects BES performance due to immediate product degradation and unwanted cathodic oxygen reduction. In contrast, our own preliminary experiments (see title photo) and a corrosion experiment show that algae can live in the dark using electrons from a cathode. While the enzymes involved in the production of some algal biofuels are known (such as olefin and aldehyde deformylation), it is not known whether these pathways are connected to H₂ utilization (perhaps via ferredoxins). Such a connection would be a promising indicator for the possibility of growing hydrocarbon producing cyanobacteria on cathodes of BES and should be examined in future research.
At Frontis Energy we believe that a number of other microorganisms show potential for BEEF production and these deserve further investigation. To avoid GMOs, BES compatible co-cultures must be identified via in silico metabolic reconstruction from existing databases. Possible inter-species intermediates are unknown but are prerequisite for successful BES operation. Finally, a techno-economical assessment of BEEF production, with and without carbon taxes, and compared with chemical methods, will direct future research.

Posted on December 21, 2018December 24, 2018 by admin

White Christmas, going … gone

In Germany, we seem to remember White Christmas from fairy tales only. Now there is also scientific evidence that winter snow cover in Europe is thinning. Thanks to global warming, the snow cover decrease accelerated

The research group behind Dr. Fontrodona Bach of the Royal Netherlands Meteorological Institute in De Bilt analyzed snow cover and climate data from six decades from thousands of weather stations across Europe. The researchers found that the mean snow depth, with the exception of some local extremely cold spots, has been decreasing since 1951 at 12% per decade. The researchers recently published their research results in the journal Geophysical Research Letters. The amount of “extreme” snow cover affecting local infrastructure has declined more slowly.

The observed decline, which accelerated after the 80s, is the result of a combination of rising temperatures and the impact of climate change on precipitation. The decreasing snow cover can reduce the availability of fresh water during the spring melt, the authors noted.

(Photo: Doris Wulf)

Posted on November 1, 2018August 18, 2019 by admin

Ammonia energy storage #1

The ancient, arid landscapes of Australia are not only fertile soil for huge forests and arable land. The sun shines more than in any other country. Strong winds hit the south and west coast. All in all, Australia has a renewable energy capacity of 25 terawatts, one of the highest in the world and about four times higher than the world’s installed power generation capacity. The low population density allows only little energy storage and electricity export is difficult due to the isolated location.

So far, we thought the cheapest way to store large amounts of energy was power-to-gas. But there is another way to produce carbon-free fuel: ammonia. Nitrogen gas and water are enough to make the gas. The conversion of renewable electricity into the high-energy gas, which can also be easily cooled and converted into a liquid fuel, produces a formidable carrier for hydrogen. Either ammonia or hydrogen can be used in fuel cells.

The volumetric energy density of ammonia is almost twice as high than that of liquid hydrogen. At the same time ammonia can be transported and stored easier and faster. Researchers around the world are pursuing the same vision of an “ammonia economy.” In Australia, which has long been exporting coal and natural gas, this is particularly important. This year, Australia’s Renewable Energy Agency is providing 20 million Australian dollars in funding.

Last year, an international consortium announced plans to build a $10 billion combined wind and solar plant. Although most of the 9 terawatts in the project would go through a submarine cable, part of this energy could be used to produce ammonia for long-haul transport. The process could replace the Haber-Bosch process.

Such an ammonia factories are cities of pipes and tanks and are usually situated where natural gas is available. In the Western Australian Pilbara Desert, where ferruginous rocks and the ocean meet, there is such an ammonia city. It is one of the largest and most modern ammonia plants in the world. But at the core, it’s still the same steel reactors that work after the 100 years-old ammonia recipe.

By 1909, nitrogen-fixing bacteria produced most of the ammonia on Earth. In the same year, the German scientist Fritz Haber discovered a reaction that could split the strong chemical bond of the nitrogen, (N₂) with the aid of iron catalysts (magnetite) and subsequently bond the atoms with hydrogen to form ammonia. In the large, narrow steel reactors, the reaction produces 250 times the atmospheric pressure. The process was first industrialized by the German chemist Carl Bosch at BASF. It has become more efficient over time. About 60% of the introduced energy is stored in the ammonia bonds. Today, a single plant produces and delivers up to 1 million tons of ammonia per year.

Most of it is used as fertilizer. Plants use nitrogen, which is used to build up proteins and DNA, and ammonia delivers it in a bioavailable form. It is estimated that at least half of the nitrogen in the human body is synthetic ammonia.

Haber-Bosch led to a green revolution, but the process is anything but green. It requires hydrogen gas (H₂), which is obtained from pressurized, heated steam from natural gas or coal. Carbon dioxide (CO₂) remains behind and accounts for about half of the emissions. The second source material, N₂, is recovered from the air. But the pressure needed to fuse hydrogen and nitrogen in the reactors is energy intensive, which in turn means more CO₂. The emissions add up: global ammonia production consumes about 2% of energy and produces 1% of our CO₂ emissions.

Our microbial electrolysis reactors convert the ammonia directly into methane gas − without the detour via hydrogen. The patent pending process is particularly suitable for removing ammonia from wastewater. Microbes living in wastewater directly oxidize the ammonia dissolved in ammonia and feed the released electrons into an electric circuit. The electricity can be collected directly, but it is more economical to produce methane gas from CO₂. Using our technology, part of the CO₂ is returned to the carbon cycle and contaminated wastewater is purified:

NH₃ + CO₂ → N₂ + CH₄

Posted on August 25, 2018August 24, 2020 by admin

Fresh CO₂ − Now Even Cheaper!

Hurry up while stocks last, you may want to add. Carbon dioxide (CO₂) is a waste product from the combustion of fossil fuels such as oil, gas and coal. It is almost worthless because it finds little use. However, technologies such as power-to-gas or electrosynthesis of methanol are able to convert CO₂ directly into a valuable, albeit cheap, product. This increases the commercial interest in CO₂ and ultimately the filtering from the air becomes economically interesting. That is, filtering CO₂ from the air is now more than just an expensive strategy to fight global warming. Recently, a detailed economic analysis has been published in the journal Joule, which suggests that this filter technology could soon become a viable reality.

The study was published by the engineers of the Canadian company Carbon Engineering in Calgary, Canada. Since 2015, the company has been operating a pilot plant for CO₂ extraction in British Columbia. This plant − based on a concept called Direct Air Capture (DAC) − formed the foundation for the presented economic analysis. It includes the costs from suppliers of all major components. According to the study, the cost of extracting a ton of CO₂ from the air ranges from $94 to $232, depending on a variety of design options. The latest comprehensive analysis of DAC estimated $600 per tonne and was published by the American Physical Society in 2011.

In addition to Carbon Engineering, the Swiss company Climeworks also works on DAC in Zurich. There, the company has launched a commercial pilot that can absorb 900 tonnes of CO₂ from the atmosphere every year for use in greenhouses. Climeworks has also opened a second plant in Iceland that can capture 50 tonnes of CO₂ per year and bury it in subterranean basalt formations. According to Daniel Egger of Climeworks, capturing a ton of CO₂ at their Swiss site costs about $600. He expect the number to fall below $100 per ton over the next five to ten years.

Technically, CO₂ is dissolved in an alkaline solution of potassium hydroxide which reacts with CO₂ to form potassium carbonate. After further processing, this becomes a solid residue of calcium carbonate, which releases the CO₂ when heated. The CO₂ could then be disposed of underground or used to make synthetic, CO₂-neutral fuels. To accomplish this, Carbon Engineering has reduced the cost of its filtration plant to $94 per ton of CO₂.

CO₂-neutral fuel, from carbon dioxide captured from the air and electrolytic hydrogen.

Assuming, however, that CO₂ is sequestered in rock, a price of $100 per ton would translate into 0.2 cent per liter gasoline. Ultimately, the economics of CO₂ extraction depend on factors that vary by location, including the price of energy and whether or not a company can access government subsidies or a carbon trading market. But the cost per ton of DAC-CO₂ is likely to remain above the real market price of CO₂ in the near future. For example, emission certificates in the European Union’s trading system are around €16 per tonne of CO₂. If CO₂ extraction technology were to gain a foothold in markets where carbon can be sold at DAC price, then DAC would of course become economical. Conversion into useful products product such as plastic or fuel could help to include the DAC premium. Alberta seems a great location because its oil is of low quality and comes at high production costs. Moreover, the size of the DAC plant suggests this is done best in Canada, given the size of the country. Albertans may want to reconsider their business model.

At Frontis Energy, we are excited about this prospect. CO₂ is accessible everywhere and DAC is helping us convert it into methane gas. Power-to-gas is perfect for this. However, there would still have something to happen. $100 per ton is already good (compared to $600), but to be able to economically place a product like methane on the market it should be more like $10 per tonne:

CO₂ economy of power-to-gas with electrolytic hydrogen. Cal, California, EOR, enhanced oil recovery.

Sure, we always complain, but we still cannot wait to see how the price of DAC continues to fall and wish Carbon Engineering to Climeworks all the best. Keep it up!

(Photos: Carbon Engineering)

Posted on August 5, 2018August 5, 2018 by admin

A Brief Account of Wind Energy in the United States, Canada, and the European Union

Wind energy is short for the conversion of energy captured from wind to electrical or mechanical energy. Wind power turbines produce electrical energy and windmills produce mechanical energy. Other forms for wind energy conversion are wind pumps which use wind energy to pump water or sails which drive sail boats.

The cheapest US energy prices by source and county, Source: Energy Institute, University of Texas Austin

Since its first use on sail boats, wind energy is wide spread. Windmills have been used for more than 2,000 years as source of mechanical energy. The Scotsman James Blythe was the first who demonstrated the transformation of wind energy into electrical energy. As wind energy is a renewable source of energy, electrical energy generated by wind turbines is a clean and sustainable form of energy. Wind energy is often also cheaper than natural gas, for example throughout the entire American Midwest, as shown by the Energy Institute of University of Texas, Austin. It is therefore not surprising that wind energy is one of the fastest growing markets in the renewable energy sector worldwide. In 2015, 38% of all renewable energy in the United States and the European Union was generated by wind turbines.

Wind and solar energy production in the US and Canada in 2015. Sources: EIA, Statistics Canada

More efficient than single wind turbines is the use of wind parks where clusters of large turbines constantly generate electrical power. There are two kinds of wind parks, on-shore and off-shore wind parks. Off-shore wind parks are often more expensive but do not use valuable farmland as it is often the case for on-shore wind parks. However, wind parks on farmland can be a valuable addition for farmers seeking an extra income.

Wind and solar energy production in the European Union and the Euro-zone in 2015. WSH is the fraction of renewable energy of the European energy market. “Hydro” is the fraction of hydro power. Source, Eurostat

Posted on July 15, 2018August 18, 2019 by admin

You Can Have the Pie and Eat It

In Paris, humanity has set itself the goal of limiting global warming to 1.5 °C. Most people believe that this will be accompanied by significant sacrifice of quality of life. That is one reason why climate protection is simply rejected by many people, even to the point of outright denial. At Frontis Energy, we think we can protect the climate and live better. The latest study published in Nature Energy by a research group around Arnulf Grubler of the International Institute for Applied Systems Analysis in Laxenburg, Austria, has now shown that we have good reasons.

The team used computer models to explore the potential of technological trends to reduce energy consumption. Among other things, the researchers said that the use of shared car services will increase and that fossil fuels will give way to solar energy and other forms of renewable energy. Their results show that global energy consumption would decrease by about 40% regardless of population, income, and economic growth. Air pollution and demand for biofuels would also decrease, which would improve health and food supplies.

In contrast to many previous assessments, the group’s findings suggest that humans can limit the temperature rise to 1.5 °C above preindustrial levels without resorting to drastic strategies to extract CO₂ from the atmosphere later in the century.

Now, one can argue whether shared car services do not cut quality of life. Nevertheless, we think that individual mobility can be maintained while protecting our climate. CO₂ recovery for the production of fuels (CO₂ recycling that is) is such a possibility. The Power-to-Gas technology is the most advanced version of CO₂ recycling and should certainly be considered in future studies. An example of such an assessment of the power-to-gas technology was published by a Swiss research group headed by Frédéric Meylan, who found that the carbon footprint can be neutralized with conventional technology after just a few cycles.

(Picture: Pieter Bruegel the Elder, The Land of Cockaigne, Wikipedia)

Posted on June 30, 2018July 25, 2018 by admin

Mapping Waste-to-Energy

Most readers of our blog know that waste can be easily converted into energy, such as in biogas plants. Biogas, biohydrogen, and biodiesel are biofuels because they are biologically produced by microorganisms or plants. Biofuel facilities are found worldwide. However, nobody knows exactly where these biofuel plants are located and where they can be operated most economically. This knowledge gap hampers market access for biofuel producers.

At least for the United States − the largest market for biofuels − there is now a map. A research team from the Pacific Northwest National Laboratory (PNNL) and the National Renewable Energy Laboratory (NREL) published a detailed analysis of the potential for waste-to-energy in the US in the journal Renewable and Sustainable Energy Reviews.

The group focused on liquid biofuels that can be recovered from sewage sludge using the Fischer-Tropsch process. The industrial process was originally developed in Nazi Germany for coal liquefaction, but can also be used to liquefy other organic materials, such as biomass. The resulting oil is similar to petroleum, but contains small amounts of oxygen and water. A side effect is that nutrients, such as phosphate can be recovered.

The research group coupled the best available information on these organic wastes from their database with computer models to estimate the quantities and the best geographical distribution of the potential production of liquid biofuel. The results suggest that the United States could produce more than 20 billion liters of liquid biofuel per year.

The group also found that the potential for liquid biofuel from sewage sludge from public wastewater treatment plants is 4 billion liters per year. This resource was found to be widespread throughout the country − with a high density of sites on the east cost, as well as in the largest cities. Animal manure has a potential for 10 billion liters of liquid biofuel per year. Especially in the Midwest are the largest untapped resources.

The potential for liquid biofuel from food waste also follows the population density. For metropolitan areas such as Los Angeles, Seattle, Las Vegas, New York, etc., the researchers estimate that such waste could produce more than 3 billion liters per year. However, food leftovers also had the lowest conversion efficiency. This is also the biggest criticism of the Fischer-Tropsch process. Plants producing significant quantities of liquid fuel are significantly larger than conventional refineries, consume a lot of energy and produce more CO₂ than they save.

Better processes for biomass liquefaction and more efficient use of biomass still remain a challenge for industry and science.

(Photo: Wikipedia)

Posted on June 13, 2018July 11, 2018 by admin

The Photosynthetic CO₂ Race − Plants vs. Algae

Algae store CO₂ but also release it. Some of us may know that. However, so far it was unknown that algae may release additional CO₂ due to global warming. That’s what researcher Chao Song and his colleagues of the University of Georgia in Athens, GA, found out.

As they published in the journal Nature Geoscience, the metabolism of algae and other microbes is accelerated by higher water temperatures in large streams. This could lead to some rivers releasing more CO₂ than they do now. This could, in turn, further accelerate global warming. Although photosynthesis in algae would accelerate, plants along the river banks would be even faster. Decomposition of the plant material would immediately release the so fixed CO₂. With extra nutrients from plants, competing microorganisms would overgrow the river algae or the algae would degrade the plant material themselves.

To calculate the CO₂ net effect, scientists monitored temperature, dissolved oxygen, and other parameters in 70 rivers worldwide. Then they used their data for computer models. These models suggest that over time, accelerated photosynthesis in some rivers may not keep pace with plant growth. This net increase of 24% of the CO₂ released from rivers could mean an additional global temperature increase of 1 °C.

However, the computer model still lacks some data. For example, the sedimentation rates are not taken into account. In addition, not all banks grow plants. Many rivers pass only sparsely vegetated land. As always, more research is needed to get better answers.

(Photo: Wikipedia)

Posted on April 10, 2018July 12, 2018 by admin

Decarbonizing Planet Earth – Nuclear vs. Renewable

Adding to the controversial scientific debate whether renewable or nuclear energy decarbonize the atmosphere quicker, Lovins et al of the Rocky Mountain Institute in Basalt, Colorado, argue that renewable energy is doing a better job. In their recent study, published in Energy Research & Social Science, they analyzed 17 years of recent energy resource development worldwide to support their conclusion. Their paper stands in contrast to numerous previous studies, including a 2016 report published by Cao et al in Science, claiming that nuclear power is better suited for fast decarbonization. However, the nuclear waste problem still remains unresolved.