Biogas CO2 sources represent specific opportunities

By Sam A. Rushing, President, Advanced Cryogenics, Ltd., www.carbondioxideconsultants.com, www.CO2consultant.us

Special to The Digest

In some world markets, biogas is the common source of methane, otherwise thought of as, and called natural gas. Such is used to heat our homes, supply industry with a combustible fuel, and a feedstock agent; and of course a supply of carbon dioxide which is significant in the by-product of digesters. From the digesters, about 60-70% methane, and 30-40% CO2, plus other constituents, like hydrogen sulfide (the foul odor), and trace substances. The products from digesters are all useful, including the solids and liquids which go back to the soil.

Per the American Biogas Council, there are over 2,200 sites producing biogas in all 50 US states, 250 anaerobic digesters on farms, 12,690 water resource recovery facilities using an anaerobic digester, of which about 8670 currently use the biogas they use; 66 stand alone systems from food waste, and 652 landfill gas projects. When comparing with Europe, with 10,000 operating digesters and some communities are fossil free due to these digesters.

The biogas potential is very significant; with around 15,000 new sites ripe for development today. When taking the full energy yield value from these plants, this could represent some 103 trillion kilowatt hours of electric power; which represent taking some 117 million passenger cars off the road, should all of these plants be operational.

Challenges

All of this sounds great, with respect to principally the value of making methane from organic wastes; and the potential for replacement of fossil natural gas. On the other hand, as I have found as a CO2 consultant, the appetite for CO2 producers, primarily the CO2 firms, is non-existent; largely since the CO2 would largely have to be directed to the industrial markets alone. All of this is of course due to the fact biogas, in most cases, contains some form of animal or human waste; and a very small portion of these plants would be sourced from agricultural waste, such as nut hulls, orange peels, and like plant – based materials. As to the latter, should such ‘purely agricultural’ sources be available, with sufficient stature, this could be appealing to the CO2 industry, for the greater markets. We must remember, that in most developed world markets, the food and beverage industries account for up to 70% of all merchant CO2 consumed; thus eliminating most of the biogas sources. The bottom line, with respect to this comment, is the consumers who purchase these food and beverage products would not accept consumable products which contain CO2 borne from such ‘dirty’ waste sources, borne from human and animal waste.

As to the potential for sources which are derived from purely plant matter, most of these operations are too small to commercialize on their own; where in the case of biogas from the ‘dirty’ sources, many are also too small to make commercial sense; when the CO2 plants are scaled up to 450 – 600 TPD, or greater. Unless there is a purely philosophical, or perception change as to the presence of waste in the feedstocks, the lion’s share of these plants, including landfill, will have to be dedicated to the industrial sector, if CO2 is to be recovered. I further understand that some years ago, the predecessor of one of today’s global CO2 majors, built a plant from such a CO2 source; however it was never commissioned due to the lack of a viable market demand for the product from this facility.

There are equipment manufacturers which offer ‘bolt on’ CO2 plants, such as Pentair. Their website indicates this is available for various applications and markets, to include CCS, industrial usage, and even food & beverage. As to the latter, as food and beverage, this would have to fit into a philosophy surrounding acceptable uses in such food and beverage markets. This represents meeting requirements of the trade association, gas company, and consumer standards, with respect to definitions of origin labeled ‘waste’ feedstocks. In this respect, the ISBT covers beverage grade in such a way, that most soft drink majors, such as Coke and Pepsi, would require such certification.

As of this writing, I have no reply from a major beverage company as to their acceptance of biogas from purely crop – based waste feedstocks. Therefore, it is unknown as to the broad acceptance of CO2 from crop waste in the biogas industry for general food and beverage applications; however this is possible in some cases.

As to the use of pure agricultural waste feedstocks (fruits, vegetable products), some operators say for the best biogas yield, the bacteria in manure and fecal matter is a requirement in the feedstock. In any event, whether or not this is a factor, with animal waste, it would not be accepted, ultimately due to the lack of consumer and industry standards & perception.

The gas companies generally have remarked they have no interest in CO2 from biogas for the industrial markets alone; where their main objection is there would have to be a separation of transport and storage vessels; which they feel could not be accommodated.

Opportunities

Technically, there are economic opportunities for CO2 from biogas plants; just first say this is for purely industrial purposes. Then, in the case of industrial grade product, there would be opportunities in traditional industrial markets, such as for welding gas, blasting services, oil and gas, industrial & waste water Ph reduction uses, chemical feedstock, and much more. Even though industrial grade only accounts for about 30% of all demands in many developed CO2 markets, this represents near 3 million tons of usage in the US today; this is significant.

Another direction for CO2 from such waste projects would be various forms of niche markets, such as producing advanced fuels, plastics, chemicals and building materials. Some of these advanced products can also receive tax credits of $35/ton, under the US federal tax code 45Q, if annual CO2 utilization in such specific applications is at least 25,000 tons annually. If green CO2 from biogas is used to produce advanced fuels, chemicals, and related materials; this would represent a relatively complete green cycle in the generation, production and use of CO2, which is a real plus for the environment.

As to the traditional industrial CO2 markets, perhaps this is the time for the gas companies to reconsider their stance on accepting from industrial sites of CO2, to fulfill such markets; where given their extraordinary capabilities in handling distribution, and covering outages, this could be a means to an end, to fulfill part of the market demands. There could be the investment and separation of industrial v. food & beverage distribution assets; this is for industrial grade alone. On the other hand, there can be opportunities from crop waste alone, which would not contain the animal waste products, for example. Therefore, conceivably, such crop waste biogas could fulfill CO2 demands for at least part of the food market. I have inquired with the major beverage firms, as to whether sources from agricultural waste would be acceptable at this time; and there is no reply as of this time. Further, when considering such sources for one market or the other, there is  the green take on such sources, whereby biomethane would be produced in turn, and a renewable CO2 from such sources is always good the environment, v. hydrocarbon based CO2 sources, for example. Such source types could help plug the hole in supply networks when seasonal, annual, or unexpected outages occur. Outages, such as those underway this summer into fall in the US and Europe; due to various factors, could in part be alleviated. The industry is in dire need to expand the overall portfolio of CO2 source types, for the sake of reliability.

About the author

Sam A. Rushing is president of Advanced Cryogenics, Ltd., a CO2 and cryogenic consulting firm, which also supplies equipment to projects, with decades of diverse expertise. Sam is also on the Gasworld editorial board. Please contact the company for your CO2 consulting and equipment needs.

Tel. 305 852 2597

Web. www.carbondioxideconsultants.com

Email: rushing@terranova.net