Cellulosic Ethanol Fuels The Future (A Comparison To Traditional Ethanol Production)
In today’s world, the demand for sustainable fuel options is higher than ever before. As we face mounting concerns over climate change, rising fuel costs, and dwindling natural resources, the need for renewable energy alternatives is more pressing than ever before.
This is where cellulosic ethanol comes in as a game-changer. This biofuel is made from non-food plant materials like grasses, wood chips, and agricultural waste. Unlike traditional corn ethanol, cellulosic ethanol doesn’t compete with food production and has a much lower carbon footprint.
Cellulosic ethanol has the potential to significantly reduce greenhouse gas emissions, provide a more reliable and cost-effective fuel supply, and support the growth of rural economies, all the while reducing dependence on foreign oil.
In fact, studies suggest that cellulosic ethanol can reduce greenhouse gas emissions by up to 86% compared to gasoline.
In this blog, we will explore why cellulosic ethanol is the future of sustainable fuel production and its potential to transform the energy industry.
- The drawbacks of traditional ethanol production
- What is cellulosic ethanol and what makes it sustainable?
- Benefits of cellulosic ethanol production
- The science behind cellulosic ethanol
- The economics and distribution of cellulosic ethanol production
- Current cellulosic ethanol projects and success stories
- Future of cellulosic ethanol production
The Drawbacks of Traditional Ethanol Production
The primary source of traditional ethanol production varies in different countries. In the United States, it’s corn (food crop), due to its abundant corn production. However, several drawbacks have proven it to be unsustainable in the long run. Some of the reasons include but are not limited to the fact that it competes with food production, automatically driving up food prices, and in severe cases, may potentially cause food shortages.
Additionally, traditional ethanol production requires a significant amount of energy and resources that indirectly still contribute to a higher measure of greenhouse gas emissions and environmental problems.
Unlike cellulosic ethanol production, traditional ethanol production has also been far less efficient. Typically, traditional ethanol yields around 2.5 gallons of ethanol per bushel of corn, while cellulosic ethanol production can yield up to 4 times as much ethanol per ton of feedstock.
Ultimately, cellulosic ethanol production requires less land and resources to produce the same amount of ethanol, making it a more sustainable option.
Despite these drawbacks, traditional ethanol production has played an important role in reducing dependence on foreign oil and promoting renewable energy. However, as we move towards a more sustainable future, it’s important to explore alternatives such as cellulosic ethanol.
What is cellulosic ethanol and what makes it sustainable?
Cellulose-based ethanol or cellulosic ethanol is produced from lignocellulosic biomass. It is mainly composed of cellulose and lignin, found in agricultural crops and trees, wood & wood waste/residues, including aquatic plants, grasses/fibers. (Lignin: a complex organic polymer deposited in the cell walls of many plants, making them rigid and woody.)
These sources are known as feedstock and are typically considered waste products that would otherwise be discarded. By using these feedstocks to produce ethanol, we can reduce waste and create a valuable source of fuel.
The process of producing cellulosic ethanol involves breaking down the feedstocks into their component sugars, which are then fermented and distilled into ethanol. This process is more complex than traditional ethanol production, but it has several advantages.
Overall, among other renewable biofuels, cellulosic ethanol is sustainable with its use of non-food feedstocks and its low carbon footprint. These factors itself has a lesser impact on the food chain than first-generation biofuels, making them a promising alternative to traditional ethanol production. This plays a key component in our sustainable energy future.
Benefits of cellulosic ethanol production
There are several more benefits of cellulosic ethanol production aside from the abovementioned advantages.
According to the Environmental and Energy Study Institute, a single cellulosic ethanol production plant can reduce emissions by up to 210,000 tons of CO2/per year with the usage of agricultural waste (corn stalks, husks, cobs) that would normally be left on the field to decompose.
On top of that, the feedstock of any waste from co-products or even dedicated crops for cellulosic ethanol does not require a high amount of water and fertilizer compared to corn when it is dedicated to traditional ethanol production.
Lastly, many feedstocks for cellulosic ethanol production are found in rural areas, which means that cellulosic ethanol production can create jobs and economic opportunities in these areas. Additionally, cellulosic ethanol production can reduce dependence on foreign oil, which can improve energy security and reduce the risk of supply disruptions.
The science behind cellulosic ethanol
The process of producing cellulosic ethanol (cellulolysis process) involves several steps, each of which is critical to the overall process.
The two major cellulolysis processes include chemical processing using acids (chemical hydrolysis), which is the traditional method, and enzymatic reactions using cellulases.
The first step of the method is to pretreat the feedstocks, which involves breaking down the lignin and other complex components of the feedstocks. This makes it easier to extract the sugars from the feedstocks and convert them into ethanol.
The next step is to hydrolyze the feedstocks, which involves breaking down the sugars into their component parts. This is typically done using enzymes, which are added to the feedstocks and allowed to break down the sugars. Once the sugars have been hydrolyzed, they are ready for fermentation.
The thermochemical conversion process involves adding heat and chemicals to a biomass feedstock to produce syngas, which is a mixture of carbon monoxide and hydrogen. Syngas is mixed with a catalyst and reformed into ethanol and other liquid co-products.
According to a study supported by the National Science Foundation and the Department of Energy, using a similar enzymatic system, lignocellulosic materials can be enzymatically hydrolyzed at a relatively mild condition (50 °C and pH 5), thus enabling effective cellulose breakdown without the formation of byproducts that would otherwise inhibit enzyme activity. All major pretreatment methods, including dilute acid, require an enzymatic hydrolysis step to achieve a high sugar yield for ethanol fermentation.
Fermentation is the process of converting sugars into ethanol. This is typically done using yeast, which is added to the feedstocks and allowed to ferment the sugars. Once the fermentation process is complete, the ethanol is ready for distillation.
Distillation is the process of separating ethanol from the other components of the mixture. This is typically done using a distillation column, which separates the ethanol based on its boiling point. Once the ethanol has been separated, it is ready for use as a fuel.
The economics and distribution of cellulosic ethanol production
The economics of cellulosic ethanol production depends on several factors. One of the main factors is the cost of the feedstocks. Non-food feedstocks like wood chips and grasses are typically cheaper than food crops like corn, but their availability and cost can vary depending on factors like location and season.
Another factor that affects the economics of cellulosic ethanol production is the cost of production. Cellulosic ethanol production is typically more expensive than traditional ethanol production, at least in the short term. However, as technology improves and economies of scale are achieved, the cost of production is expected to decrease.
Today, the US is the largest producer of ethanol for around 55% of global output, majorly sourced from corn as a feedstock. The US renewable fuel standard (RFS), enacted in a 2005 statute and expanded two years later, requires petroleum refiners to blend ethanol into each gallon of the gasoline they sell. Although it caused a sudden growth of the corn-ethanol industry, it was then capped at 15 billion gallons per year.
Roughly 40% of the annual US corn crop is currently dedicated to ethanol. The downside of this is that converting pasture or lands to grow corn or other crops would result in a large and sudden amount of CO2 from soils. Although considerably lower than that of gasoline, that ‘carbon debt’ could take decades to pay back through photosynthesis by crops.
With cellulosic ethanol, these challenges can be overcome with other feedstock of waste or co-products of corn. Today, analysis has shown that the global cellulosic ethanol market is poised to grow by USD 47.8 billion during 2020-2024, progressing at a CAGR of 46%.
Source: Dean Armstrong, National Renewable Energy Laboratory
According to the U.S. Department of Agriculture, 90% of ethanol is transported by train or truck while 10% is transported by barge with minimal amounts transported by pipeline. Most of the U.S. ethanol plants are concentrated in the Midwest, but gasoline consumption is highest along the East and West Coasts. The United States consumed nearly 14 billion gallons of ethanol in 2021.
Current cellulosic ethanol projects and success stories
There are several current cellulosic ethanol projects that are making progress toward commercialization. One of the most promising projects is the POET-DSM Project Liberty plant in Emmetsburg, Iowa. This plant is capable of producing 20 million gallons of cellulosic ethanol per year and is considered one of the most advanced cellulosic ethanol plants in the world.
Another success story in cellulosic ethanol production is the Abengoa Bioenergy plant in Hugoton, Kansas. This plant is capable of producing 25 million gallons of cellulosic ethanol per year and is one of the largest cellulosic ethanol plants in the world.
Iogen technology has also made it economically feasible to convert biomass into cellulose ethanol using a combination of thermal, chemical, and biochemical techniques. The yield of cellulose ethanol is more than 300 liters per tonne of fiber. The lignin in the plant fiber can be used to drive the process by generating electricity, recycling emissions, and reducing fossil fuel usage.
Brazil has also witnessed a successful case, with 27% of the global ethanol output, acting as the world’s second-largest producer. There, sugarcane is the raw material, and half of its annual sugarcane crop is converted to ethanol each year. Vehicles in Brazil run either on a 25% ethanol mix or pure ethanol fuel. Raízen, a joint venture of Shell and Cosan, a Brazilian conglomerate, operates 26 plants producing sugar, ethanol, and biogas, and manufactured approximately 2.5 billion liters of ethanol and 3.8 million tons of sugar in the 2019–20 crop year. It began making cellulosic ethanol commercially in 2014, using sugarcane straw and bagasse, the pulp that remains once the juice is squeezed from the cane.
Last but not least, our very own Re:Build Optimation has helped Byogy Renewables, Inc., conduct a Jet Fuel From Farm Waste renewable project with successful results.
Byogy Renewables, Inc of San Jose, CA is a biofuels organization. The summer Olympics was supposed to be held in Japan in 2020. The theme of the Olympics was to be sustainability. Housing, medals, uniforms, and other materials were made from recycled materials. A decision was made that during the Olympics there should be a stadium flyover where the jets were flying on jet fuel made from farm waste. Optimation was contacted by Byogy, who had the contract and rose to the need for the technology and the schedule.
We built a system of reactors and stills that converted farm waste to ethanol and then the ethanol to jet fuel. The system was designed and built to meet all Japanese mechanical and electrical codes, shipped to Japan, and tested. The results were amazingly successful.
Read our case study to learn more about our solution that contributed to the Olympics success: https://www.optimation.us/projects/jet-fuel-from-farm-waste/
Future of cellulosic ethanol production
Despite the challenges and limitations of cellulosic ethanol production, the future looks bright for this promising industry. Advances in technology, economies of scale, and sustainable sourcing of feedstocks are all expected to drive down the cost of production and make cellulosic ethanol more competitive with other forms of fuel production.
Additionally, as the demand for sustainable fuel options continues to grow, cellulosic ethanol is expected to play a larger role in the energy industry. With its low carbon footprint, the potential to create jobs in rural areas, and the ability to reduce dependence on foreign oil, cellulosic ethanol has the potential to transform the energy industry and create a more sustainable future for all.
Re:Build Optimation has been actively involved in the design and construction of cellulose-based ethanol development and production systems. Our depth of chemical engineering and process automation skills coupled with our fabrication facilities and plant construction experience makes us a natural partner as new feed stocks or enzymes are investigated and plant upgrades and modifications are required.
Re:Build Optimation offers turnkey services and applications such as but are not limited to:
- Conceptual design/engineering
- Converting & finishing
- Fabrication & assembly
- Inspection & test systems
- Installation & dismantlement
- Machine build
- Skid systems
- Test systems, etc.
We have extensive experience in various industries such as chemical, energy & power, and oil & gas.
Through automation & control, chemical engineering, construction/project management, process engineering & design, as well as system integration, our full team advantage of highly skilled journeymen are at your service.
Learn more about our fabrication facilities here: https://www.optimation.us/industries/renewable-energy/
Or explore what you can get by working with Re:Build Optimation for your renewable project by contacting us for more info.