A wide range of stakeholders have raised important questions about bioenergy and hydrogen opportunities and limitations, along with questions about the benefits and impacts of hydrogen and bioenergy related technologies for various applications. The U.S. Department of Energy's (DOE's) Alternative Fuels and Feedstocks Office (AFFO) developed this webpage to provide a resource to help answer these questions and support the important discussions.
AFFO has identified a number of questions through extensive engagement efforts—including requests for information, webinars, and public listening sessions held by multiple DOE offices. Questions have been compiled and condensed into a simple, clear format accessible to many audiences. The questions shown below are an initial selection identified as having the highest priority for key stakeholder groups.
The materials provided here were developed as a collaborative effort among bioenergy and hydrogen experts at DOE, followed by further review and refinement by multiple agencies across the federal government.
Frequently Asked Questions
- What kinds of biomass can be used to generate fuel and products?
- Why would the United States want to use its biomass resources for fuel and products?
- What is the current economic value of biofuels produced domestically?
- How much biomass could we sustainably produce in the United States?
- How many actual gallons of biofuels could we produce in years to come?
- How will we efficiently grow, collect, and transport the bulky, dispersed biomass required for biofuels?
- Why aren't more farmers collecting agricultural residue or growing energy crops to make biofuels right now?
- Which of the nation’s waste streams can we use to produce biofuels and how much would they amount to?
- What is DOE doing to help the U.S. bioeconomy ramp up production of advanced biofuels?
- When will we see substantial commercial production of cellulosic ethanol and hydrocarbon biofuels?
1. What kinds of biomass can be used to generate fuel and products?
Many types of plant- and algae-based material can be converted to useful products. Specific kinds of biomass include crop wastes, forestry residues, purpose-grown grasses, woody energy crops, algae, industrial wastes, non-recyclable municipal solid waste, urban wood waste, and food waste. Biomass is an alternative energy source that can be used to make liquid transportation fuels—such as gasoline, jet, and diesel fuel—in the near term. It can also be used to produce valuable chemicals for manufacturing, as well as power to supply the grid. For more information, visit the U.S. Department of Energy (DOE) Alternative Fuels and Feedstocks Office (AFFO), formerly known as the Bioenergy Technologies Office, Bioenergy Basics web page.
2. Why would the United States want to use its biomass resources for fuel and products?
Making biofuels and bioproducts from domestic, non-food and waste sources provides strategic benefits to the nation, including economic growth, energy security, environmental quality, and technology leadership. Biofuels are part of a multifaceted national strategy to improve quality of life and build a diverse and secure domestic U.S. energy supply. Domestic biofuels help to reduce U.S. reliance on imports, improve our trade balance, stabilize fuel prices, revitalize rural communities, create jobs, maintain our lead in science and innovation, and strengthen our energy security.
3. What is the current economic value of biofuels produced domestically?
The 16 billion gallons of biofuels produced in the United States in 2015 is equivalent to more than 11 billion gallons of gasoline and diesel—worth an estimated $17.5 billion. Of the 16 billion gallons produced, approximately 14.8 billion gallons was ethanol and 1.3 billion gallons was biodiesel.
Given that the energy content of ethanol is about 33% lower than conventional gasoline for equal volumes of fuel, 14.8 billion gallons of ethanol is equivalent to about 9.9 billion gallons of gasoline. Assuming the wholesale gasoline price of $1.57 per gallon at the beginning of fiscal year 2017, the total dollar value of our domestic ethanol production is about $15.5 billion.
The energy content of biodiesel is about 7% lower than that of petroleum-derived diesel fuel. Taking into account the difference in energy content, 1.3 billion gallons of biodiesel is equivalent to about 1.2 billion gallons of petroleum-derived diesel. Assuming the wholesale diesel price of $1.59 at the beginning of fiscal year 2017, the total value of our domestic biodiesel production is about $1.9 billion.
4. How much biomass could we produce here in the United States?
According to the 2016 Billion-Ton Report sponsored by DOE, the U.S. could produce—at $60 per dry ton—between 991 million dry tons per year (base-case assumptions) and 1,147 million dry tons per year (high-yield assumptions) by the year 2030. This is while continuing to meet the demands for food, feed, and fiber. This quantity of biomass could be used to produce enough biofuels to amount to more than 25% of the country's current energy consumption.
The estimated annual biomass potential available from various sources at $60 per dry ton or less by 2030 breaks down as follows:
- Forest resources currently used: 154 million tons
- Additional forest resource potential: 87 million tons
- Agricultural resources currently used: 144 million tons
- Additional agricultural residue potential: 174 million tons
- Energy crops: 380 million tons.
This amount of biomass (which includes residues in each resource category) can be produced from agricultural and forestry lands and from waste streams.
Assumptions used in the analysis significantly affect estimates of the potentially available biomass feedstock. Higher prices naturally increase the financial feasibility of producing more feedstocks. In addition, the assumed productivity improvements for agricultural and dedicated energy crops can affect these estimates.
5. How many actual gallons of biofuels could we produce in years to come?
Using the 2016 Billion-Ton Report to predict biomass resource availability and assuming a yield of 85 gallons per ton of cellulosic biomass, the United States has the potential to produce between 84 billion and 97 billion gallons of biofuels per year by 2030. This estimate is on par with the volume of U.S. gasoline consumption in 2015 (140 billion gallons).
The value that biofuels can bring to the U.S. economy in the future depends on the level of funding and other factors that are hard to predict. We do not know how rapidly fuel consumption will rise in the coming years, nor do we know with certainty the future mix or relative energy content of biofuels.
6. How will we efficiently grow, collect, and transport the bulky, dispersed biomass required for biofuels?
DOE is engaged in developing efficient systems for the large-scale harvesting, collection, preprocessing, storage, and transport of biomass feedstocks as a reliable commodity for use in biorefineries. The U.S. bioeconomy will need large quantities of high-quality cellulosic biomass that can be harvested and transported to biorefineries in an economical and reliable manner. DOE is working with diverse partners to overcome two major challenges in this area:
- Optimizing cellulosic feedstocks for biofuels. To enable large-scale production of cost-competitive cellulosic biofuels, researchers are working with selected plant varieties (not used for food, feed, or fiber production) to increase their yields, minimize water and fertilizer requirements, and optimize other critical properties that will facilitate their use in conversion processes. To compile and provide access to all of the latest results, DOE has established the Bioenergy Knowledge Discovery Framework, an online collaboration toolkit and public data resource for bioenergy research. For more information, visit AFFO’s Feedstock Supply web page.
- Developing efficient feedstock logistics systems. Biomass resources can vary widely in terms of density, moisture content, and other characteristics. The current vision is for multiple biomass feedstocks to be preprocessed into a consistent material that meets the specification requirements of biorefineries. This approach makes the biomass compatible with existing high-capacity handling systems, like those currently used for grain and other commodities. Feedstock logistics systems are undergoing rigorous, industrial-scale field testing to establish cost and productivity benefits. For more information, visit AFFO’s Feedstock Logistics web page.
7. Why aren't more farmers collecting agricultural residue or growing energy crops to make biofuels right now?
As in other industries, farmers need to be fairly certain that there will be an adequate demand for a product before they go into production. Farmers and other biomass producers are unlikely to see a significant, sustained demand for cellulosic feedstocks (such as switchgrass or corn stover) until more refineries begin producing cellulosic biofuels at commercial scale for U.S. markets.
From a farmer's perspective, collecting agricultural residues for biofuels represents a shorter-term and less risky than growing dedicated energy crops. Essentially, agricultural residues offer farmers a way to supplement revenue from their main crops at the end of the growing season; the key decision is whether the near-term market justifies the collection effort. Farmers will also consider the extent to which the residues are needed to protect and replenish the soil. The Regional Feedstock Partnership, which published a summary report in 2016, created corn stover harvesting guidelines that minimize soil erosion and retain soil carbon. By contrast, dedicated energy crops require a farmer to commit some land in advance of the growing season—when weather conditions and market prices are less predictable. Their risk is even greater in the case of crops that may need more than one season to become established and begin producing profitable yields. On the other hand, energy crops can often grow on marginal land and in harsh weather conditions.
8. Which of the nation’s waste streams can we use to produce biofuels and how much would they amount to?
In addition to the huge potential of agricultural and forestry wastes, harvested without disrupting natural ecosystem function or soil fertility, waste streams include sewage sludge, commercial and residential food wastes, livestock manure, and biogas. Urban waste streams contain a variety of potentially useful biomass materials, including construction and demolition wood waste.
The 2016 Billion-Ton Report sponsored by DOE determined that the United States currently has the potential to produce 702 million dry tons of biomass each year, and of this total, 205 million tons could potentially come from waste resources—68 million tons already being used, plus 137 million tons currently available that is not yet being used. In January 2017, AFFO published a report showing that the United States has the potential to use 77 million dry tons of wet waste per year, which would generate about 1,079 trillion British thermal units (Btu) of energy. Also, gaseous waste streams (which cannot be “dried” and therefore cannot be reported in dry tons) and other feedstocks assessed in the report could produce an additional 1,260 trillion Btu of energy, bringing the total to more than 2.3 quadrillion Btu annually. For perspective, in 2015, the United States’ total primary energy consumption was about 97.7 quadrillion Btu.
9. What is DOE doing to help the U.S. bioeconomy ramp up production of advanced biofuels?
To accelerate industry progress to diversify our domestic energy supply, DOE has strategically funded research and development projects to improve and scale up low-cost biomass conversion technologies and to ensure a reliable supply of high-quality commodity feedstocks for conversion.
Projects focus on (1) developing biomass resources as a reliable, affordable commodity for commercial-scale conversion; (2) developing cost-effective technologies to convert cellulosic biomass into fuels for commercial markets; and (3) demonstrating promising conversion technologies at various scales to reduce technical risk. To read more about each of these areas, visit AFFO’s Research and Development web page.
AFFO works with other federal agencies, national laboratories, industry, non-profit organizations, and academia to share and learn from valuable insights and perspectives that can help identify the most critical challenges facing the biofuels industry. To view a full list of AFFO’s partners, visit the Partnerships section of AFFO’s Key Activities web page.
10. When will we see substantial commercial production of cellulosic ethanol and hydrocarbon biofuels?
In 2012, after more than a decade of research and development, DOE and its partners in industry and the national laboratories validated (at pilot scale) the mature modeled price target for making ethanol from cellulosic biomass (plant materials not used for food, feed, or fiber production). This achievement led to the de-emphasis of cellulosic ethanol R&D within AFFO while continuing support for private industry to pursue commercial production with the expectation that cellulosic ethanol could be produced at a competitive price when the technology matured at scale.
As one example, the DuPont biorefinery in Nevada, Iowa, celebrated its grand opening on Oct. 30, 2015. DOE has supported DuPont by contributing more than $51 million towards key bioenergy conversion technologies and by collaborating on research and development projects. At full capacity, the DuPont facility is expected to produce 30 million gallons of cellulosic ethanol per year from corn stover that is harvested within a 30-mile radius of the site. This ethanol is slated to be used in production of detergents, a high-value bioproduct.
DOE has supported a total of 29 biorefinery projects (from pilot to pioneer commercial scale). The portfolio includes projects to produce cellulosic ethanol and projects to produce hydrocarbon fuels.
- Is hydrogen safe?
- How advanced is hydrogen leak detection—are the technologies used sufficiently accurate and reliable? Can hydrogen in the atmosphere impact global warming?
- Does the use of hydrogen produce air pollutants such as nitrogen oxides?
- Can water usage for electrolysis pose problems for parts of the United States currently facing water shortages?
More questions and responses will be added to this list as answers are refined and thoroughly vetted.
For any comments or questions related to these questions and answers please contact AFFO at AskAFFO@doe.gov.