# Presentation: 367557

## Agricultural Waste to Energy

- Robin L. Graham, PhD
**Group leader**
***Environmental Sciences Division***
***Oak Ridge National Laboratory ************ Oak Ridge, Tennessee***

**NCEP Forum:  The Future of Biomass and Transportation Fuels**
**Washington, DC**
**June 13, 2003**

## Potential Agricultural Wastes

- Primary

**Crop**
**Residues**

**Land managed for grain**

**Forest**
**Residues**

**Land managed for timber/pulp**
**Land thinned for fire protection**

## Potential Agricultural Wastes

- Secondary

**Manure and**
**Biosolids**

**Mill Wastes**

**Black Liquor**
**(pulp by-product)**

**Urban Wood**
**Wastes**

## Magnitude of Agricultural Wastes in the U.S.

**Total = 8.7 Quads primary energy**

**Forest**
**Residues**

**Crop Residues**

**Mill Wastes**

**Black Liquor**

**Manure and**
**Biosolids**

**Urban**
**Wood**
**Wastes**

**1.64 Quads**

**0.94**
**Quads**

**0.64 Quads**

**0.76**
**Quads**

**2.28 Quads**

**2.50 Quads**

## Magnitude of Unused Annual Agricultural Wastes in the U.S.

**2.05 Quads**

**0.25**
**Quads**

**Total = 3.73 Quads**

**Crop Residues**

**Mill Wastes**
**0.03 Quads**

**Forest Residues**

**Manure and**
**Biosolids**

**Urban Wood**
**Wastes**

**0.76 Quads**

**0.64 Quads**

## Agricultural Waste Can Producea Variety of Transportation Fuels

- Agricultural Waste Can Producea Variety of Transportation Fuels

**Urban Wood Waste**

**Mill Wastes**

**Forest Residues**

**Crop Residues**

**Black Liquor**

**Manure & Biosolids**

**Fermentation**

**Thermo-**
**chemical**

- Ethanol

- Hydrogen

- Fischer-Tropsch
- diesel,gasoline

## CO

- Fuels from Biomass Wastes Have Greenhouse Gas Benefits

- 2

**Fermentation to Ethanol**

**Notes:**

What do these include? Energy crops (trees and grasses), residues from agriculture (corn stover, rice straw, other “waste” biomass—forest thinnings, waste paper, MSE, other

What makes this technology different?  Harder to get at sources of sugar—cellulose and hemicelulose with lignin thrown in just to make things difficult.

Hydrolysis—chemical reaction to release sugars from these biopolymers.  It’s one of the toughest hurdles.  People have been trying to do this for over 100 years.  We did it in WWI.  Other countries have done it in times of need.  Japan, USSR.

Fermentation.  Today’s ethanol production is done using the same techniques used to convert sugars and starch to potable alcohol in beer, wine, liquor.  Conventional yeast from these industries can be used to convert the glucose found in cellulose, but not the different sugars found in hemicellulose.  Thus, the second big trick has been to develop bugs that ferment all of these sugars with no particular preferrence.

## The Current Potentialfor Transportation Fuels

- The Current Potentialfor Transportation Fuels

**Urban Wood Waste**

**Mill Wastes**

**Forest Residues**

**Crop Residues**

**Black Liquor**

**Manure & Biosolids**

- Ethanol
**37.4 billion gallons**

- Diesel/gasoline
**4.9 billion gallons**

- 14.1% of imported oil
- (yr 2000)

- 3.1% of imported oil

**37**

**90**

**138**

**150**

**55**

**51**

- Total** (million dry tons) = 521**
**                                ****(8.7 Quads)**

## The Current Potential for Transportation Fuels from Unused Agricultural Wastes

- Ethanol
**16.9 billion gallons**

- Diesel/gasoline
**2.2 billion gallons**

- 6.4% of imported oil
- (yr 2000)

- 1.4% of imported oil

**37**

**2**

**14**

**135**

**51**

- Total** (million dry tons) = 239**
**                                ****(3.73 Quads)**

**Urban Wood Waste**

**Mill Wastes**

**Forest Residues**

**Crop Residues**

**Manure & Biosolids**

## Hydrogen Potential in 2020

- _Assumptions_
**50% energy conversion ratio (biomass to H****2****)**
**2x efficiency use****w/fuel cell vehicle**

**40% U.S. light duty vehicle demand (2001)**
**22% oil consumption**
**36% imported oil**
**6% U.S. CO****2**** emissions (2001)**

**(Presentation to National Academy of Sciences, Mann and Overend 2003)**

**7 Quads****of biomass resources**
**(7 EJ biomass)**

**64 million lbs H****2****/yr**
**(29 Tg H****2****/yr)**

## Environmental Implications

- Fuels from biomass wastes can significantly reduce greenhouse gas emissions from the transportation sector.

- But only if primary agricultural and forest residues can be sustainably harvested. Sustainable harvest appears possible but may require managing the food or fiber crop differently.

- (A life-cycle comparison of gasoline and ethanol from corn stover – Sheehan et al 2003)

## CO

- 2

**Conversion**
**to Hydrogen**

- If We Could Generate H2 from Biomass

- We could pump CO2 out of the atmosphere. Applies equally to all forms of biomass resources.

**CO****2**

**H****2**

- and sequester the CO2

## Embracing a New Agricultural Paradigm?

- Food

- Fiber

- Fuels

- America's
- Agricultural
- Products

## Managing our lands for energy, food and fiber

**Managing our lands for energy, food and fiber**