# Presentation: 721552

## Biomass to Energy:Present Commercial Strategies and Future Options

- <date/time>

**Biomass to Energy:Present Commercial Strategies and Future Options**

- Healthy Landscapes, Thriving Communities: Bioenergy and Wood Products Conference January 21, 2003
- John Scahill
- National Bioenergy Center

## Biomass Feedstocks

**Wood chips**
**Urban Wood waste**
**pallets**
**crate discards**
**wood yard trimmings**

**Corn stover**
**Rice hulls**
**Sugarcane bagasse**
**Animal biosolids**

**Hybrid poplar**
**Switchgrass**
**Willow**

**Forest Wood Residues**

**Agricultural Residues**

**Energy Crops**

**Biomass Feedstocks**

**Notes:**
Point 3 areas with 1 example of each

Waste – sawdust

Ag residues – corn stover

Dedicated crops - switchgrass

## Biomass

**Lignin: 15-25%**
** ****Complex aromatic structure**
** ****Very high energy content**

**Cellulose: 38-50%**** **
** ****Polymer of glucose, very good biochemical feedstock**

- Constituents

**Hemicellulose: 23-32%**
-  **Polymer of 5 & 6 carbon sugar**

- Solid

- Gas or Liquid

## Biomass Conversion Pathways

**Thermal**

**Biological**

**Physical**

**Combustion**

**Gasification**

**Pyrolysis**

**Heat**

**Fuel Gases (CO + H****2****)**

**Liquids**

**Pretreatment**

**Fermentation**

**Ethanol**

**Hydrolysis**
**(Heat & Pressure)**

**Liquids**

**No Air**

**Partial air**

**Excess air**

**A/D**

**CH****4**

**H****2**

## Source: Cogeneration and On-site Power Production July 2003

- Jeremy Hugues

## Commercial Viability Issues  for Biomass CHP Technologies

**Difficult to exploit economies of scale  (< 20 MW)**
**Fuel costs are major cost driver (add $.01kW/$10 BDT) ***
**Water requirements**
**Combustion steam turbine (high)**
**Gasification gas turbine (low)**

- * Source: TSS Consultants

## Biomass PowerCurrent Commercial Technology

**Almost all systems are combustion / steam turbine**
**Most are grate stokers but FBC increasingly used**
**1-110 MW (avg. 20 MW)**
**Installed cost $980-$2500 kW ($1700- $2500 typical)**

- Itasca Power 20 MW Plant
- Prince Edward Island, Nova Scotia

## Combustion for Heat

**Can be cost effective if loads > 1MMBtu/hr**
**District heating a plus**
**Need wood fuel cost < $20/ton**
**Heat and power applications > 10 MMBtu/hr**
**Generally easy to permit at small scale**
**No demolition or treated wood**

## Combustion Systems

**Wood heated greenhouse**

**Automated bin feeding system**

- Source: Tim Maker – Biomass Energy Resource Center

## Wood Heating in Vermont

**20 public and 3 private schools heat with wood chips**
**Average cost $28.80/ton**
**Use ~ 8000 tons/yr**
**$220,000 savings over fuel oil**

- Source: Vermont Superintendents Association,  2000-2001 season

## Small Scale (100 kWe) Biomass CHPEconomics

- Source: McNeil Technologies June 2003

## Technical IssuesCombustion

**Conversion efficiency - 20-25% to power**
**Mineral management**
**Emissions NOx, CO, particulate**
**Mature technology**

## Gasification

**More efficient than combustion, 30%- 40%**
**Effectively manages mineral matter**
**Fuel gas (CO + H****2 ****+ CH****4****) can be used in prime movers**
**Installed Cost $1800 - $2000 / kW**

## Gasification

**Air  (0.3)**
**O****2****  (0.3)**
**Steam**

**Heat**

**Producer Gas (mol%)**
**CO****	****24**
**H****2****	****13**
**CH****4****	****3**
**CO****2****	****8**
**N****2****	****52**
**(tars & particulate)**

**Synthesis Gas (mol%)**
**CO****	****39**
**H****2****	****20**
**CH****4****	****17**
**C****2****H****2****	****6**
**CO****2****	****18**
**N****2****	****0**
**(tars & particulate)**

**Fuel Gases**

## Gasification

**Thermochemical Reactions**

**C + CO****2 ****          2 CO   ****(****Boudouard)**

** ****C + H****2****O              CO + H****2 **

**(Water gas shift)**

**Biomass**** =  CH ****1.4**** O ****0.6**

**800****° - 850° C**

## Gasifier Types

**Updraft**
**Downdraft**
**Fluidized Bed**
**Bubbling**
**Circulating Flow**
**Entrained Flow**

**Design Basis:  Fuel Properties, End Use, Scale, Cost**

## Updraft Gasifier

**Simple, reliable**
**Commercial history**
**High tars**
**Close coupled combustion**

- Source:  Renewable Energy Corp. Ltd (Waterwide Technology)

- Air

- Gas, Tar, Water

- Biomass

- Pyrolysis

- Reduction

- Combustion

- C + CO2 = 2CO
- C + H2O = CO + H2

- C + O2 = CO2
- 4H + O2 = 2 H2O

## Downdraft Gasifier

**Requires low moisture (<20%)**
**Lowest Tar**
**Can use gas in engines (after conditioning)**

- Air

- Biomass

- Gas, Tar, Water

- Pyrolysis

- Combustion

- Reduction

- Ash

- C + O2 = CO2
- 4H + O2 = 2H2O

- C + CO2 = 2CO
- C + H2O = CO + H2

## Fluidized Bed Gasifier

**Highest throughput**
**Fuel flexible**
**Tolerates moisture**
**Complex operation**

- Ash

- Product Gas

- Freeboard

- Fluid Bed

- Biomass

- Air/Steam

- Plenum

## Gasification Technical Issues

**Gas Conditioning**
**Tars**
**Particulates  (< 2 micron in size)**
**Acid gases  ( H****2****S, NH****3****, HCN, HCl)**

## Technology Performance

- Power Generation Technologies

## Source: Biopower Technical Assessment: State of the Industry and Technology,  March 2003

## Biomass CHP Technology Risk

**Commercial**

**Demonstration**

**Prototype**

**Stoker grate**
**combustion**

**FB Combustion**

**Updraft Gasification**

**FB Gasification**

**Downdraft Gasification**

**Small**** ****Modular Systems**

**Synthesis Gas Production**
- (entrained and FB)

- (small)

**Low installed cost**
**Low Efficiency**
**Low Risk**

**High installed cost**
**High Efficiency**
**High Risk**

## Requirements for Commercial Viability

**Sustainable fuel supply (long term contract)**
**Fuel costs $10- $20/ BDT**
**Capital costs $1000 - $1500 / kW**
**Power purchase agreement $.10 - $.20/ kWhr**
**Identify niche market for CHP**

**Site Specific**

- Source: TSS Consultants & McNeil Technologies

## Slide 25

## Gas Cleanup RequirementsFor Fischer-Tropsch gas-to-liquids

| Impurity | Removal level |
| --- | --- |
| H2S, NH3, HCN | < 1 ppmv |
| HCl | < 10 ppbv |
| Soot, dust, ash | Essentially completely |
| Tars  | Below dew point < 1 ppmv |

- Source: H. Boerrigter et al, October 2002

## Historical Natural Gas Costs

## Making Biomass Disappear 

- Air curtain burner

- Making Biomass Disappear

- 400 tons / day

- $0.00 Productivity