Paper beats rock, straw beats paper
(and helps to address China’s air quality problems)
October 7, 2014
Dave Hartter
dave@earthshift.com
Lise Laurin
lise@earthshift.com
Today in China
• 700 to 800 million tons of crop residue
are produced every year.1
• Though banned, millions of tons continue
to be burned by farmers leading to
human health and economic damage.
• Burning one ton of wheat straw has
human health impacts equivalent to
driving a car 44,000 kilometers.2
• 2.5 billion years of life expectancy are lost
in Northern China to air pollution from
sources such as burning straw.3
Yu (2013)
Based on air emissions from the burning of wheat (Li et al. , 2007), average European LCI data
for the operation of a car in ecoinvent 2.2 (Frishknecht et al., 2007) and the IMPACT 2002+
impact assessment method (Humbert et al., 2011)
3 Chen et al. (2013)
1
2
What should be done with all that straw?
• Use it as energy source?
• Turn it into agricultural product?
• Produce paper and packaging materials?
The benefits of transforming straw into npulp
• Chemical free “Enzymatic”
process to convert waste straw
into pulp.
• Converts 1 ton of straw into
0.55 tons of pulp.
• Eliminates burning and
provides economic incentive to
local farmers.
• Can produce organic fertilizer
as a byproduct.
• Longer fiber lengths enable
potential weight savings vs.
recycled pulp (up to 25%).
YFY Straw Bio-Pulping Process
Goal and Scope
• Intended application
– Cradle-to-grave comparative LCA of molded pulp packaging using
npulpTM and recycled pulp.
• Reasons for carrying out the study
– To understand the environmental benefits of using npulp in molded pulp
packaging, compared to recycled pulp.
– To understand the environmental benefits for multiple market scenarios.
• Target audience
– The audience will be YFY Group clients and the Chinese government.
What are the environmental benefits not only today,
but in potential future scenarios?
Goal & Scope
• Functional unit
– One molded pulp package (i.e. The
protection of an electronic product.)
• Material Systems
npulp molded pulp
– Npulp material system: 70% npulp /
30% recycled pulp (203 grams)
– Recycled pulp material system:
100% recycled pulp (260 grams)
Recycled molded pulp
System Boundary Diagram
Molded recycled pulp (cradle-to-grave)
Tree Cultivation
Energy and resources
Production and Use
of Corrugated
Cardboard
Recycled Pulp System Boundary Diagram (Cradle-to-grave)
Collection and
Transportation of
OCC
Pulping Process
Pulp Molding
Distribution and
Storage
Use
Collection
Waste Material
Output and
Treatment
WR
Emissions and waste
Recycled Material
Output
System Boundary Diagram
Molded pulp utilizing npulp (cradle-to-grave)
Grain Cultivation
Grain
Energy and resources
Npulp System Boundary Diagram (Cradle-to-grave)
Collection and
Transportation of
Straw
Burning Straw
(avoided)
Pulping Process
Pulp Molding
Distribution and
Storage
Use
Collection
Waste Material
Output and
Treatment
WR
Emissions and waste
Recycled Material
Output
Today burning the straw is common practices. What
will the results like in the future when it is not?
Allocation – Simulating Multiple Market Scenarios
• System expansion: npulp is credited
for avoided burning (current practice)
• Cut-off: npulp is not credited for
avoided burning (near future)
• Economic: npulp is economically
allocated a portion (8%) of the
burdens of growing the grain (longterm future)
Grain Cultivation
X%
Grain
Y%
Collection and
Transportation of
Straw
Burning Straw
(avoided)
Pulping Process
Given the dramatic amount of air pollution and the Chinese government’s
interest in solutions like npulp, it was important to evaluate solutions
based on future market scenarios.
LCI of Burning Straw (Per kg of Straw)
Air emission
Carbon dioxide, biogenic
Carbon monoxide
Non-methane VOCs
Nitrogen oxides
Particulates, < 2.5 μm
Amount (g)
/ kg of Rice Straw
1,100
30
5.1
3.4
5.7
Amount (g)
/ kg of Wheat Straw
1,500
60
7.5
3.4
7.6
Note: Rice straw emissions are based on Yu et al. (2012) and Zhang et al. (2013. Wheat
straw emissions are based on Li et al. (2007).
IMPACT 2002+ Impact Assessment Method
Damage Category
Units
Human health
DALY
Ecosystem quality
PDF * m2 * yr
Resources
MJ Primary
Climate change
kg CO2 eq.
Comments
Accounts for years lived disabled as well as
life cut short.
The damage to ecosystems is measured by
considering the percentage of species that
disappear in a given area during a certain
time period.
The two midpoint categories contributing to
the resources damage category are mineral
extraction and non-renewable energy
consumption. Resources impact is expressed
as MJ primary non-renewable energy.
Same method used by most GHG accounting
programs.
Modifications were made to IMPACT 2002+ to account for
the carbon dioxide sequestered by the crops
Npulp Results
System Expansion (Current Scenario)
100%
80%
60%
40%
20%
93%
89%
94%
Use (transportation)
93%
Molding
recycled pulp
0%
-20%
End-of-life
Human
health
Ecosystem
quality
Climate
change
Resources
npulp
-40%
-60%
The avoided burning results in net environmental benefits in human
health and climate change categories.
• The molding contributes about 90% of the environmental impacts.
• The npulp process produces fewer human health and climate change impacts
cradle-to-gate than burning the straw in the field.
Npulp Results
Cut-off (Future Scenario)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
89%
85%
78%
86%
End-of-life
Use (transportation)
Molding
recycled pulp
npulp
Human
health
Ecosystem
quality
Climate
change
Resources
Cradle-to-grave, npulp production is 12% or less of the life cycle impacts.
• Cradle-to-grave, recycled pulp production is 3% or less of the life cycle impacts.
Molded Pulp Comparison – Cradle-to-Grave
110%
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Human health
Ecosystem quality
Climate change
Resources
Recycled Pulp system
npulp system (system expansion)
npulp system (cutoff)
npulp system (economic)
Using Impact 2002+ impact assessment method (Hubert et al. (2011)
Npulp scenario analysis
Impact of the type of straw
140%
120%
100%
80%
60%
40%
20%
0%
Human health
Ecosystem quality
Baseline (50% Wheat, 50% Rice)
Climate change
100% Rice
Resources
100% Wheat
Using wheat straw results in a greater credit due to higher particulate and
carbon dioxide emissions when burned.
•
•
System expansion allocation method
Using Impact 2002+ impact assessment method (Hubert et al. (2011)
Npulp Scenario Analysis
Impact of the energy mix
100%
80%
60%
40%
20%
0%
Human health
Ecosystem quality
Climate change
RP (default)
RP (YFY energy for pulping)
npulp (default)
npulp (all YFY energy)
Resources
RP (all YFY energy)
The environmental impacts of both material systems is reduced
significantly when the molding processes uses the YFY energy mix.
• The comparative results do not change as long as material systems compared
using consistent energy mix.
Key Conclusions and Recommendations
• Human health, climate change and resources impacts are lower for npulp
in all market scenarios.
• Greater than approximately 80% of the cradle-to-grave impacts are due to
the molding process  Work with supplies to improve efficiency and
energy mix.
• Increasing use of wheat straw will have increased human health benefits
while burning straw is current practice.
• The absolute results are dependent on the energy mix and YFY should
continue reducing the amount of coal derived electricity.
Recommendations for LCA Practitioners
• Test different market conditions / allocation methods
representing short and long term scenarios.
• Identify key parameters (e.g. electricity mix, geography) that
may change over time and affect the conclusions of your study.
• Identify solutions for stakeholders that are independent of
allocation method and other factors that may change over time.
Sometimes solutions are only the best in terms of
sustainability in the short term  Key stakeholders need to
understand this.
References
Chen, Y., Ebenstein, A., Greenstone, M., & Li, H. (2013). Evidence on the impact of sustained exposure to air
pollution on life expectancy from China's Huai River policy. Proceedings of the National Academy of
Sciences of the United States of America, 110(32), 12936-12941.
Frischknecht, R., Jungbluth, N., Althaus, H.-J., Doka, G., Dones, R., Heck, T., . . . Spielmann, M. (2007). The
ecoinvent Database: Overview and Methodology. Dubendorf, CH: Swiss Centre for Life Cycle Inventories.
Retrieved from http://www.ecoinvent.org/fileadmin/documents/en/01_OverviewAndMethodology.pdf
Humbert, S., Margni, M., & Jolliet, O. (2011). IMPACT 2002+: User Guide. Lausanne, CH: Swiss Federal Insituted
of Technology. Retrieved August 1, 2013, from
http://www.impactmodeling.org/files/IMPACT2002+_UserGuide_for_v2.1_Draft_21Dec2011.pdf
Li, X., Wang, S., Duan, L., Hao, J., Li, C., Chen, Y., & Yang, L. (2007). Particulate and Trace Gas Emissions from
Open Burning of Wheat Straw and Corn Stover in China. Environmental Science Technology, 41, 60526058.
Yu, L. H. (2013). Straw purchasing and storage equipment problems to be solved. Retrieved from China Source
Report: http://news.sciencenet.cn/sbhtmlnews/2013/7/275748.shtm?id=275748
Yu, T.-Y., Lin, C.-Y., & Chang, L.-F. (2012). Estimating air pollutant emission factors from open burning of rice
straw by the residual mass method. Atmospheric Environment, 54, 428-438.
Zhang, Y., Shao, M., Lin, Y., Luan, S., Mao, N., Chen, W., & Wang, M. (2013). Estimating air pollutant emission
factors from open burning of rice straw by the residual mass method. Atmospheric Environment, 76, 189199.