Quantitative estimation of biomass energy and comprehensive evaluation of
biomass utilization:—A case study of Jilin Province, China

Chapter 1

University of Tsukuba

Song Junnian*

University of Tsukuba

Helmut Yabar

University of Tsukuba

Mizunoya Takeshi

University of Tsukuba

Higano Yoshiro

Introduction

Energy shortage and environmental crisis are significant problems that restricting the socio-economic development of theworld. With the increasingly depletion of conventional energy, research on biomass energy that is a kind of renewable,
abundant and environmentally friendly substitutive energy has been a hot issue around the world.
Jilin Province as a large agricultural and forestry province owns abundant biomass resources generated from production
and living activities. Besides, Jilin Province is short of energy whose primary energy storage accounts for only 0.3% of China
and the self-sufficiency rate is less than 50%. According to the 12th 5-year plan, Jilin Province has a target to raise thebiomass energy production to 840t of standard coal. So the comprehensive utilization of biomass resources in Jilin Province
has obvious socio-economic and ecological benefit in energy saving and emission reduction.
This paper makes a quantitative estimation of supply potential of biomass energy in Jilin Province. Then it makes Life
Cycle Assessment on biomass utilization taking biomass power generation system as example.
Chapter 2

Supply potential of biomass energy

The availability evaluation of biomass energy and the amount calculation of organic biomass resources have different
index in corresponding to different criterion (LI, REN and ZHUANG). Here three definitions including physical reserve,
theoretical acquirable amount and conversion of standard energy are introduced (LIU and SHEN). The amount of majororganic biomass resources is evaluated step by step according to these three definitions.
2.1 Physical reserve
Physical reserve is the total amount of theoretically physical production of major biomass resources from four sources as
straw and agricultural residues, firewood and forestry residues, livestock manure and municipal waste.
(1) Straw and agricultural residues
Straw and other agricultural residues mainly come from food crops, oil crops, cotton, hemp and sugar. Straw-grain ration
method is widely adopted to calculate the amount of crop straw. Straw-grain ratio is the ration of the amount of stems above
the ground and the amount of economic yield of crops. The yield of straw can be calculated as:

CR: physical amount of straw, Qci: yield of Crop i, ri: straw-grain ratio of Crop i.
(2) Firewood and forestry residues
Forestry biomass resources mainly generate from clearing, cutting and processing residues of forestry production, firewood
forests and forest tending and thinning. The amount of forestry biomass resources can be calculated either with index as areaof forests, firewood coefficient and production of per unit area (YAN, WU and HUANG) or by respectively calculating theamount of firewood forests, residues of forestry production and other forestry biomass (Research Group of Chinese Forest
Bio-energy). This paper mainly calculates the amount of forestry residues, firewood forests, forest tending and thinning andthe adjacent small trees with the formula as:

FR: physical amount of forestry biomass, Qfi: amount of Forestry biomass i, r i: conversion coefficient.
(3) Livestock manure
The amount of manure is related to species, breeds, genders, growing season and so on (DING). Here the livestock is
assumed as mature and the breeding cycle is assumed as fixed. The amount of manure can be calculated with daily yields andbreeding cycle with the formula as:

D: Physical amount of manure, Qdi: the number of Livestock i, di: daily yield of Livestock i, mi: breeding cycle, Mi: manureyield of Livestock i within the whole breeding cycle.
(4) Municipal waste
Municipal waste consists of municipal solid waste and municipal waste water. Municipal solid waste can be divided into
organic waste and inorganic waste according to the composition. The organic waste can be utilized as biomass resources
through harmless treatment. Municipal waste water is divided into domestic sewage and industrial wastewater, both can betreated to produce biogas . The amount of total municipal waste can be calculated with the formula as:

MW=SW·r1+QW·r2(4)

SW: the amount of municipal solid waste, r1: the percentage of organic waste from municipal solid waste, Qw: the amount ofwaste water, r2: the percentage of COD in waste water.
2.2 Theoretical acquirable amountPhysical reserve of biomass resources is the amount representing the theoretically richest developing potential (LIU and
SHEN). Not all the reserve can be acquired and utilized to produce energy. There is availability coefficient and energy
efficiency of biomass resources for energy generation. So the theoretical acquirable amount refers to the amount of biomass
resources that can be acquired and utilized to produce energy under theoretical conditions, which can be calculated from theamount of physical reserve.

CR’: Theoretical acquirable amount of straw, λi: availability coefficient of Crop i. δi: energy efficiency. Theoreticalacquirable amount of forestry residues (FR’), livestock manure (D’) and municipal waste (MW’) can be calculated withcorresponding λi and δi. Table 1 concludes the availability coefficient and energy efficiency of different biomass resources(Research Group of Chinese Forest Bio-energy; A M ilbrandt; ZHONG, YUE, FAN; ZENG, WANG).
Table 1

Availability coefficient and energy efficiency of different biomass resources(λi and δi)
Forestry

Types

Straw

Availability coefficient(λi)

90%

40%

Energy efficiency(δi)

85%

1/3

residues

Municipal solid

Municipal waste

waste

water

100%

40%

100%

1/3

60%

50%

Livestock manure

2.3 Conversion of standard energy
When put into unified and practical studies, the amount of various biomass resources isusually converted to standard

energy, which is generally defined as standard coal. The determination of conversion coefficient is key point of theconversion. In terms of the calculation of straw standard energy (ECR), ηi is introduced into the calculation of physicalamount of straw as:

As for the calculation of forestry residues standard energy (EFR), livestock manure standard energy (ED) and municipal
waste standard energy (EMW), corresponding ηi should be introduced. When waste water is converted to standard energy, it
is firstly converted to biogas (0.907m3 biogas

can be generated from 1kg COD) (A M ilbrandt).

2.4 Calculation results and analysis
With the calculation analysis and data summary, results of physical reserves, theoretical acquirable amount and standard
energy are finally obtained and shown in Table 2.
Table 2

Results summary of organic biomass energy in Jilin Province
Physical reserves

Types

Theoretical acquirable

Standard energy

4

Percentage

4(10 t)

amount (10 t)(104tce)

Straw and agricultural residues

3504.22680.71336.549.8%

Firewood and forestry residues

1100.3

146.7

83.8

3.1%

Livestock manure

7800.92600.31198.6

44.7%

Municipal waste

557.7

328.8

65.5

2.4%

In total

12963.2

5756.62684.4100%

88Physical reserves of biomass resources in Jilin Province is 1.3×10 t, from which 0.58×10 t can be acquired and utilized to
produce energy. This amount is equivalent to 0.27×108t standard energy, among which agricultural biomass accounts for themost (49.8%) followed by livestock manure (44.7%). When utilizing biomass energy, agricultural biomass and livestock
manure should be focused on.

2.4%

Straw and agriculturalresidues

49.8%

44.7%

Firewood and forestry
residues
Livestock manure
Municipal waste

3.1%
Fig 1
Chapter 3

Amount composition of various biomass energyLife Cycle Assessment on biomass utilization

Life Cycle Assessment (LCA) is a tool used to assess the impacts on environment brought by products or conduct during
the life cycle. LCA can identify and quantify the utilization of energy and materials and the emission of wastes, assess theimpact extent of the utilization and emission and strive to seek the chance to improve the environmental quality (LIU and
WANG). This chapter makes comprehensive evaluation on biomass utilization taking a biomass power generation system in
Jilin Province as example.
3.1 Introduction of biomass power generation system
Songyuan City is a new petrochemical city located in the west of Jilin Province. It has 76×10 4hm2 of farmland whose total
yield of corn is 400×104t, accounting for 1/4 of the amount of Jilin Province. In order to utilize straw resources more

efficiently, the government deployed the overall route of straw power generation, namely constructing Datang Songyuan
biomass power generation project in Songyuan City to promote biomass utilization. The study object of this research is
15MW straw direct-fired power generation system, whose annual electricity generation time is 6000h and rated annual
generating capacity is 1.8×108kWh. Environmental impacts brought by 10000kWh of power generation will be calculated
and analyzed.
3.2 Assessment scope and boundary demarcation
When determining the assessment boundary, several points should be considered: (1) In order to form a closed loop system,
the coal, oil, electricity, steel and water consumed during construction period of the plant are not involved into the boundary;(2) Because biomass power generation system is a new system that has not reached the scrapping age, equipment recovery
unit is not considered; (3) Electricity does not bring impacts to environment directly so electricity using process is not
involved into the boundary. Based on the assumptions above, biomass power generation system can be divided into threeparts: (1) Agricultural production period; (2) Transportation period; (3) Plant operation period (LIU Junwei).
3.3 Inventory analysis
Table 3
Pollutants

The inventory of life cycle emission of biomass power generation system Unit: t/104kWh
Agricultural
production period

Transportation period

Plant operation period

Total amountCO2

773.160

205.3280.000

978.488

CO

1.873

1.215

0.000

3.088

CH4

0.610

0.016

0.000

0.626

N2O

0.276

0.008

0.000

0.284

NOx

3.528

1.826

24.61829.972

Smoke

0.010

0.046

1.479

1.535

SO2

6.979

0.261

13.92321.163

3.4 Calculation of environmental impact burden(1) Environmental impact potential
Environmental impact potential refers to the sum of all the impacts of similar pollutant emission within the system. Similar
pollutants can be converted to reference’s environmental impact potential with equivalent coefficient. Calculation formula ofenvironmental impact potential is:EP(m): Environmental impact potential m, EP(m)n: Environmental impact potential m of Pollutant n, Q(m)n: emission
amount of Pollutant n, EF(m)n: coefficient of Environmental impact potential m of Pollutant n.
Table 4
Environmental
impacts

Pollutants

Results of life cycle environmental impact potential
Equivalent

Raw material

coefficientacquisition

CO2

1

Global warming

CO

2(kgCO2eq)

CH4

25

N2O

320

Acidification

NOx

0.7

(kgSO2eq)

SO2

1

Photochemical

CO

0.03

smog (kgC2H4eq)

CH4

0.007

TransportationPowergeneration

In total

880.334210.8280.000

1091.162

9.449

1.539

31.15542.143

0.060

0.037

0.000

0.097

Human toxicity(kg)
Smoke&dust (kg)

CO

0.012

NOx

0.78

SO2

1.2

Smoke&dust

1

11.1491.752

35.90948.811

0.010

0.046

1.479

1.535

(2) Standardization and weighted assessment
Standardization of data is to make environmental impact potential dimensionless. In order to compare the relative value ofthe environmental impact potential, standardization of the data must be selected within the same period. This paper chooses
the environmental impact potential of per capita of the whole society in 1990 as the norm of the standardization.
By endowing different weights to the extent of environmental damage induced by different environmental impacts,
environmental impacts of biomass power generation system can be more reasonably assessed. This paper adopts Analytic
Hierarchy Process (AHP) to analyze the relative importance of the five environmental impacts and to determine the weightsof them.
Table 5

Standardized and weighted results of life cycle environmental impact potential of biomass power generation system

Environmental

Weightimpacts

Raw material
acquisition

Transportation

Power generation

Weighted results

Global warming

0.48

0.049

0.012

0.000

0.060

Acidification

0.25

0.066

0.011

0.216

0.293

Photochemical smog

0.05

0.005

0.003

0.000

0.007

Human toxicity

0.13

0.081

0.013

0.259

0.353

Smoke&dust

0.09

0.000

0.000

0.007

0.008

In total

1

0.199

0.038

0.483

0.721

0.400
0.300
0.200
0.100
0.000

Fig 2

Standardized and weighted results of life cycle environmental impact potential of biomass power generation system

3.5 Analysis and discussion about Life Cycle Assessment
Among three processes of the power generation system, power generation brings the most environmental impacts. Among
all the environmental impacts, human toxicity accounts for the largest proportion and the next is acidification, which isresulted from the emission of CO, NOx and SO2 with high concentration. Besides, the use of fertilizers during straw plating
period contributes to the emission of NOx and SOx. Therefore when improving environmental impacts, the technologies andmeasures to lower the concentration of CO, NOx and SO2 should be focused on to reduce the impacts of human toxicity andacidification.
Taking reference to the research of Life Cycle Assessment on thermal power generation system (the calculation ofpollutant emission and energy consumption on average level of China) done by Di Xianghua and Nie Zuoren, the emission
amount of pollutants of thermal power generation system by generating 10000kWh electricity can be obtained and theenvironmental impacts brought by the pollutants can be calculated.
Table 6

Standardized and weighted results of life cycle environmental impact potential of thermal power generation systemFig 3Comparison of environmental impacts of biomass power generation system and thermal power generation system

We can see that total environmental impact burden of thermal power generation system is 25.321, which is much larger
than 0.721 of biomass power generation system. Acidification potential is the largest due to the combustion of coalcontaining high amount of sulfur. So the environmental advantage of biomass power generation system is obvious.

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