Energy consumption and greenhouse gas emissions of biodiesel ...

JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY 5, 063134 (2013)

Energy consumption and greenhouse gas emissions of biodiesel production from rapeseed in Iran Mohammad Ali Rajaeifar,1,a) Barat Ghobadian,2 Mohammad Davoud Heidari,1 and Ebrahim Fayyazi2 1

Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran 2 Department of Mechanical Engineering, Tarbiat Modares University, Jalal ale Ahmad highway, Tehran, Iran (Received 7 August 2013; accepted 6 December 2013; published online 23 December 2013)

The issue of searching alternatives for diesel fuel in transport sector that is one of the largest diesel fuel consuming sectors in each country has become more attractive nowadays. In this study, the energy consumption and CO2 emissions of biodiesel production from rapeseed as an alternative for diesel fuel in transport sector was assessed in terms of three main stages including agricultural crop production, transport, and industrial conversion. The results revealed that the total fossil energy input cost was calculated as 28 122.16 MJ ha1 and the renewable energy output content (biodiesel as the final outcome) was estimated as 31 802.06 MJ ha1. The net energy returns and the fossil energy ratio were calculated as 3679.9 MJ ha1 and 1.13, respectively. It shows rapeseed could be a suitable energy crop for biodiesel production. CO2 emissions assessment showed that the total greenhouse gas emissions over biodiesel production life cycle were 1054.98 kg CO2 eq ha1 and the agricultural crop production stage ranks the first. In order to establish energy crops cultivation such as rapeseed and achieve the sustainable development, meteorological and water source availability data collected and analyzed for all the 31 provinces in Iran to generate a map of regions capable of rapeseed cultivation. The results revealed that 24 provinces among 31 provinces C 2013 AIP Publishing LLC. have a great potential for rapeseed cultivation. V [http://dx.doi.org/10.1063/1.4854596] NOMENCLATURE

NER FER GHG IEA GDP UNFCCC

net energy return fossil energy ratio greenhouse gas international energy agency gross domestic product United Nations framework convention on climate change

I. INTRODUCTION

Nowadays, the sustainable realistic development and growth is one which does not have adverse effects on environment and should not destroy the natural resources.1 In order to succeed in the sustainable development and reduce greenhouse gases (GHGs) produced by fossil fuels, a developing trend for using renewable energies instead of non-renewable energies should become an important part of the energy policy for each country. There are some alternatives

a)

Author to whom correspondence should be addressed. Electronic mail: [email protected]. Tel.: þ998-26-32801011. Fax: þ98-26-32808138

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C 2013 AIP Publishing LLC V

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such as biodiesel, bioethanol, electricity, hydrogen, and natural gas considered as alternative choices for reducing the transport sector’s dependency on petroleum and to decrease its environmental impacts.2,3 Between 2005 and 2010, the global production of biofuels (bioethanol and biodiesel) has grown from 585 thousand barrels to 1519 thousand barrels per day and 71 thousand barrels to 335 thousand barrels per day for bioethanol and biodiesel, respectively.4 The annual world production of biofuels in 2011 increased 0.7% (compared to 2010) while this increase was 3.4% for annual biofuel production for Asian countries.5 This increase in production of biofuels shows a new perspective of different countries across the world, especially the Asian ones. Several studies were carried out by scientists about the possibility of biofuels production in Asian countries. Barnwal and Sharma studied the prospects of biodiesel production from vegetable oils in India in 2005.6 Palm oil potential as a source of biofuels in Malaysia was investigated by Lam et al.7 In 2008, Hu et al. studied life cycle energy, environment, and economic assessment of soybean-based biodiesel as an alternative automotive fuel in China.8 In a study conducted by Phalan, the social and environmental impacts of biofuels in Asia were assessed and the results revealed that biofuels will form a small but significant share of Asia’s energy supply in the next decades.9 The possibility of biodiesel and bioethanol production in different countries of Asia was studied by other researchers (Refs. 10–13) and the results indicated that several countries in Asia had different plants to produce biofuels in order to achieve sustainable development and increase energy security. One of these countries, which has different potential plants to produce biofuels is Iran. In a recent research by Ghobadian,14 liquid biofuels potential in Iran (which is mainly produced as ethanol and biodiesel) and its outlook was investigated. The results showed that there are many regions in Iran, which have a substantial potential for oil production as biodiesel feedstocks. Safieddin Ardebili et al. investigated the biodiesel production potential from oil seeds such as rapeseed (canola cultivar), cotton, soybean, corn, seasem, sunflower, olive, safflower, almond, coconut, walnut, and hazelnut in Iran and the results revealed that canola (Brassica napus L.) with the potential of 142 756 tons of biodiesel production per year can be one of the suitable plants for biodiesel production.15 Biodiesel as a substitute for diesel fuel (in blends or in its neat form) has several advantages and consequently can support a number of strategies for addressing national issues (reducing national concerns about economy, environment, etc.) such as reducing dependence on foreign petroleum, leveraging limited supplies of fossil fuels, diminishing GHG emissions, reducing air pollution and related public health risks, and improving the domestic economy.16 Extensive investigations have been emerged for energy performances of biodiesel. The first comprehensive assessment of energy for biodiesel production from soybean oil in the United States was completed by Sheehan et al. in 1998.16 They characterized all energy inputs for soybean biodiesel production process as a life cycle assessment including six subsystems: feedstock production, feedstock transportation (soybean and soybean oil), soybean crushing, soybean processing with biodiesel conversion, biodiesel distribution, and biodiesel usage in engines. Their results indicated that the fossil energy ratio (FER) of biodiesel is equal to 3.2. In other words, biodiesel yields 3.2 units of energy for every unit of fossil energy consumed over its life cycle. In another study, an analysis of the energy consumed and the useful energy produced by rapeseed oil for biodiesel production was carried out by Richards and the results showed that 1.5 tons of biodiesel with energy content of 54 346 MJ was produced form the yield of 1 ha rapeseed.17 Since fossil energy consumption of 30 505 MJ was reported for the industrial stages including agricultural crop production, packing, transportation, and processing; the FER of biodiesel was calculated as 1.8. In a similar work, Venturi and Venturi investigated the energy input and output of three energy crop chains in Europe such as rapeseed-based biodiesel and the ratio of biodiesel energy output to its energy input was estimated as ranging from 0.7 to 1.0 for this crop.18 Janulis calculated the energy ratio of rapeseed oil methyl ester in Lithuania for three stages including rapeseed production, oil pressing and transesterification, and (for a rapeseed yield of 3.0 tons ha1) the FER was estimated as 1.2.19 Beside energy supply issue in biodiesel production systems, the GHG emissions are also critical. GHG emissions estimation has been considered by several authors in biodiesel production systems. Wood and Corley calculated GHG emissions for biodiesel from palm oil in Malaysia and found that agricultural crop

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production stage in biodiesel production had the most influence on environment with 1920.85 kg CO2 eq ha1yr1.20 In a study conducted by Yusoff and Hansen, a life cycle assessment of palm oil in Malaysia21 was investigated and the results revealed that total GHG emissions for biodiesel from palm oil was 2496.45 kg CO2 eq ha1yr1 and agricultural crop production stage had the most influence on environment. Results of similar studies on GHG emissions also indicated that agricultural crop production stage ranks the first in GHG emissions (CO2 eq ha1yr1).22–25 Since there is no similar investigation on this case in Iran, this paper aimed to assess the energy consumption and CO2 emissions of rapeseed-based biodiesel as an alternative energy in Iran. Moreover, to achieve sustainable development, a map was generated to show the potential of rapeseed cultivation across the country as a bioenergy crop. Although Iran has the second largest oil reserves in the Middle East and the second largest natural gas reserves in the world, primary energy demand in Iran is estimated to be increased at an average annual rate of 2.6% between 2003 and 2030, down from around 5% over the past decades15 and this increasing trend, makes Iran as a major fossil fuel importer in the future. The increasing demand of energy is mainly due to inordinate consumption of gasoline and diesel fuels in the transport sector that forces Iran to import more fuels in the future. According to the IEA (International Energy Agency) statistics, Iran’s diesel fuel and gasoline consumption in the transport sector was 19 575 and 23 115 106 l, respectively, in 2009.26 Iran’s transport sector relies almost exclusively on petroleum as a source of energy due to the high level of demand for gasoline and diesel fuel. The problem can be solved with some visionary plans about renewable energy usage and investments on energy demand regulation in the future decades.27 Agriculture is considered to be one of the most important sectors of Iran’s economy. This sector is responsible for 14% of Iran gross domestic product (GDP) and nearly 23 million (35%) of population is occupied in this sector. Agriculture sector plays a vital role in achieving self-efficiency in major food crops and ensuring food security for the country’s increased population.28 As edible oil production in Iran is highly depends on foreign edible oil (about 70% in 2012)29 the primary policy of the government in agriculture sector allocates to increase the level of national edible oil production in order to decrease the high amount of edible oil import in the country. According to this policy, long-term plans was considered in order to cultivate edible oil crops throughout the country such as olive cultivation (Tuba program), soybean cultivation, canola cultivation, sunflower cultivation, etc. In 2010, canola harvested area in Iran was about 185 000 ha and it is estimated that the harvested area will increase to 660 000 ha production in 2014.29 Considering the fact that Iran is one of the UNFCCC (United Nations Framework Convention on Climate Change) members and with regard to its commitment to Kyoto treaty (which is signed and ratified on 22/08/05),30 Iran committed (as a developing country) to reduce its GHG emissions. Based on Kyoto protocol, emission reduction activities should not endanger the food security, social and economic development.31 Therefore, the best policy could be the one which protects food security besides reducing GHG emissions. In other words, with extensive oilseeds cultivation throughout the country (in potential regions) both food security prevention (through edible oil supply) and GHG emissions reduction (through biodiesel production from a part of edible oil production) are attainable. Biodiesel can be produced domestically from agricultural oils and from waste oils. With its ability to be used directly in existing diesel engines, biodiesel can offer the immediate potential to reduce Iran’s demand for petroleum in the transport sector in the next decades. Regardless of the fact that biofuels can regulate the demand of fossil fuel in Iran, there is no doubt that biofuels production needs more complete and concrete research to investigate the other economic issues related to biofuels specially biodiesel for the Iranian situation.15 II. MATERIALS AND METHODS A. Study framework

In this study, the production of biodiesel from rapeseed was assessed in three main stages including agricultural crop production, transportation, and industrial conversion (oil pressing

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and transesterification), then the potential for cultivation of this crop was investigated and a map of regions capable of rapeseed cultivation in Iran was generated. Since the production of biodiesel from rapeseed in Iran is under study by the academic research centers and has not vastly established in practice, we investigated rapeseed production and its oil extraction in the main production region of Iran and studied its biodiesel conversion in the research centers. Golestan province is the main center of oilseed production with the share of 60% from total oilseed production in Iran.29 This province is located within 36 and 38 north latitude and 53 and 56 east longitude, in the north-east of Iran. The major oilseed crops cultivated in this province are rapeseed (canola cultivar), soybean and sunflower. About 40% from the total harvested land area and 39% from the total rapeseed production in Iran is from this province.32 B. Methodology

In order to assess the biofuels as a suitable replacement for petroleum the FER was calculated as the following:16,33 FER ¼

Renewable Energy Output ; Fossil Energy Input

(1)

where FER is defined as the ratio of the energy output of the final biofuel product to the fossil energy consumed to produce the biofuel. The FER as defined above only includes fossil energy in the denominator.33 In biodiesel production from rapeseed, all three stages are based on the consumption of specific resources, so the first step in this analysis was to convert all of the inputs and outputs into their energy equivalents by multiplying the quantity of each input by their corresponding embodied energy equivalent. Basic information on fossil energy inputs are entered into Excel spreadsheets, SPSS 19 spreadsheets then used an input-output analysis for all stages. The second step in this analysis was to determine the amount of CO2 emissions in biodiesel production from rapeseed through its life cycle and to specify which stage has the most influence on environment. The final step in this analysis was to collect and analyze meteorological and water source availability data for all of the 31 provinces in Iran in order to generate a map of regions suitable for rapeseed cultivation. C. Data collection 1. Agricultural crop production

Energy input-output data for rapeseed (canola cultivar) production was adopted from Mousavi-Avval et al. and then the amount of fossil energy inputs was extracted in order to calculate the fossil energy consumption for this stage (Table I).32 2. Transportation

In this study, farmyard manure and chemical biocides (Herbicides, Fungicides, and Insecticides) transportation to farms and rapeseed transportation to oil extraction manufactures were considered. Since rapeseed oil extraction manufactures and biodiesel production centers should be next to each other, there is no transportation considered for rapeseed oil from oil extraction manufactures to biodiesel production centers. It should be noted that the energy used for the transportation of chemical fertilizers to farms was not calculated separately because it was considered in the energy equivalents used for agricultural crop production stage.34 The data used in the transportation was collected based on diesel fuel consumption in three distances. Average distances from farmyard manure production centers to farms, average distances from chemical biocides distribution centers to farms, and average distances from farms to rapeseed oil extraction manufactures. Farmyard manure, chemical biocides, and rapeseed are often transported by trucks. The energy equivalent for this type of transportation system is about 3 MJ ton1 km1.34

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TABLE I. Energy cost of agricultural crop production stage per hectare.

Unit

Quantity

Source

Energy equivalent

Unit

Source

l

101.48

32

47.8

MJ l1

34 and 35

4850.65

26.25

kW h

195.02

32

11.93

MJ kW h1

32

2326.57

12.60

Nitrogen fertilizer (N) Phosphorus fertilizer (P2O5)

kg kg

111.41 50.65

32 32

78.1 17.4

MJ kg1 MJ kg1

34 34

8701.38 881.30

47.01 4.80

Potassium fertilizer (K2O)

kg

13.39

32

13.7

MJ kg1

34

183.51

0.99

Sulfur fertilizer (S) Herbicides

kg kg

11.50 1.28

32 32

1.12 238

MJ kg1 MJ kg1

36 and 37 38

12.88 303.55

0.06 1.64

Fungicides

kg

0.88

32

216

MJ kg1

38 and 39

190.41

1.03

Insecticides Tractor

kg h

0.43 3.62

32 32

101.2 93.61

MJ kg1 MJ h1

38 and 39 32

43.59 338.94

0.26 1.86

Self-propelled combine

h

5.39

32

87.63

MJ h1

32

472.65

2.56

Agricultural machinery Total

h

2.77

32

62.7

MJ h1

32

173.68 18 479.11

0.94 100

Inputs Diesel Electricity

Energy cost (MJ)

Percentage (%)a

a

Percentage from total fossil energy input.

3. Industrial conversion

The main currently used oil extraction methods across the world are pressing and extraction by organic solvents. These methods are performed at a higher range temperature (110 C–120 C) in comparison to cold pressing methods (at maximum 60 C) and produce higher amount of oil. However, cold pressing methods are used due to their less energy requirement and less phospholipids in the final oil, which is desirable in the production of the biodiesel.19 In order to estimate oil pressing energy consumption, electricity consumption in oil pressing and crude oil purification were calculated. The conversion of vegetable oils or animal fats to biodiesel can be carried out by the technologies that are classified as follows: direct use and blending, microemulsion, pyrolysis, and transesterification. Transesterification reaction of vegetable oils and animal fats with alcohol in the presence of catalyst is the most common technology used to produce methyl or ethyl ester named as biodiesel.40–42 The four major used methods of this reaction are conventional (catalytic), supercritical processes, microwave, and ultrasound systems.43–45 Catalysts can be classified as alkali, acid, and enzyme.46–48 Transesterification using alkali catalyst or alkali-catalyzed transesterification has been vastly used due to its faster reaction time and its lower cost. It is reported that the free fatty acid content in the vegetable oil should be less than 1% for alkalicatalyzed transesterification to occur.43,49,50 In this study, transesterification using conventional method with respect to alkali-catalyzed reaction using KOH as catalyst and methanol as alcohol was considered in order to characterize the conversion process. Fig. 1 shows the steps of a conventional (alkali-catalyzed) transesterification in a flowchart. As shown in Fig. 1, methanol and potassium hydroxide are mixed before the reaction, then the mixture and rapeseed oil are pumped in to a reactor in order to observe transesterification reaction. After the reaction, the mixture products are sent to a distillation column in order to recover methanol and restore it to the reactor again, then biodiesel mixture and glycerin mixture are separated in the separation phase by water washing. Finally, biodiesel mixture is refined in order to separate methanol and methyl ester. 4. CO2 emission

GHGs are those that absorb infrared radiation in the atmosphere, trap heat and warm the surface of the Earth. The three main GHGs are carbon dioxide (CO2), methane (CH4), and

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FIG. 1. Conventional (alkali-catalyzed) transesterification.

nitrous oxide (N2O). Other important GHGs are water vapor and many halo carbon compounds and their emissions are not mainly considered.51 Production of these gases as a result of human activities increases the natural greenhouse effect and lead to global warming and other environmental pollution. In this study, the amount of GHG emissions in each stage of biodiesel production cycle from rapeseed was calculated based on Eq. (2) (Ref. 52) by using CO2 emission coefficients, E¼

X

ðAi Ci Þ;

(2)

where E is the total CO2 emissions which is calculated as the sum of input factors (Ai) per hectare multiplied by their corresponding CO2 emission conversion coefficients (Ci) (which are shown in Table II). 5. Map generation

Iran with about 1 648 000 km2 width and 31 provinces is the eighteenth largest country in the world. It is located in the Middle East between Turkey and Iraq on the west and Afghanistan and Pakistan on the east. Iran lies between latitudes 24 and 40 N and longitudes 44 and 64 E and has a variable climate, mostly arid and semi-arid with the average temperature between 10 C–25 C in the winter and 19 C–38 C in the summer.14 Roughly one-third of Iran’s total surface area is suited for farmland. In 2010, rapeseed (canola cultivar) harvested area in Iran was about 185 000 ha with production of 380 000 tons56 and it is estimated that the harvested area will increase to 660 000 ha with 1 581 000 tons production in 2014,29 so with a comprehensive assessment of ecological indices and water availability data, we can specify the regions that are suitable to cultivate this crop. In order to specify the regions that have the potential for rapeseed cultivation, meteorological (annual precipitation, humidity, minimum temperature, maximum temperature, sunshine hours), and water source availability data for all the 31 provinces were collected from year 2000–2005,57 then all of them were analyzed with considering ecological indices to generate a map of potential regions.

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TABLE II. GHG emission coefficient of inputs. Inputs

Unit

GHG coefficient (kg CO2 eq unit1)

Reference

Machinery

MJ

0.071

53

Diesel fuel Electricity

l kW h

2.76 0.78

53 54

Nitrogen (N) Phosphorus (P2O5)

kg kg

1.3 0.2

55 55

Chemical fertilizers

Potassium (K2O)

kg

0.2

55

Biocide Herbicide

kg

6.3

55 55

Fungicide

kg

3.9

55

Insecticide Methanol

kg Kg

5.1 0.79

55 22

KOH

kg

1.20

22

III. RESULTS AND DISCUSSION A. Agricultural crop production data analysis

Table I shows the fossil inputs consumption and their energy cost in rapeseed production in Iran. The total fossil energy consumption for this stage was 18 479.11 MJ ha1 while this quantity is higher than that of Mousavi-Avval et al.32 reported, due to higher energy equivalents considered in this study for the chemical fertilizers. Results of this stage revealed that the machinery used hours was 11.87 h ha1, mostly used for harvesting and tillage operations.32 The average diesel fuel consumption for agricultural operations such as operating tractors, combine harvesters, and water pumping systems was 101.48 l ha1.32 Agricultural crop production data analysis revealed that nitrogen fertilizer has the greatest share of the total agricultural fossil energy input with the share of 47.01%, due to its heavy usage in farms and high embodied energy intensities. Similar results were reported by Rathke et al.58 and Tsoutsos et al.59 Apart from the nitrogen fertilizer energy, the second largest fossil energy input for agricultural crop production stage was diesel fuel consumption with the share of 26.25%. B. Transportation data analysis

As mentioned above, transportation of farmyard manure, chemical biocides, and rapeseed was calculated in this study. In the studied area, the average distances between farmyard manure centers and farms was 20 km, between chemical biocides distribution centers and farms was 50 km and between farms to the oil extraction manufactures was 100 km. Accordingly, fossil energy consumption (that was only diesel fuel) for this stage was calculated as 743.01 MJ ha1. The contribution of farmyard manure, chemical biocides, and rapeseed transportation from total fossil energy consumption were 97.43 MJ ha1, 1 MJ ha1, and 645.58 MJ ha1, respectively. C. Industrial conversion data analysis

Energy consumption of oil pressing via cold pressing method was investigated due to its widespread application in Iran. Table III shows the inputs consumption and their energy cost of industrial conversion stage (oil pressing and transesterification) per hectare rapeseed yield. According to the results of this stage, the total fossil energy consumption for this stage was 8900.04 MJ ha1. Also to produce 1 kg rapeseed oil for biodiesel production, 2.6 MJ of electrical energy in oil pressing and 0.14 MJ in purification were used. These electrical energy values are higher than that of reported by Janulis19 and Sheehan et al.16 due to this fact that almost all

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TABLE III. Energy cost of industrial conversion stage per hectare rapeseed yield. Inputs

Unit

Quantity

Energy intensity

Unit

Source

Energy cost (MJ)

Oil pressing electricity

kW h

185.6

11.93

MJ kW h1

34 and 36

2214.21

Crude oil purification electricity Transesterification

kW h kW h

9.95

11.93

MJ kW h1

34 and 36

118.70

Electricity

kW h

12.53

11.93

MJ kW h1

34 and 36

149.48

Machinery Alcohol (methanol)

h kg

8.68 167.18

8 33.67

MJ kg1 a1 MJ kg1

34 60

501.33 5628.97

Catalyst (KOH)

kg

14.46

19.87

MJ kg1

16

Total

287.35 8900.04

of the electrical energy in Iran is generated from fossil fuel sources.61 Iran’s electricity grid is highly dependent on fossil fuels, so that 95% of the electrical energy in Iran is generated in thermal power plants using fossil fuels sources. Also, roughly 10% of electricity generated in power plants is wasted by transmission lines.27 It is estimated that 843.56 kg of biodiesel can be produced from 1 ha of rapeseed production in Iran, with considering 2151.94 kg ha1 rapeseed yield32 in Iranian’s farm, oil content as 40% (Ref. 15) and conversion ratio of biodiesel to rapeseed oil as 0.98. Moreover, 167.18 kg methanol is required for the transesterification reaction, so 0.198 kg of methanol was used for 1 kg biodiesel produced. Methanol consumption with share of 63.3% of total fossil energy input had the highest share in industrial conversion stage followed by electricity with 27.9% share. The (A) high amount of methanol was consumed in order to shift the transesterification equilibrium to the products side (biodiesel/glycerol). Also a large amount of electrical energy was consumed by oil pressing and transesterification equipment. Fig. 2 shows the integrated energy inputs and output flows for biodiesel production from 1 ha of rapeseed consisting of all the main fossil inputs that can be used in the accounted life cycle of rapeseed-based biodiesel in Iran. According to Fig. 3, agricultural crop production stage with the share of 65.71% of total fossil energy input had the highest share among three different stages in the energy cost of biodiesel production from rapeseed, followed by industrial conversion stage by 33.2%. The lowest share belonged to transportation stage by 2.64%. The total fossil energy input cost was calculated as 28 122.16 MJ ha1 and the renewable energy output content (biodiesel as the final

FIG. 2. The integrated energy input and output flows for biodiesel production from 1 ha of rapeseed.

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FIG. 3. Energy cost contributions for biodiesel production.

outcome) was estimated as 31 802.06 MJ ha1. So the FER was calculated as 1.13 that is close to the results of Janulis.19 Also the net energy return (NER) was positive (3679.9 MJ ha1). Both FER and NER show that rapeseed could be a suitable energy crop for biodiesel production.

D. CO2 emission analysis

The results of GHG emissions (the amounts of CO2 eq) for inputs in the three main stages are shown in Table IV. Diesel fuel had the highest emission in the agricultural crop production stage and the transport stage with the share of 41.6% and 100%, respectively. Electricity had the highest emission in the industrial conversion stage with the share of 46.7% and followed by methanol with 38%. Using high amount of diesel fuel in the agricultural crop production stage produced 280.08 kg CO2 eq ha1 that was higher than similar research studies on various crop TABLE IV. Greenhouse gas emission of inputs in biodiesel production from rapeseed per hectare in the three main stages. GHG emission (kg CO2 eq ha1)

Inputs

Agricultural crop production stage

(%)

Machinery

69.95

10.4

Diesel fuel

280.08

41.6

Electricity Chemical fertilizers

152.12

22.6

Nitrogen (N)

144.83

21.5

10.13 2.68

1.5 0.4

Herbicide Fungicide

8.06 3.43

1.2 0.5

Insecticide

2.19

0.3

Phosphorus (P2O5) Potassium (K2O)

Transportation stage

(%)

34.20a

100

Industrial conversion stage

(%)

35.59

10.3

162.30

46.7

132.07 17.35

38 5

347.31

100

Biocide

Methanol KOH Total

673.47

100

34.20

100

Diesel consumption intensity for highway calculated as 0.05 l ton1 km1 (Ref. 64).

a

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FIG. 4. The total GHG (kg CO2 eq ha1) in the three main stages of biodiesel production.

productions.62,63 This high amount of emission is due to using worn-out tractors in farm operations and improper matching of agricultural machinery and equipment to tractors. Applying new and proper tractors in farms and proper matching the agricultural machinery and equipment to tractors can be considered as the beneficial ways of decreasing the amount of diesel fuel consumption and its environmental impacts. The high amount of electricity used in the industrial conversion stage produced 162.30 kg CO2 eq ha1 that was also higher than similar research studies on biodiesel from palm oil.20–25 The main reason of this high amount of emission is due to the higher electrical CO2 emission coefficient used for this study in Iran than other research studies.20–25 The second reason is that all of the equipment in the cold pressing oil extraction lines has worked by electrical energy instead of natural gas. Using extraction method by organic solvents and utilize the equipment that work by natural gas and electricity can be considered in order to reduce the amount of electrical emissions. Fig. 4 shows the total GHG (kg CO2 eq ha1) in the three main stages of biodiesel production from rapeseed in Iran. The total GHG emissions were calculated as 1054.98 kg CO2 eq ha1 that was lower than the mentioned research studies.20–25 Agricultural crop production stage with 673.47 kg CO2 eq ha1 had the most share in the GHG emissions with the share of (63.84%) followed by industrial conversion stage with 347.31 kg CO2 eq ha1and the share of (32.92%). As the results showed, the Agricultural crop production stage ranks the first in GHG emissions (CO2 eq ha1 yr1), which is expected based on the other similar research studies such as palm oil biodiesel in Malaysia, palm oil-derived methyl ester in Brazil and Colombia, palm oil biodiesel in Thailand.20–25 E. Map generation

Meteorological and water source availability data investigations showed that 24 provinces among 31 provinces in Iran have a great potential for rapeseed cultivation. Among these 24 provinces, 8 provinces produce 79% of total rapeseed yield, now.15,29 These provinces are Golestan, Mazandaran, and Ardebil in the north latitude; Hamedan, Markazi, and Lorestan in the center and west; Fars and Khuzestan in the south and south west. The Meteorological and water source availability data analysis showed that growth in rapeseed cultivation for biodiesel production in terms of sustainable development can occur through an increase in area cultivation in these 8 provinces and the other provinces that rapeseed production is not common but have a great potential to cultivate. Also it is recommended to change the old irrigation methods used in these areas in order to protect water resources. Fig. 5 shows the map of the provinces suitable for rapeseed cultivation.

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FIG. 5. Map of the (provinces suitable) for rapeseed cultivation across Iran.

IV. CONCLUSIONS

In this study in order to calculate the energy cost of biodiesel production and its CO2 emissions from rapeseed in Iran, three main stages including agricultural crop production, transportation, and industrial conversion (oil pressing and transesterification) were assessed in terms of life cycle process of biodiesel production and the following results are drawn: 1. The total fossil energy consumption was about 28 122.16 MJ ha1. Agricultural crop production stage had the greatest amount of total energy cost with the share of 65.71% among three different stages and the industrial conversion stage has the second place with the share of 33.2%. 2. In the agricultural crop production stage, the amount of nitrogen fertilizer energy consumption was the highest. The second largest fossil energy input for this stage was diesel fuel. Transportation stage only consumed diesel fuel and the highest fuel consumption in this stage belonged to rapeseed transportation. For the industrial conversion stage, methanol and electricity consumption had the highest shares from the total energy cost. 3. The renewable energy (biodiesel) output was estimated as 31 802.06 MJ ha1. NER and FER were calculated as 3679.9 MJ ha1 and 1.13, respectively. These values for biodiesel production from rapeseed in Iran were satisfactory but were lower than that of estimated in economically developed countries due to the lower rapeseed yield per hectare in Iranian’s farm. 4. CO2 emission analysis showed that the total GHG emission over biodiesel production life cycle was 1054.98 kg CO2 eq ha1 and the agricultural crop production stage ranks the first in GHG emission as expected. Diesel fuel had the highest emission in the agricultural crop production stage and the transport stage and electricity had the highest emission in the industrial conversion stage. 5. Studies on meteorological and water source availability data in Iran provinces showed that rapeseed has a great potential to be cultivated in Iran and it can be cultivated in 24 provinces among 31 provinces.

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6. In order to establish energy crops cultivation such as rapeseed, increase the FER and decrease the difference between energy balance of rapeseed-based biodiesel in Iran and economically developed countries, widespread and comprehensive policy-making such as giving subsidies, price guaranteed, lower taxes, or exemptions should be considered by the Iranian government in terms of sustainable development of renewable biofuels.

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