Feasibility of Biodiesel for Rural Electrification in India

It can be used for decentralized micro-grid electricity generation at the village level and as a replacement for diesel fuel in small-scale applications such as irrigation pump sets.. Th

Printed 4/16/2024 4/16/2024

Feasibility of Biodiesel for Rural Electrification in India

[DRAFT, June 2000]

Jeffrey L Rosenblum, Carnegie Mellon University (now at Tellus Institute, jrosenblum@tellus.org)

Abstract

Biodiesel, a biofuel directly substitutable for petroleum-based diesel, can be derived using simple technology from locally grown oil crops in rural regions in developing countries It can be used for decentralized micro-grid electricity generation at the village level and as a replacement for diesel fuel in small-scale applications such as irrigation pump sets Benefits include: increased energy independence, minimal net life-cycle CO2 emissions, increased economic activity from fuel production and utilization This paper evaluates (a) the feasibility of local production of biodiesel, and (b) the cost of micro-grid electricity generation using biodiesel for a small

representative village in southern India as an example The Jatropha curcas (or Physic nut) plant

is used in the evaluation Results indicate that half of available agricultural land for a rural village would be required to produce enough biodiesel to provide 100% of fuel needed for modest electrification demand (80 kW), and the cost of electricity would be over twice that for the use of federally-priced petroleum-diesel It is important to recognize the significant land requirements for biodiesel, and the high costs of such energy sources when compared to fossil fuels.

1 Introduction

Developing countries will not be able to lift themselves out of poverty without increased use of energy Assuming energy demand in developing countries grows by 2.6 percent per year the total consumption of energy will be double the level of total consumption in industrialized countries by 2050 Even under this scenario, energy consumption per capita in the developing world would still by only one quarter that of industrialized world (1)

Rural electrification has long been recognized as needed to improve conditions in rural areas and help stem the migration of people to already overcrowded cities In the past 25 years, developing countries have extended electricity supplies to more than 500 million people in rural areas (2) Out of four billion people in the developing world, about two billion, mostly in rural areas, are still without electricity (3), relying on electricity and rely on traditional fuels, such as dung and fuelwood Those who are fortunate

enough to have access spend an average of nearly 12 percent of their income on energy, more than five times the average for people living in OECD countries (1) According to the Central Electricity Board in India, about 15 percent of villages in India were not yet electrified by March 1998 (4)

Present day concerns over the growing energy needs of a growing world population have shifted from limited fossil fuel supplies to climate change, air pollution, and inequity resulting from the lack of

economic means to develop India’s interest in rural electrification goes back several generations Until recently, the demand for rural electricity has been met by extension of the central grid, but this is often the most costly form of energy because of the high connection costs and high losses associated with

transmission and distribution In order for the delivered power to be economical for the local villagers it must be heavily subsidized, provided at a price less than 1¢ per kWh

The last decade has shown increased attention toward renewable energy (e.g., biomass, photovoltaic, wind, hydro) with the hopes that locally generated fuel can increase local independence, reduce

greenhouse gas emissions, and hopefully be cost competitive In most cases, the high “first cost” and the low (or negative) rate of return of these projects render them economically unfeasible Annual income from agricultural villages is only about $300 per capita Average per capita purchasing power parity in dollars was about $700 for rural India in 1995 compared with a US average of $26,000 (2)

Through a simple chemical process, oil from seed crops (e.g., sunflower, cottonseed, Jatropha) can be converted to a fuel commonly referred to as “biodiesel.” Technology for such a process is easily

accessible to rural communities No engine modifications are necessary to use biodiesel in place of petroleum-based diesel Biodiesel can be mixed with petroleum-based diesel in any proportion Biodiesel can be used for decentralized micro-grid electricity generation at the village level as well as a replacement for diesel fuel in small-scale applications such as irrigation pump sets More reliable electricity can be produced from mini-grid systems than central grid extension

This paper evaluates the feasibility of using oil crops as a source of fuel and the cost of micro-grid electricity production from biodiesel for a typical rural village in southern India

2 Village characterization

Feasibility of biodiesel for micro-grid electrification is evaluated for a hypothetical rural Indian village The demographic and agricultural profile characteristic of a village in the southern state of Karnataka This village (say) has 1000 acres of land and 500 people (100 households) The primary economic activity is agriculture (rice, sugarcane, and coconut) Large and medium-size landholders make up 8% of the farmers, owning about 30-40 acres each, while small and marginal farmers own about 1 to 3 acres (5)

2.1 Land use

Land use broken down by category is shown in Table 1 Land designated as forest land (though it has low tree cover) is only 15 percent of the total area, which is less than half the amount that should be

maintained in tropical countries for a proper ecological This low tree cover has contributed significantly

to soil erosion, land degradation, and low groundwater infiltration 45 percent of land designated for crops and plantations is not irrigated This rain-fed land is single-cropped and lies fallow for at least eight months a year Runoff and erosion are high resulting in low productivity Wastelands that can be

cultivated are about 20 percent of the total area and include land that was originally grazing land and tree groves Over-exploitation by grazing, deforestation, and the loss of topsoil has resulted in decreased productivity Land unavailable for cultivation because of hills and hard rock-exposure account for 15 percent of total land area (5)

Table 1: Land use in 1981 (5)

2.2 Water consumption

Over the last two decades, there had been a shift from the use of tanks and canal networks (now silted and unusable) to groundwater borewells About 15 percent of water is used for drinking, domestic use, and

livestock, while 85 percent is used for irrigation Flood irrigation is practiced for both annual crops and plantations The water requirements are in Table 2 The large and medium farmers use almost 90 percent

of the extracted groundwater, mostly for irrigation of plantations (5) Most of the 400 mm per year of rain falls during the months of August and September, with one or two showers having accumulations of 100

mm in 24 hours

Table 2: Water irrigation requirements (5)

Crop type Number of

irrigation cycles

Liters per hour per acre Hours per irrigation

cycle

Months of irrigation a Total per acre

per year in Million liters

a assumption used for the calculations in this paper.

2.3 Energy demand

There are two major categories of electricity loads: (a) irrigation pumping, and (b) residential/community uses, mostly lighting and radio/television Generally, about 80 percent of the energy needs of a rural village are for irrigation Table 3 summarizes estimated power requirements for the village

Table 3: Power requirements

Lighting and radio/TV requirements

public buildings @ 1 kW (500 W average) a 0.5 kW

1 school

1 public health center

2 misc buildings

100 houses @ 100 W (50 W average) b 5 kW

a Community (school, health center, public buildings) 5 kWh/day

b One home uses 0.5 kWh/day

A representation of this load profile is presented in Table 4, and shown graphically in Figure 1 It is assumed that this profile is valid for the entire year The energy required is about 250,000 kWh per year

To satisfy the expected load profile, the analysis in this paper assumes an 80 kW diesel generator

operating 10 hours per day all year

Table 4: Village energy load profile

5 am – 10 am 66 kW

10 am – 5 pm 0 kw

5 pm – 10 pm 66 kW

Figure 1: Load profile

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of day

Other Irrigation

Centralized grid power has already been extended to 35 households in the village Although this power is heavily subsidized, yielding electricity at a consumer rate of about 0.5¢ per kWh, it is erratic occurring for only a few hours per day Water pumping for irrigation is unreliable given this situation, and the voltage irregularities cause frequent damage to the electric pump sets Wealthier farmers can afford a diesel generator to operate their pump sets at a cost of about 12¢ per kWh (5 Rs per kWh)

2.3.1 Irrigation demand

Irrigation load energy requirements per acre are estimated based on the flow rate and lift elevation required An overall efficiency of 50 percent is assumed: 75% pump, 90% motor, 85% T&D, 85% pipe

losses (16) Equation 1 was developed Assuming the required flow values in Table 2, the power

requirements per acre for 22 gpm and 26 gpm are 0.42 kW and 0.50 kW respectively Typically 3 hp (2.2 kW) pumps are used in rural irrigation applications For a power requirement of 0.50 kW per acre, one well and pump combination will supply irrigation to about 4 acres of land

Equation 1: Power requirements per acre

h Q h

Q

P   (3.810- 4) 





where P = power requirement per acre [kW]

Q = flow rate per acre [gpm]

h = water lift height [ft]

 = efficiency

 = constant

Based on the usage requirements in Table 2 and assuming that power for pumping is available from the village micro-grid 10 hours per day, 5 days of pumping would be required per cycle for crops, and 3 days

of pumping per cycle for plantations One cycle is needed per month for crops, and two cycles are needed per month for plantations This results in the possibility to have 6 pumps operate in sequence over the month for crops, and 5 for plantations

For the land use characteristics in Table 1, assuming that 4 acres are served per pump, 13 pumps would be required to serve the 50 acres of irrigated land Assuming that 5 pumps can be operated in sequence, the amount of power required would be about 6 kW for the 50 acres (13 pumps  5 simultaneously  2.2 kW) which comes to about 0.12 kW per acre An additional 113 pumps would be required to irrigate the remaining 450 agricultural acres, with an additional load of 54 kW The irrigation of 500 acres of land would require a load of about 60 kW for 10 hours per day

2.3.2 Residential and community demand

Residential, community, and street lighting needs are estimated to be about 6 kW for the 10 hours per day Homes typically use 0.5 kWh per day, which over 10 hours averages 50 W of power per home The community load is estimated to be about 5 kW, and streetlighting estimated to be about 0.5 kW Together, these loads are estimated at 6 kW

3 Biodiesel system

A rural biodiesel system involves growing the oil crop, pressing the seeds into oil, processing the oil into biodiesel by transesterification, and electricity production using biodiesel in a generator (Figure 2) The following subsections detail each stage in this process for the case of Jatropha curcas oil plant Costs models for each stage are developed In the end, the critical cost comparison is between diesel price and biodiesel price

Figure 2: General flow diagram for rural biodiesel production

grow

crop

trans-esterification

Electricity generator

(or biogas

or petrodiesel)

3.1 Jatropha Curcas oil

Several studies (e.g., Mali, Nicaragua, India, Zimbabwe) have indicated that the Jatropha Curcas (or

Physic nut) plant shows promise for use as an oil crop for biodiesel The Jatropha plant is Latin American

in origin and is closely related to the castor plant It is a large shrub/ small tree able to thrive in a number

of climactic zones in arid and semi-arid tropical regions of the world An easy to establish perennial, it can grow in areas of low rainfall (250 mm per year minimum, 900-1,200 mm optimal) and is drought resistant In addition, it is valued for crop protection, prevents wind/water erosion, is not browsed by animals, will reach maximum productivity by year five, and has a 50 year life-span Planting for

maximum yield is done at a density about 400 plants per acre (6) The energy efficiency of the

agricultural and industrial production process is between 1:3.75 and 1:5 (12)

A study of a Jatropha plantation in Nicaragua indicates the yield of seed to be about 1800 kg per acre, which then yields 360 liters of oil at 5 kg seed to the liter (6) A Zimbabwe case study indicates a

somewhat lower yield because of a cooler climate (7) For the analysis conducted in this paper, a value of

300 liters per acre is assumed

The Mali study indicated that Jatropha seeds cost about US $0.10 per kg to grow and harvest, and about

US $0.05 per kg to press into oil (8) The cost of raw oil, then, is calculated to be about $0.75 per liter Table 5 compares the cost of Jatropha oil to other oil crops based on market prices If a power press equipment is used, about 10% of the energy content of the resulting oil is needed to operate the press (8) The seedcake resulting from the pressing process is rich in nitrogen and is an excellent fertilizer Selling this seedcake could help offset the cost of oil production (7)

Based on the analysis conducted in following sections, about 100,000 liters per year of fuel (diesel or biodiesel) are needed operate the generator Figure 3 presents the relationship between percent of fuel needs satisfied versus percent of available land (out of 700 acres irrigated, unirrigated, and not used but usable land) planted with Jatropha and several other crops To supply 100 percent of village fuel needs, Jatropha would need to replace 330 acres, or about half, of existing agriculture acreage The other oil crops in Table 5 would not be able to supply enough biodiesel for the village even for the case where 100 percent of the agriculture land was used These results underscore the large amount of land that would need to be dedicated to biodiesel crops in order to replace fossil fuels for a rural village

Table 5: Average yields and prices for various crops in India.

tonnes/ha (9)

oil yield percent of seed (10)

oil yield liters/acrea

acres needed per 100,000 liters

India wholesale price (11) b

US $/liter

Jatropha

Curcas (6)

a assumes 0.9 kg per liter

b US $1 = Rs 43.6 (May 2000)

Figure 3: Percent of fuel needs satisfied versus percent of agricultural land needed for biocrop.

0%

20%

40%

60%

80%

100%

120%

140%

160%

180%

200%

220%

% land used

50%

Jatropha

Rapeseed Soybean

3.2 Transesterification

The most common derivatives of agricultural oil for fuels are methyl esters These are formed by transesterification of the oil with methanol in the presence of a catalyst (usually basic) to give methyl ester and glycerol Sodium hydroxide (NaOH) is the most common catalyst, though others such as potassium hydroxide (KOH) can also be used Equation 2 presents a mass balance for transesterification, and Figure 4 presents the underlying chemistry

Equation 2: Transesterification mass balance

100 kg oil + 24 kg methanol + 2.5 kg NaOH  100 kg biodiesel + 26 kg glycerine

Figure 4: Transesterification chemistry

R’ R’’ R’’’ = oil acids; R = (CH2)xCH3

The technology required for carrying out the transesterification process is very simple In it’s crudest form, it can be in low volumes as a batch process The methanol and NaOH are premixed and added to the oil, mixed for a few hours, and allowed to gravity settle for about 8 hours The glycerine settles to the bottom, leaving biodiesel on the top With this process, the biodiesel contains some residual methanol which is acceptable for rural applications (rubber hoses in vehicle engines must first be replaced) , and the glycerine is unrefined (refined glycerine can bring about $5 per kilogram on the market for use in

pharmaceuticals and cosmetics.) The unrefined glycerin can be used to make soap which can be an addition source of income for the village Ethanol could be used in place of methanol and could be made locally The physical and chemical properties of the resulting biodiesel (Jatropha methyl esters) is

presented in Table 6 alongside those for petroleum diesel and European Union standards for biodiesel

Table 6: Jatropha Biodiesel properties compared with petro-diesel and EU standards (12)

biodiesel Petroleum diesel E.U standards for biodiesel