Contribution of the sugar cane industry to reduce carbondioxide emissions in the energy sector: the caseof Mauritius

A. Khoodaruth1

Received: 6 May 2015 / Accepted: 14 September 2015 / Published online: 18 September 2015� Springer Science+Business Media Dordrecht 2015

Abstract The aim of this paper was to present the contribution of the sugar cane industry

to reduce carbon dioxide emissions in the energy sector. Mauritius is taken as a case study.

Sugar cane was introduced in Mauritius during the seventeenth century and production of

sugar started around 60 years later. Since then, the cane industry has been one of the

economic pillars of the country. Bagasse, a by-product of sugar cane, is used as fuel in

cogeneration power plants to produce process heat and electricity. This process heat and

the generated electricity are used by an annexed sugar mills for the production of sugar,

while the remaining electricity is exported to the national grid. In fact, Mauritius is a

pioneer in the field of bagasse-based cogeneration power plant; the first bagasse-based

cogeneration power plant that was commissioned in the world was in Mauritius in 1957.

The contribution of the cane industry in the electricity sector has been vital for the eco-

nomic development of Mauritius and also in terms of mitigating carbon dioxide emissions

by displacing fossil fuels in electricity generation, as bagasse is classified as a renewable

source. Data obtained from Statistics Mauritius on electricity production for the past

45 years were analysed, and carbon dioxide emissions were calculated based on interna-

tional norms. It is estimated that savings on heavy fuel oil importation were by 1.5 million

tons of oil—representing a value of 2.9 billion dollars—thus avoiding 4.5 million tons of

carbon dioxide emissions. This figure can be further increased if molasses, a by-product of

sugar cane juice, is used to produce bio-ethanol to be used as fuel in vehicles.

Keywords Sugar cane � Carbon dioxide emissions � Electricity � Bio-ethanol �Cogeneration

& A. Khoodarutha.khoodaruth@uom.ac.mu

1 Mechanical and Production Engineering Department, University of Mauritius, Reduit, Mauritius

123

Environ Dev Sustain (2016) 18:1719–1731DOI 10.1007/s10668-015-9713-3

1 Introduction

Sugar cane is cultivated in more than 100 countries with a total area of about 27 million

hectares harvested in 2013, resulting into the production of 2 billion tons of sugar cane

(Sun et al. 2013; FAO 2013). The main countries producing sugar cane are Brazil, India,

China and Thailand (Jena and Poggi 2013). In Mauritius, sugar cane was introduced by

Dutch settlers in the seventeenth century, and since then, sugar cane industry has been one

of the economic pillars of Mauritius (Paturau 2008).

Sugar cane is crushed in sugar mills to produce sugar cane juice and bagasse. The latter

is the residue obtained after milling the sugar cane, while the sugar cane juice is used for

the manufacture of raw sugar and ethanol. In some countries like Mauritius, the juice is

converted to sugar only while in other countries like Brazil, the juice is converted to sugar

and bio-ethanol. The bio-ethanol is used as fuel in flexi-vehicles which consume either a

blend of gasoline and up to 25 % anhydrous ethanol or 100 % gasoline or 100 % anhy-

drous ethanol (Freitas and Kaneko 2011; Pacini and Silveira 2011; Moreira et al. 2014;

Macedo et al. 2008).

Molasses, a by-product obtained after the processing of sugar cane juice, can be further

processed to produce bio-ethanol and liquor; this is the practice in Mauritius. Moreover,

bagasse is burnt in boilers to produce super-heated steam which is then fed to steam turbine

coupled with an alternator to generate electricity and process heat. This helps the cane

industry to be self-sufficient in their energy needs. The simultaneous production of heat

and electricity from a single source of fuel is called cogeneration (Kanoglu and Dincer

2009).

Cogeneration in cane industry is practiced in all sugar-producing countries. Process heat

is used to process sugar cane juice to raw and refined sugars. The electricity generated by

cogeneration plant in Mauritius is mainly used by the sugar mills for their own con-

sumption, and the rest is exported to the national grid. The Mauritian cane industry is a

pioneer in the field of bagasse-based cogeneration power as it is the first country in the

world that had commissioned a cogeneration power plant in 1957 (Baguant 1984).

Mauritius has an agreement with the European Union (EU) under the Africa Caribbean

and Pacific (ACP) protocol for the sales of its sugar at a guaranteed and favourable selling

price. The revenues obtained have helped the country to develop and to diversify its

economy from a mono-crop industry, relying solely on sugar production, to tourism, textile

and tertiary sector. However, following the decision of the EU in 2006 to reduce the price

of sugar by 36 % with respect to the price under the agreement to be effective as from

2009, the cane industry was no longer considered that profitable. Moreover, sugar cane

production is also dependent on the climatic conditions prevailing in the country during the

off-crop and harvesting seasons. More and more growers gradually abandoned their sugar

cane plantation to convert the land into residential plots or shopping malls as these were

more lucrative as business. The land area under sugar cane cultivation, which was about

80,000 ha in the 1970s, scaled down to 53,000 ha in 2013 and the amount of sugar cane

harvested decreased from an average of 5.5 million tons in the 1970s to below 4 million

tons in 2013 as shown in Fig. 1.

The Government then devised a Multi-Annual Adaptation Strategy (MAAS), whereby,

amongst others, electricity generation from bagasse is promoted by the Government of

Mauritius through a favourable power purchasing agreement with the owners of the sugar

mills for the purchase of their excess electricity production by the Central Electricity Board

(CEB), a Government of Mauritius owned organization (MAIF 2006). This encouraged the

1720 A. Khoodaruth

123

sugar mills owners to make huge investment in cogeneration power plants through the

commissioning of higher pressure and temperature boilers and condensing extraction steam

turbine to increase the electricity generation.

The revenue obtained from the sales of electricity to the national grid has helped to sustain

the cane industry. Bagasse is used during the harvesting season of approximately 6 months,

and during the off-crop season, coal is used instead for the generation of electricity by the

cogeneration power plant. This arrangement thus made cogeneration plants to operate all

year round. There are presently four cogeneration power plants in Mauritius. Furthermore, in

order to maximize its revenue, the industry has re-engineered itself to a flexi-factory where

raw and refined sugars, electricity, bio-ethanol from molasses and bio-fertilizers are now

being promoted. The flexi-factory is also called bio-refinery which is similar to petro-refinery

(Dantas et al. 2013). A cane flexi-factory comprises a sugar mill for the production of raw

sugar, a refinery for the manufacture of refined sugar, a cogeneration power plant for the

production of heat and for electricity generation, a fertilizer blending plant for the manu-

facture of bio-fertilizers to be used for the cultivation of sugar cane and a distillery for the

production of bio-ethanol. Table 1 shows the milestones of sugar cane in Mauritius.

Fossil fuels are used for the sugar cane farming and harvesting such as for the manu-

facture and transportation of fertilizers to sugar cane fields, irrigation of the sugar cane

fields, loading of harvested sugar cane and transportation of harvested sugar cane to sugar

mills. The use of bagasse to produce heat and electricity in cogeneration power plant emits

carbon dioxide because fossil fuels energy is used for the farming, transportation of sugar

cane to sugar cane mills. However, bagasse is considered as a renewable source (Beeharry

2001) because the sugar cane crops have the capacity to absorb much more carbon dioxide

than the amount of carbon dioxide emitted for the farming and transportation of sugar cane

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

50

55

60

65

70

75

80

85

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

2011

2013

mill

ion

tons

x 1,

000

ha

Year Area harvested Cane produc�on

Fig. 1 Land area of harvested sugar cane in Mauritius (SM 1975, 1984a, 1993a, 2003a, 2013a)

Contribution of the sugar cane industry to reduce carbon… 1721

123

and manufacturing of sugar. Beeharry (2001) estimated that one hectare of sugar cane

plantations in Mauritius with an average yield of 66 tons of sugar cane can absorb 58 tons

of carbon dioxide annually. However, this figure might not be the same in other countries

where forests are being converted to sugar cane fields (Walter et al. 2011).

Mauritius gained its independence from the British in 1968, that is, 45 years ago.

The Mauritian economy was then based solely on agricultural production namely sugar

production. The demand for electricity was on average 130 GWh in the early seventies

(SM 1972). The share of renewable energy (RE) was about 50 % at that time as shown

in Fig. 2. However, with the diversification of its economies to textile and tourism

industries in the 1970s and 1980s, and to the tertiary sector in the 2000s, the demand

for electricity in Mauritius, which was relatively small and manageable before inde-

pendence, started increasing by an average annual growth of 5 %. While Mauritian

textile industries had to shift from a labour to capital intensive one to maintain the

competiveness of the textile sector, the tourism industry also witnessed a rapid devel-

opment with the construction of five-star hotels and integrated resort scheme—which

are high consumers of electricity—to attract rich and high-spending tourists to visit and

stay in Mauritius. Due to such modernization and automation of our industries, resulting

in higher standard of livings and population growth, the demand for electricity increased

considerably, and in order to cater for same, a new thermal power plant running on

heavy fuel oil (HFO) and one coal power station were commissioned in the 1990s. A

gas turbine running on dual purpose kerosene (DPK) was also put into operation to

cater for the peak hours during the day. Subsequently, all thermal power stations also

increased their capacity to ensure security of supply. Government also incentivized the

use of bagasse as fuel for electricity generation through favourable power purchase

contract of sales of electricity by independent power producers (IPPs). The latter used

coal in the cogeneration plants during the off-crop season. Cogeneration power plants in

Mauritius were used as base load, that is, they supplied electricity to the national grid

on a 24-h basis all year round.

Table 1 Sugar cane in Mauritius(adapted from Autrey 2012)

Years Milestones

1639 Introduction of sugar cane by Dutch settlers

1696 Production of first sugar crystals

1812 Sugar production 457 tons

1860 Sugar production reaches 121,000 tons with 259 factories

1957 Cogeneration of electricity

1973 Record production of 718,464 tons of sugar

1975 Signature of the sugar protocol of the Lome Convention

1984 First bagasse/coal power plant in operation

1999 Second bagasse/coal power plant in operation

2006 EU announced a reduction in the price of sugar

2006 Multi-Annual Adaptation Strategy Action Plan 2006–2015

2007 Third bagasse/coal thermal power plant in operation

2009 First flexi-factory in operation

2009 Sugar refineries in operation

2009 Reduction in price of sugar obtained from EU

2014 First ethanol plant in operation

1722 A. Khoodaruth

123

Due to the coming into operation of these thermal power plants and the use of coal during

off-crop season by the cogeneration plants, the share of the RE in the electricity-mix has

decreased to 17 % in 2011. The share of RE is now on the increasing side due to the

commissioning of a photovoltaic (PV) farm and generation of electricity by small producers

using PV systems. The share of RE in the electricity-mix has slightly increased to 18 % in

2013 and is expected to increase further with the coming into operation of wind and PV

farms in a very near future. Although there was a decrease in land area under cane cultivation

for the past decade, the electricity production from bagasse has remained fairly stable due to

the use of higher pressure and temperature boiler, new varieties of sugar cane of higher fibre

content and falling thin film evaporators (Khoodaruth and Elahee 2013; Khoodaruth 2014).

Bagasse, being a renewable source, has thus displaced fossil fuels in the electricity

production. It has contributed to the mitigation of carbon dioxide emissions in the energy

sector which represents about 62 % of the total carbon dioxide emissions of Mauritius (SM

2013c) by displacing fossil fuels in electricity generation. The aim of this paper is therefore

to present the contribution of the Mauritian cane industry in the reduction in carbon dioxide

emissions.

2 Materials and methods

The amount of electricity generated by bagasse-based cogeneration power plants depends

on the quantity of bagasse fed in the boilers, the operating pressure and temperature of the

boilers, the type of turbines used such as condensing extraction steam turbine (CEST) and

0

500

1000

1500

2000

2500

3000

0%

20%

40%

60%

80%

100%

1968

1971

1974

1977

1980

1983

1986

1989

1992

1995

1998

2001

2004

2007

2010

2013

GWh

Perc

enta

ge

Year

Fossil fuels Renewable sources Total GWh

Fig. 2 Electricity supplied to the grid in Mauritius (SM 1972, 1979, 1984b, 1993b, 2003b, 2013b)

Contribution of the sugar cane industry to reduce carbon… 1723

123

back pressure steam turbine (BPST), the amount of superheated steam fed in the turbine

and the amount of steam used as process heat.

The annual electricity generated by all the power plants using bagasse as fuel is cal-

culated as shown in Eq. (1).

EFbagasse ¼Xn

i¼1

EBi; ð1Þ

where EFbagasse = annual electricity generated by all power plants using bagasse as fuel

(kWh), EB = the annual electricity generated by the ith power plant using bagasse (kWh),

i = 1, 2, 3, …., n, and n is the number of bagasse-based cogeneration power plants under

study.

Moreover, bagasse-based cogeneration power plants, PV farms, hydropower stations

and landfill gas station use renewable sources for electricity production, whereas fossils

fuels are used by thermal power stations, gas turbine stations and coal power plants for

electricity generation.

The annual total electricity generation from renewable sources and non-renewable

sources (fossil fuels) is calculated using Eqs. (2) and (3), respectively.

EFTOTRE ¼ EFbagasse þ EFhydro þ EFwind þ EFpv þ EFlandfill; ð2Þ

EFTOTNRE ¼ EFcoal þ EFHFO þ EFDPK; ð3Þ

where EFTOTRE = total annual electricity generated from all renewable sources (kWh),

EFhydro = the total annual electricity generated by hydro power stations (kWh),

EFwind = the total annual electricity generated by wind farms (kWh), EFpv = the total

annual electricity generated by PV farms (kWh), EFlandfill = the total annual electricity

generated by landfill gas stations (kWh), and EFTOTNRE = total annual electricity gener-

ated from non-renewable sources (kWh), EFcoal = the total annual electricity generated by

power stations using coal as fuel (kWh), EFHFO = the total annual electricity generated by

thermal power stations using HFO as fuel (kWh), EFDPK = the total annual electricity

generated by gas turbine power stations (kWh).

The annual electricity generation from all sources of energy (EFTOT) is thus calculated

as shown in Eq. (4).

EFTOT ¼ EFTOTRE þ EFTOTNRE ð4Þ

Taking into consideration all the power plants generating electricity from all sources of

energy, the average annual carbon dioxide emissions per kWh electricity generated for a

particular year is calculated as shown in Eq. (5) under the assumption that electricity

generated by hydropower stations, landfill gas stations, PV and wind farms does not emit

carbon dioxides.

CO2GRID¼CO2HFO�EFHFOþCO2DPK�EFDPKþCO2coal�EFcoalþCO2bagasse�EFbagasse

EFTOT;

ð5Þ

where CO2GRID = average carbon dioxide emissions to generate 1 kWh (g/kWh),

CO2HFO = amount of carbon dioxide emitted per 1 kWh electricity generated using HFO

as fuel (g/kWh), CO2DPK = amount of carbon dioxide emitted per 1 kWh electricity

generated using DPK as fuel (g/kWh), CO2coal = amount of carbon dioxide emitted per

1724 A. Khoodaruth

123

1 kWh electricity generated using coal as fuel (g/kWh), CO2bagasse = amount of carbon

dioxide emitted per 1 kWh electricity generated using bagasse as fuel (g/kWh), and

CO2HFO ¼ QPHFO � CFHFO; ð6Þ

CO2DPK ¼ QPDPK � CFDPK; ð7Þ

CO2coal ¼ QPcoal � CFcoal; ð8Þ

CO2bagasse ¼ QPbagasse � CFbagasse; ð9Þ

where QPHFO = amount of HFO needed to generate 1 kWh electricity (g/kWh),

QPDPK = amount of DPK needed to generate 1 kWh electricity (g/kWh), QPcoal =

amount of coal needed to generate 1 kWh electricity (g/kWh), QPbagasse = amount of

bagasse needed to generate 1 kWh electricity (g/kWh), and CFHFO = carbon dioxide

emissions factor for HFO, CFDPK = carbon dioxide emissions factor for DPK,

CFcoal = carbon dioxide emissions factor for coal, CFbagasse = carbon dioxide emissions

factor for bagasse.

Now if bagasse were not used as fuel and HFO is used instead, the average carbon

dioxide emissions per kWh electricity generated (CO2GRID) for a particular year is cal-

culated as shown in Eq. (10).

CO2GRID0 ¼ CO2HFO � EFHFO þ CO2DPK � EFDPK þ CO2coal � EFcoal þ CO2HFO � EFbagasse

EFTOT;

ð10Þ

The total savings of carbon dioxide emissions avoided (TCO2avoided) due to the utilization

of bagasse as fuel for the generation of electricity for a certain number of years are

calculated as shown in Eq. (11).

TCO2AVOIDED ¼Xyn

YEAR¼y0

CO2GRID0ð ÞYEAR � CO2GRIDð ÞYEAR; ð11Þ

where y0 is the starting year of the study, for example, 1968, yn is the ending year of the

study for example 2013.

The savings in terms of amount of HFO that has not been imported due to the utilization

of bagasse are calculated as shown in Eq. (12).

STOT ¼Xyn

YEAR¼y0

EFbagasse � QPHFO1;000;000

� �

YEAR

; ð12Þ

where STOT = savings of HFO in tons for a period of years starting from y0 to yn.

The total amount in foreign currency saved can be calculated for a certain period of

years from y0 to yn as shown as Eq. (13).

FOREX ¼ STOT � CIFHFO; ð13Þ

where FOREX = savings in terms of foreign currency (USD), CIFHFO = cost, insurance

and freight for the import of one ton of HFO (USD/t).

Contribution of the sugar cane industry to reduce carbon… 1725

123

3 Results and discussions

Available data for electricity production for the past 45 years were used to estimate the

savings in carbon dioxide emissions due to the use of bagasse as fuel for electricity

production in the electricity-mix of Mauritius. Data were not available prior to 1968, and it

is also not meaningful since the electricity was produced mainly from hydro and access to

electricity was low. The amount of carbon dioxide emitted by each fossil fuel used in

Mauritius for the production of 1 kWh electricity was calculated using Eqs. (6)–(8) and

tabulated in Table 2. The carbon dioxide emissions factor for each fossil fuel was obtained

from IPPC guidelines (IPCC 2007), and the amount of each fuel needed to generate 1 kWh

electricity was obtained from the CEB (2014).

Ramjeawon (2008) had applied a life cycle assessment (LCA) methodology to evaluate

the environmental impacts of using bagasse as fuel in cogeneration power plants in

Mauritius. The scope of the study included fertilizers manufacture, sugar cane cultivation

and harvest, irrigation, loading of harvested cane, sugar manufacture, electricity generation

and transportation of: fertilizers to sugar cane plantations, harvested cane to sugar mills

and sugar to port for export to EU. Moreover, in the production pathways of sugar,

electricity is generated and molasses is produced; the carbon dioxide emissions have to be

allocated among sugar, electricity and molasses. In the LCA done by Ramjeawon (2008),

the market value of the products viz electricity, molasses and sugar is used for the allo-

cation of carbon dioxide emissions. Fortunately, the market values of USD 500 per ton of

sugar, USD 33 per ton of molasses and USD 0.1 for each kWh generated are still valid

presently. For each kWh of electricity generated by bagasse-based cogeneration power

plant, 35.6 g of carbon dioxide is emitted. This figure is used in this paper in the com-

putation of the yearly average carbon dioxide emitted by power plants in Mauritius.

The amount of carbon dioxide emissions to produce 1 kWh electricity for the national

grid was calculated for each year for the past 45 years using Eq. (5). Furthermore, the

amount of carbon dioxide that would have been emitted in case bagasse was not utilized

during the past 45 years and HFO was used instead was also calculated on a yearly basis

using Eq. (10).

Figure 3 shows the trend in carbon dioxide emissions of the grid-electricity by each fuel

used, that is, HFO, bagasse, coal and DPK, on a yearly basis and the percentage of RE in

the electricity-mix of Mauritius for the period 1968–2013.

Analysis of the trend of carbon dioxide emissions for the period 1968–2013 shows that:

• In the early seventies, the share of RE was more than 50 % in the electricity with a

peak of around 55 % in 1974.

• The increase in the share of RE in the electricity-mix during the period 1983–1984 was

due to the full utilization of the hydropower plant. This is normally the case when the

Table 2 Amount of carbon dioxide emitted by each fossil fuel

Fuel Amount of fuel neededto generate 1 kWhelectricity (g/kWh)

Carbon dioxideemissions factor

Amount of carbon dioxideemitted for each kWhelectricity generated (g/kWh)

Coal 600 2.22 1332

HFO 230 3.03 697

DPK 330 3.02 997

1726 A. Khoodaruth

123

rainfall is above average. Water is primarily stored in dams for potable water

production.

• The share of RE in the electricity-mix started decreasing as from 1985 due to the

coming into operation of the first cogeneration plant running on bagasse during the

harvesting season and on coal during the off-crop season. To cater for the peak demand

in the evening, a gas power plant was also put into operation at that time. The

Government incentivized the utilization of bagasse and coal for electricity production

through attractive power purchasing agreement with IPPs. Pending the commissioning

of other similar cogeneration plants and one coal power plant, the CEB utilized the gas

power plant to its full potential to ensure electricity supply, although it is not

economically viable for them due to the very high cost of operation. Consequently, the

grid carbon dioxide emissions started increasing rapidly. In the 1990s, the grid carbon

dioxide emissions had doubled as compared to the values in the late 1970s; it was

344 g/kWh in 1968 and 693 g/kWh in 1999.

• The CEB did not invest much in new power plants due to the financial constraints, and

because of contractual obligations towards IPPs for the purchase of all their electricity

production, the share of coal in the electricity-mix has increased considerably to the

extent that it has become the most important fuel used in electricity production in

Mauritius. The grid carbon dioxide emission was 840 g/kWh in 2013. This figure

would have been greater had it not been for the commissioning of a PV farm and a

landfill gas plant. The CEB has also incentivized the use of PV at homes, educational

and religious institutions through an attractive buying price of excess electricity. A total

of 5 MW is now connected to the grid.

0

10

20

30

40

50

60

70

80

90

100

0

100

200

300

400

500

600

700

800

900

1968

1971

1974

1977

1980

1983

1986

1989

1992

1995

1998

2001

2004

2007

2010

2013

%RE

Carb

on D

ioxi

de E

miss

ions

(g/k

Wh)

YearDPK Coal HFO Bagasse %RE

Fig. 3 Trend in carbon dioxide emissions of the grid-electricity

Contribution of the sugar cane industry to reduce carbon… 1727

123

• A wind farm and other PV farms are expected to come into operation shortly. This

might curb the grid carbon dioxide emissions for Mauritius in the years to come.

Figure 4 shows the trend in carbon dioxide emissions of the grid-electricity by each

fossil fuel used on a yearly basis, under the assumption that HFO has replaced fuel in the

electricity-mix, and the resulting percentage of RE in the electricity-mix of Mauritius for

the period 1968–2013.

It is observed that the share of RE in the electricity-mix would have been 37 % instead

of 51 % in 1968 and 5 % instead of 18 % in 2013. Coal would have also remained the most

important fuel used for electricity in 2013. Moreover, the grid carbon dioxide emissions

would have been 441.1 g/kWh in 1968, representing a 28 % increase, and 928.8 g/kWh in

2013, representing a 10 % increase. This is mainly attributed to the use of PV and waste-

to-energy technologies.

The total savings in carbon dioxide emissions due to the use of bagasse were calculated

using Eq. (11). Assuming that Government would have invested in thermal power plant

fuelled by HFO to cater for the ever increasing demand of electricity instead of promoting

the use of bagasse as fuel in cogeneration power plants, the amount of HFO that would

have been imported and the cost of HFO in USD for the past 45 years are calculated using

Eqs. (12) and (13), respectively. The results are tabulated in Table 3.

In addition, the utilization of bagasse as fuel for the production of electricity has

allowed the country to avoid around 90 shipments of HFO from Middle East and India. The

Government would have also invested in capacity expansions or new thermal power

fuelled by HFO of a total amount of 160 MW representing an investment of USD 350 M

given that the cost of 4 9 15 MW generators running on HFO is USD 130 M (AFD 2014).

0

10

20

30

40

50

60

70

80

90

100

0

100

200

300

400

500

600

700

800

900

1000

1968

1971

1974

1977

1980

1983

1986

1989

1992

1995

1998

2001

2004

2007

2010

2013

%RE

Carb

on D

ioxi

de E

miss

ions

(g/k

Wh)

Year

DPK Coal HFO %RE

Fig. 4 Trend in carbon dioxide emissions of the grid-electricity without bagasse

1728 A. Khoodaruth

123

According to the long-term energy strategy for the period 2009–2025 devised by the

Government of Mauritius, the share of bagasse in the electricity was supposed to increase

to 17 % by the 2025 (MRPU 2009). However, as shown in Fig. 1, the land area under sugar

cane has drastically decreased from around 80,000 ha in the early 1970s to around

54,000 ha in 2013. With this trend, Mauritius will not be in a position to produce sufficient

amount of sugar to fulfil the sales contract with European Union and the bagasse-based

electricity will be decreasing in the years to come. Moreover, as only two out of the four

cogeneration power plants are presently equipped with high-pressure and high-temperature

boilers, the owners of the other two cogeneration plants will not be willing to invest in

upgrading their facility to increase electricity production in spite of the favourable power

purchasing agreement because of reduced availability of bagasse. The Government will

thus be compelled to invest in thermal power plant using fossil fuels. This will inevitably

increase our carbon dioxide emissions, while policy makers in many countries are trying to

mitigate theirs due to adverse climate change associated with carbon dioxide emissions

level. Finally, the contribution of the sugar cane to reduce carbon dioxide emissions can be

further increased if E10, a blend of 10 % ethanol and 90 % gasoline by volume, is used as

fuel for vehicles. Ethanol is produced from molasses, a by-product formed during the

processing of sugar cane juice to sugar. An annexed distillery plant, using process heat and

electricity generated from the cogeneration power plant for the manufacture of ethanol,

having an annual capacity production of 25 million litres of ethanol, started operation in

early 2015. Sultan et al. (2012) have estimated that about 42 g of carbon dioxide is emitted

for each litre of ethanol produced from molasses based on the assumption that the distillery

gets all its energy needs from the cogeneration power plant and the carbon dioxide

emissions are allocated among sugar, molasses and electricity using the market value

allocation approach. Khoodaruth and Elahee (2013) have estimated that around 11,000 tons

of gasoline would not be imported if E10 as fuel is promoted and used in motor vehicles

propelled by spark-ignition engine. About 33,300 tons of carbon dioxide emissions could

have been further avoided.

4 Conclusion

The use of bagasse, a renewable source, has contributed to reduce carbon dioxide emis-

sions in the electricity sector. Policy measures from the Government to promote the use of

bagasse have been fruitful to the country in terms of preserving the environment and

reducing fossil fuels imports. Data on fuels used in the electricity production for the past

45 years were analysed, and carbon dioxide emissions per kWh were calculated based on

international norms for these years. It is estimated that savings on heavy fuel oil impor-

tation were by 1.5 million tons of oil—representing a value of 2.9 billion dollars—thus

avoiding 4.5 million tons of carbon dioxide emissions. This figure can be further increased

Table 3 HFO, foreign currency and carbon dioxide emission savings

Parameters Unit Value

Savings in HFO t 1,467,069

Savings in foreign currency USD 2.9 billion

Carbon dioxide emissions avoided t 4,451,087

Contribution of the sugar cane industry to reduce carbon… 1729

123

if molasses, a by-product of sugar cane juice, is used to produce bio-ethanol to be used as

fuel in vehicles.

Acknowledgments The author expresses his gratitude to Dr. K. Elahee for his constructive comments andcritical views in the writing of this paper.

References

AFD. (2014). African Development Bank, Saint Louis Power Plant Redevelopment Project. http://www.afdb.org/fileadmin/uploads/afdb/Documents/Project-and-Operations/Mauritius_-_Saint_louis_Power_Plant_Redevelopment_Project_-_Appraisal_Report.pdf. Accessed 2 Feb 2015.

Autrey, J. C. (2012). Mauritius Future Orientations of Research and Development for Sugar Cane Industriesof ACP States ACP Sugar Research Programme Mid-Term Review Workshop MSIRI. www.acpsrp.eu/sites/default/files/documents/pwp/04%20Future%20actions%20SRP%20ACP.pptx. Accessed 5 Dec2013.

Baguant, J. (1984). Electricity production from the biomass of the sugarcane industry in Mauritius. Biomass,5(4), 283–297.

Beeharry, R. P. (2001). Carbon balance of sugarcane bioenergy systems. Biomass and Bioenergy, 20(5),361–370.

CEB. (2014). Personal Communication with Mr. Mukoon, Central Electricity Board.Dantas, G. A., Legey, L. F. L., & Mazzone, A. (2013). Energy from sugarcane bagasse in Brazil: An

assessment of the productivity and cost of different technological routes. Renewable and SustainableEnergy Reviews, 21, 356–364.

FAO. (2013). Food and Agricultural Statistics. http://faostat3.fao.org/home/E. Accessed 5 Jan 2015.Freitas, L. C. D., & Kaneko, S. (2011). Ethanol demand in Brazil: Regional approach. Energy Policy, 39(5),

2289–2298.IPCC. (2007). Climate change 2007: Synthesis report. Cambridge: An Assessment of the Intergovernmental

Panel on Climate Change, Cambridge University Press.Jena, S. D., & Poggi, M. (2013). Harvest planning in the Brazilian sugar cane industry via mixed integer

programming. European Journal of Operational Research, 230(2), 374–384.Kanoglu, M., & Dincer, I. (2009). Performance assessment of cogeneration plants. Energy Conversion and

Management, 50(1), 76–81.Khoodaruth, A. (2014). Optimisation of a cogenerated energy systems: The cane biomass flexi-factory case

study. Energy Procedia, 62, 656–665.Khoodaruth, A., & Elahee, M. K. (2013). Use of higher fibre cane for increasing cogenerated electricity:

Policy implications for Mauritius. Utilities Policy, 22, 67–75.Macedo, I. C., Seabra, J. E. A., & Silva, J. E. A. R. (2008). Green house gases emissions in the production

and use of ethanol from sugarcane in Brazil: The 2005/2006 averages and a prediction for 2020.Biomass and Bioenergy, 32(7), 582–595.

MAIF. (2006). Ministry of Agro-Industry & Fisheries, Multi Annual Adaptation Strategy Action Plan2006–2015: Safeguarding the Future through Consensus. http://agriculture.gov.mu/English/Documents/Land%20Conversion%20Unit/mass.pdf. Accessed 10 Jan 2015.

Moreira, J. R., Pacca, S. A., & Parente, V. (2014). The future of oil and bioethanol in Brazil. Energy Policy,65, 7–15.

MRPU. (2009). Ministry of Renewable Energy and Public Utilities, Republic of Mauritius. Long-TermEnergy Strategy 2009–2025. https://sustainabledevelopment.un.org/content/documents/1245mauritiusEnergy%20Strategy.pdf. Accessed 2 Feb 2015.

Pacini, H., & Silveira, S. (2011). Consumer choice between ethanol and gasoline: Lessons from Brazil andSweden. Energy Policy, 39(11), 6936–6942.

Paturau, M. (2008). Histoire Economique de l’ile Maurice 2008, Port-Louis, Mauritius.Ramjeawon, T. (2008). Life cycle assessment of electricity generation from bagasse in Mauritius. Journal of

Cleaner Production, 16, 1727–1734.SM. (1972). Statistics Mauritius, Digest of Energy and Water Statistics, Ministry of Finance and Economic

Development, Republic of Mauritius.SM. (1975). Statistics Mauritius, Digest of Agricultural Statistics, Ministry of Finance and Economic

Development, Republic of Mauritius.

1730 A. Khoodaruth

123

SM. (1979). Statistics Mauritius, Digest of Energy and Water Statistics, Ministry of Finance and EconomicDevelopment, Republic of Mauritius.

SM. (1984a). Statistics Mauritius, Digest of Agricultural Statistics, Ministry of Finance and EconomicDevelopment, Republic of Mauritius.

SM. (1984b). Statistics Mauritius, Digest of Energy and Water Statistics, Ministry of Finance and EconomicDevelopment, Republic of Mauritius.

SM. (1993a). Statistics Mauritius, Digest of Agricultural Statistics, Ministry of Finance and EconomicDevelopment, Republic of Mauritius.

SM. (1993b). Statistics Mauritius, Digest of Energy and Water Statistics, Ministry of Finance and EconomicDevelopment, Republic of Mauritius.

SM. (2003a). Statistics Mauritius, Digest of Agricultural Statistics, Ministry of Finance and EconomicDevelopment, Republic of Mauritius.

SM. (2003b). Statistics Mauritius, Digest of Energy and Water Statistics, Ministry of Finance and EconomicDevelopment, Republic of Mauritius.

SM. (2013a). Statistics Mauritius, Digest of Agricultural Statistics, (2013) Ministry of Finance and Eco-nomic Development, Republic of Mauritius. http://statsmauritius.govmu.org/English/StatsbySubj/Documents/Digestagri2013.pdf. Accessed 1 Jan 2015.

SM. (2013b). Statistics Mauritius, Digest of Energy and Water Statistics, (2013) Ministry of Finance andEconomic Development, Republic of Mauritius. http://statsmauritius.govmu.org/English/Publications/Documents/Regular%20Reports/energy%20and%20water/Energy2013.pdf. Accessed 1 Jan 2015.

SM. (2013c). Statistics Mauritius, Digest of Environment Statistics, Republic of Mauritius. http://statsmauritius.govmu.org/English/StatsbySubj/Documents/Digest_Envstats2013.pdf. Accessed 1 Jan2015.

Sultan, R., Khoodaruth. A., & Tandrayen-Ragoobar, V. (2012). Bio-ethanol for sustainable development:The case of sugar cane in Mauritius. CEEPA Discussion Paper No: 53 ISBN-920160-53-1.

Sun, X., Fujimoto, S., & Minowa, T. (2013). A comparison of power generation and ethanol productionusing sugarcane bagasse from the perspective of mitigating GHG emissions. Energy Policy, 57,624–629.

Walter, A., Dolzan, P., Quilodran, O., Oliveira, J. D. D., Silva, C. D., Piacente, F., & Segerstedt, A. (2011).Sustainability assessment of bio-ethanol production in Brazil considering land use change, GHGemissions and socio-economic aspects. Energy Policy, 39(10), 5703–5716.

Contribution of the sugar cane industry to reduce carbon… 1731

123