Combined Heat and Power Generation in Jamaica’s Sugar Cane Industry Niconor Reece Sugar Industry Research Institute Manchester, Jamaica

Combined Heat and Power Generation in Jamaica’s Sugar Cane IndustryNiconor Reece

Sugar Industry Research Institute

Manchester, Jamaica

Introduction

• Energy potential of Bagasse being underutilized in Jamaica.

• Potential for Factories to expand Power production.

• At harvest about 30% of total biomass is lost in the field.

Introduction

• Biomass provides significant environmental benefits.

– CO2 emission reduction

– Carbon Credits

• Biomass provides economic benefits.

– Reduce oil imports

– Foreign Exchange savings

• Industry presently in a state of uncertainty

• Industry up for divestment

• Divestment should bring needed investment to the industry

Introduction

The Jamaican Power Sector

• Government control since 1974 (JPSco)

• 80% Equity sold to Mirant of Atlanta

• Licensing Agreement makes JPSco the sole buyer of bulk electricity and power from independent power providers (IPP) in Jamaica.

• IPP provide total of 134MW to the national supply

• Jamaica’s demand for power is growing at a rate of 4.5% annually.

• In 2004 3,717million kwh of electricity

• Less than 9% of the power comes from renewable resources.


• Government policy towards renewable energy.

• 114 MW from renewable sources by 2012

• Currently 42 MW from renewable sources

• Total capacity of 1070 MW by 2012

• Tax rebates for special technologies

• 15% premium above JPSco’s avoided cost


The Sugar Industry in Jamaica

• One of the most important crop in Jamaica

• In 2004 total production was approximately 2 million tonnes of cane.

• Projections of over 3 million tonnes from 46,000 hectares of land still available for cane production.

• Crushing season last for about six months running for December to June.

• Sugar mills in Jamaica are partially self sufficient fuel wise.

• Two of the seven mills use bagasse as their sole source of fuel during the crushing season.

• 5 mills depend heavily on Bunker C

• In 2004 the industry consumed 6.2 million litres of oil at a cost of approximately 2.4 million US$


Factory Crushing Rate No. Boilers Pressure Steam Output Power Generation

2004 Oil Usage

TCH PSI Lbs/Hr Turbine (MW) L/oil Worthy Park 75 3 200 105,000 2.05 0 St. Thomas 62 4 180 130,000 2.28 0 Monymusk 180 8 200 320,000 8 1,657,184 Trelawny Sugar 160 3 150 126,000 2.85 1,292,307 Frome 300 10 200 420,000 8.5 1,998,181 B/Lodge 170 7 200 350,000 5.2 758,808 Appleton 150 3 220 357,000 3.25 441,867 Total 1097 32.13 6,148,347

Summary of crushing rate, steam and power generating capacities, and

oil use of sugar mills currently operating in Jamaica.


• Typical factory CHP cogenerates 20 kwh/tonne cane and 400-500kg steam/tonne cane.

• The Industry is heavily dependent on oil due to poor state of the boilers and factory equipment.


• Possible reduction in steam usage by:

– Retrofitting factories to economize on steam use.

– Use plate heaters, falling film evaporators, and continuous vacuum pans.

– The two privately owned factories have made moves to improve steam usage by installing continuous vacuum pans. One factory also put in a 250,000 lb boiler to replace the smaller older boilers.


• Turbines predominantly in use are the non-condensing back pressure type.


Incentives on CHP inJamaica

• 1989 Larson modelled the use of biomass integrated gasification combine cycle (BIGCC) technology and high pressure condensing extraction steam turbine (CEST) after Monymusk sugar factory.

CEST- steam is exhausted directly to condensers, that maintain vacuum conditions at the exhaust end of the turbine.

Steam at intermediate pressure is extracted for use in the milling process.


• BIGCC use the combined cycle format with a gas turbine driven by syngas from the gasifier. The exhaust gas are heat exchanged with water/steam to generate super heated steam.


Typical BIGCC

• Using BIGCC typically 60-70% of the power comes from the gas turbine.

• Steam production limited to 300kg/tc

• BIGCC produce substantially more energy than CEST


Potential Cogeneration Using Sugar Cane Residue and bagasse

0

50

100

150

200

250

300

350

400

450

500

Typical Existing CEST in Season CEST Year Round BIGCC Year Round

kwh

Gen

erat

ed P

er T

on

ne

Can

e


• Model results indicate:

– Typical system 20kwh/tc

– CEST 249kwh/tc

– BIGCC 460kwh/tc

– Results extrapolated for 2 million tonnes of cane:

• 920 million kwh BIGCC

• 480 million kwh CEST


Power generation initiatives

• Study - 1991 and 2000 Frome– 1995 Monymusk– 1997/98 St Thomas

• SEDEC/ Frome (SCJ) 2000– Co fired bagasse/coal CEST system– 1200 psi high pressure boilers– 70 mw out put

• The technology adopted was high pressure condensing extraction steam turbine (CEST)

• The studies looked at the use of auxiliary fuel in the off season.

• This varied from the use of:

– cane field residue

– coal and heavy oil


• Model of CHP generation for the BIGCC and CEST at Monymusk– Crushing rate 175 tc/h

– 27 MW CEST

– 53 MW BIGCC

• Rate of return depended strongly on price paid to utility company– avoided cost of 5.0-5.8 cents US/ kwh (1989)

– rate of return 18-23% for BIGCC

– compared to 13-16% for CEST


Electricity Sale Price 5.0 US cents

5.0 US cents 5.8 US cents

5.8 US cents

Co-generation Technology CEST BIGCC CEST BIGCC Exported electricity Million kwh/year 178 360 178 360 Internal Rate of Return (%/year) Base case a 13 18 16 23 Alternative BIGCC fuel processing None 24 29 Drying 22 27 Baling/drying 21 26 Pelletizing 11 16 Alternative off season fuel Oil/biomass 10 11 12 13

1989 results of financial calculations, based on a 206-day milling season (Larson 1989)


• In 2000 SEDEC/SCJ co-gen at Frome

• CEST technology

– 1200 PSI boilers

– co-fired by bagasse and coal

– 70MW output


• delivery of 440 million kwh/year

• cane supply to Frome of 750,000 tonnes

• bagasse rate of 85 tonnes/hr.

• mill steam consumption 400kg/tc

• electricity requirement of 30kwh/tc

• Cropping season of 2885 hour.


• economic evaluation indicated that

– at maximum capacity of 440 GWh/year, the price of electricity would be at 6.2 cents US/kwh

– and at a minimum 340 GWh/year 7.1 cents US.

– This would realize a yearly profit of 20%.


Present Problems and Future Potentials

• In 2000 the United Nations Development Programme (UNDP) promote the adoption of renewable energy by removing barriers and reducing incremental costs.

An analysis of barriers to the development of CHP in Jamaica showed the following:

• Information awareness and other barriers:

• There was a lack of awareness with key decision makers at the highest political level.

• Limited knowledge on cost effective co-generation market potential for the sugar sector.

• Investment on bagasse co-generation must be done jointly with upgrading efficiency of the sugar process.

• Social impacts of potential change in harvesting practices.

• Concerns about fall off in sugarcane production.


Technical Barriers

• Limited technical capacity to design, install, operate, manage and maintain co-generation technologies.

• The infrastructure for supply of cane residue on a cost effective basis

• No infrastructure for the storage of bagasse and cane residue


Policy Barriers

• Despite having an energy policy favourable for the development of renewable energy sources; no clear strategy, including fully developed policy instrument does not exist for the implementation of the renewable energy policy.

• Unclear political responsibility for an electricity generation project, in the agricultural sector.

Financial Barriers

• High capital cost of co-generation equipment and projects.

• Investment capital of the sugar mills is often completely committed for sugar related investment.

• Government budgets are limited and demands for financing various national priority areas are extensive, leaving no space for financial incentives to promote co-generation projects.


Factors that make CHP feasible for Jamaica include:

The centralization of the industry – closing of two smaller factories

– increasing the cane supply

– added throughput for the remaining factories

– more bagasse production

Jamaica, being a signatory to the Kyoto protocol

– will have to give serious consideration to green cane harvesting.

– This will provide significant field residue to be used as auxiliary fuel for bagasse in a co-generation system provided economic collection and storage systems are put in place.


• Prospective investors will have to invest heavily in upgrading factory and CHP systems

• It would be more beneficial if this capital was used to establish modern CHP systems that would supply the sugar production process with steam and power and sell the excess power to the national grid.

• There is ongoing research in the development of varieties to increase cane fiber yields through genetic improvement. This could increase fiber in bagasse to co-generation plants and consequently increase power out-put, possibly eliminating the need for auxiliary fuel.


Conclusion• There have been numerous initiatives in Jamaica for the

sugar mills to supply power to the national grid both during and outside their sugar harvesting season.

• This way of power generation is likely to trigger mainly positive environmental impacts and a higher than usual national value added in the cost of electricity generation.

• Inability to overcome some barriers hampering implementation, 15 years have elapsed without any meaningful move to produce excess power via cogeneration.

• It is hoped that the divestment of the Industry will help to bring about some of these changes.

Documents

Combined Heat and Power Generation in Jamaica’s Sugar Cane Industry Niconor Reece Sugar Industry Research Institute Manchester, Jamaica