combined heat and power: an alternative to grid distribution

CARIBBEAN THERMAL TECHNOLOGIES INC.

Combined Heat and Power: An Alternative to Grid Distribution

Dr. Jorge Gonzalez Cruz


Distributed Generation

Distributed generation is (DG) is the integrated or stand-alone use of small, modular electricity generation resources by utilities, industry and retail centers, in applications that benefit the entire electric system.


Introduction to CHPSimultaneous production of two or more types of usable energy from a single energy source (also called “Cogeneration”).Use of waste heat from power generation equipment.

ELECTRICITY

HEAT RECOVERY

UNIT

GENERATORTURBINE

HE

AT

STEAM ABSORPTION CHILLER

CHILLED WATER

FUEL

COOLING TOWER

STE

AM

FOR PROCESS


CHP vs. Grid GenerationTraditional central power system is inefficient

One-half to two-thirds of energy is wasted as heat

This heat, otherwise lost, can be used for industrial processes, space and water heating, cooling, etc.

Electricity istypically morevaluable thanheat.


CHP DescriptionEquipment & Technologies

Power EquipmentGas turbineSteam turbineGas turbine-combined cycleReciprocating engineFuel cell, etc.

Heating EquipmentWaste heat recoveryBoiler / Furnace / Heater HRSG

Cooling equipmentCompressorAbsorption chillerHeat pump, etc.


Absorption Machines

• An absorption machine is a heat operated Air Conditioning System that uses a liquid salt and water as refrigerant. It has no mechanical parts and consumes very small amount of electricity. An absorption machine can be powered by any heat source available at the site including solar energy.


Yazaki Absorption Machine

PROVIDES COOLING

AND HEATING

10 TO 100 TONS


INJECTION MOLDING

FUELL CELLS

INTERNAL COMBUSTION ENGINES

EXCEDENT VAPOR

THERMAL OXIDIZER

Heat Sources to Power Absorption Machines

EXHAUST

TURBINES


Developments: Energy Efficient Buildings

Technology integrated to the building structure.

HIGH-PERFORMANCE SOLAR COLLECTORS

ABSORPTION MACHINE

WINDOWS WITH LOW-E

GLASS

INSULATION IN ROOF AND

WALLS

AIR-HANDLING UNITS

HOT WATER STORAGE TANK


Electricity from Cogeneration

ELECTRICITY FROM COGENERATION IN USA

0

5

10

15

20

25

1983 2010

Year

%

ELECTRICITY FROM COGENERATION IN GERMANY

0

10

20

30

40

1983

Year

%


DG BenefitsPower reliability: reduced power outages & avoid loss of production associated with power loss from the grid.Improved power quality: voltage fluctuations are minimized.Reduced total energy costs: these systems can produce hot or cold water for heating, cooling, and steam. Efficiencies could reach 80% with CHP.


Why DG in Puerto Rico?

High electricity costsNeed of reliable power supplyHigh fuel costsHigh need for heat (at industry)High need for air conditioning (at industry and business)


Barriers to DG

Technical requirements for interconnectionBusiness practices and contractual requirementsRegulatory barriers


CHP ApplicationsCHP Applications• Single buildings• Commercial and industrial

• Multiple buildings

• District energy systems (e.g. communities)

• Industrial processes

• HotelsLFG CHP for district heating system, Sweden

Photo Credit: Urban Ziegler, NRCan Photo Credit: Urban Ziegler, NRCan Micro turbine at greenhouse

Photo Credit: Urban Ziegler, NRCan

CHP Kitchener City Hall


Comparison of CHP Technologies

Hydrogen, natural gas, propane

Natural gas, biogas, propane, distilate oil

Natural gas, biogas, propane, distilate oil

allNatural gas, biogas, propane

Diesel and residual oil

Fuels

0.003-0.0150.002-0.010.002-0.0080.0040.007-0.0150.005-0.008O&M Cost ($/kWh)

>3,000500-1,300900-1,800800-1,000800-1,500800-1,500CHP Installed Cost ($/kW)

0.2-20.025-0.253-200Any0.05-50.05-5Size (MW)

40-70%20-30%25-40%30-42%25-45%30-50%Electric efficiency (LHV)

FUEL CELLSMICRO-TRUBINE

GAS TURBINE

STEAM TURBINE

NATURAL GAS ENGINE

DIESEL ENGINE


Payback

• Less than two years for Heat & Power• Less than three years for Waste Heat &

Cogeneration.• About Six Years for Solar Energy

Applications.


Economic analysis (100-RT)

0123456789

10

500 1000 1500 2000 2500 3000 3500 4000

Installation Cost ($/Ton)

Payb

ack

Tim

e (y

ears

)

Ce = $0.10/kWh; Ce = $0.10/kWh; VC=$500/TonCe = $0.12/kWh; Ce = $0.12/kWh; VC=$500/TonCe = $0.16/kWh; Ce = $0.16/kWh; VC=$500/ton


CHP Project Considerations

• Reliable, long-term supply of fuel

• Capital costs must be kept under control

• Need “customer” for both heat and power– Must negotiate sale of electricity onto grid if not all consumed on-site

• Typically plant is sized for heating base load (i.e. minimum heating load under normal operating conditions)– Heat output typically equal to 100% to 200% of the electricity output

– Heat can be used for cooling through absorption chillers

• Risk associated with uncertainty of future electricity / natural gas (“spark”) price spread


RETScreen® CHP Project Model Cooling Systems


Example: CanadaSingle Buildings

• Buildings requiring heating, cooling, and a reliable power supply– Hospitals, schools, commercial

buildings, agricultural buildings, etc.

Reciprocating EnginePhoto Credit: GE Jenbacher

Exhaust Heat Recovery Steam BoilerPhoto Credit: GE Jenbacher

Hospital, Ontario, CanadaPhoto Credit: GE Jenbacher


Examples: Sweden and USAMultiple Buildings

• Groups of buildings served by a central heating/cooling power plant– Universities, commercial complexes, communities,

hospitals, industrial complexes, etc.– District energy system


Example: Brazil Industrial Processes

• Industries with a high, constant heating or cooling demand are good candidates for CHP

Bagasse for Process Heat at a Mill, Brazil

Photo Credit: Ralph Overend/ NREL Pix

• Also applicable to industries that produce waste material which can then be used to generate heat and power


Examples: Canada and SwedenLandfill Gas

• Landfills produce methane as waste decomposes

• This can be used as the fuel for cooling, heating or power projects


Vision: “Sustainable Communities”

Energy & water needs

Low ImpactBuildings

Ecosystem

Energy, water,

transportation& air qualityinformation management

system

SustainableVillage


177 BALBOA ST.LA QUINTA INDUSTRIAL PARK

MAYAGUEZ, PR 00680 USAPhone: 787-834-5700 xt 1032

Fax: [email protected]


combined heat and power: an alternative to grid distribution

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