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Co- and Poly- generation. Martin Hannemann Andi Prah Nuri Feichtinger Paul Polterauer. The Co-generation Concept. Co-generation is often referred to as a technology.
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Co- and Poly- generation Martin Hannemann Andi Prah Nuri Feichtinger Paul Polterauer
The Co-generation Concept • Co-generation is often referred to as a technology. • Actually co-generation is a principle that describes how energy, which is produced as a natural bi-product of the electricity production process, is captured and turned into useful heat. • This process is also known under the shortcut “CHP”, which means Combined Heat and Power.
Examples for CHP Plants • Co-generation is applicable to all situations where electricity is produced by thermal combustion • Co-generation systems are a modern way to reach very high energy efficiency • maximize fuel savings and avoid CO2 emissions. • Most common types of CHPs are: • Steam and Gas turbines • Fast evolving technology • Fuel Cells, Combustion Engines
Efficiency of Co- generation • Backpressure steam turbine units are characterized by high thermal efficiencies up to 90% and a moderate electricity generation efficiency of 15% to 25%. • Gas turbine heat recovery units show a thermal efficiency of 75% - 80%. In case post-firing is applied, thermal efficiency reaches close to 100%. • Thermal efficiency of combined gas/steam cycle systems reaches and sometimes exceeds 50%.
Scale of Co- generation • Decentralization • Mirco CHP • usually less than 5 kWe in a house or small business • electricity can be used within the home or business or, sold back into the electric power grid • A high overall energy conversion efficiency • Low maintenance requirements • Very low noise and vibration levels • Very low emissions of NOx, COx, SOx and particulates.
Centralization • DisctrictHeating • It centralizes the source of heat and electricity into a single source • + lower investment costs • + higher efficiency • + lower operation and maintenance cost • + higher reliability • + more design flexibility • + less energy is wasted • + more space for home owners
Economic Aspects • The majority of early adoptions of decentralized energy technology were not good investments under reasonable assumptions. • There is a minimum treshhold for a positive NPV on investment of about 160kWe • Bigger scale plants yield a better profit ratio
Environmental Aspects • + environmental benefits by making use of waste heat and waste products • - Air pollution is a concern any time fossil fuels or biomass are burned • + New cogeneration plants often have to meet higher environmental standards • - High initial cost of cogeneration facilities located in urban areas • + Decentralized CHP unitseliminatetheenergylossof a distributionsystem • - SomeCoGensystems do not captureasmuchwasteheatasothersorcantmakeuseofit due totheirlocation
Polygeneration • Polygeneration describes an integrated process which has three or more outputs
Trigeneration • mostpopular form ofpolygeneration • combineheat, coolingand power • find application wherever the demand for heat, cold and power occurs • Comercial • Office • Hospital…
Efficiency of Trigeneration • The mainadvantageistheefficientusageoffuel. • Thisleadstosavingfuelsandmoneyand also lessgreengas will beproduced. • A reductionoffuelconsumption will raisetheenergysecurityof countries. • Trigenerationsystemssupporttheusageoflocalenergysourceslikebiomass, biogas, orbiofuels.
Economy • The profitabilitydepends on variousfactorsandcertainconditions. • Austria supports CHP biomassplantsconnectedtolocalheatingnetworks. (15% to 35% oftheinvestmentcost) • In the United Kingdomthereis a VAT discountexistfrom 17.5% to 5% formicro CHP installations. • The investmentsarevery sensitive forfuelunitcost, andfuelpricesarevery variable.
Perspectives • E.g. The potential of trigeneration technology application in the food industry in Europe was evaluated at approximately 16 TWhe per year. • The most significant barriers of using the potential of trigeneration systems are: • a product of market conditions • mainly unfavorable electricity and gas prices • uncertainty over future market conditions
These barriers need to be removed. • In order to stimulate the market there is also the task of technology development, the trigeneration needs to be more reliable, efficient and flexible.