ENERGY SUPPLY MICRO AND DISTRIBUTED GENERATION AND TRIGENERATION I Prof. dr. Marija Todorovic DERES - DIVISION FOR ENERGY EFFICIENCY AND RENEWABLE ENERGY SOURCES Faculty of Agriculture, University of Belgrade, Serbia deresmt@EUnet. yu, deres@agrifaculty. bg. ac. yu www. rcub. bg. ac. yu/deres 2006 6 th November
AIM OF THIS LECTURE Introduction to the relevant definitions and aspects of the combined heat & power (CHP), micro and distributed generation and trigeneration for all UNESCO E Learning target groups, UNESCO E Learning target groups Its aim is to provide an understanding of power generation technologies and to show “waste” heat from electric generation process can be used for: heating and/or cooling to increase systems integral energy efficiency, to reduce operating costs and the need for new electric utility construction, as well as to reduce the load on electric transmission systems. It is an introduction to the Fundamentals of CHP Systems, Engineering Issues, Benefits and Barriers to CHP’s broader utilisation, Micro and Distributed Generation – Cogeneration and Trigeneration, Examples of implementation
ACRONYMS Combined Heat & Power (CHP) Buildings Cooling, Heating & Power (BCHP) CHP for Buildings (CHPB) Integrated Energy Systems (IES) Total Energy Systems (TES) Trigeneration Systems (Trigen) CHP for Industry Cogeneration
COMBINED HEAT & POWER (CHP) - MICRO AND DISTRIBUTED GENERATION AND TRIGENERATION Micro Combined Heat and Power or Micro. CHP is an extension of the well established idea of COGENERATION to the single/multi family home or small office building Micro - CHP Systems Technologies What is CHP - Cogeneration - HP Production Why Consider CHP What is Trigeneration CHP Characteristics of Good Applications CHP Barriers CHP Managing Overview & Services
Combined Heat and Power Productioon Exhaust Gas Natural Gas Air Kathalyst Exhaust Gas Heat Exchanger < 120 °C Lubricant Oil Electrical 79 °C 84 °C 90 °C Peak Load Boiler . 82 °C V = f(DP) Grid Engine Cooling Waterr- / -Oil Heat Exchanger . V = f(T) 70 °C Final Heat User Thermostat
What is CHP Combined Heat and Power – Cooling, Heating & Power – Total energy systems – Cogeneration / trigeneration – Energy recycling It is an Integrated System that: – Supplies electrical or mechanical power – Uses thermal output for space or water heating, cooling, dehumidification, or process heat – Is located at or near user – Can serve a single facility or district energy system – Can range in size from a few k. W to 100+MW
How CHP Saves Energy
Electrical efficiency Heat efficiency Overall efficiency (also called “Cogeneration efficiency or “Total efficiency )
Power-to-Heat Ratio Where is: Qe – Gross electrical output, k. We Qheat – Usefull heat output, k. Wth Qfuel – Fuel energy input (based on Net Caloric Value (Lower Heating Value: LHV)), k. Wth
Separate Production of Electricy and Heat POWER PLANT Fuel 100 Electricity 36 BOILER Fuel 100 Heat 80 Total Efficiency: 0, 58 Cogeneration POWER and HEAT Fuel 100 Electricity 30 and Heat 55 Total efficiency: 0, 85
CHP System Sizes (Terminology)
TECHNOLOGIES Micro CHP systems are currently based on several different technologies Internal combustion engines Stirling engines Steam engines Microturbines Fuel cells
Combined Heat and Power Productioon Exhaust Gas Natural Gas Air Kathalyst Exhaust Gas Heat Exchanger < 120 °C Lubricant Oil Electrical 79 °C 84 °C Peak Load Boiler 90 °C . 82 °C V = f(DP) Grid Engine Cooling Waterr- / -Oil Heat Exchanger . V = f(T) 70 °C Final Heat User Thermostat
QK Condenser Compressor Expansion Power Evaporator Q 0 Vapour compression cooling mashine
Wapor Steam Heat From back cooling Condenser Trigen Block Generator dilute solution Concentrated Wasser Expans. Valve pump Abwärme Absorber Evaporator To back cooling Wasserdampf Air Conditioninig Plant Absorptions refrigeration plant
Trigeneration Module Exhau st Gas Natural Gas Air 3 -Waycatalyst Exhaust Gas. Heat Exchanger Cooling Engine watercooling- / -oil Heat Exchanger TRIGENERATION Heat. Storage Absorptionscooling plant Power-Heat-Cool-Coupling Cool. Energy. Storage Electricity
POWER – HEAT – COOL - COUPLING hel = 35 % 34 % Gas 100 % hth = 55 % 53 % Electricity Heat 13% Losses Absorption Cooling Plant 38 % Kälte zref = 71 % 6 °C / 12 °C Absorption Cooling „fueled“ by the Heat
Separated Production Primary energy 121 % Electricity 9% Compression coolingmashine hel = 36 % 38% Cooling e. KKM = 4 77 % 34 % Eliectricity Losses Power-Heat-Cooling-Coupling Primary energy 100 % hel = 35 % hth = 55 % 13 % Heating 53 % Absorbtion cooling plant 38% Cooling z. AKA = 0, 71 34 % Electricity Losses POWER – HEAT – COOL - COUPLING
Back cooling Supermarket/ Office building/Hospital Natural Gas Heating in Winter Electrical Grid Safety cooling Trigen Block Heat Storage Absorber Cool. Storage Electricity Power – Electr. Grid – Heat – Cooling - Coupling
Back Cooling Natural Gas Supply Oil for Natural Gas Supermarket/Office Building/Hospital Supply heating Electrical Grid Energy Supply and Saving Safety cooling Trigen Block Boiler Power – Electr. Grid – Heat – Cooling - Coupling
THE BUILT ENVIRONMENT MAJOR CONSUMER OF HEAT AND ELECTRICITY The environmental damage caused by the use of energy coupled with advances in technology has led to a change in the view of the building as an energy system. Technologies such as photovoltaic facades, fuel cells, ducted wind turbines and cogeneration allow a building to produce clean energy for own needs – heating/cooling/electr. Raised best performance related issues, matching demand supplied heat and power, optimization (design & control) of the interaction of the EG (DEG) with HVAC/technical systems in transient conditions. The answer to most of these questions requires some form of integrated building design and systems simulation.
MODELLING AND SIMULATION OF SMALLSCALE EMBEDDED GENERATION SYSTEMS Advances in heat and power production lead to a revolution in buildings perception as an energy system. The addition of heat and power production increases buildings complexity and new design issues must be addressed: – integration of DEG with traditional systems; – optimal demand supply matching; – demand side management and its impact on environmental performance; – interaction of the DEG system with the local electricity network, etc.
Small-scale CHP installation analysis CHP contribution: - 30% electrical load - 23% heating load CHP benefits (Feb-May 05): - 7, 000 k. Wh primary fuel savings - 1, 450 kg CO 2 savings Optimisation: - 2 units running simultaneously 5. 5 k. W el, 12. 5 k. W th Max 83 o. C water out Sustainable Research Building Nottingham University
ELECTRICAL POWER COOL USEFUL HEAT
TRIGENERATION STATE OF THE ART Existing installations: medium to large scale Prime movers: Internal Conmbustion engines and turbines Cooling: absorption chillers Challenges in small-scale applications Cooling technology? Costs? Fuel and emissions?
TESTING, SIMULATION AND ANALYSIS OF A SMALL-SCALE TRIGENERATION Designers need simulation tools to help answer questions relating to building environmental performance. For the development of integrated EG schemes, building simulation tools must evolve to facilitate all aspects of DEG systems modeling: EG components, electrical power flow, demand supply control algorithms, etc. To assess the interactions between an EG system and all other components of a building, modeling, must be undertaken in an integrated manner.
MODELING AND SIMULATION Simulation – modeling tools have evolved to assist in the design and assessment of building performance, particularly in: low energy building design, modeling of active and passive solar systems, modeling natural ventilation systems daylighting and effects of saving technologies modeling of modern, building integrated heat and power sources such as photovoltaics and fuel cells.
SUMMARY AND CONCLUSION MICRO SCALE DEG AND TRIGENERATION Evaluation of benefits of CHP installation Optimisation: Interaction CHP/Building’s heating system Trigen Heat/Power/Cooling capacities ratios • Outcomes: Trigen offers Significant primary fuel savings CO 2 emissions reductions However, payback period can be/very long! ? Future work: Improve component efficiencies COP
CHP FOR INDUSTRY - THE CONCEPT THE IOWA ETHANOL INDUSTRY Improved Reliability Support Grid Infrastructure Lower Energy Costs – Defer Costly Grid Upgrades Better Power Quality – Price Stability Lower Emissions (including CO 2) Facilitates Deployment of New Conserve Natural Resources Clean Energy Technologies Resources Enhances Competition
CHP FOR HIGH ENERGY USERS Example Ethanol Facility –Thermal » 75– 80% Energy Costs are Natural Gas Steam Production Dryers» » $10 Million/Year –Electrical » ~ $2. 5 Million/Year » 3. 5 to 4. 5 MWe Load => 30 to 40 Million k. Wh/Yea –Process Can Use all the Thermal Produced » Expect Between 4, 300 and 5, 300 lbs/hour per Installed MWe
CHP AT AN ETHANOL FACILITY? Both Thermal and Electric Reliability Very Important –Lose Batch –Several Hours to Restart Electric Reliability –Grid Backs Up CHP System –CHP System Backs up Grid Thermal Reliability –CHP System Provides Part of Thermal Load –Boilers Sized to Provide All of Thermal Load Reliability In Design –Systems Need to be Designed to Do This!
CHP AT AN IDUSTRIAL FACILITY? Long Hours (7/24/365) Availability of Fuels Other than Natural Gas –Coal –Biofuels –Waste Water or Land Fill Gas Saves Energy –Efficiencies Upwards of 85% because of High Thermal Use and Value Reduces Energy Costs
TYPICAL INDUSTRIAL CHP SYSTEM
RELIABLE CHP TECHNOLOGIES Electric Generation Equipment Gas Turbines and Engines, Reciprocating Engines and Steam Turbines
RELIABLE CHP TECHNOLOGIES Heat Recovery Systems - Steam and Hot Water - Exhaust Gases
Absorption Chillers Desiccant Dehumidification
Northern Power supplied a hybrid solar PV / microturbine standalone power system for a new PEMEX natural gas production platform. The Lankahuasa 1 platform, an innovative tripod design is the first offshore site deployed as part of PEMEX’s strategic gas initiative program, tapping the newly discovered gas reserves southeast of Tampico in Mexico.
KEY FACTORS FOR CHP INDUSTRIAL ATTRACTIVENESS High Energy Use Coincident Needs for Electrical and Thermal Energy Cost of Buying Electric Power from the Grid Relative to the Cost of Fuel Installed Cost Differential Between a Conventional System and a CHP System
WHY THE OPPORTUNITIES FOR DEG ARE IN GROWTH? Aging Electric Transmission and Distribution Systems – Difficult to Site New Lines – Capacity Constrained – Costly to Maintain Rising Concerns Over – Blackouts/Brownouts – Power Supply Constraints – Electricity Prices
MAIN IMPEDIMENTS TO CHP High First Cost Discourages Investment Despite Life Cycle Benefits Assessing CHP Value (Beyond Energy Cost Reduction) Hard to Identify, Quantify, and Allocate Among Parties Stakeholder Apathy Lack of Incentive for Facility Managers and Engineering Firms to Try Something Different Too Few Case Studies Inconsistent, Hard to Find, and Often Incomplete in Financial Details Permitting Process Sometimes Long, Cumbersome, and Costly
Electric Utility Response / Interconnection Often Times Ambivalent at Best, Hostile at Worse Inconsistent Standards, Complex Process, Network Issues and Unpredictable or High Costs Natural Gas Prices / Volatility Creates Uncertainty in Energy Costs Utility Tariffs Standby Charges and General Rate Design Lack of Familiarity With CHP Technologies, Concepts, and Environmental Benefits Electric Restructuring Creates Uncertainty and a “Wait and See” Attitude
Ultimately this should lead to creating an environment that enables DER to succeed.
DECENTTRALISED GENERATION
Central power station Photovoltaics power plant Transmission Network Storage Flow Control Storage House Distribution Network Local CHP plant Power quality device Wind power plant Factory Commercial building Yesterday Power quality device House with domestic CHP Tomorrow: distributed/ on-site generation with fully integrated network management CHP : cleaner, cheaper and competitive
DISTRIBUTED GENERATION WITH HIGH PENETRATION OF RENEWABLE ENERGY SOURCES Distributed Generation (DG) is growing in popularity to meet urban, rural, and diverse customer loads. Integrating the various Distributed Generation technologies into a power system in efforts to improve reliability vary for each application.
Distributed generation a new trend in the generation of heat and electrical power, or Distributed Energy Resources (DER) concept permits "consumers" who are generating heat or electricity for their own needs (hydrogen station and microgeneration) to send surplus electrical power back into the power-grid so known as net metering or share excess heat via a distributed heating grid. Distributed generation systems with (CHP) systems can be very efficient, using up to 90% of the potential energy in the fuel they consume. CHP can also save a lot of money and fuel. Estimates are that CHP has the potential to reduce the energy usage of the USA by up to 40%. A cluster of distributed generation installations is view as a Virtual power plant. Even if the term "distributed generation" is quite well established, terms like distributed power, distributed energy resources, embedded generation, decentralized power, dispersed generation, and onsite generation can also be found in the literature. Although some of those terms may be used with a different meaning, typically they exactly refer to distributed generation.
DISTRIBUTED GENERATION OFFICE BUILDINGS DEG energy resources are wind, solar, biomass, fuel cells, gas microturbines, hydrogen, combined heat and power (CHP), and hybrid power systems. DEG technologies maturity coincided with energy deregulation, creating a fertile environment for DEG projects General benefits of building’s DEG applications: Overall load reduction Energy independence Standby/backup power Peak shaving Net energy sales Combined heat and power Grid support Premium power for sensitive applications
Central power loses 73 percent of total input energy before it reaches the consumer (65 percent in heat loss at the generator plus eight percent lost in transmission). DG electricity travels a shorter distance, so are losses during transmission. Furthermore, these smaller generators tend to be more efficient as the new technologies and site appropriate equipment systems. DEG can be more efficient than central power, but it must not be environmentally clean. DEG does encompass renewable energy systems that reduce greenhouse gas emissions, but it also includes generators that burn fossil fuels, particularly natural gas and diesel. DEG environmental impact depend on the fuel kind. Solar turbine and 5. 2 MW cogeneration plant Arden Realty USA
SOME UTILITY BENEFITS OF USING DEG Dispatchable peak demand reduction Maximum use of standby capacity through safe parallel operation with the utility grid Cost-effective solution consistent with least cost planning emphasis Improved system load factor Enhanced voltage stability and avoided line losses during heavy-load conditions Improved customer relations
CUSTOMER BENEFITS AND FORCES OF DEG Bill reduction Reliability improvement Power Quality (PQ) improvement Customer partnerships Customer Forces Restructuring and evolving regulation drive customers to be more proactive and informed about energy purchases and investments. Increasing need for differentiated energy services, – reliability – quality Cogeneration/thermal - “green” energy
TECHNOLOGY FORCES Smaller, More Modular Generation Shifting Economies of Scale equipment manufacturing versus central generation Improving Efficiencies of Smaller Technologies More Flexible “Optimizable” Solutions Many Improvements Driven by Significant Technology Push in Automotive Sector
BARRIERS Technical - addressable with traditional technology based RD&D – DR technologies – technical evaluation techniques & tools Institutional - requires covering new, mostly nontechnical ground – business/management theories – new regulatory structures – new standards
Fundamentals of Combined Heat and Power Systems Introduction to DG and CHP; Prime Mover Technologies; Thermal Loads for CHP; Generators and Electrical and Utility Interconnections; Heat Recovery Technologies; Commercial and Industrial Applications; Application Opportunities; Financial Evaluation; Design Project Management Engineering Issues in Combined Heat and Power Systems Prime Mover Cycles, Efficiencies, and Thermodynamics; Thermal Technologies and Interconnection Design Commercial; Thermal Technologies and Interconnection Design Industrial; Economic Analysis Techniques; Economic Analysis Software Training; Case Study Exercises;
THE INTERNATIONAL JOURNAL OF DISTRIBUTED ENERGY RESOURCES is a scholarly peer-reviewed archival Journal. It publishes experimental, theoretical and applied results in both science and engineering for distributed energy resources in electrical grids. A thorough peer-review of each paper is performed by at least two independent experts for the special topics addressed. Contact and Call for Papers: ISET e. V. Editorial Office info@der-journal. org http: //www. derjournal. org/
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