Cogeneration. Industrial Sector Building Sector

Transcription

1 Cogeneration Cogeneration Definition Thermodynamics background Cogeneration Parameters National Legislation Cogeneration Systems & Technologies Cogeneration in Portugal Cogeneration Facilities (examples) Industrial Sector Building Sector

2 Cogeneration Definition What is cogeneration Cogeneration: simultaneous production of power and heat, with a view to the practical application of both products

3 Cogeneration Definition What is cogeneration Integrated system Located at or near a building/facility A way of local energy production Uses heat that is lost otherwise (cooling, heating, dehumidification and process heat) Way to use energy more efficient Different areas of application Different technologies

4 Cogeneration Synonyms Cogeneration Combined Heat and Power (CHP) Cooling, Heating and Power (CHP) Trigeneration (Trigen) Integrated Energy Systems (IES) Building Cooling, Heating, and Power (BCHP)

5 Benefits of Cogeneration Improves energy efficiency Conserves natural resources (fossil fuels) Lower emissions (including CO 2 ) Lower energy costs If heat fits demand, cheapest way of electricity production Improves security of supply Reduces transmission and distribution losses Enhances competition

6 Thermodynamics and Cogeneration Thermodynamics: To produce work from heat is necessary a thermal cycle and part of the energy (heat) obtained from the hot reservoir is release to the could reservoir. Carnot Cycle Efficiency T B - Cold reservoir temperature T A - Hot reservoir temperature Cogeneration: Is necessary produce heat at an appropriate temperature (Q u useful Heat).

7 Combined Gas Turbine Cycle The combine Gas turbine cycle can be used as a cogeneration system. Even when useful heat are not produced, there are a recover of heat of the gas turbine in the recover boiler. The generated steam is used tor produce electricity by a Rankine Cycle. The efficiency of the combined cycle is the sum of the efficiency of both Cycles

8 Cogeneration Parameters I Electrical/Mechanical Efficiency / Rendimento Mecânico/Electico Global Efficiency / Rendimento global ou Factor de utilização de Energia Heat/Power ratio / Razão Calor/Electricidade

9 Cogeneration Parameters II FESR-Fuel Energy Saving ratio / PEP Poupança de Energia Primária EEE-Equivalente electrical efficiency / REE - Rendimento Elétrico Equivalente specific consumption (inverse)

10 Equivalent Electrical Efficiency Rendimento Eléctrico equivalente DL 538/99 EEE = 55 % (from 1999) -EEE = 45 % ( ) DL 313/01 from 2001 defines the EEE was a function of the Fuel used in the Combined heat and Power Plant 55 % Natural Gás, LPG-liquefied petroleum gas, liquid fuel (not fuel oil) 50 % Fuel oil, heavy fuel oil 45 % Biomass or residual fuels with support Reference boiler efficiency 90 % - Fossil Fuel 70 % - Renewable Fuel CR - Energy from Renewable Fuel The FESR depends on the Country Electric Systems

11 Conventional Generation Versus Cogeneration Fuel input Separate generation Cogeneration Fuel input Power plant h = 38% Boiler h = 95% Electricity 35 Heat 50 Electricity h = 35% Heat h = 50% 100 Total Total Energy conservation = ( )/145 = 31%

12 Conventional Generation Versus Cogeneration Fuel input Separate generation Cogeneration Fuel input Power plant h = 43% Boiler h = 95% Electricity 35 Heat 50 Electricity h = 35% Heat h = 50% 100 Total Total Energy conservation = ( )/134 = 25%

13 Conventional Generation Versus Cogeneration Fuel input Separate generation Cogeneration Fuel input Power plant h = 55% Boiler h = 95% Electricity 35 Heat 50 Electricity h = 35% Heat h = 50% 100 Total Total Energy conservation = ( )/117 = 15%

14 Parameters analyze Thermal Power Plant Boiler Heat

15 Influence of increase the heat production with a low efficiency equipment The demand of heat increase The demand of Heat/Electricity change over the year but the legislation is based on the annual value

16 FESR Influence of the electric and thermal efficiency on FESR for different values of Heat/Electricity ratio

17 FESR/Global Efficiency Specific technologies Heat/Electricity ratio typical values: TG Gas Turbine: 0,5-1,5 TV Stream Turbines: 1-4 (back pressure) Source: Pita, 1995

18 How cogeneration Saves Energy?

19 Thermodynamic Cycles Classification Depending on the temperatures at the thermal energy is used -Bottom Cycles (Heat Power/Work) -Top Cycles (Power/Work Heat) Depending on the Technologies Gas Cycles Gas turbines, Diesel/SI Engines with recovery boiler to produce steam or with the use of flue gases direct on a process (greenhouses, drying processes) Steam Cycles (Rankine cycles) Water/steam is the work fluid. The hot water/steam could be used directly on a process or as a energy transport fluid. Back Pressure Turbines/ Turbinas de Contrapressão (process that need steam at an elevate temperature or at high pressure) Extraction Condensing Turbines/ Turbinas de Extracção/Condensação to maximize the Electric generation Gas turbine combined cycle Gas turbine cycle with a recover boiler to generate steam used in a Rankine Cycle Others: Heat Pumps, Fuel Cells

20 Technologies Main Properties Technology Power (MW) Electric Efficiency Extraction/Condensing Steam Turbine Back Pressure Stream Turbines Gas Turbines Cycles (0.15) Internal Combustion Engines Fuel Cells The efficiency of a Rakine cycle can reach 40 % and the gas turbine combined cycle 55 % For all cases the global efficiency is near 80 % in CHP CHP whit heat pumps have normally a Global Efficiency greater than 100 %

21 Turbine Cycles used on Electric Power Generation Cycle W Q The electric efficiency increase Gas Turbine Steam Turbine Combined Gas Turbine The cycle with the lower electric efficiency allows the use of heat at a higher temperatures Source: Horlock, 1987 In the steam turbine and combined gas turbine cycle to maximize the electric efficiency the heat should be reject at the lower possible temperature

22 Cycle Sigel Turbine Cycles for Combined Heat and Power Plats In the steam turbines plant an increase in the useful Heat Q u decrease the electric efficiency Its normal have several levels of temperature to use the Q u In the steam turbine and combined gas turbine cycle the thermal energy is used to generate steam in the recover boiler, In the stream turbine cycle the steam is expand in a turbine to produce electricity Source: Horlock, 1987

23 Cogeneration Parameters for Single Turbines Cycles Cycle E Q u η g FESR QU/E Extraction/Condensing Steam Turbine Back Pressure Stream Turbines Gas Turbines Cycles with recuperator Combined gas turbines (Gas/back pressure Steam Turbines) Source: Horlock, 1987 (reference values considered η T =0.9 and η E =0.4) In the gas turbine cycle the injection of steam (generated in the recover boiler) in the turbine increase the electric capacity and the electric efficiency (STIG).

24 CHP Applications

25 Main Cogeneration Technologies Source: Horlock, 1987

26 Typical Cogeneration Performance Parameters * taken from Cogeneration Guide, Cogen Europe

27 DL 23/2010 de 25 de Março de 2012 Adaptation of the European directive 2004/8/CE Defines benefits/premium to the cogenerations sector based on: 1) Reduction of the primary energy consumption and CO 2 emissions 2) Promote the high efficiency cogeneration plants and renewable cogeneration based on renewable sources of energy 3) Promote the integration of Cogeneration in the electricity market Define two exploration regimes General regime (all capacity): The market define the energy price (temporary-benefit/premium for Plant with Electric capacity < 100 MW) Special regime (Electric capacity < 100 MW): The market define the Heat price The tariff of the electricity have benefit/premium based on the efficiency

28 Portaria 140/2012 de 14 de Maio de 2012 Review of the Cogeneration Electric Tariff Reference tariff for the Natural Gas, LPG or liquid Fuel (except Fueloil) Cogeneration Plants: /MWh for Electric capacity < 10 MW /MWh for Electric capacity between 10 MW and 20 MW /MWh for Electric capacity between 20 MW and 50 MW /MWh for Electric capacity between 50 MW and 100 MW Reference tariff for the Cogeneration from renewable sources: /MWh for Electric capacity < 2 MW /MWh for Electric capacity between 2 MW and 100 MW Reference tariff for the Fueloil Cogeneration Plants: /MWh for Electric capacity < 10 MW /MWh for Electric capacity between 10 MW and 100 MW Hora ponta/hours with high electricity demand + 10% Vazio e supervazio/ hours with low electricity demand -13 %

29 Prémios de eficiência / Efficiency premium a) PEm Efficiency premium value in month m b) PC Reference costs for the valorization of Primary Energy saving /MWh c) PEP Primary energy savings (certified) d) EEPlm Net electric energy generated by the cogeneration plant in month m (total electric energy generated electric energy consumed by the Cogeneration Plant) e) K Primary energy saved differentiates factor (0.5 to high efficient cogeneration plant and 0.3 efficient plant) f) EP/EE Ratio between the Primary Energy consumed by the Cogeneration Plant and the Electric energy generated (typical values)

30 Ratio EP/EE i) Natural gas Internal combustion engines: 2.86 ii) Gas Turbines (Natural Gas) eclectic capacity < 20 MWe: 3.70 iii) Gas Turbines (Natural Gas) eclectic capacity > 20 MWe: 3.12 iv) Fueloil Internal combustion engines: 2.60 v) Steam turbines: 5 vi) Combined gas turbines: 2.5 vii) Renewable cogenerations plats: 5

31 Portaria 140/2012 de 14 de Maio de 2012 Transition Regime: Plants with electric capacity > 20 MW The transition to the new remuneration regime occurs at the beginning of the month following the EEGO audit (EEGO - entity that certifies the primary energy savings) For all other cases the transition occurs in the following quarter During the extension period, the reference tariff for no renewable installations is depreciated annually by one percent, for installation with a capacity of 20 MW or less

32 Portaria 140/2012 de 14 de Maio de 2012 Cogeneration Classification: According to capacity -< 1 MW Small Cogeneration -< 50 kw Micro Cogeneration (Biomass Plant Electric capacity < 3.68 kwe have a subsidized regime DL 363/2007) introduces efficiency levels : -high efficient cogeneration plant: -Efficiency: Other cases

33 Electric Energy Certification The electricity produced in cogeneration plant with high efficiency is certified based on a series of data (fuel, amount of heat used, PEP, CO 2 emissions) EEGO Is the entity responsible for certificates the Cogenerations electrical energy (and control the CO 2 emissions) DGEG Is the entity that identify the high efficiency Cogenerations Plants. For the installations type a) and c) the annual global efficiency as to be > 80 % For the installations type b), d), e), f), and g) as to be > 75 % When the annual global efficiency are lower, the C implicit value is used to calculate the: E CHP = H CHP /C

34 Cogenerations Installations Types Implicit ratio C = E/H a) Combined gas turbine cycle with heat recover 0.95 b) Back pressure steam turbines 0.45 c) Extraction/condensing steam turbine 0.45 d) Gas turbine wit heat recovery 0.55 e) Internal combustion Engines 0.75 f) Microturbines g) Stirling Engines h) FuelCells i) Steam Engines j) Rankine Organic Cycles l) Other technologies Technologies for small plants

35 Economics Cogeneration Economics Analysis Costs: Capital Operation and maintenance Fuel Benefits: Heat Electricity less purchase sell to grid Economic value of cogeneration Depends very much on tariff system Heat: avoided cost of separate heat production Electricity: less purchase (kwh); sale of surplus electricity and peak shaving (kwe) Carbon credits

36 Economic Analysis PT-Payback Time \ Tempo de retorno do investimento NPV - Net Present Value \ VAL Valor Atual líquido IRR - Internal Rate of Return \ TIR Taxa interna de Rentabilidade The Payback time in a first approach is determine by: PT = Initial Investment / Annual Cash flow Cash flow= (Revenues - Expenses) NPV/VAL: CF i Cash Flow in year i I i Investment value in year i a i Discount Rate (the rate of return that could be earned on an investment in the financial markets with similar risk.); the opportunity cost of capital i time period TIR/IRR- The discount rate that makes the net present value of all cash flows from a particular project equal to zero. Generally speaking, the higher a project's internal rate of return, the more desirable it is to undertake the project.

37 Economic Analysis IRR - Example Year (i) Cash flow (i) In this case r = 5.96%

38 Economical Parameters The Fuel price/cost The Electricity price/cost The useful heat price/cost The cost of the useful heat depends of the temperature level at the heat is used. Price-weighted Global Efficiency / Factor de utilização de energia ponderado pelo preço Heat approximate costs (Investment costs not included) Fuel Heat /kwh(η T = 90 %) Propane/Butane Gas LGP 0.09 Natural Gas 0.05 Diesel for heat 0.05 *Heat pump (Cop = 4) 0.03 *Heat pump produce heat by a compressor cycle (using electricity) PE = 0.1

39 Cogeneration Economics

40 Cogeneration Economics

41 Cogeneration System Design Options

42 Reference Efficiency Values Source: Manual de Procedimentos da EEGO Entidade Emissora de Garantias de Oringem Available: (areas sectoriais-energia electrica-produção em regime especial

43 Reference Efficiency Values Source: Manual de Procedimentos da EEGO Entidade Emissora de Garantias de Oringem Available: (areas sectoriais-energia electrica-produção em regime especial

44 Reference Efficiency Values Source: Manual de Procedimentos da EEGO Entidade Emissora de Garantias de Oringem Available: (areas sectoriais-energia electrica-produção em regime especial

45 Reference Efficiency Values Source: Manual de Procedimentos da EEGO Entidade Emissora de Garantias de Oringem Available: (areas sectoriais-energia electrica-produção em regime especial

46 Reference Efficiency Values Source: Cogen Portugal

47 Reference Efficiency Values Source: Cogen Portugal

48 Example Otto Natural gas Engine Gas engine Nominal Electrical Power 1100 kw Fuel Natural Gas Electrical Grid Connection Tension kv Annual Average Temperature 19 ºC Construction year 2006 Annual operating hours h Fuel consumption (LHV based) MWh Useful Heat MWh Electrical Energy Generated MWh Electrical Energy Consumptions 176 MWh Reference Electrical efficiency corrected by the average temperature Global Efficiency Fraction of Electric Energy Exported to the National Electric System Correction factors FESR-Fuel Energy Saving Ratio Source: Cogen Portugal

49 CO 2 Emission- EEGO Proceedings Manual CO 2 emissions from CHP Avoid CO 2 emissions The CO 2 emissions factor are defined by the IPCC, intergovernmental Panel on Climate Change, publish in Despacho 17313/2008 (June 26). Source: Manual de Procedimentos da EEGO Entidade Emissora de Garantias de Oringem

50 Despacho 17313/2008 (June 26)

51 Demand Heat Curve

52 Cogeneration in Portugal The installation of Cogeneration Plants in Portugal occurred in three phases: -1 st Large industries -2 nd The possibility of sold electricity to the National Electric System -3 rd The introduction of Natural Gas in Portugal (Otto, GT and CC) Cogeneration Install Capacity in Portugal New CHP Plants: Combined gas turbine cycles in Sines and Matosinhos Petroleum Refinery Natural gas Engines Natural gas Turbines Heavy Fueloil Engines Back pressure Turbines Propane Engines Biogas Engines Micro Turbines Source: Cogen Portugal

53 Sector by Technologies The back pressure Steam turbine are installed mainly in the Pulp paper and chemical Industries Pulp Paper Industry Chemical and Petroleum Industry Cogeneration Install Capacity by Technologies Heavy Fueloil Engines Natural gas Engines Natural gas Turbines Biogas Engines Propane Engines Textile Industry Others Industry Food Industry Micro Turbines Actually the Combined Gas Turbines and the Gas turbines are present in some of this sectors Back pressure Turbines Total capacity at the end of MW

54 Sector by Fuel Fueoil Cogeneration Install Capacity by Sector Natural Gas Cogeneration Install Capacity by Sector Others Tertiary Textile Others Textile Wood Food Chemical Tertiary Glass an Ceramics Chemical Pulp paper Food Wood Glass an Ceramics Pulp paper Total Natural Gas Capacity at the end MW Other include the building Sector Fueloil Engines have environmental limitations Some Fueloil Engines can be converted to Natural Gas

55 Pulp Paper Industry Cogeneration Plant The biomass boiler burn wood residues rejected by the pulp paper process The recover boiler burn black liquor Two steam boiler produce steam for one circuit The steam circuit have different pressures levels

56 Internal Combustion Engines Capacity MW Input Energy Fraction Electricity % Heat % Capacity MW Economizer 1.0 Recover Boiler 3.0 Jacket 2.7 Source: Horlock, 1987

57 Commercial Center Colombo Cogeneration Plant Diesel /Fueliol Engines Convertibles to Natural gas Electric Capacity 37 MW Shops 11.2 MW Hyper Market 4 MW Commons Spaces 21.7 MW Cooling Capacity 14.8 MW 3 Compressor Chillers 2 Absorptions Chillers η g = 86 % EEE = 37 %

58 Combined Gas Turbine Plants GALP - Oil Refining Plants - combined gas cycle Electric Capacity [MW] Exported Eclectic Energy (MW) Steam Production (t/h; bar) EEE/REE (%) Matosinhos ; Sines 2 X ; 82 Fuel: Natural Gas and Refinery Gas

59 Typical Cogeneration Applications Industrial cogeneration wood and agro-industries, food processing, pharmaceutical, pulp and paper, oil refinery, textile industry, steel industry, cement industry, glass industry, ceramic industry Residential/commercial/institutional cogeneration hospitals, schools and universities, hotels, houses and apartments, stores and supermarkets, office buildings

60 Trigeneration Plant Climaespaço Gas turbine Heat exchanger inside the buildings absorption chiller

61 Trigeneration Plant Climaespaço

62 Fuelcell IST

63 Cogeneration as a Share of National Power Production in EU

64 Main Steps to Realize The Cogeneration Project 1) Obtain the representative annual diagram of useful/economical Heat/Cooling based on demand. 1) Based on the dally diagram for different month of the year 2) Careful with the temperature/condition necessary to use the heat 2) Research /define the technology appropriate to the Energy demand 1) Electrical capacity 2) Economical Useful Heat capacity 3) Turn down ratio 4) Availability Factor 5) Type of Fuel and efficiency of the equipments 6) Energy needed to operate (peripherals equipments) 7) Energy Storage Systems 8) Startup time 9) Live time of the equipments 3) Define the business model and the Operation Conditions 1) Useful heat price Based on Market values 2) Electricity Energy Price Based on Market values 3) Investment 4) Maintenance/Operational Cost Based on Technical information 5) Other cost (environmental tariffs, eventual financial penalties when the cogeneration plant have to stop, other cost associate to the project, taxis,)

65 Main Steps to Realize The Cogeneration Project 4) Verify The Legislation/Regulation Check if the defined operating conditions are according to the legislation / regulation 5) Economical Analisys Sensitivity analysis of the main project variables The Final Report: A descriptions of the heat useful demand and the conditions of the heat client A descriptions of the CHP and the technology (technical/economical justification of the option) Economic analysis of the project (with a justification of the values used) Technique analysis that proves the cogeneration benefits: Reduction of the primary energy consumption Increasing the efficiency Reduction of the green gas emissions

66 Useful Documentation Available Online Decreto Lei n.º 23/2010 de 25 de Março Lei n.º 19/2010 de 23 Agosto Portaria n.º 140/2012 de 14 de Maio Portarian.º 325-A/2012 de 16 de Outubro Despacho 17313/2008 de 26 de Junho Manual de Procedimentos da Entidade Emossora da Garantias de Origem (areas sectoriais-energia electrica-produção em regime especial Cogen Portugal- Cogeração Estudo do Potencial de Cogeração de Elevada Eficiência em Portugal (Direcção Geral de Energia e Geologia)