REFERENCE VALUES OF EFFICIENT COGENERATION AND POTENTIAL OF EFFICIENT COGENERATION IN ESTONIA

Transcription

1 REFERENCE VALUES OF EFFICIENT COGENERATION AND POTENTIAL OF EFFICIENT COGENERATION IN ESTONIA REPORT ABBREVIATED VERSION Customer: The Ministry of Economic Affairs and Communications Performed by: Tallinn University of Technology, Department of Thermal Engineering Responsible executor: Andres Siirde Tallinn December 2005

2 REFERENCE VALUES OF EFFICIENT COGENERATION AND POTENTIAL OF EFFICIENT COGENERATION IN ESTONIA REPORT ABBREVIATED VERSION Customer: Performed by: Ministry of Economic Affairs and Communications Tallinn University of Technology, Department of Thermal Engineering Responsible executor: Andres Siirde Tallinn University of Technology, Department of Thermal Engineering Prepared by: Andres Siirde Tallinn University of Technology, Department of Thermal Engineering Heiki Tammoja Tallinn University of Technology, Department of Electrical Power Engineering 2

3 Content Introduction Directive 2004/8/EC of the European Parliament and the Council Definitions Cogeneration technologies Calculation of electricity from cogeneration Methodology for determining the efficiency of the cogeneration process Combined heat and power plants in Estonia as of December Combined heat and power plants using internal combustion engines Combined heat and power plants using steam power units The Iru power plant Kohtla-Järve power station Thermal power station of Kiviõli Oil Shale Processing and Chemicals Plant Sillamäe thermal power station using steam turbine power units VKG Energia (former Fortum AS) thermal power station Ahtme power station Sangla Turvas Ltd. power station Tootsi Turvas Ltd. power station Narva Power Plants Baltic Power Station Reference values of high-efficiency cogeneration About qualifying Estonian cogeneration plants as high-efficiency cogeneration Combined heat and power plants based on internal combustion engines The Iru power station Narva Power Plants Baltic Power Station Kohtla-Järve, Kiviõli Oil Shale Processing and Chemicals Plant, Sillamäe power station (the part using oil shale), VKG Energia, Ahtme, Horizon, Sangla and Turba power stations Heat load potential and access to energy sources to establish efficient cogeneration of heat and power Barriers that prevent establishing efficient cogeneration Bibliography

4 Introduction Combined heat and power production ensures fuel savings. The characteristics of combined heat and power plants are as follows: the main function of combined heat and power plants is to provide consumers with heat energy. This means that these plants operate according to the heat scheme and the electricity produced belongs to the basic part of the power system. In the summertime, extraction turbines may also operate in a condensation regime and participate in regulating the power load of the power system; the operation of combined heat and power plants using district heating is seasonal; combined heat and power plants producing technological steam (e.g. the peat industry) are also often characterised by a seasonal heat load. Hot water consumption largely depends on the season. In the summertime, with no district heating load, cogeneration units are often underloaded. Efficiency of combined heat and power plants can be significantly increased by using heat accumulators. In Denmark, for instance, all combined heat and power plants are equipped with heat accumulators. The following equipment is used in combined heat and power plants for producing heat: Back-pressure turbines Single extraction steam turbines Double extraction steam turbines Industrial and fuel extraction steam turbines Powered peak boilers Hot water boilers (using natural heat or electric boilers) Gas turbines Diesels and gas engines Network water heating with capacitor residual heat of condensation power stations Fuel elements 4

5 According to agreements concluded with the European Union, Estonia should ensure that by 2020 electricity produced in combined heat and power plants forms 20% of the gross consumption. Approximately 11% of electricity in Estonia is currently produced in combination with heat and power plants. The present work deals with adopting Directive 2004/8/EC of the European Parliament and of the Council in Estonia. The purpose of this Directive is to increase energy efficiency and to improve security of supply by efficient combined heat and power production. The main goal is primary energy savings in the internal energy market, taking into account the specific national circumstances especially concerning climatic and economic conditions. The customer and the executor of the work agreed that thee research work would cover the following issues: 1. Reference values of efficient cogeneration: 1.1. criteria to determine efficient cogeneration; 1.2. power and heat co-relation reference values in the view of different production technologies in conformity with the methodology presented in Annex 3 to the Directive; 1.3. formulas to determine primary energy savings. 2. An overview of existing combined heat and power plants The following data will be given for each plant: year of construction; capacity; implemented cogeneration technologies according to Annex 1 of the directive; implemented power sources; possible modes for producing heat, power and fuel volume needed to implement the corresponding mode; savings of primary energy compared to separate production of heat and power; conformity to reference values of efficient cogeneration. 3. Analysis of efficient cogeneration potential in Estonia. 5

6 3.1. Heat load potential and access to energy sources suitable for establishing efficient cogeneration Barriers preventing the implementation of efficient cogeneration, including the price of fuel, access to various networks, administrative barriers set by local governments and underestimation of external costs included in the price of electricity. 6

7 1. Directive 2004/8/EC of the European Parliament and of the Council The purpose of this Directive is to increase energy efficiency and to improve security of supply by efficient combined heat and power production. The main aim is for primary energy savings in the internal energy market, taking into account the specific national circumstances especially concerning climatic and economic conditions Definitions (a) cogeneration shall mean the simultaneous generation in one process of thermal and electrical and/or mechanical energy; (b) useful heat shall mean heat produced in a cogeneration process to satisfy an economically justifiable demand for heat or cooling; (c) economically justifiable demand shall mean the demand that does not exceed the needs for heat or cooling and which would otherwise be satisfied in market conditions by energy generation processes other than cogeneration; (d) electricity from cogeneration shall mean electricity generated in a process linked to the production of useful heat and calculated in accordance with the methodology set out in Article 1.3; (e) back-up electricity shall mean electricity supplied through the electricity grid whenever the cogeneration process is disrupted, including maintenance periods, or out of order; (f) top-up electricity shall mean electricity supplied through the electricity grid in cases where the electricity demand is greater than the electrical output of the cogeneration process; (g) overall efficiency shall mean the annual sum of electricity and mechanical energy production and useful heat output divided by the fuel input used for heat produced in a cogeneration process and gross electricity and mechanical energy production; (h) efficiency shall mean efficiency calculated on the basis of net calorific values of fuels (also referred to as lower calorific values ); (i) High efficiency cogeneration shall mean cogeneration meeting the criteria of Article 1.4; 7

8 (j) efficiency reference value for separate production shall mean the efficiency of the alternative separate productions of heat and electricity that the cogeneration process is intended to substitute; (k) power to heat ratio shall mean the ratio between electricity from cogeneration and useful heat using operational data of the specific unit; (l) cogeneration unit shall mean a unit that can operate in cogeneration mode; (m) micro-cogeneration unit shall mean a cogeneration unit with a maximum capacity below 50 kwe; (n) small-scale cogeneration shall mean cogeneration units with an installed capacity below 1 Mwe; (o) cogeneration production shall mean the sum of electricity and mechanical energy and useful heat from cogeneration Cogeneration technologies Cogeneration technologies covered by this Directive: (a) Combined cycle gas turbine with heat recovery; (b) Steam back-pressure turbine; (c) Steam condensing extraction turbine; (d) Gas turbine with heat recovery; (e) Internal combustion engine; (f) Microturbines; (g) Stirling engines; (h) Fuel cells; (i) Steam engines; (j) Organic Rankine cycles; (k) Any other type of technology or combination thereof falling under the definition cogeneration, whereas cogeneration shall mean the simultaneous generation in one process of thermal and electrical and/or mechanical energy. 8

9 1.3. Calculation of electricity from cogeneration Values used for calculation of electricity from cogeneration shall be determined on the basis of the expected or actual operation of the unit under normal conditions of use. For micro-cogeneration units the calculation may be based on certified values. (a) Electricity production from cogeneration shall be considered equal to the total annual electricity production of the unit measured at the outlet of the main generators: (i) In cogeneration units of type (b, d, e, f, g and h) with an annual overall efficiency at a level of at least 75%; and (ii) in cogeneration units of type (a) and (c) with an annual overall efficiency at a level of at least 80%. (b) In cogeneration units with an annual overall efficiency below the value referred to earlier cogeneration is calculated according to the following formula: E CHP = H CHP C where: E CHP is the amount of electricity from cogeneration. C is the power to heat ratio. H CHP is the amount of useful heat from cogeneration (calculated for this purpose as total heat production minus any heat produced in separate boilers or by live steam extraction from the steam generator before the turbine). The calculation of electricity from cogeneration must be based on the actual power to heat ratio. If the actual power to heat ratio of a cogeneration unit is not known, the following default values may be used, notably for statistical purposes. 9

10 Type of unit Power to heat default ratio, C Combined cycle gas turbine with heat 0.95 recovery Steam back-pressure turbine 0.45 Steam condensing extraction turbine 0.45 Gas turbine with heat recovery 0.55 Internal combustion engine 0.75 If Member States introduce default values for power to heat ratios for type (f), (g), (h), (i), (j) and (k) units as referred to in Annex I, such default values shall be published and notified to the Commission: (c) if a share of the energy content of the fuel input to the cogeneration process is recovered in chemicals and recycled this share can be subtracted from the fuel input before calculating the overall efficiency used in paragraphs (a) and (b); (d) Member States may determine the power to heat ratio as the ratio between electricity and useful heat when operating in cogeneration mode at a lower capacity using operational data of the specific unit. Until 2011, Member States may use other reporting periods than the methods outlined here Methodology for determining the efficiency of the cogeneration process Values used for the calculation of efficiency of cogeneration and primary energy savings shall be determined on the basis of the expected or actual operation of the unit under normal conditions of use. (a) High-efficiency cogeneration For the purpose of this Directive high-efficiency cogeneration shall fulfil the following criteria: 10

11 - cogeneration production shall provide primary energy savings of at least 10% compared with the references for separate production of heat and electricity, primary energy savings shall be calculated according to the formula outlined in point (b); - production from small-scale and micro cogeneration units providing primary energy savings may qualify as highefficiency cogeneration. (b) Calculation of primary energy savings The amount of primary energy savings provided by cogeneration production shall be calculated on the basis of the following formula: 1 PES = 1 100% CHPHη CHPEη + REFHη REFEη where: PES CHPHη REFfHη CHPEη REFEη is primary energy savings is the heat efficiency of the cogeneration production defined as annual useful heat output divided by the fuel input used to produce the sum of useful heat output and electricity from cogeneration is the efficiency reference value for separate heat production is the electrical efficiency of the cogeneration production defined as annual electricity from cogeneration divided by the fuel input used to produce the sum of useful heat output and electricity from cogeneration is the efficiency reference value for separate electricity production (c) Calculations of energy savings using alternative calculation according to Article 12(2) 11

12 If primary energy savings for a process are calculated in accordance with Article 12(2), the primary energy savings shall be calculated using the formula in paragraph (b), with the following replacements: CHPHη = Hη CHPEη = Eη where: Hη shall mean the heat efficiency of the process, defined as the annual heat output divided by the fuel input used to produce the sum of heat output and electricity output Eη shall mean the electricity efficiency of the process, defined as the annual electricity output divided by the fuel input used to produce the sum of heat output and electricity output (d) Member States may use other reporting periods than one year (e) For micro-cogeneration units the calculation of primary energy savings may be based on certified data (f) Efficiency reference values for separate production of heat and electricity The efficiency reference values shall be calculated according to the following principles: 1. for cogeneration units and separate electricity, production shall be based on the principle that the same fuel categories are used; 12

13 2. each cogeneration unit shall be compared with the best available and economically justifiable technology for separate production of heat and electricity built at the same time; 3. the efficiency reference values for cogeneration units older than 10 years of age shall be fixed on the reference values of units of 10 years of age; 4. the efficiency reference values for separate electricity production and heat production shall reflect the climate difference between Member States. 13

14 2. Combined heat and power plants in Estonia as of December Combined heat and power plants using internal combustion engines Tables contain general data on combined heat and power plants using internal combustion engines in Estonia as of December AS Kunda Nordic Tsement Table 2.1 Name of the combined heat and power AS Kunda Nordic Tsement plant Year of construction Maximum installed power and heat 3,1/3,3 capacity, MW el /MWth Implemented technology Internal combustion engine Fuel input Natural gas Possible modes for producing heat and Operating in cogeneration mode with an power overall efficiency of ~92%, power efficiency of ~39-40% AS Eraküte, Põlva division Table 2.2 Name of the combined heat and power AS Eraküte, Põlva division plant Year of construction 1999 Maximum installed power and heat 0,922/1,253 capacity, MW el /MWth Implemented technology Internal combustion engine Fuel input Natural gas Possible modes for producing heat and Operating in cogeneration mode with an power overall efficiency of ~92%, power efficiency of ~39-40% AS Grüne Fee Table 2.3 Name of the combined heat and power AS Grüne Fee plant Year of construction Maximum installed power and heat Installed 4 cogeneration units, 1/1.2 each capacity, MW el /MWth (in total 4/4.8) Implemented technology Internal combustion engine Fuel input Natural gas Possible modes for producing heat and power Operating in cogeneration mode with an overall efficiency of ~92%, power efficiency of ~40% 14

15 Narva Vesi Ltd. Table 2.4 Name of the combined heat and power Narva Vesi Ltd. plant Year of construction 1999 Maximum installed power and heat 0,5/0,7 capacity, MW el /MWth Implemented technology Internal combustion engine Fuel input Natural gas Possible modes for producing heat and Operating in cogeneration mode with an power overall efficiency of ~92%, power efficiency of ~40% AS Kristiine Kaubanduskeskus Table 2.5 Name of the combined heat and power AS Kristiine Kaubanduskeskus plant Year of construction 2000 Maximum installed power and heat 0,5/0,7 capacity, MW el /MWth Implemented technology Internal combustion engine Fuel input Natural gas Possible modes for producing heat and Operating in cogeneration mode with an power overall efficiency of ~92%, power efficiency of ~40% AS Terts Table 2.6 Name of the combined heat and power AS Terts plant Year of construction Maximum installed power and heat Installed 2 cogeneration units, each capacity, MW el /MWth (1.68/2 in total) Implemented technology Internal combustion engine Fuel input Landfill gas Possible modes for producing heat and power Operating in cogeneration mode with an overall efficiency of ~92%, power efficiency of ~40% 15

16 Sillamäe thermal power station (using internal combustion engine) Table 2.7 Name of the combined heat and power Sillamäe thermal power station (using plant internal combustion engine) Year of construction 2004 Maximum installed power and heat 5,95/6,7 capacity, MW el /MWth Implemented technology Internal combustion engine Fuel input Natural gas Possible modes for producing heat and Operating in cogeneration mode with an power overall efficiency of ~92%, power efficiency of ~43% ELME AS (BLRT Grupp AS ) Table 2.8 Name of the combined heat and power ELME AS (BLRT Grupp AS ) plant Year of construction Maximum installed power and heat Installed 4 cogeneration units, 1.2/1.4 each capacity, MW el /MWth (in total 2.4/2.8) Implemented technology Internal combustion engine Fuel input Natural gas Possible modes for producing heat and power Operating in cogeneration mode with an overall efficiency of ~92%, power efficiency of ~43%, is also used with reduced heat output. AS Tallinna Vesi, Paljassaare waste water station Table 2.9 Name of the combined heat and power AS Tallinna Vesi plant Year of construction Maximum installed power and heat 0,65/0,86 *) value needs to be specified capacity, MW el /MWth Implemented technology Internal combustion engine (2 engines) Fuel input Natural gas *) to be specified Possible modes for producing heat and power Serves as a mechanical drive for a fan. Heat is used in the technological process. 16

17 2.2 Combined heat and power plants using steam power units Iru power plant General data on the Iru power plant is presented in table Iru power plant Table 2.10 Name of the combined heat and power Iru power plant plant Year of construction Maximum installed power and heat Power block No 1 80/120 capacity, MW el /MWth Power block No 2 110/220 Implemented technology Steam power turbine with steam extraction, with back-pressure (note: in 2002 the turbine No 2 (T-110/ ) was modernised to a back-pressure turbine. Fuel input Natural gas (note: in 1998 residual fuel oil was totally replaced by gas (gasification) in Iru power plant. Possible modes for producing heat and Both condensation and cogeneration modes power (modes are shown in tables 2.11 and 2.12). Tables 2.11 and 2.12 present calculated modes of Iru power plant energy blocks and the efficiency thereof. Calculated modes and efficiency of these of Iru power plant energy block No 2 Table 2.11 Gross power output Overall efficiency (to gross output) Overall efficiency (to net output) Net power output Heat input MW MW MW % %

18 Calculated modes and of Iru power plant energy unit No 1 and their efficiency Table 2.12 Gross power output Net power output Heat input Overall efficiency (to gross output) MW MW MW % % Overall efficiency (to net output) Kohtla-Järve power station General data on Kohtla-Järve power station are presented in table Kohtla-Järve power station Table 2.13 Name of the combined heat and power Kohtla-Järve power station plant Year of construction Maximum installed power and heat 27/70 (detailed description follows after the capacity, MW el /MWth table) Implemented technology Steam power turbine with steam extraction, back-pressure turbines Fuel input Oil shale, generator gas Possible modes for producing heat and Both condensation and cogeneration modes power Technical data on steam generators working in Kohtla-Järve power station are provided in Table 2.14 and technical data on steam turbines and power generators are provided in Table

19 Technical data on steam generators of Kohta-Järve power station Table 2.14 Boiler No 5 Name Description Boiler type BKZ-75-39fsl Boiler capacity / steam output 48 MW / 75 t/h Burner type Fantail pulverised-fuel burners Heat carrying agent Water - steam Superheated steam parameters (pressure / temperature) 32 atmospheric excess pressure / 420 C Efficiency, % Structural improvements Type of fuel Oil shale, generator gas (since 2005) Shale oil for reserve and firing-up Entry into service of the boiler 1955 Boiler condition Satisfactory Boiler No 6 Boiler type BKZ-75-39fsl Boiler capacity / steam output 48 MW / 75 t/h Burner type Tangential pulverised-fuel burners Heat carrying agent Water - steam Superheated steam parameters 32 atmospheres overpressure / 420 C (pressure / temperature) Efficiency, % Structural improvements Type of fuel Oil shale Shale oil for reserve and firing-up Entry into service of the boiler 1955 Boiler condition Satisfactory Boiler No 7 Boiler type BKZ-75-39fsl Boiler capacity / steam output 48 MW / 75 t/h Burner type Fantail pulverised-fuel burner Heat carrying agent Water - steam Superheated steam parameters 32 atmospheres overpressure / 420 C (pressure / temperature) Efficiency, % Structural improvements Type of fuel Oil shale Shale oil for reserve and firing-up Entry into service of the boiler 1957 Boiler condition Satisfactory Boiler No 8 Boiler type Boiler capacity / steam output Burner type Heat carrying agent Superheated steam parameters (pressure / temperature) BKZ-75-39fsl 48 MW / 75 t/h Fantail pulverised-fuel burner Water - steam 32 atmospheric excess pressure / 420 C 19

20 Efficiency, % Structural improvements Type of fuel Oil shale, generator gas (since 2005) Shale oil for reserve and firing-up Entry into service of the boiler 1959 Boiler condition Satisfactory Boiler No 9 Boiler type BKZ-75-39fsl Boiler capacity / steam output 48 MW / 75 t/h Burner type Fantail pulverised-fuel burner Heat carrying agent Water - steam Superheated steam parameters (pressure / temperature) 32 atmospheric excess pressure / 420 C Efficiency, % Structural improvements Type of fuel Oil shale Shale oil for reserve and firing-up Entry into service of the boiler 1968 Boiler condition Boiler No 10 The boiler has not been used for a long time, since there has been no need for it. Requires extended general repairs. Boiler type KVGM 100 Boiler house capacity 116 MW Burner type PMGG 40 Heat carrying agent Water Type of fuel Gas, residual fuel oil Entry into service of the boiler 1984 Boiler condition Satisfactory Boiler No11 Boiler type KVGM 100 Boiler house capacity 116 MW Burner type PMGG 40 Heat carrying agent Water Type of fuel Gas, residual fuel oil Entry into service of the boiler 1986 Boiler condition Satisfactory Kohtla-Järve power station owns five steam generators PKZ-75-39fsl operating with oil shale with a total output of 240 MW th and two hot water boilers. Since 2005, boilers No 5 and No 8 have been reconstructed to cogenerate generator gas supplied by the oil shale and shale oil industry. Kohtla-Järve 20

21 boiler KVGM100 has a total output of 232 MW th. Hot water boilers are designed to operate on natural gas or residual fuel oil. These boilers have not been used for long and are not in operational order. Data on turbo sets used in Kohtla-Järve power station Table 2.15 Turbine Generator No l 1 Type ПP-8-29/7/2, /1 Manufacturer Fraser Chalmers Output, MWel 8 12 Launching date No 2 2 Type ПT-12-29/7/2,2 T Manufacturer Turbine factory in Kirov Output, MWel Operation started on No 3 3 Type P-8-29/07 OF-760x Manufacturer Lang. Output, MWel 8 12 Launching date No 4 4 Type ПP -9-29/11,5/1,5 T Manufacturer Turbine factory in Brjansk Output, MWel 9 12 Launching date Turbine No 1 is characterised by two automatic-extraction systems: - industrial extraction with a pressure of 6-8 kgf/cm 2, maximum steam capacity of 80 t/h; - thermofication extraction with a pressure of kgf/cm, maximum steam capacity of 66 t/h; - the turbine was rebuilt in 1990 to a back-pressure turbine kgf/cm 2 2. Turbine No 2 is characterised by two automatic extraction systems: 21

22 - industrial extraction with a pressure of 6-8 kgf/cm 2, maximum steam capacity of 120 t/h; - thermofication extraction with a pressure of kgf/cm 2, maximum steam capacity of 66 t/h. Turbine No 3 operates on impaired vacuum kgf/cm 2. May also work in condensation mode. Turbine No 4 is characterised by one automatic industrial extraction with a pressure of 8-13 kgf/cm 2, maximum steam capacity of 70 t/h. The turbine was rebuilt in 1971/1972 to a back-pressure turbine, kgf/cm 2. 22

23 2.2.3 Thermal power station of Kiviõli Oil Shale Processing and Chemicals Plant General data on the thermal power station of Kiviõli Oil Shale Processing and Chemicals Plant is presented in Table The Thermal power station of Kiviõli Oil Shale Processing and Chemicals Plant Table 2.16 Name of the combined heat and power plant The Thermal power station of Kiviõli Oil Shale Processing and Chemicals Plant Year of construction ~1958 Maximum installed power and heat 10/x capacity, MW el /MWs usable 8/20 Implemented technology Steam power turbine with steam extraction, with back-pressure Fuel input Generator gas, oil shale Possible modes for producing heat and Both condensation and cogeneration modes power The following equipment is used to generate steam in the thermal power plant of Kiviõli Chemicals Plant: two steam boilers E-25/ GM with a nominal capacity of 14.5 MW. These boilers, constructed in 1966, are equipped with burners that were specially designed to burn gas with low calorific value. Operating on residual gas (generator gas) generated in the process of oil shale production, the total output of these boilers is 30 t/h; one steam boiler Babcock-Willcox, made in 1950, with a nominal capacity of 11.5 MW and output 15 t/h. The boiler is fired by generator gas. Fine oil shale screened from industrial oil shale is used as a reserve and firing-up fuel; two steam boilers TS-35, made respectively in 1958 and 1967 with a nominal capacity of 26.5, also fired by generator gas. Solid residue is used for reserve and firing-up fuel. Note: the said Babcock-Willcox and TS-35 boilers are designed for burning solid fuel (fine oil shale) on a grid but the boilers are re-adjusted and provided with special burners to burn generator gas. There are two steam turbines installed in the thermal power station of Kiviõli Chemicals Plant: 4 MW turbine P-4-35/5 with back-pressure and extraction, with maximum extraction steam consumption of 25 t/h; 6 MW turbine AP-6 with condensation and extraction, with maximum extraction steam consumption of 34 t/h. 23

24 The principle heat scheme is shown in Figure 2.1. The boilers are connected by means of a series connected steam trunk, so that each boiler unit can deliver steam to both turbines. Figure 2.1. Principle heat scheme of the thermal power station of Kiviõli Oil Shale Processing and Chemicals Plant Sillamäe thermal power station using steam turbine power units General data on Sillamäe thermal power station using steam turbine power units is shown in table General data on Sillamäe thermal power station Table 2.17 Name of the combined heat and power plant Sillamäe thermal power station (the part using oil shale) Year of construction Maximum installed power and heat Two steam power units, 6/12 each capacity, MW el /MWth Implemented technology Back-pressure and extraction turbines Fuel input Oil shale pulverised combustion Possible modes for producing heat and power Both condensation and cogeneration modes A principle scheme of AS Sillamäe thermal power station is shown in figure

25 Figure 2.2. Principle heat scheme of Sillamäe thermal power station Numbering: 6. turbo generator АПР-6 (6MW) 13. capacitor Steam parameters: chemical water purification 7. turbo generator АП-6 (6MW) 14. boilers for heating water superheated steam 420 C/35 bar deaerators 8. reduction cooling unit 40/ collector for water returning from heat network supply pumps 9. reduction cooling unit 40/5 16. collector for water supplied in to heat network Extraction steam of the turbine 190 C/5 bar supply water high pressure pre-heater 10, 11 network water heaters 17. steam consumers Turbine back-pressure steam 120 C/1.2 bar 5. steam boilers 3 ТП-35-40, 2 С network water pumps 25

26 AS Sillamäe thermal power station owns 5 steam boilers using pulverised oil shale and 2 water heating boilers using gas or residual fuel oil. The three first oil-shale boilers (no. 1, 2 and 3) are of ΤΠ-35 type, whereas the other two (no. 4 and 5) are of C type. The following is a general description of the steam turbines: Turbine No 1 AП-6 type, one cylinder, one automatic extraction condensation turbine, constructed in 1952 by the Nevski machinery factory. Capacity 6 MW, speed 3,000 rpm. Steam parameters inside the turbine: - pressure 35 bar; - temperature 435 C; - maximum steam consumption 53 t/h; - extraction steam pressure 5 bar; - pressure in the capacitor 0.04 bar; The flow part of the turbine is reconstructed in connection with the transition to impaired vacuum mode. During the summer period, the capacitor is cooled down by seawater, and during the heating period by network water. Turbine No 2 AПP-6 type, one cylinder back-pressure turbine, bleeder steam turbine. Constructed in 1963 by the Kaluga turbine factory. Capacity 6 MW, speed 3,000 rpm. Steam parameters inside the turbine: - pressure 35 bar; - temperature 435 C; - nominal back-pressure 1.2 bar; - extraction steam pressure 5 bar; - maximum consumption of extraction steam 40 t/h. Dead steam maximum temperature 200 C 26

27 2.2.6 VKG Energia (former Fortum AS) thermal power station General data on VKG Energia thermal power station is presented in table General data on VKG Energia thermal power station Table 2.18 Name of the combined heat and power plant Year of construction Maximum installed power and heat capacity, MW el /MWth Implemented technology Fuel input Possible modes for producing heat and power VKG Energia 1997 (a second-hand unit was installed) 8/12 Back-pressure steam turbine Generator gas Cogeneration mode There are 4 steam boilers installed in VKG thermal power station, two of which work with a steam turbine power unit. Boiler No 1 and boiler No 2, type PKK These boilers, made in the Belgorod factory, are equipped with burners specially designed for burning generator gas. The maximum steam output of these boilers is 75 t/h of steam, provided the temperature value is 370 ºC and pressure 24 kg/cm 2. Calculated thermal capacity (in the condition of steam output of 75 t/h, pressure 24 kg/cm 2, steam temperature 370 ºC, supply water temperature 150 ºC) is 53 MW. These boilers were installed in 1978 and The boilers do not operate on a steam turbine unit. Boiler No 3 and boiler No 4 of types BKZ D and E-75-4º-G respectively. These boilers, made in the Belgorod factory, are equipped with burners specially designed for burning generator gas. The maximum steam output of these boilers is 75 t/h of steam, provided the temperature value is 440º and pressure 40 kg/cm 2. Calculated thermal capacity (in the condition of steam output of 75 t/h, pressure 40 kg/cm 2, steam temperature 440 ºC, supply water temperature 150 ºC) is 57 MW. The boilers were installed in 1985 and 1984, respectively. Since 1996 there has been a steam turbine PR 8-43/10/5 working with a capacity of 8 MW, extraction of 10 bar and back-pressure of 5 bar. 27

28 2.2.7 Ahtme power station General data on Ahtme power station is presented in table General data on Ahtme power station Table 2.19 Name of the combined heat and power Ahtme power station plant Year of construction 1953 Maximum installed power and heat 30/ (needs to be specified) capacity, MW el /MWth Implemented technology Back-pressure steam turbines, (to be specified) Fuel input Pulverised oil shale Possible modes for producing heat and Cogeneration mode power There is a turbine AT-25-2 installed in Ahtme power station, which operates with steam at a pressure of 29 bar and temperature of 425ºC, with a maximum steam consumption of 160 and a thermofication turbine with a power rating of 10 MW, made in 1965 by VEB Görlitzer Maschienenbau, Germany. The turbine was reinstalled in the Ahtme power station and has been in operation since The actual steam back-pressure of the AT-25-2 turbine is 1.2 bar and its useful thermal capacity is 20 MWe. It is planned to close the Ahtme power station in the course of Horizon Pulp and Paper Ltd thermal power station General data on Horizon Pulp and Paper Ltd s thermal power station are presented in table General data on Horizon Pulp and Paper Ltd thermal power station Table 2.20 Name of the combined heat and power plant Horizon Pulp and Paper Ltd. thermal power station Year of construction 1953, 1983 Maximum installed power and heat Total capacity 10/125* capacity, MW el /MWth *) heat capacity also includes possible heat production from boilers Implemented technology Back-pressure steam turbine and condensation turbine Fuel input Natural gas, heavy fuel oil, black liquor, wood waste Possible modes for producing heat and Cogeneration mode, condensation mode 28

29 power Technical data on boiler units installed in the power station are shown in table Technical data on boiler units installed in Horizon Pulp and Paper Ltd. thermal power station Table 2.21 Soda exhaust-steam Boiler No 4 Boiler No 5 Boiler No 6 boiler 315 tds/d Steam boiler Steam boiler GM Steam boiler GM Industrial steam boiler Wood waste + bark Natural gas/black oil Natural gas/black oil Maximum fuel consumption 4,000 kg/h Thermal capacity and steam output: 5 MW, 10 t/h Steam pressure 10 Maximum fuel consumption Maximum fuel consumption 4,500 m 3 n/h 4,500 m 3 n/h Thermal capacity and Thermal capacity and steam output: steam output: 40 MW, 50 t/h 40 MW, 50 t/h Black liquor/heavy fuel oil Maximum fuel consumption 315 tds/24h (3.,65 l/s, 73.1%, 125ºC) Thermal capacity and steam output: 40 MW, 51 t/h bar Steam pressure 40 bar Steam pressure 40 bar Steam pressure 39 bar Steam temperature 180ºC Steam temperature 440 ºC Steam temperature 440 ºC Steam temperature 440 ºC Year of construction 1958/1998 Year of construction 1976 Year of construction 1983 Year of construction 1964/2001 The power station includes two steam turbines, a back-pressure turbine TG-1 made in the Kaluuga turbine factory, with a nominal capacity of and an adjustableextraction condensation turbine made in the Brno factory, with a nominal capacity of 4 MW el Sangla Turvas AS power station General data on Sangla Turvas Ltd. power station are presented in table General data on Sangla Turvas AS power station Table 2.22 Name of the combined heat and power Sangla Turvas AS power station plant Year of construction Reconstructed in 1998 Maximum installed power and heat 2,5/7 capacity, MW el /MW th 29

30 Implemented technology Fuel input Possible modes for producing heat and power Back-pressure steam turbine, (to be specified) Peat Cogeneration mode Tootsi Turvas Ltd. power station General data on Tootsi Turvas Ltd. power station are presented in table Tootsi Turvas Ltd. power station Table 2.23 Name of the combined heat and power plant Year of construction Maximum installed power and heat capacity, MW el /MWth Implemented technology Fuel input Possible modes for producing heat and power Tootsi Turvas Ltd. power station (to be specified) 5/14 Back-pressure steam turbine? Peat Cogeneration mode Narva Power Plants Baltic Power Station Until 2004/2005 Narva was supplied with heat by I-III stage equipment of the Baltic Power Station. The total district heating length of AS Narva Soojus, who sells heat from the Baltic Power Station, is 68.5 km. The designed thermal capacity of consumers of AS Narva Soojus is MW, from which heat forms MW and ventilation MW. In addition it sells industrial steam with the parameters of 16.0 bar, ºC with an approx. maximum volume of 16.1 kg/s to the Baltic Power Station. In connection with the renovation of the Narva Power Plants, the technological solution of heat output in the Baltic Power Station will change. By 2006, the I-III stage will be closed in the Baltic Power Station and heat output will be possibly based on three steam boilers NSTB or a reconstructed steam turbine K (automatic extractions were reconstructed). The designed maximum heat output is 160 MW t/h and power capacity (excluding heat output) 215 MW. Heat output possibilities from the reconstructed energy block: Industrial steam: 30

31 Heat extraction steam parameters of the steam turbine II (behind the second reduction cooling unit): 16.0 bar; 300 ºC; 18.4 kg/s. District heating: District heating steam parameters from heat extraction of the steam turbine VI: 1.69 bar; ºC, 50.4 kg/s. 31

32 3. Reference values of high-efficiency cogeneration Pursuant to Annex III, section (f) of the directive efficiency reference values of the separate production of heat and power compared to cogeneration shall meet the following principles: for cogeneration units and separate electricity, production shall be based on the principle that the same fuel categories are used; each cogeneration unit shall be compared with the best available and economically justifiable technology for separate production of heat and electricity built at the same time; the efficiency reference values for cogeneration units older than 10 years shall be fixed on the reference values of units of 10 years; the efficiency reference values for separate electricity production and heat production shall reflect the climate difference between Member States. Based on the above information, we recommend the following reference values be used to determine efficient cogeneration: For combined power and heat plants using oil shale: for units older than 10 years, with a capacity not exceeding 20 MWe (Sillamäe thermal power station using oil shale, Kohtla-Järve thermal power station, Ahtme power station) reference value in the case of separate heat and power production is 22%. When determining the value it is assumed that steam units older than 10 years with a small capacity and using oil shale, operate on steam parameters, where temperature does not exceed ºC and pressure bar. 32

33 reference value in the case of separate heat production for industrial steam or district heating water is 86%. Here it should be noted that boilers using oil shale and implemented in separate production (neither water heating nor steam boilers) have not been used for decades. The presented reference value should be regarded as an expert evaluation. in the case of units older than 10 years and with a capacity exceeding 20 MWe (the Baltic Power Station block No 9, we assume that within renovations of the Baltic Power Station the steam power unit needed for cogeneration was replaced and not changed). The reference value in the case of separate production of heat and power is 29%. When determining this value we based our assumption on the efficiency of the Estonian Power Station, which has been using oil shale most efficiently for 10 years. The reference value in the case of separate heat production for industrial steam or district heating water is 86%. Here it should also be noted that boilers using oil shale and implemented for separate production (either water heating or steam boilers) have not been used for decades. The presented reference value should be regarded as an expert evaluation. For cogeneration units using generator gas manufactured in the process of shale oil production: for units older than 10 years, with a capacity not exceeding 20 MWe (Kiviõli Oil Shale Processing and Chemicals Plant thermal power station, VKG Energia thermal power station) the reference value in the case of separate production of heat and power is 22%. When determining the value it is assumed that steam units older than 10 years with small capacity, operating with generators operated on steam parameters 450 ºC and pressure bar. 33

34 the reference value in the case of separate heat production for industrial steam or district heating water is 85%. The efficiency corresponds to efficiency of a special burner equipped with an adiabatic extended furnace as it is used in VKG Energia thermal power station. For cogeneration plants using peat: for the units older than 10 years, with a capacity not exceeding 10 MWe (AS Tootsi Turvas and AS Sangla Turvas thermal power stations) the reference value in the case of separate production of heat and power is 22%. When determining the value it is assumed that more efficient condensation steam units older than 10 years with small capacity and using peat should have been operating on steam parameters ºC and pressure bar. the reference value in the case of separate heat production for industrial steam or district heating is 86%. The presented reference value should be regarded as an expert evaluation. For cogeneration units using natural gas: in the case of units older than 10 years and with a capacity exceeding 50 MWe (Iru thermal power station energy blocks no. 1 and no. 2) the reference value in the case of separate production of heat and power is 40%. When determining the value it was considered that ten years ago it was not economical to use condensation power units with a 34

35 combined cycle. There are no limitations regarding steam parameters and there were no limitations in using supercritical parameters. the reference value for separate production for industrial steam and district heating is 91%. This reference value corresponds to the value given in the report from June 2005 Analysis and Guidelines for Implementation of the CHP Directive 2004/8/EC Interim version 1 Annex Report I, Draft reference Values. Note: In case of Iru thermal power station it has to be considered that in 1998 the use of black oil was completely replaced by gas (gasification). This is certainly an additional reason as to why it is not correct to use values of a condensation power unit with combined cycles as a reference value. For cogeneration units using natural gas: as per year of construction: o the reference value in the case of separate production of power Recommended reference values for cogeneration plants using natural gas Table 3.1 Operation hours 7,500 Operation hours 4,000 Operation hours 2, % 56.6% 58.6% 52.0% 53.9% 55.8% 50.3% 52.2% 54.1% Within the range of 7,500-6,000 operation hours, the reference value may lower 0.25% for every 500 hours; within the range of 6,000-3, % for every 500 hours 35

36 and within 3,000-1, % for every 500 hours. This reference value corresponds to the value given in the report dated June 2005 Analysis and Guidelines for the Implementation of the CHP Directive 2004/8/EC Interim version 1 Annex Report I, Draft reference Values. o The reference value in the case of separate heat production for industrial steam or district heating is 90%. This reference value corresponds to the value given in the report from June 2005 Analysis and Guidelines for Implementation of the CHP Directive 2004/8/EC Interim version 1 Annex Report I, Draft reference Values. Here the consultants of the commission have made a mistake the efficiency of steam boilers is less than the efficiency of water boilers. Our calculations are based on the reference value of 91% regardless of the type of heat. For cogeneration units using landfill gas: as per the year of construction (AS Terts two cogeneration plants) o the reference value in the case of separate production of power Recommended reference values for cogeneration plants using landfill gas and biogas Table Operation hours 7,500 25% 25% 25% Operation hours 4,000 25% 25% 25% Operation hours 2,500 25% 25% 25% o The reference value for separate heat production is 88%. This reference value corresponds to the value given in the report from June 2005 Analysis and Guidelines for the Implementation of the CHP 36

37 Directive 2004/8/EC Interim version 1 Annex Report I, Draft reference Values. 37

38 4. About qualifying Estonian cogeneration plants as high-efficiency cogeneration 4.1 Combined heat and power plants based on internal combustion engines A summary of recommended reference values for combined heat and power plants based on internal combustion engines working in Estonia are presented in table 4.1. Reference values for combined heat and power plants based on internal combustion engines working in Estonia Table 4.1 AS Kunda Nordic Tsement AS Eraküte, Põlva division AS Grüne Fee AS Kristiine Kaubanduskeskus Sillamäe thermal power station internal combustion engine ELME AS (BLRT Grupp) AS Tallinna Vesi Narva Vesi Ltd. Reference value for power Reference value for heat % depending on operating hours 91% % depending on operating hours 91% % depending on operating hours 91% and installation year of the engine % depending on operating hours 91% % depending on operating hours 91% % depending on operating hours 91% % depending on operating hours, in case of biogas used for fuel, the reference value is 25% % depending on operating hours, in case of biogas used for fuel the reference value is 25% 91% 91% AS Terts 25% 91% Note: Consultants of the Commission have expressed in a joint statement that lowering of power transmission costs should be taken into consideration, due to the fact that in major cases the combined heat and power plant is situated closer to the consumer and connected to the distribution network with lower voltage. It is recommended to conduct sensitivity analysis, considering that high voltage losses are 1%, intermediate voltage losses 3% and low voltage losses 5%. Organisations such as CEFIC, CEPI, COGEN Europe and IFIEC have expressed their joint statement and proposing the following amendments depending on the connection parameters of the combined heat and power plant (see table 4.2). 38

39 Recommended amendments to reference values considering connection method of combined heat and power plants to the power network made by CEFIC, CEPI, COGEN Europe and IFIEC Table 4.2 Connection voltage level Power consumption inside the network saves network losses Power consumption outside the network saves network losses High voltage (>200 KV) 2.5% 0% Intermediate voltage 6.4% 2.5% Low voltage ( < 400 V) 12.0% 6.4% Note: Organisations such as CEFIC, CEPI, COGEN Europe and IFIEC have expressed their joint statement and are of the opinion that reference values determined by the consultants of the Commission to power production with equipment operating on gas are too high and they recommend that the consultants of the commission would review these. A more fair reference value would remain (for net production) within the range of 49%-51%. For gross production 2.5% higher than the latter. Note: Organisations such as CEFIC, CEPI, COGEN Europe and IFIEC have expressed their joint statement and are of the opinion that reference values determined by the consultants of the Commission to power production are too high and draw attention to the mistake made that reference value for steam production is higher than for district water production. A more fair reference value would be 85%. With reference values presented in Table 3.3, all combined heat and power plants operating based on internal combustion engines are efficient when they are working in cogeneration mode. Calculated primary energy savings would remain within the range of 20-28%. When using biogas or landfill gas calculated primary energy savings would remain in the range of ~53%. 39

40 4.2 Iru power station Iru power station energy block operating on back-pressure turbine qualifies as efficient. Calculated primary energy savings values depending on the operation mode are presented in table 4.2 Calculated modes and calculated values of primary energy savings in Iru power station energy block No 2 Table 4.2 Gross power output Overall efficiency (to gross output) Calculated primary energy savings Net power output Heat input MW MW MW % % Iru power station energy block operating on extraction steam turbine qualifies as efficient. Calculated primary energy savings values depending on the operation mode are presented in table 4.3 Calculated modes and calculated values of primary energy savings in Iru power station energy block No 2 Table 4.3 Gross power output Overall efficiency (to gross output) Calculated primary energy savings Net power output Heat input MW MW MW % % Qualification limit of efficient cogeneration for energy block No 1 would be if the power production reference value was 48-49% or higher. 40