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
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REFERENCE VALUES OF EFFICIENT COGENERATION AND POTENTIAL OF EFFICIENT COGENERATION IN ESTONIA
REPORT
ABBREVIATED VERSION
Customer:Ministry of Economic Affairs and Communications
Performed by: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
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Content
Introduction
1. Directive 2004/8/EC of the European Parliament and the Council
1.1. Definitions
1.2. Cogeneration technologies
1.3. Calculation of electricity from cogeneration
1.4. Methodology for determining the efficiency of the cogeneration process
2. Combined heat and power plants in Estonia as of December 2005
2.1 Combined heat and power plants using internal combustion engines
2.2 Combined heat and power plants using steam power units
2.2.1 The Iru power plant
2.2.2 Kohtla-Järve power station
2.2.3 Thermal power station of Kiviõli Oil Shale Processing and Chemicals Plant
2.2.5 Sillamäe thermal power station using steam turbine power units
2.2.6 VKG Energia (former Fortum AS) thermal power station
2.2.7 Ahtme power station
2.2.9 Sangla Turvas Ltd. power station
2.2.10 Tootsi Turvas Ltd. power station
2.2.11 Narva Power Plants Baltic Power Station
3. Reference values of high-efficiency cogeneration
4. About qualifying Estonian cogeneration plants as “high-efficiency cogeneration”
4.1 Combined heat and power plants based on internal combustion engines
4.2 The Iru power station
4.3 Narva Power Plants Baltic Power Station
4.4 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
5. Heat load potential and access to energy sources to establish efficient cogeneration of heat and power
6. Barriers that prevent establishing efficient cogeneration
Bibliography
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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
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.
2.1.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.
3.1. Heat load potential and access to energy sources suitable for establishing efficient cogeneration.
3.2. 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.
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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.
1.1. 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;
(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.
1.2. 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.
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:
ECHP = HCHP C
where:
ECHPis the amount of electricity from cogeneration.
Cis the power to heat ratio.
HCHPis 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.
Type of unit / Power to heat default ratio, CCombined cycle gas turbine with heat recovery / 0.95
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.
1.4. 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:
-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 high-efficiency 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:
where:
PESis primary energy savings
CHPHis 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
REFfHis the efficiency reference value for separate heat production
CHPEis 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
REFEis the efficiency reference value for separate electricity production
(c)Calculations of energy savings using alternative calculation according to Article 12(2)
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:
CHPH = H
CHPE = E
where:
Hshall 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
Eshall 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:
- 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 of age shall be fixed on the reference values of units of 10 years of age;
- the efficiency reference values for separate electricity production and heat production shall reflect the climate difference between Member States.
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2. Combined heat and power plants in Estonia as of December 2005
2.1 Combined heat and power plants using internal combustion engines
Tables 2.1 - 2.9 contain general data on combined heat and power plants using internal combustion engines in Estonia as of December 2005.
AS Kunda Nordic TsementTable 2.1
Name of the combined heat and power plant / AS Kunda Nordic TsementYear of construction / 1998-1999
Maximum installed power and heat capacity, MWel/MWth / 3,1/3,3
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 ~39-40%
AS Eraküte, Põlva divisionTable 2.2
Name of the combined heat and power plant / AS Eraküte, Põlva divisionYear of construction / 1999
Maximum installed power and heat capacity, MWel/MWth / 0,922/1,253
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 ~39-40%
AS Grüne FeeTable 2.3
Name of the combined heat and power plant / AS Grüne FeeYear of construction / 1997-2005
Maximum installed power and heat capacity, MWel/MWth / Installed 4 cogeneration units, 1/1.2 each
(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%
Narva Vesi Ltd.Table 2.4
Name of the combined heat and power plant / Narva Vesi Ltd.Year of construction / 1999
Maximum installed power and heat capacity, MWel/MWth / 0,5/0,7
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%
AS Kristiine KaubanduskeskusTable 2.5
Name of the combined heat and power plant / AS Kristiine KaubanduskeskusYear of construction / 2000
Maximum installed power and heat capacity, MWel/MWth / 0,5/0,7
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%
AS TertsTable 2.6
Name of the combined heat and power plant / AS TertsYear of construction / 2002-2003
Maximum installed power and heat capacity, MWel/MWth / Installed 2 cogeneration units, 0.84 1 each
(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%
Sillamäe thermal power station (using internal combustion engine)Table 2.7
Name of the combined heat and power plant / Sillamäe thermal power station (using internal combustion engine)Year of construction / 2004
Maximum installed power and heat capacity, MWel/MWth / 5,95/6,7
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%
ELME AS (BLRT Grupp AS )Table 2.8
Name of the combined heat and power plant / ELME AS (BLRT Grupp AS )Year of construction / 2002 -2003
Maximum installed power and heat capacity, MWel/MWth / Installed 4 cogeneration units, 1.2/1.4 each
(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 stationTable 2.9
Name of the combined heat and power plant / AS Tallinna VesiYear of construction / 2002 -2003
Maximum installed power and heat capacity, MWel/MWth / 0,65/0,86 *) value needs to be specified
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.
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