Report on the development of cogeneration

IEC TR 63388:2021 introduces the widely used technical scheme of cogeneration (also known as combined heat and power (CHP)), and gives the corresponding cases. The technical schemes of cogeneration covered in this technical report can be divided into two categories. One is cogeneration based on steam turbine, which is generally applied in thermal power plants; The other is cogeneration based on other prime movers, such as fuel cell, micro gas turbine, internal combustion engine, Stirling engine, ORC, etc.
This document gives some cases of cogeneration, mainly including:
• CHP based on extraction turbine;
• CHP based on back pressure turbine;
• Low-vacuum heating mode;
• LP cylinder steam bypassed heating mode;
• CHP based on steam turbine with synchro-self-shift clutches;
• Gas-steam combined cycle CHP;
• Micro gas turbine CHP;
• Stirling engine CHP;
• Fuel cell CHP; and
• ORC CHP.
The characteristics, components and technical requirements of these technical schemes are introduced in this document.
By collecting existing standards of CHP, this document also identifies the gaps of CHP standardization and put forward a roadmap for future CHP standards.
This document is prepared based on limited expert resources. Thus, some cogeneration cases could not be covered in this document, such as:
• Solar cogeneration; and
• Internal combustion engine cogeneration.

General Information

Status
Published
Publication Date
06-Dec-2021
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
07-Dec-2021
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IEC TR 63388
Edition 1.0 2021-12
TECHNICAL
REPORT
colour
inside
Report on the development of cogeneration
IEC TR 63388:2021-12(en)
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---------------------- Page: 2 ----------------------
IEC TR 63388
Edition 1.0 2021-12
TECHNICAL
REPORT
colour
inside
Report on the development of cogeneration
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.040 ISBN 978-2-8322-1058-7

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TR 63388:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Background ..................................................................................................................... 6

1.1 Task following SMB decision ................................................................................... 6

1.2 Scope ..................................................................................................................... 7

1.3 Purpose .................................................................................................................. 8

2 Terms, definitions and abbreviated terms ......................................................................... 8

2.1 Terms and definitions .............................................................................................. 8

2.2 Abbreviated terms ................................................................................................. 10

3 Overview of CHP ........................................................................................................... 10

3.1 What is CHP? ....................................................................................................... 10

3.2 Benefits of CHP .................................................................................................... 12

3.3 Efficiency of CHP system ...................................................................................... 13

4 Market situation of cogeneration .................................................................................... 14

4.1 Global situation ..................................................................................................... 14

4.2 European situation ................................................................................................ 14

4.3 American situation ................................................................................................ 15

4.4 Asian situation ...................................................................................................... 15

4.5 Summary .............................................................................................................. 17

5 CHP based on steam turbine ......................................................................................... 17

5.1 General introduction ............................................................................................. 17

5.2 Technical characteristics ....................................................................................... 18

5.2.1 CHP based on extraction turbine ................................................................... 18

5.2.2 CHP based on back pressure turbine ............................................................. 18

5.2.3 Low-vacuum heating mode ............................................................................ 19

5.2.4 LP cylinder steam bypassed heating mode .................................................... 20

5.2.5 CHP based on steam turbine with synchro-self-shift clutch ............................ 21

5.2.6 Special case: gas-steam combined cycle CHP ............................................... 22

5.3 Components ......................................................................................................... 23

5.4 Requirements ....................................................................................................... 24

5.5 Summary .............................................................................................................. 26

6 CHP based on other processes ..................................................................................... 26

6.1 General ................................................................................................................. 26

6.2 Technical characteristics ....................................................................................... 27

6.2.1 Gas turbine CHP ........................................................................................... 27

6.2.2 Stirling engine CHP ....................................................................................... 28

6.2.3 Fuel cell CHP ................................................................................................ 29

6.2.4 ORC CHP ...................................................................................................... 30

6.3 Components ......................................................................................................... 31

6.4 Requirements ....................................................................................................... 32

6.5 Summary .............................................................................................................. 33

7 Standardization demand of CHP .................................................................................... 33

7.1 Necessity to develop CHP technical standards...................................................... 33

7.2 Current status of ISO/IEC standards related to CHP ............................................. 34

7.2.1 General ......................................................................................................... 34

7.2.2 CHP system level .......................................................................................... 35

7.2.3 CHP communication level .............................................................................. 35

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IEC TR 63388:2021 © IEC 2021 – 3 –

7.2.4 CHP component level .................................................................................... 35

7.3 Summary .............................................................................................................. 40

8 CHP standardization roadmap ....................................................................................... 40

8.1 Envisaged CHP standard architecture ................................................................... 40

8.2 Description of the standard architecture ................................................................ 41

8.3 Developing the path of future standards ................................................................ 42

8.3.1 Develop path– Start from system to component level ..................................... 42

8.3.2 Work of joint working group ........................................................................... 43

8.4 Developing committee recommendations .............................................................. 43

8.5 Summary .............................................................................................................. 43

Figure 1 –CHP based on steam turbine ................................................................................. 11

Figure 2 – CHP based on combustion turbine or reciprocating engine ................................... 11

Figure 3 – Example of energy efficiency for different generating systems .............................. 12

Figure 4 – Proportion of different heating modes in urban areas of northern China ............... 16

Figure 5 – Cogeneration status in Japan by fuel types .......................................................... 17

Figure 6 – Heating system based on extraction steam turbine ............................................... 18

Figure 7 – Back pressure turbine heating system .................................................................. 19

Figure 8 – Typical diagram of a low-vacuum heating system ................................................. 20

Figure 9 –Schematic of LP cylinder steam bypass heating technology .................................. 21

Figure 10 – Heating turbine with synchro-self-shift clutch ...................................................... 22

Figure 11 – Schematic diagram of combined cycle unit cogeneration .................................... 23

Figure 12 – Typical work flow of CHP system based on steam turbine .................................. 23

Figure 13 – Energy efficiency comparison between small-scale CHP system and

traditional energy services .................................................................................................... 27

Figure 14 – CHP system based on micro gas turbine ............................................................ 28

Figure 15 –CHP system based on STIG ................................................................................ 28

Figure 16 – Typical Stirling engine CHP unit process ............................................................ 29

Figure 17 – Fuel cell CHP system ......................................................................................... 30

Figure 18 – ORC CHP system ............................................................................................... 31

Figure 19 – Link between CHP system and user demands .................................................... 34

Table 1 – Installed capacity of cogeneration units in Japan as of March 2020 ....................... 16

Table 2 – Status of CHP standards ....................................................................................... 36

Table 3 – CHP standard architecture .................................................................................... 41

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– 4 – IEC TR 63388:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
REPORT ON THE DEVELOPMENT OF COGENERATION
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

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IEC TR 63388 has been prepared by IEC technical committee 5: Steam turbines. It is a

Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
5/243/DTR 5/244/RVDTR

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this Technical Report is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement,

available at www.iec.ch/members_experts/refdocs. The main document types developed by

IEC are described in greater detail at www.iec.ch/standardsdev/publications.
---------------------- Page: 6 ----------------------
IEC TR 63388:2021 © IEC 2021 – 5 –

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under webstore.iec.ch in the data related to the

specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it

contains colours which are considered to be useful for the correct understanding of its

contents. Users should therefore print this document using a colour printer.
---------------------- Page: 7 ----------------------
– 6 – IEC TR 63388:2021 © IEC 2021
REPORT ON THE DEVELOPMENT OF COGENERATION
1 Background
1.1 Task following SMB decision
Following the Standards Management Board (SMB) decision 141/10, IEC Technical

Committee 5 (Steam Turbine) was tasked to lead a joint working group with related IEC and

ISO committees to explore potential standardization opportunities.
SMB decision 141/10reads as follows:

SMB decision 141/10 – SMB AhG 30: Co-generation – IEC involvement in joint work with

ISO

The SMB, further to having taken decisions confirming IEC's commitment to providing

support to the areas of cogeneration technology within its area of competence in particular

aspects related to electrical power generation, decided to instruct IEC TC 5 to be the

primary point of contact, to follow this activity in coordination with TC 45 and TC 105.

The SMB requests AhG 30 to submit a final report and recommendations on future work

and any future activities by end July 2011, and decided to disband the SMB AhG 30 after

submission of the report.

Based on the AhG recommendations, SMB will then communicate an IEC perspective on

this matter to ISO.

With the above SMB decision, IEC Technical Committee 5 established Joint Working Group

16 (Cogeneration Combined Heat and Power (CHP)) in 2012-09.

After IEC/TC5/JWG16 was established, working steps were proposed (see 5/168/AC) as

follows:
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IEC TR 63388:2021 © IEC 2021 – 7 –
No. Working step Remarks

1 Complete an overview on standards related to CHP Also include standards if they only partly cover

technology. CHP aspects

2 Clarification of status and application experience of Efficiency of CHP solutions is in focus for all

Manual CWA 45547 applications. The Manual CWA 45547 from 2004
could be a basis for an IEC standardization project.
There might be valuable feedback available from
application of the Manual.
3 Screening of world-wide applied alternative
methods for determination of CHP efficiency

4 Clarification of the need for standards dealing with Consider the different needs for the residential,

aspects different to efficiency such as safety, commercial and industrial needs including the

performance and installation. A differentiation different power sizes. EN 50465:2008 GAS

between residential / commercial mass products APPLIANCES – COMBINED HEAT AND POWER

and power plants should be considered. It should APPLIANCE OF NOMINAL HEAT INPUT

be identified where the current standardisation INFERIOR OR EQUAL TO 70 KW? IEC62282 Fuel

activities are going on in ISO or IEC and where the Cell Technologies Germany: FW308 July 2011

need for new coordination between IEC / ISO TCs
Status per 03-2012: The common aspects of safety
is suggested.
related control are already covered by other IEC
and ISO standards on Functional Safety. No
additional aspects for standardization with respect
to CHP identified. The common aspects of
application of gas and oil valves are covered by
other IEC and ISO standards. No additional
aspects for standardization with respect to CHP
identified.

5 Clarification if there is any other product/solution Possible aspects are also grid parallel operation of

specific standardization need in the area of CHP the CHP.

6 Update necessary liaisons with other TCs within IEC TC45 Nuclear instrumentation? IEC TC105

IEC or ISO Fuel cell technologies? ISO TC192 Gas Turbines?
ISO TC208 Thermal turbines for industrial
application (steam turbines, gas expansion
turbines)? Other TCs?

7 Prepare Proposal of standardization Work Item Proposal might include the target to align the

(PWI) for voting in TC5 and relevant other TCs context of the new IEC standard in a way that it

later – as an EN IEC standard – can be
harmonized with the EC Directive 2004/08
(Combined Heat and Power (CHP) Directive).

8 Clarification of which other IEC or ISO standards Chapters on CHP efficiency in other standards for

have to be adapted, when new IEC standard in individual applications should be replaced by a

CHP efficiency becomes valid. Preparation of reference on the new IEC standard.
requests to other TCs for adaptation/update of
In C-type standards describing the efficiency of a
other standards.
certain technology relevant to CHP a reference on
the new IEC standard on CHP efficiency should be
included.
9 Clarification with CEN/CENELEC on withdrawal of
Manual CWA 45547

This technical report is intended to address the above items 1, 3, 4, 5, 7, and 8.

Other items will be addressed depending on the outcome of this report.
1.2 Scope

This document, which is a technical report, introduces the widely used technical scheme of

cogeneration (also known as combined heat and power (CHP)), and gives the corresponding

cases. The technical schemes of cogeneration covered in this technical report can be divided

into two categories. One is cogeneration based on steam turbine,which is generally applied

in thermal power plants; The other is cogeneration based on other prime movers, such as fuel

cell, micro gas turbine, internal combustion engine, Stirling engine, ORC, etc.
---------------------- Page: 9 ----------------------
– 8 – IEC TR 63388:2021 © IEC 2021
This document gives some cases of cogeneration, mainly including:
• CHP based on extraction turbine;
• CHP based on back pressure turbine;
• Low-vacuum heating mode;
• LP cylinder steam bypassed heating mode;
• CHP based on steam turbine with synchro-self-shift clutches;
• Gas-steam combined cycle CHP;
• Micro gas turbine CHP;
• Stirling engine CHP;
• Fuel cell CHP; and
• ORC CHP.

The characteristics, components and technical requirements of these technical schemes are

introduced in this document.

By collecting existing standards of CHP, this document also identifies the gaps of CHP

standardization and put forward a roadmap for future CHP standards.

This document is prepared based on limited expert resources. Thus, some cogeneration

cases could not be covered in this document, such as:
• Solar cogeneration; and
• Internal combustion engine cogeneration.
1.3 Purpose

Based on the decision of the SMB, the purpose of this document is to briefly introduce the

technical characteristics and requirements of different cogeneration schemes, analyse the

standard status and standard gap, put forward roadmap and suggestions for the development

of cogeneration standards in the future.
2 Terms, definitions and abbreviated terms
2.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
2.1.1
combined heat and power (CHP)

energy efficient technology that generates electricity and captures the heat that would

otherwise be wasted to provide useful thermal energy - such as steam or hot water - that can

be used for space heating, cooling, domestic hot water and industrial processes
[SOURCE: "Combined Heat and Power (CHP) Partnership" from EPA]
---------------------- Page: 10 ----------------------
IEC TR 63388:2021 © IEC 2021 – 9 –
2.1.2
cogeneration

simultaneous production in series of two forms of useful energy such as electrical energy first

and then useful thermal energy from a single fuel source
Note 1 to entry: In this document, cogeneration refers to CHP.
2.1.3
primary energy
energy that has not been subjected to any conversion or transformation process

Note 1 to entry: Primary energy includes non-renewable energy and renewable energy. If both are taken into

account it can be called total primary energy.
[SOURCE: ISO 52000-1:2017, 3.4.29]
2.1.4
heating

process of increasing the temperature of medium by the means of the transportation fluid from

the heating plant over a heat exchanger
2.1.5
heating season

part of the year during which heating is needed to keep the indoor temperature within

specified levels, at least part of the day and in part of the rooms

Note 1 to entry: The length of the heating season differs substantially from country to country and from region to

region.
Note 2 to entry: This term is especially for district heating period of a year.
[SOURCE: ISO 17772-1:2017, 3.15]
2.1.6
heating system

system where the working fluid is heated by the transportation fluid coming from the CHP

plant for any purposes, such as process, building heating, hot water, etc.
2.1.7
district heating

heating systems that distribute steam or hot water through pipes to a number of buildings

across a district

Note 1 to entry: Heat is provided from a variety of sources, including geothermal, combined heat and power

plants, waste heat from industry, or purpose-built heating plants.
[SOURCE: ISO 14452:2012, 2.23]
2.1.8
industrial heat supply

heat supply where the working fluid takes part with the industrial process or the heat of the

working fluid is transferred to the industrial process over a heat exchanger

Note 1 to entry: In the former case, no residual heat is returned to the CHP system. In the latter case, the residual

heat may be returned to the CHP system.
2.1.9
extraction turbine

turbine in which some of the steam is extracted part-way through the expansion using

pressure control means for the extracted steam
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– 10 – IEC TR 63388:2021 © IEC 2021

Note 1 to entry: The control means are located inside the turbine flow path or in a cross-over line between turbine

sections. The target is to provide process steam.

Note 2 to entry: Control of extraction pressure can be internal, external or combined internal/external. For

externally controlled extractions the control means are located in the extraction steam line. The aim is to control

steam parameters downstream of the control means, i.e. on the process side. In this case the turbine is not called

an extraction turbine.

Note 3 to entry: If no means for controlling the pressure are used, this steam line is called a bleed, and the

turbine is not called an extraction turbine.
[SOURCE: IEC 60045-1:2020 © IEC 2020]
2.1.10
back pressure turbine

turbine whose exhaust heat typically will be used to provide process heat (e.g. industrial

process, district heating, post combustion carbon capture system and desalination), and

whose exhaust is not directly connected to a condenser

Note 1 to entry: The exhaust pressure will normally be above atmospheric pressure.

[SOURCE: IEC 60045-1:2020© IEC 2020]
2.2 Abbreviated terms
CHP combined heat and power
SMB standardization management board
ORC organic Rankine cycle
HP high pressure
IP intermediate pressure
LP low pressure
HRSG heat recovery steam generator
3 Overview of CHP
3.1 What is CHP?

CHP is an energy efficient technology that generates electricity and captures the heat that

would otherwise be wasted to provide useful thermal energy - such as steam or hot water -

that can be used for space heating, cooling, domestic hot water and industrial processes. A

CHP system can be located at an individual facility or building, or be a district energy or utility

resource. CHP is typically located at facilities where there is a need for both electricity and

thermal energy. (Source: Combined Heat and Power Partnership, EPA)

Nearly two-thirds of the energy produced (or obtained) by conventional electricity generation

is wasted in the form of heat discharged to the atmosphere. Additional energy is wasted

during the distribution of electricity to end users. In contrast, in a combined heat and power

process, the vaporizing heat input happens only once and the sensible heat (condensing heat)

is used in the heating process. The total fuel efficiency of this combined process is then much

better than the one for separate processes. By capturing and using heat that would otherwise

be wasted, and by avoiding distribution losses, CHP can achieve efficiencies even over 80 %.

CHP applications cover a wide range of technology. Smaller heat demands are met by fuel

cells, internal combustion engines, Stirling engines and so on. For higher demands solutions

gas turbines, back pressure turbines and stea
...

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