View source for Energy system

{{Short description|All components related to production, conversion, delivery, and use of energy}}

[[File: Generic energy system supplying fuels and electricity.svg|thumb|300px|Physical components of a generic energy system supplying fuels and electricity (but not [[Physics:District heating|district heat]]) to end-users]]

An '''energy system''' is a [[Philosophy:System|system]] primarily designed to supply energy-services to [[End user|end-users]].<ref name="groscurth-etal-1995"/>{{rp|941}} The intent behind energy systems is to minimise energy losses to a negligible level, as well as to ensure the efficient use of energy.<ref>{{cite book |last1=O’Malley |first1=Eoin |last2=Sorrell |first2=Steve |title=The Economics of Energy Efficiency |date=2004 |publisher=Edward Elgar Publishing |isbn=978-1-84064-889-8 |url=https://www.e-elgar.com/shop/gbp/the-economics-of-energy-efficiency-9781840648898.html |access-date=20 June 2022}}</ref> The [[Earth:IPCC Fifth Assessment Report|IPCC Fifth Assessment Report]] defines an energy system as "all components related to the production, conversion, delivery, and use of energy".<ref name="allwood-etal-2014"/>{{rp|1261}}

The first two definitions allow for demand-side measures, including [[Earth:Daylighting (architecture)|daylighting]], retrofitted [[Physics:Building insulation|building insulation]], and [[Engineering:Passive solar building design|passive solar building design]], as well as socio-economic factors, such as aspects of [[Finance:Energy demand management|energy demand management]] and remote work, while the third does not. Neither does the third account for the [[Finance:Informal sector|informal economy]] in traditional [[Biology:Biomass|biomass]] that is significant in many [[Finance:Developing country|developing countries]].<ref name="van-ruijven-etal-2008"/>

The analysis of energy systems thus spans the disciplines of [[Engineering:Engineering|engineering]] and [[Finance:Economics|economics]].<ref name="hoffman-and-wood-1976"/>{{rp|1}} Merging ideas from both areas to form a coherent description, particularly where macroeconomic dynamics are involved, is challenging.<ref name="boehringer-and-rutherford-2008"/><ref name="herbst-etal-2012"/>

The concept of an energy system is evolving as new regulations, technologies, and practices enter into service – for example, [[Earth:Emissions trading|emissions trading]], the development of [[Engineering:Smart grid|smart grid]]s, and the greater use of [[Finance:Energy demand management|energy demand management]], respectively.

== Treatment ==

<!-- {(see also|Energy industry|Energy modeling|Open energy system models}} -->

From a structural perspective, an energy system is like any [[Philosophy:System|system]] and is made up of a set of interacting component parts, located within an environment.<ref name="merriam-webster-system"/> These components derive from ideas found in [[Engineering:Engineering|engineering]] and [[Finance:Economics|economics]]. Taking a process view, an energy system "consists of an integrated set of technical and economic activities operating within a complex societal framework".<ref name="hoffman-and-wood-1976"/>{{rp|423}} The identification of the components and behaviors of an energy system depends on the circumstances, the purpose of the analysis, and the questions under investigation. The concept of an energy system is therefore an abstraction which usually precedes some form of computer-based investigation, such as the construction and use of a suitable [[Earth:Energy modeling|energy model]].<ref name="anandarajah-etal-2009"/>

Viewed in engineering terms, an energy system lends itself to representation as a flow network: the [[Glossary of graph theory#vertex|vertices]] map to engineering components like [[Chemistry:Power station|power station]]s and [[Physics:Pipeline transport|pipelines]] and the [[Glossary of graph theory#edge|edges]] map to the interfaces between these components. This approach allows collections of similar or adjacent components to be aggregated and treated as one to simplify the model. Once described thus, flow network algorithms, such as [[Minimum-cost flow problem|minimum cost flow]], may be applied.<ref name="quelhas-etal-2007"/> The components themselves can be treated as simple dynamical systems in their own right.<ref name="groscurth-etal-1995"/>

===Economic modeling===
Conversely, relatively pure economic modeling may adopt a sectoral approach with only limited engineering detail present. The sector and sub-sector categories published by the [[Organization:International Energy Agency|International Energy Agency]] are often used as a basis for this analysis. A 2009 study of the UK residential energy sector contrasts the use of the technology-rich Markal model with several UK sectoral housing stock models.<ref name="kannan-and-strachan-2007"/>

====Data====
International [[Statistical study of energy data|energy statistics]] are typically broken down by carrier, sector and sub-sector, and country.<ref name="ires-2016"/> [[Physics:Energy carrier|Energy carrier]]s ({{abbr|aka|also known as}} energy products) are further classified as [[Physics:Primary energy|primary energy]] and [[Physics:Primary energy#Conversion to energy carriers (or secondary energy)|secondary]] (or intermediate) energy and sometimes final (or end-use) energy. Published energy datasets are normally adjusted so that they are internally consistent, meaning that all energy stocks and flows must [[Engineering:Energy balance (energy economics)|balance]]. The IEA regularly publishes energy statistics and energy balances with varying levels of detail and cost and also offers mid-term projections based on this data.<ref name="iea-2016a"/><ref name="iea-2016b"/> The notion of an energy carrier, as used in [[Physics:Energy economics|energy economics]], is distinct and different from the definition of [[Physics:Energy|energy]] used in physics.

=== Scopes ===
Energy systems can range in scope, from local, municipal, national, and regional, to global, depending on issues under investigation. Researchers may or may not include demand side measures within their definition of an energy system. The Intergovernmental Panel on Climate Change ([[Organization:Intergovernmental Panel on Climate Change|IPCC]]) does so, for instance, but covers these measures in separate chapters on transport, buildings, industry, and agriculture.{{efn|The IPCC chapter on agriculture is titled: Agriculture, forestry, and other land use (AFOLU).}}<ref name="allwood-etal-2014"/>{{rp|1261}}<ref name="bruckner-etal-2014"/>{{rp|516}}

Household consumption and investment decisions may also be included within the ambit of an energy system. Such considerations are not common because consumer behavior is difficult to characterize, but the trend is to include human factors in models. Household decision-taking may be represented using techniques from [[Bounded rationality|bounded rationality]] and [[Agent-based model|agent-based behavior]].<ref name="wittmann-and-bruckner-2009"/> The American Association for the Advancement of Science (AAAS) specifically advocates that "more attention should be paid to incorporating behavioral considerations other than price- and income-driven behavior into economic models [of the energy system]".<ref name="aaas-2011"/>{{rp|6}}

== Energy-services ==


The concept of an energy-service is central, particularly when defining the purpose of an energy system:

{{blockquote|It is important to realize that the use of energy is no end in itself but is always directed to satisfy human needs and desires. Energy services are the ends for which the energy system provides the means.<ref name="groscurth-etal-1995"/>{{rp|941}}}}

Energy-services can be defined as amenities that are either furnished through energy consumption or could have been thus supplied.<ref name="morrison-etal-2005"/>{{rp|2}} More explicitly:

{{blockquote|Demand should, where possible, be defined in terms of energy-service provision, as characterized by an appropriate intensity{{efn|The term ''intensity'' refers to quantities which do not scale with component size. See [[Physics:Intensive and extensive properties|intensive and extensive properties]].}} – for example, air [[Physics:Temperature|temperature]] in the case of space-heating or [[Lux|lux]] levels for [[Physics:Illuminance|illuminance]]. This approach facilitates a much greater set of potential responses to the question of supply, including the use of energetically-passive techniques – for instance, retrofitted [[Physics:Building insulation|insulation]] and [[Earth:Daylighting (architecture)|daylighting]].<ref name="bruckner-etal-2003"/>{{rp|156}}}}

A consideration of energy-services per capita and how such services contribute to human welfare and individual quality of life is paramount to the debate on [[Earth:Sustainable energy|sustainable energy]]. People living in poor regions with low levels of energy-services consumption would clearly benefit from greater consumption, but the same is not generally true for those with high levels of consumption.<ref name="haas-etal-2008"/>

The notion of energy-services has given rise to [[Physics:Energy service company|energy-service companies]] (ESCo) who contract to provide energy-services to a client for an extended period. The ESCo is then free to choose the best means to do so, including investments in the thermal performance and [[Biology:HVAC|HVAC]] equipment of the buildings in question.<ref name="duplessis-etal-2012"/>

== International standards ==

ISO{{nnbsp}}[[Physics:Energy carrier|13600]], ISO{{nnbsp}}13601, and ISO{{nnbsp}}13602 form a set of [[International standard|international standard]]s covering technical energy systems (TES).<ref name="iso-13600-1997-main"/><ref name="iso-13600-1997-corrigendum-1"/><ref name="iso-13601-1998"/><ref name="iso-13602-2002"/> Although withdrawn prior to 2016, these documents provide useful definitions and a framework for formalizing such systems. The standards depict an energy system broken down into supply and demand sectors, linked by the flow of tradable energy commodities (or energywares). Each sector has a set of inputs and outputs, some intentional and some harmful byproducts. Sectors may be further divided into subsectors, each fulfilling a dedicated purpose. The demand sector is ultimately present to supply energyware-based services to consumers (see energy-services).

== Energy system redesign and transformation ==
Energy system design includes the redesigning of energy systems to ensure [[Earth:Sustainability|sustainability]] of the system and its dependents and for meeting requirements of the Paris Agreement for [[Earth:Climate change mitigation|climate change mitigation]]. Researchers are designing energy systems models and transformational pathways for [[Earth:Renewable energy transition|renewable energy transition]]s towards [[100% renewable energy|100% renewable energy]], often in the form of peer-reviewed text documents created once by small teams of scientists and published in a [[Scientific journal|journal]].

Considerations include the system's [[Engineering:Variable renewable energy#Solutions for their integration|intermittency management]], [[Earth:Air pollution|air pollution]], various risks (such as for human safety, environmental risks, cost risks and feasibility risks), stability for prevention of [[Engineering:Power outage|power outage]]s (including grid dependence or grid-design), resource requirements (including water and rare minerals and recyclability of components), technology/[[Research and development|development]] requirements, costs, [[Feasibility study|feasibility]], other affected systems (such as land-use that affects [[Earth:Food system|food system]]s), carbon emissions, available energy quantity and transition-concerning factors (including costs, labor-related issues and speed of deployment).<ref>{{cite journal |last1=Bogdanov |first1=Dmitrii |last2=Gulagi |first2=Ashish |last3=Fasihi |first3=Mahdi |last4=Breyer |first4=Christian |title=Full energy sector transition towards 100% renewable energy supply: Integrating power, heat, transport and industry sectors including desalination |journal=Applied Energy |date=1 February 2021 |volume=283 |pages=116273 |doi=10.1016/j.apenergy.2020.116273 |language=en |issn=0306-2619|doi-access=free }}</ref><ref>{{cite news |last1=Clifford |first1=Catherine |title=U.S. can get to 100% clean energy with wind, water, solar and zero nuclear, Stanford professor says |url=https://www.cnbc.com/2021/12/21/us-can-get-to-100percent-clean-energy-without-nuclear-power-stanford-professor-says.html |access-date=16 January 2022 |work=CNBC |date=21 December 2021 |language=en}}</ref><ref>{{cite journal |last1=Fonseca |first1=Juan D. |last2=Commenge |first2=Jean-Marc |last3=Camargo |first3=Mauricio |last4=Falk |first4=Laurent |last5=Gil |first5=Iván D. |title=Sustainability analysis for the design of distributed energy systems: A multi-objective optimization approach |journal=Applied Energy |date=15 May 2021 |volume=290 |pages=116746 |doi=10.1016/j.apenergy.2021.116746 |s2cid=233552874 |language=en |issn=0306-2619|url=https://hal.science/hal-03161645 }}</ref><ref>{{cite journal |last1=Jacobson |first1=Mark Z. |last2=von Krauland |first2=Anna-Katharina |last3=Coughlin |first3=Stephen J. |last4=Palmer |first4=Frances C. |last5=Smith |first5=Miles M. |title=Zero air pollution and zero carbon from all energy at low cost and without blackouts in variable weather throughout the U.S. with 100% wind-water-solar and storage |journal=Renewable Energy |date=1 January 2022 |volume=184 |pages=430–442 |doi=10.1016/j.renene.2021.11.067 |s2cid=244820608 |language=en |issn=0960-1481|url=https://www.sciencedirect.com/science/article/abs/pii/S0960148121016499|url-access=subscription}}</ref><ref>{{cite web |title=Collection of 47 peer-reviewed research papers about 100% renewable energy systems |url=https://web.stanford.edu/group/efmh/jacobson/Articles/I/CombiningRenew/100PercentPaperAbstracts.pdf |access-date=25 January 2022}}</ref>

Energy system design can also consider energy consumption, such as in terms of absolute energy demand,<ref>{{cite journal |last1=Klemm |first1=Christian |last2=Wiese |first2=Frauke |title=Indicators for the optimization of sustainable urban energy systems based on energy system modeling |journal=Energy, Sustainability and Society |date=6 January 2022 |volume=12 |issue=1 |pages=3 |doi=10.1186/s13705-021-00323-3 |s2cid=256233632 |issn=2192-0567|doi-access=free }}</ref> waste and consumption reduction (e.g. via reduced energy-use, increased efficiency and flexible timing), process efficiency enhancement and waste heat recovery.<ref>{{cite journal |last1=Fan |first1=Yee Van |last2=Pintarič |first2=Zorka Novak |last3=Klemeš |first3=Jiří Jaromír |title=Emerging Tools for Energy System Design Increasing Economic and Environmental Sustainability |journal=Energies |date=January 2020 |volume=13 |issue=16 |pages=4062 |doi=10.3390/en13164062 |language=en|doi-access=free }}</ref> A study noted significant potential for a type of energy systems modelling to "move beyond single disciplinary approaches towards a sophisticated integrated perspective".<ref>{{cite journal |last1=Keirstead |first1=James |last2=Jennings |first2=Mark |last3=Sivakumar |first3=Aruna |title=A review of urban energy system models: Approaches, challenges and opportunities |journal=Renewable and Sustainable Energy Reviews |date=1 August 2012 |volume=16 |issue=6 |pages=3847–3866 |doi=10.1016/j.rser.2012.02.047 |language=en |issn=1364-0321|hdl=10044/1/10206 |hdl-access=free }}</ref>

== See also ==

* [[Physics:Control volume|Control volume]] – a concept from mechanics and thermodynamics
* [[Physics:Electric power system|Electric power system]] – a network of electrical components used to generate, transfer, and use electric power
* [[Physics:Energy development|Energy development]] – the effort to provide societies with sufficient energy under the reduced social and environmental impact
* [[Earth:Energy modeling|Energy modeling]] – the process of building computer models of energy systems
* Energy industry – the supply-side of the energy sector
* [[Mathematical model]] – the representation of a system using mathematics and often solved using computers
* [[Object-oriented programming]] – a computer programming paradigm suited to the representation of energy systems as networks
* [[Network science]] – the study of complex networks
* [[Open energy system databases]] – database projects which collect, clean, and republish energy-related datasets 
* [[Earth:Open energy system models|Open energy system models]] – a review of energy system models that are also open source
* [[Sankey diagram]] – used to show energy flows through a system

== Notes ==

{{notelist}}

== References ==

{{reflist|30em|refs=

<ref name="aaas-2011">{{cite book
 | title = Beyond technology: strengthening energy policy through social science
 | date = 2011
 | publisher = American Academy of Arts and Sciences (AAAS)
 | location = Cambridge, MA, USA
 | url = http://www.amacad.org/pdfs/alternativeenergy.pdf
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<ref name="allwood-etal-2014">
{{cite book
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 | first2 = Valentina | last2 = Bosetti
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 | chapter = Annex I: Glossary, acronyms and chemical symbols
 | publisher = {{wipe|Cambridge University Press}}
 | location = Cambridge, United Kingdom and New York, NY, USA
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 | chapter-url = https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-i.pdf
 | access-date = 2016-10-12 <!--
 | quote = An energy-service is the benefit received as a result of energy use.{{nbsp}}... The energy system comprises all components related to the production, conversion, delivery, and use of energy. (page 1261)
-->
}}</ref>

<ref name="anandarajah-etal-2009">
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 | first5 = Nick | last5 = Hughes
 | title = Pathways to a low carbon economy: Energy systems modelling — UKERC Energy 2050 Research Report 1 — UKERC/RR/ESM/2009/001
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}}</ref>

<ref name="boehringer-and-rutherford-2008">
{{cite journal
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 | last2 = Rutherford | first2 = Thomas F
 | title = Combining bottom-up and top-down
 | date = March 2008
 | journal = Energy Economics
 | volume = 30
 | issue = 2
 | pages = 574–596
 | doi = 10.1016/j.eneco.2007.03.004
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 | access-date = 2016-10-21
| citeseerx = 10.1.1.184.8384
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<ref name="bruckner-etal-2003">
{{cite journal
 | last1 = Bruckner | first1 = Thomas
 | last2 = Morrison | first2 = Robbie
 | last3 = Handley | first3 = Chris
 | last4 = Patterson | first4 = Murray
 | title = High-resolution modeling of energy-services supply systems using ''deeco'': overview and application to policy development
 | date = July 2003
 | journal = Annals of Operations Research
 | volume = 121
 | issue = 1–4
 | pages = 151–180
 | doi = 10.1023/A:1023359303704
 | s2cid = 14877200
 | url = http://www.wifa.uni-leipzig.de/fileadmin/user_upload/iirm-tm/energiemanagement/publikationen/reviewed_journals/2003_HighResolModelingEnergySystemsDeeco.pdf
 | access-date = 2016-10-14 <!--
 | quote = Demand should, where possible, be defined in terms of energy-service provision, as characterized by an appropriate intensity – for example, air temperature in the case of space-heating or lux levels for illuminance. This approach facilitates a much greater set of potential responses to the question of supply, including the use of energetically-passive techniques – for instance, retrofitted insulation and daylighting. (page 156)
-->
}}</ref>

<ref name="bruckner-etal-2014">
{{cite book
 | first1 = Thomas | last1 = Bruckner
 | first2 = Igor Alexeyevic | last2 = Bashmakov
 | first3 = Yacob | last3 = Mulugetta
 | display-authors = etal
 | editor = IPCC
 | year = 2014
 | title = Climate change 2014: mitigation of climate change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change
 | chapter = Chapter 7: Energy systems
 | publisher = {{wipe|Cambridge University Press}}
 | location = Cambridge, United Kingdom and New York, NY, USA
 | pages = 511–597
 | isbn = 978-1-107-65481-5
 | chapter-url = https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_chapter7.pdf
 | access-date = 2016-10-12
}}</ref>

<ref name="duplessis-etal-2012">
{{cite journal
 | last1 = Duplessis | first1 = Bruno
 | last2 = Adnot | first2 = Jérôme
 | last3 = Dupont | first3 = Maxime
 | last4 = Racapé | first4 = François
 | title = An empirical typology of energy services based on a well-developed market: France
 | date = June 2012
 | journal = Energy Policy
 | volume = 45
 | pages = 268–276
 | doi = 10.1016/j.enpol.2012.02.031
 | issn = 0301-4215
}}</ref>

<ref name="groscurth-etal-1995">
{{cite journal
 | last1 = Groscurth| first1 = Helmuth-M
 | last2 = Bruckner | first2 = Thomas
 | last3 = Kümmel | first3 = Reiner
 | title = Modeling of energy-services supply systems
 | date = September 1995
 | journal = Energy
 | volume = 20
 | issue = 9
 | pages = 941–958
 | doi = 10.1016/0360-5442(95)00067-Q
 | issn = 0360-5442
 | url = http://www.groscurth.de/uploads/media/NEMESS_energy_1995.pdf
 | access-date = 2016-10-14 <!--
 | quote = In energy economics, energy systems are usually defined as technical and economic systems meeting the energy demand. "However, the energy demand is not a fixed quantity but is subject to various influences, e.g., prices, regulations, and consumer preferences. Thus, the definition of energy systems should provide a much broader, socioeconomic view and refer to the technical and economic side of energy supply as well as the socioeconomic phenomena occurring in a society, which uses energy to enhance its standard of living; furthermore, the impact on the natural environment is important. ... It is important to realize that the use of energy is no end in itself but is always directed to satisfy human needs and desires. Energy services are the ends for which the energy system provides the means. (page 941)
-->
}}</ref>

<ref name="haas-etal-2008">{{cite journal
 | last1 = Haas
 | first1 = Reinhard
 | last2 = Nakicenovic
 | first2 = Nebojsa
 | last3 = Ajanovic
 | first3 = Amela
 | last4 = Faber
 | first4 = Thomas
 | last5 = Kranzl
 | first5 = Lukas
 | last6 = Müller
 | first6 = Andreas
 | last7 = Resch
 | first7 = Gustav
 | title = Towards sustainability of energy systems: a primer on how to apply the concept of energy services to identify necessary trends and policies
 | date = November 2008
 | journal = Transition Towards Sustainable Energy Systems
 | volume = 36
 | issue = 11
 | pages = 4012–4021
 | doi = 10.1016/j.enpol.2008.06.028
 | issn = 0301-4215
 | url = http://www.eeg.tuwien.ac.at/eeg.tuwien.ac.at_pages/publications/pdf/HAA_PAP_2008_1.pdf
 | access-date = 2016-10-22
 | archive-url = https://web.archive.org/web/20170705063737/http://eeg.tuwien.ac.at/eeg.tuwien.ac.at_pages/publications/pdf/HAA_PAP_2008_1.pdf
 | archive-date = 5 July 2017
 | url-status = dead
 }}</ref>

<ref name="herbst-etal-2012">
<!-- listed at: http://econpapers.repec.org/article/sesarsjes/2012-ii-2.htm -->
{{cite journal
 | first1 = Andrea | last1 = Herbst
 | first2 = Felipe | last2 = Toro
 | first3 = Felix | last3 = Reitze
 | first4 = Eberhard | last4 = Jochem
 | title = Introduction to energy systems modelling
 | date = 2012
 | journal = Swiss Journal of Economics and Statistics
 | volume = 148
 | number = 2
 | pages = 111–135
 | url = http://www.irees.de/irees-wAssets/docs/publications/journal-reviewed/Herbst-et-al-2012_Introduction-to-Energy-Systems-Modelling_SJES.pdf
 | access-date = 2016-11-04
| doi = 10.1007/BF03399363
 | s2cid = 13683816
 | doi-access = free
 }}</ref>

<ref name="hoffman-and-wood-1976">
{{cite journal
 | last1 = Hoffman | first1 = Kenneth C
 | last2 = Wood | first2 = David O
 | title = Energy system modeling and forecasting
 | date = 1 November 1976
 | journal = Annual Review of Energy
 | volume = 1
 | issue = 1
 | pages = 423–453
 | doi = 10.1146/annurev.eg.01.110176.002231| doi-access=free
 | hdl = 1721.1/27512
 | issn = 0362-1626
 | url = https://dspace.mit.edu/bitstream/handle/1721.1/27512/MIT-EL-75-013WP-03830861.pdf
 | access-date = 2016-10-07 <!--
 | quote = The energy system consists of an integrated set of technical and economic activities operating within a complex societal framework. Energy is a vital component in the economic and social well-being of a nation and must be considered explicitly in the formulation of regional, national, and international policy. As the importance of energy in policymaking has become apparent, research and analysis in the field of energy system modeling and forecasting has grown rapidly. The field has evolved from one almost exclusively the domain of planning groups in the major sectors of the energy industry and of government regulatory agencies to one in which many Federal and State agencies are active in the development and application of energy models and forecasts. Energy system models are now used extensively for regional, national and international forecasting and for policy formulation and analysis.
-->
}}</ref>

<ref name="iea-2016a">
{{cite book
 | title = Key world energy statistics
 | date = 2016
 | publisher = International Energy Agency (IEA)
 | location = Paris, France
 | url = https://www.iea.org/publications/freepublications/publication/KeyWorld2016.pdf
 | access-date = 2016-12-15
}}</ref>

<ref name="iea-2016b">
{{cite book
 | title = World Energy Outlook 2016 — Executive summary
 | date = 2016
 | publisher = OECD/IEA
 | location = Paris, France
 | url = https://www.iea.org/publications/freepublications/publication/WorldEnergyOutlook2016ExecutiveSummaryEnglish.pdf
 | access-date = 2016-11-30
}}</ref>

<ref name="ires-2016">
<!-- print ISBN: 978-92-1-161584-5 -->
<!-- PDF dated: 23 September 2016 -->
{{cite book | title = International Recommendations for Energy Statistics (IRES) — ST/ESA/STAT/SER.M/93 | date = 2016 | publisher = Statistics Division, Department of Economic and Social Affairs, United Nations | location = New York, NY, USA | isbn = 978-92-1-056520-2 | url=http://unstats.un.org/unsd/energy/ires/IRES_edited2.pdf }} Annotated as final edited version prior to typesetting. Also covers energy-related greenhouse gas emissions accounting.</ref>

<ref name="iso-13600-1997-main">
<!--
web: http://webstore.ansi.org
web: http://www.iso.org
-->
{{cite book
 | title = Technical energy systems: basic concepts — ISO 13600:1997 — First edition
 | date = 15 November 1997
 | publisher = International Standards Organization
 | location = Geneva, Switzerland
}} Status withdrawn.</ref>

<ref name="iso-13600-1997-corrigendum-1">
{{cite book
 | title = Technical energy systems: basic concepts — ISO 13600:1997 — Technical corrigendum 1
 | date = 1 May 1998
 | publisher = International Standards Organization
 | location = Geneva, Switzerland
}} Status withdrawn.</ref>

<ref name="iso-13601-1998">
{{cite book
 | title = Technical energy systems: : structure for analysis : energyware supply and demand sectors — ISO 13601:1998
 | date = 11 June 1998
 | publisher = International Standards Organization
 | location = Geneva, Switzerland
}} Status withdrawn.</ref>

<ref name="iso-13602-2002">
{{cite book
 | title = Technical energy systems: methods for analysis: part 1: general — ISO 13602-1:2002
 | date = 1 November 2002
 | publisher = International Standards Organization
 | location = Geneva, Switzerland
}} Status withdrawn.</ref>

<ref name="kannan-and-strachan-2007">
{{cite journal
 | last1 = Kannan | first1 = Ramachandran
 | last2 = Strachan | first2 = Neil
 | title = Modelling the UK residential energy sector under long-term decarbonisation scenarios: Comparison between energy systems and sectoral modelling approaches
 | date = April 2009
 | journal = Applied Energy
 | volume = 86
 | issue = 4
 | pages = 416–428
 | doi = 10.1016/j.apenergy.2008.08.005
 | issn = 0306-2619
}}</ref>

<ref name="merriam-webster-system">
{{cite web
 | title = Definition of ''system''
 | website = Merriam-Webster
 | location = Springfield, MA, USA
 | access-date = 2016-10-09
 | url = http://www.merriam-webster.com/dictionary/system
}}</ref>

<ref name="morrison-etal-2005">
{{cite conference
 | last1 = Morrison | first1 = Robbie
 | last2 = Wittmann | first2 = Tobias
 | last3 = Heise | first3 = Jan
 | last4 = Bruckner | first4 = Thomas
 | title = Policy-oriented energy system modeling with ''xeona''
 | date = 20–22 June 2005
 | conference = ECOS 2005
 | editor = Norwegian University of Science and Technology (NTNU)
 | book-title = Proceedings of ECOS 2005: shaping our future energy systems: 18th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems
 | publisher = Tapir Academic Press
 | location = Trondheim, Norway
 | volume = 2
 | pages = 659–668
 | isbn = 82-519-2041-8
 | url = http://www.wifa.uni-leipzig.de/fileadmin/user_upload/iirm-tm/energiemanagement/publikationen/Conference_Proceedings/2005_PolicyOrientedEXeona.pdf
 | access-date = 2016-10-14
}}</ref>

<ref name="quelhas-etal-2007">
{{cite journal
 | last1 = Quelhas | first1 = Ana
 | last2 = Gil | first2 = Esteban
 | last3 = McCalley | first3 = James D
 | last4 = Ryan | first4 = Sarah M
 | title = A multiperiod generalized network flow model of the US integrated energy system: Part I — Model description
 | date = May 2007
 | journal = IEEE Transactions on Power Systems
 | volume = 22
 | issue = 2
 | pages = 829–836
 | doi = 10.1109/TPWRS.2007.894844
 | bibcode = 2007ITPSy..22..829Q
 | s2cid = 719700
 | issn = 0885-8950
 | url = https://www.researchgate.net/publication/3267854
 | access-date = 2016-10-22
}}</ref>

<ref name="van-ruijven-etal-2008">
{{cite journal
 | last1 = van Ruijven | first1 = Bas
 | last2 = Urban | first2 = Frauke
 | last3 = Benders | first3 = René MJ
 | last4 = Moll | first4 = Henri C
 | last5 = van der Sluijs | first5 = Jeroen P
 | last6 = de Vries | first6 = Bert
 | last7 = van Vuuren | first7 = Detlef P
 | title = Modeling energy and development: an evaluation of models and concepts
 | date = December 2008
 | journal = World Development
 | volume = 36
 | issue = 12
 | pages = 2801–2821
 | doi = 10.1016/j.worlddev.2008.01.011
 | hdl = 1874/32954
 | s2cid = 154709268
 | issn = 0305-750X
 | url = http://dspace.library.uu.nl/bitstream/handle/1874/32954/NWS-E-2008-55.pdf
 | access-date = 2016-10-25
}}</ref>

<ref name="wittmann-and-bruckner-2009">
{{cite conference
 | last1 = Wittmann | first1 = Tobias
 | last2 = Bruckner | first2 = Thomas
 | title = Agent-based modeling of urban energy supply systems facing climate protection constraints
 | date = 28–30 June 2009
 | conference = Fifth Urban Research Symposium 2009: Cities and Climate Change: Responding to an Urgent Agenda
 | conference-url = http://web.worldbank.org/WBSITE/EXTERNAL/TOPICS/EXTURBANDEVELOPMENT/EXTUWM/0,,contentMDK:22446625~menuPK:6725106~pagePK:148956~piPK:216618~theSitePK:341511,00.html
 | publisher = The World Bank
 | location = Marseille, France
 | url = http://siteresources.worldbank.org/INTURBANDEVELOPMENT/Resources/336387-1256566800920/6505269-1268260567624/Wittmann.pdf
 | access-date = 2016-11-11
}}
</ref>

}} <!-- reflist -->

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