An energy system is a

system A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its open system (systems theory), environment, is described by its boundaries, str ...

primarily designed to supply energy-services to end-users. The intent behind energy systems is to minimise energy losses to a negligible level, as well as to ensure the efficient use of energy. The

IPCC Fifth Assessment Report The Fifth Assessment Report (AR5) of the United Nations Intergovernmental Panel on Climate Change (IPCC) is the fifth in IPCC#Assessment reports, a series of such reports and was completed in 2014.IPCC (2014The IPCC's Fifth Assessment Report (A ...

defines an energy system as "all components related to the production, conversion, delivery, and use of

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

". The first two definitions allow for demand-side measures, including daylighting, retrofitted

building insulation Building insulation is material used in a building (specifically the building envelope) to reduce the flow of thermal energy. While the majority of insulation in buildings is for thermal insulation, thermal purposes, the term also applies to ...

, and

passive solar building design In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unli ...

, as well as socio-economic factors, such as aspects of

energy demand management Energy demand management, also known as demand-side management (DSM) or demand-side response (DSR), is the modification of consumer energy demand, demand for energy through various methods such as financial incentives and behavioral change through ...

and

remote work Remote work (also called telecommuting, telework, work from or at home, WFH as an initialism, hybrid work, and other terms) is the practice of work (human activity), working at or from one's home or Third place, another space rather than from ...

, while the third does not. Neither does the third account for the

informal economy An informal economy (informal sector or grey economy) is the part of any economy that is neither Taxation, taxed nor monitored by any form of government. Although the informal sector makes up a significant portion of the economies in developin ...

in traditional

biomass Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...

that is significant in many

developing countries A developing country is a sovereign state with a less-developed Secondary sector of the economy, industrial base and a lower Human Development Index (HDI) relative to developed countries. However, this definition is not universally agreed upon. ...

. The analysis of energy systems thus spans the disciplines of

engineering Engineering is the practice of using natural science, mathematics, and the engineering design process to Problem solving#Engineering, solve problems within technology, increase efficiency and productivity, and improve Systems engineering, s ...

and

economics Economics () is a behavioral science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviour and interac ...

. Merging ideas from both areas to form a coherent description, particularly where

macroeconomic Macroeconomics is a branch of economics that deals with the performance, structure, behavior, and decision-making of an economy as a whole. This includes regional, national, and global economies. Macroeconomists study topics such as output/ GDP ...

dynamics are involved, is challenging. The concept of an energy system is evolving as new regulations, technologies, and practices enter into service – for example,

emissions trading Emissions trading is a market-oriented approach to controlling pollution by providing economic incentives for reducing the emissions of pollutants. The concept is also known as cap and trade (CAT) or emissions trading scheme (ETS). One prominen ...

, the development of

smart grid The smart grid is an enhancement of the 20th century electrical grid, using two-way communications and distributed so-called intelligent devices. Two-way flows of electricity and information could improve the delivery network. Research is main ...

s, and the greater use of

, respectively.

Treatment

From a structural perspective, an energy system is like any

and is made up of a set of interacting component parts, located within an environment. These components derive from ideas found in

and

. Taking a process view, an energy system "consists of an integrated set of technical and economic activities operating within a complex societal framework". 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 Abstraction is a process where general rules and concepts are derived from the use and classifying of specific examples, literal (reality, real or Abstract and concrete, concrete) signifiers, first principles, or other methods. "An abstraction" ...

which usually precedes some form of computer-based investigation, such as the construction and use of a suitable energy model. Viewed in engineering terms, an energy system lends itself to representation as a

flow network In graph theory, a flow network (also known as a transportation network) is a directed graph where each edge has a capacity and each edge receives a flow. The amount of flow on an edge cannot exceed the capacity of the edge. Often in operations re ...

: the vertices map to engineering components like

power station A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...

s and pipelines and the 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, may be applied. The components themselves can be treated as simple

dynamical systems In mathematics, a dynamical system is a system in which a Function (mathematics), function describes the time dependence of a Point (geometry), point in an ambient space, such as in a parametric curve. Examples include the mathematical models ...

in their own right.

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

International Energy Agency The International Energy Agency (IEA) is a Paris-based autonomous intergovernmental organization, established in 1974, that provides policy recommendations, analysis and data on the global energy sector. The 31 member countries and 13 associatio ...

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 MARKAL is a numerical model used to carry out economic analysis of different energy related systems at the country level to represent its evolution over a period of usually of 40–50 years. The word MARKAL was generated by concatenating two wor ...

with several UK sectoral housing stock models.

Data

International energy statistics are typically broken down by carrier, sector and sub-sector, and country.

Energy carrier An energy carrier is a substance (fuel) or sometimes a phenomenon (energy system) that contains energy that can be later converted to other forms such as mechanical work or heat or to operate chemical or physical processes. Such carriers inclu ...

s ( energy products) are further classified as

primary energy Primary energy (PE) is the energy found in nature that has not been subjected to any human engineered conversion process. It encompasses energy contained in raw fuels and other forms of energy, including waste, received as input to a system. Pri ...

and 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

balance Balance may refer to: Common meanings * Balance (ability) in biomechanics * Balance (accounting) * Balance or weighing scale * Balance, as in equality (mathematics) or equilibrium Arts and entertainment Film * Balance (1983 film), ''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. The notion of an energy carrier, as used in

energy economics Energy economics is a broad scientific subject area which includes topics related to supply and use of energy in societies. Considering the cost of energy services and associated value gives economic meaning to the efficiency at which energy ...

, is distinct and different from the definition of

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 The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to "provide governments at all levels with scientific information that they can use to develop climate policies". The World Met ...

(IPCC) does so, for instance, but covers these measures in separate chapters on transport, buildings, industry, and agriculture. 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 is the idea that rationality is limited when individuals decision-making, make decisions, and under these limitations, rational individuals will select a decision that is satisficing, satisfactory rather than optimal. Limitat ...

and agent-based behavior. The

American Association for the Advancement of Science The American Association for the Advancement of Science (AAAS) is a United States–based international nonprofit with the stated mission of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsib ...

(AAAS) specifically advocates that "more attention should be paid to incorporating behavioral considerations other than price- and income-driven behavior into economic models f the energy system.

Energy-services

The concept of an energy-service is central, particularly when defining the purpose of an energy system: Energy-services can be defined as amenities that are either furnished through energy consumption or could have been thus supplied. More explicitly: 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

sustainable energy Energy system, Energy is sustainability, sustainable if it "meets the needs of the present without compromising the ability of future generations to meet their own needs." Definitions of sustainable energy usually look at its effects on the e ...

. 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. The notion of energy-services has given rise to 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

HVAC Heating, ventilation, and air conditioning (HVAC ) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. ...

equipment of the buildings in question.

International standards

ISO 13600, ISO13601, and ISO13602 form a set of

international standard An international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International O ...

s covering technical energy systems (TES). 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 A design is the concept or proposal for an object, process, or system. The word ''design'' refers to something that is or has been intentionally created by a thinking agent, and is sometimes used to refer to the inherent nature of something ...

includes the redesigning of energy systems to ensure

sustainability Sustainability is a social goal for people to co-exist on Earth over a long period of time. Definitions of this term are disputed and have varied with literature, context, and time. Sustainability usually has three dimensions (or pillars): env ...

of the system and its dependents and for meeting requirements of the

Paris Agreement The Paris Agreement (also called the Paris Accords or Paris Climate Accords) is an international treaty on climate change that was signed in 2016. The treaty covers climate change mitigation, adaptation, and finance. The Paris Agreement was ...

for

climate change mitigation Climate change mitigation (or decarbonisation) is action to limit the greenhouse gases in the atmosphere that cause climate change. Climate change mitigation actions include energy conservation, conserving energy and Fossil fuel phase-out, repl ...

. Researchers are designing energy systems models and transformational pathways for renewable energy transitions towards 100% renewable energy, often in the form of peer-reviewed text documents created once by small teams of scientists and published in a journal. Considerations include the system's intermittency management,

air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

, various risks (such as for human safety, environmental risks, cost risks and feasibility risks), stability for prevention of

power outage A power outage, also called a blackout, a power failure, a power blackout, a power loss, a power cut, or a power out is the complete loss of the electrical power network supply to an end user. There are many causes of power failures in an el ...

s (including grid dependence or grid-design), resource requirements (including water and rare minerals and recyclability of components), technology/

development Development or developing may refer to: Arts *Development (music), the process by which thematic material is reshaped * Photographic development *Filmmaking, development phase, including finance and budgeting * Development hell, when a proje ...

requirements, costs, feasibility, other affected systems (such as land-use that affects food systems), carbon emissions, available energy quantity and transition-concerning factors (including costs, labor-related issues and speed of deployment). Energy system design can also consider

energy consumption Energy consumption is the amount of energy used. Biology In the body, energy consumption is part of energy homeostasis. It derived from food energy. Energy consumption in the body is a product of the basal metabolic rate and the physical acti ...

, such as in terms of absolute energy demand, waste and consumption reduction (e.g. via reduced energy-use, increased efficiency and flexible timing), process efficiency enhancement and waste heat recovery. A study noted significant potential for a type of energy systems modelling to "move beyond single disciplinary approaches towards a sophisticated integrated perspective".

Notes

References

External links

{{DEFAULTSORT:Energy system Energy Energy development Energy economics Networks Energy infrastructure Systems science