Energy modeling or energy system modeling is the process of building
computer model
Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be det ...
s of
energy systems in order to analyze them. Such models often employ
scenario analysis
Scenario planning, scenario thinking, scenario analysis, scenario prediction and the scenario method all describe a strategic planning method that some organizations use to make flexible long-term plans. It is in large part an adaptation and gene ...
to investigate different assumptions about the technical and economic conditions at play. Outputs may include the system feasibility,
greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and ...
, cumulative
financial costs,
natural resource
Natural resources are resources that are drawn from nature and used with few modifications. This includes the sources of valued characteristics such as commercial and industrial use, aesthetic value, scientific interest and cultural value. ...
use, and
energy efficiency of the system under investigation. A wide range of techniques are employed, ranging from broadly economic to broadly engineering.
Mathematical optimization
Mathematical optimization (alternatively spelled ''optimisation'') or mathematical programming is the selection of a best element, with regard to some criterion, from some set of available alternatives. It is generally divided into two subfi ...
is often used to determine the least-cost in some sense. Models can be international, regional, national, municipal, or stand-alone in scope. Governments maintain national energy models for
energy policy
Energy policy is the manner in which a given entity (often governmental) has decided to address issues of energy development including energy conversion, distribution and use as well as reduction of greenhouse gas emissions in order to cont ...
development.
Energy models are usually intended to contribute variously to system operations,
engineering design, or
energy policy
Energy policy is the manner in which a given entity (often governmental) has decided to address issues of energy development including energy conversion, distribution and use as well as reduction of greenhouse gas emissions in order to cont ...
development. This page concentrates on policy models. Individual
building energy simulations are explicitly excluded, although they too are sometimes called energy models.
IPCC
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to advance scientific knowledge about climate change caused by human activities. The World Meteorological Organization (WMO) a ...
-style
integrated assessment models, which also contain a representation of the world energy system and are used to examine global transformation pathways through to 2050 or 2100 are not considered here in detail.
Energy modeling has increased in importance as the need for
climate change mitigation
Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly caused by emissions from fossil fuels bu ...
has grown in importance. The energy supply sector is the largest contributor to global
greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and ...
.
[
] The
IPCC reports that climate change mitigation will require a fundamental transformation of the energy supply system, including the substitution of unabated (not captured by
CCS)
fossil fuel conversion technologies by low-GHG alternatives.
Model types
A wide variety of model types are in use. This section attempts to categorize the key types and their usage. The divisions provided are not hard and fast and mixed-paradigm models exist. In addition, the results from more general models can be used to inform the specification of more detailed models, and vice versa, thereby creating a
hierarchy
A hierarchy (from Greek: , from , 'president of sacred rites') is an arrangement of items (objects, names, values, categories, etc.) that are represented as being "above", "below", or "at the same level as" one another. Hierarchy is an important ...
of models. Models may, in general, need to capture "complex dynamics such as:
* energy system operation
* technology stock turnover
* technology innovation
* firm and household behaviour
* energy and non-energy capital investment and labour market adjustment dynamics leading to economic restructuring
* infrastructure deployment and urban planning"
[
]
Models may be limited in scope to the electricity sector or they may attempt to cover an energy system in its entirety (see below).
Most energy models are used for
scenario analysis
Scenario planning, scenario thinking, scenario analysis, scenario prediction and the scenario method all describe a strategic planning method that some organizations use to make flexible long-term plans. It is in large part an adaptation and gene ...
. A scenario is a coherent set of assumptions about a possible system. New scenarios are tested against a baseline scenario – normally
business-as-usual (BAU) – and the differences in outcome noted.
The
time horizon of the model is an important consideration. Single-year models – set in either the present or the future (say 2050) – assume a non-evolving
capital
Capital may refer to:
Common uses
* Capital city, a municipality of primary status
** List of national capital cities
* Capital letter, an upper-case letter Economics and social sciences
* Capital (economics), the durable produced goods used fo ...
structure and focus instead on the operational dynamics of the system. Single-year models normally embed considerable temporal (typically hourly resolution) and technical detail (such as individual generation plant and transmissions lines). Long-range models – cast over one or more decades (from the present until say 2050) – attempt to encapsulate the structural evolution of the system and are used to investigate capacity expansion and energy system transition issues.
Models often use
mathematical optimization
Mathematical optimization (alternatively spelled ''optimisation'') or mathematical programming is the selection of a best element, with regard to some criterion, from some set of available alternatives. It is generally divided into two subfi ...
to solve for redundancy in the specification of the system. Some of the techniques used derive from
operations research
Operations research ( en-GB, operational research) (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a discipline that deals with the development and application of analytical methods to improve dec ...
. Most rely on
linear programming
Linear programming (LP), also called linear optimization, is a method to achieve the best outcome (such as maximum profit or lowest cost) in a mathematical model whose requirements are represented by linear relationships. Linear programming is ...
(including
mixed-integer programming), although some use
nonlinear programming. Solvers may use classical or
genetic optimisation, such as
CMA-ES Covariance matrix adaptation evolution strategy (CMA-ES) is a particular kind of strategy for numerical optimization. Evolution strategies (ES) are stochastic, derivative-free methods for numerical optimization of non-linear or non- convex con ...
. Models may be recursive-dynamic, solving sequentially for each time interval, and thus evolving through time. Or they may be framed as a single forward-looking intertemporal problem, and thereby assume perfect foresight. Single-year engineering-based models usually attempt to minimize the
short-run financial cost, while single-year market-based models use optimization to determine
market clearing
In economics, market clearing is the process by which, in an economic market, the supply of whatever is traded is equated to the demand so that there is no excess supply or demand. The new classical economics assumes that in any given market, as ...
. Long-range models, usually spanning decades, attempt to minimize both the short and long-run costs as a single intertemporal problem.
The demand-side (or end-user domain) has historically received relatively scant attention, often modeled by just a simple
demand curve
In economics, a demand curve is a graph depicting the relationship between the price of a certain commodity (the ''y''-axis) and the quantity of that commodity that is demanded at that price (the ''x''-axis). Demand curves can be used either for t ...
. End-user energy demand curves, in the short-run at least, are normally found to be highly
inelastic.
As
intermittent energy source
Variable renewable energy (VRE) or intermittent renewable energy sources (IRES) are renewable energy sources that are not dispatchable due to their fluctuating nature, such as wind power and solar power, as opposed to controllable renewable ene ...
s and
energy demand management
Energy demand management, also known as demand-side management (DSM) or demand-side response (DSR), is the modification of consumer demand for energy through various methods such as financial incentives and behavioral change through education.
Us ...
grow in importance, models have needed to adopt an hourly temporal resolution in order to better capture their real-time dynamics.
[
] Long-range models are often limited to calculations at yearly intervals, based on typical day profiles, and are hence less suited to systems with significant
variable renewable energy
Variable renewable energy (VRE) or intermittent renewable energy sources (IRES) are renewable energy sources that are not dispatchable due to their fluctuating nature, such as wind power and solar power, as opposed to controllable renewable ene ...
. Day-ahead dispatching optimization is used to aid in the planning of systems with a significant portion of intermittent energy production in which uncertainty around future energy predictions is accounted for using stochastic optimization.
Implementing
languages
Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of met ...
include
GAMS
Gams is a municipality in the ''Wahlkreis'' (constituency) of Werdenberg in the canton of St. Gallen in Switzerland.
History
Gams is first mentioned in 835 as ''Campesias''. In 1210 it was mentioned as ''Chames'', in 1236 as ''Gamps''. Unt ...
,
MathProg,
MATLAB
MATLAB (an abbreviation of "MATrix LABoratory") is a proprietary multi-paradigm programming language and numeric computing environment developed by MathWorks. MATLAB allows matrix manipulations, plotting of functions and data, implementa ...
,
Mathematica
Wolfram Mathematica is a software system with built-in libraries for several areas of technical computing that allow machine learning, statistics, symbolic computation, data manipulation, network analysis, time series analysis, NLP, optimi ...
,
Python,
Pyomo,
R,
Fortran,
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
,
C,
C++, and
Vensim. Occasionally
spreadsheet
A spreadsheet is a computer application for computation, organization, analysis and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in ce ...
s are used.
As noted,
IPCC
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to advance scientific knowledge about climate change caused by human activities. The World Meteorological Organization (WMO) a ...
-style
integrated models (also known as integrated assessment models or IAM) are not considered here in any detail.
[
] Integrated models combine simplified sub-models of the
world economy
The world economy or global economy is the economy of all humans of the world, referring to the global economic system, which includes all economic activities which are conducted both within and between nations, including production, consumpti ...
, agriculture and
land-use, and the global
climate
Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologica ...
system in addition to the world energy system. Examples include GCAM,
[
] MESSAGE, and REMIND.
[
]
Published surveys on energy system modeling have focused on techniques,
[
] general classification,
[
] an overview,
[
] decentralized planning,
[
] modeling methods,
[
] renewables integration,
[
] energy efficiency policies,
[
][
] electric vehicle integration,
[
] international development
International development or global development is a broad concept denoting the idea that societies and countries have differing levels of economic development, economic or human development (humanity), human development on an international scal ...
,
[
] and the use of layered models to support
climate protection policy.
[
] Deep Decarbonization Pathways Project researchers have also analyzed model typologies.
A 2014 paper outlines the modeling challenges ahead as energy systems become more complex and human and social factors become increasingly relevant.
[
]
Electricity sector models
Electricity sector models are used to model electricity systems. The scope may be national or regional, depending on circumstances. For instance, given the presence of national interconnectors, the western European electricity system may be modeled in its entirety.
Engineering-based models usually contain a good characterization of the technologies involved, including the high-voltage
AC transmission grid where appropriate. Some models (for instance, models for Germany) may assume a single common bus or "copper plate" where the grid is strong. The demand-side in electricity sector models is typically represented by a fixed
load profile.
Market-based models, in addition, represent the prevailing
electricity market
In a broad sense, an electricity market is a system that facilitates the exchange of electricity-related goods and services. During more than a century of evolution of the electric power industry, the economics of the electricity markets had u ...
, which may include
nodal pricing
In a broad sense, an electricity market is a system that facilitates the exchange of electricity-related goods and services. During more than a century of evolution of the electric power industry, the economics of the electricity markets had un ...
.
Game theory and
agent-based model
An agent-based model (ABM) is a computational model for simulating the actions and interactions of autonomous agents (both individual or collective entities such as organizations or groups) in order to understand the behavior of a system and what ...
s are used to capture and study
strategic behavior within
electricity market
In a broad sense, an electricity market is a system that facilitates the exchange of electricity-related goods and services. During more than a century of evolution of the electric power industry, the economics of the electricity markets had u ...
s.
[
][
][
]
Energy system models
In addition to the electricity sector, energy system models include the heat, gas, mobility, and other sectors as appropriate.
[
] Energy system models are often national in scope, but may be municipal or international.
So-called ''top-down models'' are broadly economic in nature and based on either
partial equilibrium or
general equilibrium
In economics, general equilibrium theory attempts to explain the behavior of supply, demand, and prices in a whole economy with several or many interacting markets, by seeking to prove that the interaction of demand and supply will result in an ov ...
. General equilibrium models represent a specialized activity and require dedicated
algorithms
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ...
. Partial equilibrium models are more common.
So-called ''bottom-up models'' capture the engineering well and often rely on techniques from
operations research
Operations research ( en-GB, operational research) (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a discipline that deals with the development and application of analytical methods to improve dec ...
. Individual plants are characterized by their efficiency curves (also known as input/output relations), nameplate capacities, investment costs (
capex
Capital expenditure or capital expense (capex or CAPEX) is the money an organization or corporate entity spends to buy, maintain, or improve its fixed assets, such as buildings, vehicles, equipment, or land. It is considered a capital expenditure ...
), and operating costs (
opex). Some models allow for these parameters to depend on external conditions, such as ambient temperature.
[
]
Producing hybrid top-down/bottom-up models to capture both the economics and the engineering has proved challenging.
[
]
Established models
This section lists some of the major models in use. These are typically run by national governments.
In a community effort, a large number of existing energy system models were collected in model fact sheets on the
Open Energy Platform.
[
]
LEAP
LEAP, the Low Emissions Analysis Platform (formerly known as the Long-range Energy Alternatives Planning System) is a software tool for
energy policy
Energy policy is the manner in which a given entity (often governmental) has decided to address issues of energy development including energy conversion, distribution and use as well as reduction of greenhouse gas emissions in order to cont ...
analysis, air pollution abatement planning and
climate change mitigation
Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly caused by emissions from fossil fuels bu ...
assessment.
[
][
]
LEAP was developed at the
Stockholm Environment Institute
The Stockholm Environment Institute, or SEI, is a non-profit, independent research and policy institute specialising in sustainable development and environmental issues, with seven affiliate offices around the world. SEI works on climate chang ...
's (SEI) US Center. LEAP can be used to examine city, statewide, national, and regional energy systems. LEAP is normally used for studies of between 20–50 years. Most of its calculations occur at yearly intervals. LEAP allows policy analysts to create and evaluate alternative
scenarios and to compare their energy requirements,
social costs and benefits, and environmental impacts. As of June 2021, LEAP has over 6000 users in 200 countries and territories
Power system simulation
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...
's MAPS (Multi-Area Production Simulation) is a production simulation model used by various
Regional Transmission Organizations and
Independent System Operators in the United States to plan for the economic impact of proposed electric transmission and generation facilities in FERC-regulated electric wholesale markets. Portions of the model may also be used for the commitment and dispatch phase (updated on 5 minute intervals) in operation of wholesale electric markets for RTO and ISO regions.
ABB's PROMOD is a similar software package. These ISO and RTO regions also utilize a GE software package called MARS (Multi-Area Reliability Simulation) to ensure the power system meets reliability criteria (a
loss of load expectation (LOLE) of no greater than 0.1 days per year). Further, a GE software package called PSLF (Positive Sequence Load Flow) and a
Siemens software package called PSSE (Power System Simulation for Engineering) analyzes load flow on the power system for short-circuits and stability during preliminary planning studies by RTOs and ISOs.
MARKAL/TIMES
MARKAL (MARKet ALlocation) is an integrated energy systems modeling platform, used to analyze energy, economic, and environmental issues at the global, national, and municipal level over time-frames of up to several decades. MARKAL can be used to quantify the impacts of policy options on technology development and natural
resource depletion
Resource depletion is the consumption of a resource faster than it can be replenished. Natural resources are commonly divided between renewable resources and non-renewable resources (see also mineral resource classification). Use of either ...
. The software was developed by the Energy Technology Systems Analysis Programme (ETSAP) of the
International Energy Agency
The International Energy Agency (IEA) is a Paris-based autonomous Intergovernmental organization, intergovernmental organisation, established in 1974, that provides policy recommendations, analysis and data on the entire global energy sector, wit ...
(IEA) over a period of almost two decades.
TIMES (The Integrated MARKAL-EFOM System) is an evolution of MARKAL – both energy models have many similarities.
[
] TIMES succeeded MARKAL in 2008.
[
] Both models are technology explicit, dynamic
partial equilibrium models of
energy markets. In both cases, the equilibrium is determined by maximizing the total
consumer and producer surplus via
linear programming
Linear programming (LP), also called linear optimization, is a method to achieve the best outcome (such as maximum profit or lowest cost) in a mathematical model whose requirements are represented by linear relationships. Linear programming is ...
. Both MARKAL and TIMES are written in
GAMS
Gams is a municipality in the ''Wahlkreis'' (constituency) of Werdenberg in the canton of St. Gallen in Switzerland.
History
Gams is first mentioned in 835 as ''Campesias''. In 1210 it was mentioned as ''Chames'', in 1236 as ''Gamps''. Unt ...
.
The TIMES model generator was also developed under the Energy Technology Systems Analysis Program (ETSAP). TIMES combines two different, but complementary, systematic approaches to modeling energy – a technical engineering approach and an economic approach. TIMES is a technology rich, bottom-up model generator, which uses
linear programming
Linear programming (LP), also called linear optimization, is a method to achieve the best outcome (such as maximum profit or lowest cost) in a mathematical model whose requirements are represented by linear relationships. Linear programming is ...
to produce a least-cost energy system, optimized according to a number of user-specified constraints, over the medium to long-term. It is used for "the exploration of possible energy futures based on contrasted scenarios".
[
]
, the MARKAL and TIMES model generators are in use in 177 institutions spread over 70 countries.
[
]
NEMS
NEMS (National Energy Modeling System) is a long-standing United States government policy model, run by the
Department of Energy (DOE). NEMS computes equilibrium fuel prices and quantities for the US energy sector. To do so, the software iteratively solves a sequence of linear programs and nonlinear equations.
[
] NEMS has been used to explicitly model the demand-side, in particular to determine consumer technology choices in the residential and commercial building sectors.
[
]
NEMS is used to produce the ''Annual Energy Outlook'' each year – for instance in 2015.
[
]
Criticisms
Public policy energy models have been criticized for being insufficiently
transparent. The
source code
In computing, source code, or simply code, is any collection of code, with or without comment (computer programming), comments, written using a human-readable programming language, usually as plain text. The source code of a Computer program, p ...
and data sets should at least be available for
peer review
Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work ( peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer revie ...
, if not explicitly published.
[
] To improve transparency and public acceptance, some models are undertaken as
open-source software
Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Ope ...
projects, often developing a diverse community as they proceed. OSeMOSYS is one such example.
[
][
]
See also
General
*
Climate change mitigation
Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly caused by emissions from fossil fuels bu ...
– actions to limit long-term climate change
*
Climate change mitigation scenarios – possible futures in which global warming is reduced by deliberate actions
*
Economic model
In economics, a model is a theoretical construct representing economic processes by a set of variables and a set of logical and/or quantitative relationships between them. The economic model is a simplified, often mathematical, framework desi ...
*
Energy system – the interpretation of the energy sector in system terms
*
Energy Modeling Forum – a
Stanford University-based modeling forum
*
Open Energy Modelling Initiative – an
open source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...
energy modeling initiative, centered on Europe
*
Open energy system databases
Open energy system database projects employ open data methods to collect, clean, and republish energy-related datasets for open use. The resulting information is then available, given a suitable open license, for statistical analysis and for b ...
– database projects which collect, clean, and republish energy-related datasets
*
Open energy system models – a review of
energy system models that are also
open source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...
*
Power system simulation
Models
*
ACEGES
The ACEGES model (Agent-based Computational Economics of the Global Energy System) is a decision support tool for energy policy by means of controlled computational experiments. The ACEGES tool is designed to be the foundation for large custom-pur ...
– a global agent-based computational economics model
*
iNEMS (Integrated National Energy Modeling System) – a national energy model for China
*
MARKAL
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 ...
– an energy model
*
NEMS – the US government national energy model
*
POLES (Prospective Outlook on Long-term Energy Systems) – an energy sector world simulation model
* KAPSARC Energy Model - an energy sector model for Saudi Arabia
Further reading
* Introductory video on open energy system modeling with
python language example
[
Video00:11:42. Presentation to Climate forecasting for energy workshop on 4December 2020.
]
* Introductory video with reference to public policy
[
Video 00:13:17. Filmed 9June 2019 in Berlin, Germany. Reference LP-001-01.
]
References
External links
COST TD1207 Mathematical Optimization in the Decision Support Systems for Efficient and Robust Energy Networks wiki– a typology for optimization models
EnergyPLAN— a
freeware
Freeware is software, most often proprietary, that is distributed at no monetary cost to the end user. There is no agreed-upon set of rights, license, or EULA that defines ''freeware'' unambiguously; every publisher defines its own rules for t ...
energy model from the Department of Development and Planning,
Aalborg University
Aalborg University (AAU) is a Danish public university with campuses in Aalborg, Esbjerg, and Copenhagen founded in 1974. The university awards bachelor's degrees, master's degrees, and PhD degrees in a wide variety of subjects within humanitie ...
, Denmark
Open Energy Modelling Initiative open models page– a list of open energy models
model.energy— an online "toy" model utilizing the
PyPSA framework that allows the public to experiment
Building Energy Modeling Toolsby
National Renewable Energy Laboratory
The National Renewable Energy Laboratory (NREL) in the US specializes in the research and development of renewable energy, energy efficiency, energy systems integration, and sustainable transportation. NREL is a federally funded research and ...
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