# Energy balance

﻿
Energy balance

Energy balance has the following meanings in several fields:

* In physics, energy balance is a systematic presentation of energy flows and transformations in a system. Theoretical basis for an energy balance is the first law of thermodynamics according to which energy cannot be created or destroyed, only modified in form. Energy sources or wave of energy are therefore inputs and outputs of the system under observation.

* In biology, total body energy balance is measured with the following equation: "Energy intake = internal heat produced + external work + energy storage". The Dynamic Energy Budget theory makes explicit use of energy, mass and time balances. One Calorie (or kilogram calorie) equals the energy needed to increase the temperature of 1 kg of water by 1 °C. This is about 4.184 kJ.

* In energy economics, the energy balance of a country is an aggregate presentation of all human activities related to energy, except for natural and biological processes. National energy balances are compiled on at least an annual basis. Common methodology for compilation and presentation of energy balances allows simple addition of national energy balances to form supranational ones, such as is compiled for the European Union. United Nations compile energy balances for all member countries. International Energy Agency, a specialised agency of OECD is regularly preparing world energy balances.

* In engineering, energy balances are used to quantify the energy used or produced by a system. This can be used to build complex differential equation models to design and analyze real systems. To make an energy balance for a system is very similar to making a Mass balance but there are a few differences to remember, e.g. 1) that a specific system might be closed in a mass balance sense, but open as far as the energy balance is concerned and 2) that while it is possible to have more than one mass balance for a system there can be only one energy balance. If a balance is made for total energy, the energy balance becomes IN=OUT+ACC (where ACC stands for accumulation). Notice that there is no production (PROD) term since energy can not be produced, only converted. If instead some kinds of energy are ignored, e.g. if a heat balance is made the energy balance becomes IN+PROD=OUT+ACC (if heat is consumed the PROD term is negative, compare Mass balance.

* When comparing fuel production, energy balance is the difference between the energy produced by 1 kg of the fuel (i.e. biodiesel, petroleum, uranium ) and the energy necessary to produce it (extraction (e.g. drilling or cultivation of energetic plants), transportation, refining etc). Other factors affect fuel selection, such as portability. See also net energy gain and EROEI.

* In geography, specifically climatology and hydrology, the "'energy balance'" refers to the total of all energy inputs and outputs at any location; these include solar, atmospheric transfer, and ground conducted energy.

* In groundwater and groundwater flow the energy balance of a groundwater body is the balance of incoming hydraulic energy associated with inflow into the body, energy associated with the outflow, energy associated with conversion into heat due to friction of flow, and the resulting change of energy status or groundwater level. See also Groundwater energy balance.

ee also

*Population dynamics
*Energy Accounting
*Ecodynamics
*Bioeconomics
*Econophysics
*Energy and Environment
*Thermoeconomics

There are three journals of energy economics:
* " Energy Economics"
* [http://www.iaee.org/en/publications/journal.aspx "Energy Journal"]
* [http://www.elsevier.com/wps/find/journaldescription.cws_home/505569/description#description "Resource and Energy Economics"]

There are several other journals that regularly publish papers in energy economics:
* [http://www.elsevier.com/wps/find/journaldescription.cws_home/483/description#description "Energy" -- The International Journal]
* [http://www.elsevier.com/wps/find/journaldescription.cws_home/30414/description#description "Energy Policy"]
* [http://inderscience.metapress.com/link.asp?id=110856 "International Journal of Global Energy Issues"]
* [http://www.elsevier.com/wps/find/journaldescription.cws_home/30478/description#description "Utilities Policy"]

There is also a [http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%2324617%231985%23999989999%23567366%23FLP%23&_cdi=24617&_pubType=HS&view=c&_auth=y&_acct=C000047720&_version=1&_urlVersion=0&_userid=1005040&md5=890c0e4443c2391345f63ed9f24eb1ad handbook] in three volumes.

Much progress in energy economics has been made through the model comparison exercises of the (Stanford) Energy Modeling Forum and the meetings of the [http://www.iiasa.ac.at/Research/ECS/IEW/index.html International Energy Workshop] .

IDEAS/RePEc has a [http://ideas.repec.org/i/eene.html list of energy economists] and a [http://ideas.repec.org/top/top.ene.html ranking of the same] .

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• energy balance — energijos balansas statusas T sritis ekologija ir aplinkotyra apibrėžtis Materialinis balansas, kuriuo apibūdinama energijos išteklių ir energijos rūšių gavimo šaltiniai ir vartojimas. Jis parodo energijos išteklių sunaudojimą elektros energijos… …   Ekologijos terminų aiškinamasis žodynas

• energy balance — energijos balansas statusas T sritis fizika atitikmenys: angl. energy balance vok. Energiebilanz, f rus. энергетический баланс, m pranc. bilan d’énergie, m; bilan énergétique, m …   Fizikos terminų žodynas

• energy balance — energijos pusiausvyra statusas T sritis Kūno kultūra ir sportas apibrėžtis Energijos, kurią žmogaus organizmas gauna ir suvartoja natūraliai medžiagų apykaitai ir atliekamam darbui nekintant kūno masei, lygybė. atitikmenys: angl. energy balance… …   Sporto terminų žodynas

• energy balance — In biology, the state at which the number of calories eaten equals the number of calories used. Energy balance is affected by physical activity, body size, amount of body fat and muscle, and genetics …   English dictionary of cancer terms

• energy balance — noun : the relation between intake of food and output of work (as in muscular or secretory activity) that is positive when the body stores extra food as fats and negative when the body draws on stored fat to provide energy for work …   Useful english dictionary

• energy balance — Смотри энергетический баланс …   Энциклопедический словарь по металлургии

• Ethanol fuel energy balance — † depending on production method All biomass needs to go through some of these steps: it needs to be grown, collected, dried, fermented, and burned. All of these steps require resources and an infrastructure. The total amount of energy input into …   Wikipedia

• Groundwater energy balance — The groundwater energy balance is the energy balance of a groundwater body in terms of incoming hydraulic energy associated with groundwater inflow into the body, energy associated with the outflow, energy conversion into heat due to friction of… …   Wikipedia

• thermonuclear fusion energy balance — termobranduolinės sintezės energijos balansas statusas T sritis radioelektronika atitikmenys: angl. thermonuclear fusion energy balance vok. thermonukleare Fusionsenergiebilanz, f rus. баланс энергии термоядерного синтеза, m pranc. balance de l… …   Radioelektronikos terminų žodynas

• Energy Accounting — is the hypothetical system of distribution, proposed by Technocracy Incorporated in the Technocracy Study Course , which would record the energy used to produce and distribute goods and services consumed by citizens in a Technate.… …   Wikipedia