Energy refers to the capacity to do work and is commonly measured in joules. There are two major problems in the area, namely a reduction in available energy and environmental side-effects from using various energy sources. This page is an overview for energy, with a focus on these issues.
Although strictly speaking energy cannot be created or destroyed, it is common to speak of “extracting” or “generating” energy, either from fuels or “sources” such as wind, and energy being “used” when it is applied for some purprose which causes the energy to be too diffuse to be usable further.
Energy sources have always been important for humans. Even in primitive societies, wood or charcoal is used for cooking and heating. Energy sources provided light for illumination, heat for metallurgy, heat for brick kilns, and heat for warmth during cold weather.
One subset of energy sources are known as fuels, i.e., substances which can be burned or otherwise consumed to produce energy. Firewood was the first major fuel, then charcoal, then coal, then petroleum (or oil). Oil was the dominant energy source for the 20th century and remains so today.
The industrial revolution was made possible by the presence of large coal deposits which provided the fuel for steam which powered factories and train locomotives in the 19th century. Virtually all of modernity relies on energy. Energy is used to power automobiles, electrical motors, construction equipment, to automate most agricultural tasks, to heat furnaces, ovens, houses and buildings. and to distill and enable chemical reactions that require energy inputs, amongst many other things. In the absence of such cheap and abundant energy, many current activities either require much, much more human mechanical effort or even become infeasible.
An important concept for thinking about energy is substitutability, i.e., the degree to which one fuel may need to be converted, potentially with significant losses, to a different form for a given usage. For example, an ore smelting plant must run continuously and hence cannot be powered directly from intermittent source like wind power but from a temporary “buffering” storage medium (such as batteries) fed from the wind turbines (generally incurring conversion losses).
A concept related to energy is power, the capacity to do work over time. Power is measured in watts (which are defined as joules/second). In many contexts the terms are used interchangeably since an energy source is also a source of power, and a power source supplies energy.
There are several potential crises related to energy:
Global warming - Fossil fuels like crude oil, natural gas, and coal are carbon-based fuels. About 85% of the worldwide energy usage came from fossil fuels in 2007. When burned the carbon in the fuels combines with oxygen to emit CO2 into the atmosphere. The burning of fossil fuels are the largest factor in the increase in CO2 concentrations which, in turn, are the major cause of global warming.
Peak oil - The reserves for fossil fuels are finite whilst global population and average per capita energy use are increasing. At some point, with debate about whether in the immediate future in or further out, progressively the rate of extraction will drop and the cost of extraction rise.
Energy dependency? - Most countries import a portion of their fuel or energy from other countries. The most common ways to import energy are by electricity pylon, pipeline (oil and natural gas), by tanker, and by bulk cargo ship. Geopolitical events can disrupt the supply of energy greatly harming the economies of countries dependent on imports. Additionally, rising internal energy use may lead to decreased exports available to the rest of the world.
Energy is a ‘category’ in the Azimuth Library. For a comprehensive list of the pages in this category, go here.
Here are some of the most important:
International Energy Statistics database - International Energy Outlook 2010 (as of November 2009), U.S. Energy Information Administration (EIA).
Agent-based Computational Economics of the Global Energy System. This is an agent-based model for exploratory energy policy by means of controlled computational experiments. ACEGES is designed to be the foundation for large custom-purpose simulations of the global energy system. The full version of the ACEGES is based on i) the MASON library, ii) the R Project for statistical computing, iii) the ECJ, which is an evolutionary computation system written in Java, and iv) the GAMLSS framework.