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Energy crisis
An energy crisis, also called an energy shortage, is a widespread disruption in energy supply or a steep rise in its price, recurring since the 1970s oil shocks.
Energy decomposition analysis
Energy decomposition analysis is a computational chemistry method that splits the interaction energy between molecules into components such as electrostatics, Pauli repulsion, polarization, and charge transfer.
Energy density
Energy density, also called fuel value, is the amount of energy stored in a system per unit volume, measured in joules per cubic meter; for fuels and batteries it is reported as watt-hours per liter.
Energy detection
Energy detection is a signal-detection method used for spectrum sensing in cognitive radio, measuring received signal energy over an interval and comparing it with a threshold.
Energy development
Energy development, also called sources of energy, is the effort to produce and expand access to energy services, including electricity, clean cooking, and low-carbon sources.
Energy Development Oman
Energy Development Oman (EDO) is Oman's wholly state-owned energy holding company, established by royal decree in 2020, holding a 60 percent stake in Petroleum Development Oman and owning the green hydrogen body Hydrom.
Energy diplomacy
Energy diplomacy: use of foreign policy and diplomatic instruments to secure energy supplies, promote government-to-government energy cooperation, and manage critical minerals; also called oil diplomacy, marked by US shale-era limits and post-2022 crisis mobilization.
Energy Dome
Energy Dome is an Italian long-duration energy storage company founded in Milan in 2020, known for its CO2 Battery, which stores electricity by compressing carbon dioxide into a liquid.
Energy drink
Energy drink: caffeinated functional beverage with taurine, B vitamins, guarana, and sugars; Red Bull and Monster lead the market. Covers caffeine doses, EU/US/Australian regulation, health effects, and the sports-drink distinction.
Energy efficiency design index
The energy efficiency design index is a mandatory International Maritime Organization measure under MARPOL Annex VI that limits new ships' CO2 emissions per tonne-mile, in force since 2013.
Energy Efficiency Directive
The Energy Efficiency Directive is the European Union's framework law setting binding targets for reducing energy consumption, recast in 2023 under the Fit for 55 package.
Energy Efficiency First Principle
The Energy Efficiency First principle (EE1st) is a rule of European Union energy policy requiring cost-efficient efficiency measures to be considered as alternatives to new supply infrastructure.
Energy filtering (electron microscopy)
Energy filtering, known as energy-filtered TEM (EFTEM), is a transmission electron microscopy technique that removes inelastically scattered electrons or uses them to form elemental maps.
Energy flow (ecology)
Energy flow (ecology): one-way transfer of solar energy through trophic levels, from producers to consumers and decomposers. Key figures: Lindeman's 1942 trophic-dynamic concept, the 10% rule, and measured mean transfer efficiency of 5.92%.
Energy Harbor
Energy Harbor Corp. was an independent, privately held energy producer and retailer headquartered in Akron, Ohio, created in 2020 when FirstEnergy Solutions emerged from bankruptcy; Vistra acquired it in 2024.
Energy harvesting
Energy harvesting, also called energy scavenging, converts ambient mechanical, thermal, and radiative energy into usable electrical power, letting wireless sensors, wearables, and biomedical implants run without batteries.
Energy in France
Energy in France is dominated by nuclear power, which supplies about two thirds of its electricity and 41% of primary energy, reaching 95% low-carbon generation in 2024.
Energy in Germany
Energy in Germany is supplied by a system in transition: it imports 67 percent of its energy, and renewables generated a record 54.4 percent of electricity in 2024.
Energy in Italy
Energy in Italy is characterized by heavy import dependency, with over 74% of net energy consumed imported and 92% of fossil fuel supplies covered by imports.
Energy in Japan
Energy in Japan describes how the country supplies its power and fuels, importing most of them, with fossil fuels at 88% of supply in 2019.
Energy in the United Kingdom
Energy in the United Kingdom covers the production, import, conversion, and consumption of energy across electricity, gas, oil, and renewable systems, guided by the Clean Power 2030 target.
Energy in the United States
Energy in the United States, also called energy use in the US, comes mainly from petroleum and natural gas; 2024 production hit a record 103.3 quads.
Energy industry
The energy industry, also called the energy sector, is the economic sector that produces fossil fuels, generates and delivers electricity, and builds renewable energy equipment, and it is the largest source of global greenhouse gas emissions.
Energy Information Administration
The U.S. Energy Information Administration (EIA), established in 1977, is the independent statistical agency of the Department of Energy, collecting and publishing energy data for the public.
Energy Innovation Capital
Energy Innovation Capital is an American venture capital firm, founded in 2016 and headquartered in Orinda, California, that invests in next-generation energy technology companies across the United States.
Energy Institute
The Energy Institute is a British chartered professional membership body for people across the whole energy sector, incorporated by Royal Charter in 2003 and counting more than 20,000 members worldwide.
Energy Intake
Energy intake (EI): energy consumed in food and drink, in kcal or MJ/day. Measured by self-report (recalls, records, FFQs) and validated against doubly labeled water; self-reports under-report by roughly 1–47%.
Energy intensity
Energy intensity is the energy used per unit of economic output, measured as total energy supply divided by GDP, and the official indicator for SDG target 7.3.
Energy Land
Energy Land (白浜エネルギーランド, Shirahama Energy Land) is an experiential theme park in Shirahama, Wakayama Prefecture, Japan. Opened in 1981, it teaches energy through gravity and optical illusions.
Energy level
An energy level, also called an energy state, is one of the allowed values of the total energy of a quantum system such as an atom or molecule.