Energy Flashcards
2 main types of energy
- potential: energy in storage (ex. gravity, chemical, nuclear)
- kinetic: energy in motion (ex. electrical, sound, thermal)
3 main pathways of energy transfer
- convection: hot air rises, cold air sinks
- conduction: mol by mol transfer of heat
- radiation: energy passes thru space
Laws of Thermodynamics
- energy can’t be created or destroyed, but can be converted from one form to another
- Energy use results in dissipation, dispersion, or conversion (changes quality and quantity, but never consumed)
entropy
quality of energy where low entropy is higher quality energy
why energy is important
- all biogeochemical and physical actions require energy, has the capacity to change position, physical composition, and temp of matter, able to do work,
Earth’s energy systems require:
- gravitational energy: holds everything downhill, used to induce motion, dictates structure of the atmosphere
- geothermal: originates in the core of the planet, rise thru the layers of the Earth, moves tectonic plates, radiogenic heat
- solar energy: primary engine for most essential processes, most energy on Earth’s surface comes from the sun, insolation is absorbed and sustains life
features of energy
- Earth’s energy system is open (allows energy to be exchanged) and balanced
- laws of thermodynamics can’t be avoided
- energy production is conversion and storage
- energy use is conversion and release of energy
- energy expense enables production and use
- scale of use (parts of energy systems are global and local)
- nature of impacts (some energy sources don’t do a lot, some are damaging)
- system design (how pathways allow energy to move)
- societal considerations (sometimes isn’t interested in energy forms)
non-renewable energy sources are:
- finite in supply in long-term storage
- may be depleted
- cannot be restored in the practical sense
renewable energy sources are:
- involving short-term storage
- can be readily restored but can also be depleted
- most are perpetually available but spatial and temporal variability
energy system design
- non-renewable based
- centralized vs distributed (a single place where energy is produced and distributed or multiple, smaller places which cuts down on waste)
- wasteful and inefficient (emit heats and other waste)
- lack of full-cost accounting (cost fo energy production should consider waste production too)
non-renewable energy
finite quantity, unable to be replenished, unsustainable, will be depleted
renewable energy
supplies of energy generally not depleted by usage, may be sustainable with the right regulation and maintenance
2 main types of non-renewable energy:
- combustible fossil fuels (ex. coal, oil, natural gas)
- fissionable materials (ex. nuclear)
improvements in energy efficiency that delay transition from non-renewables:
- reducing impacts and saving money
- invention of energy-efficient things
tidal power
energy is drawn from the interaction between solar and lunar gravity on the rotating world ocean, alternating land- and seaward currents generate electricity (tide comes in and again when it goes out, turbines are driven by this direction), perpetually available, has potential impacts on tidal zone habitats, only a few, ideal locations
wave energy
produced when electricity generators are placed on the surface of the ocean and energy can be derived from the waves as they move across water, equipment is susceptible to erosion in water, potential is huge but low actualization
hydropower
flowing or falling water spins turbines, forms largest percentage of global renewable energy, has expensive construction costs, a reservoir may be required
env consequences of hydropower
- damage to ecosystems and species
- displaces humans
- reduces downstream flows (which leads to fish habitat degradation)
- reservoirs become sediment traps
- danger of dap collapse and downstream flooding
- alters streamflow regimes
- increases waterborne diseases and evaporation losses
geothermal power
uses energy from Earth’s interior, heat pumps are placed in the ground and pump cold water down to make warm water come up and heat is circulated, expensive to install, very efficient, has a lot of potential, perpetually available
direct solar power
energy is generated from solar heating via heliostats and photovoltaic cells that concentrate solar power, perpetually available, heliostats are used to warm water and drive turbines, dependent on the length of days and weather patterns
passive solar heating
captures sunlight within the building’s materials and releases heat during periods of the absence of the sun, highly efficient, cost-effective, restrictive building design,
indirect solar power
energy produced by processes that the sun influences, ex. wind, biomass, biofuels
wind power
blades of turbines catch the wind and spin, generator converts mechanical energy into electricity which can be transmitted, can be on land or offshore, perpetually available, differential heating of the surface by the sun results in pressure variations that drive winds
biomass burning
energy produced by burning living and dead plants and animal wastes, potentially renewable when managed properly, used on smaller scales, releases various pollutants and disproportionately affects female health
biofuels
produced by milling, liquifying, fermenting, saccharification, distillation, and denaturation, mixing biofuels with other things (like fossil fuels) reduces the impact of fossil fuels but promotes deforestation (ex. methanol, ethanol, biogas)
hydrogen power
uses water as a renewable storage medium and requires electrolysis to free H from O which is energy intensive, only considered renewable if renewable energy is sued to power the reaction, insufficient infrastructure to drive transition to hydrogen fuel
nuclear fusion
energy is produced by a reaction between two nuclei merging to form one larger nucleus, fusion reaction has been created but cannot be controlled, it becomes self-sustaining which may lead to unlimited power,
global energy use
has increased due to pop and economic growth, major disparity between developing and developed nations, greater demand for power, major energy sources are still fossil fuels, energy systems decentralization is necessary to transition away from fossil fuels
energy co-generation
combined heat and power, uses steam to generate electricity and provide heating, has a lot of expansive potential, divides water into heat and electricity which can be used for diff things
micropower generation
make every building its own power source, everyone makes the energy that they require individually (ex. solar panels)
ecological economics
considers that our econ systems are part of the global ecosystem and that preservation of resources is critical to human development, econ system is based on resources and the ecol effects of this are far too extensive
energy conservation
using less energy, improving things so they waste less energy
energy efficiency
using less energy for a task
