Energy and the Environment Flashcards

Flashcards for Energy and the Environment review.

Energy

Capability to do work

Unit of measure for energy

Joule (J)

Per-capita energy use

Energy usage per person

Energy efficiency

Measure of useful output energy vs the input energy of the device

Percent efficiency formula

Output/Input x 100%

Sustainable

Capable of being maintained at length without interruption, weakening, or loss of essential characteristics such as matter and energy

How solar energy reaches Earth

Absorbed, reflected, used for photosynthesis, used to drive the water cycle, transported through air and water currents

Solar heat collector

A device that absorbs solar energy and converts it into thermal energy which is then carried by a fluid and distributed

Photovoltaic Cells (Solar Panels)

Photons of EMR are absorbed by the photovoltaic cell, causing the material in the cell to eject electrons

Energy Conversions for Solar Energy

Solar -> Electrical (photovoltaic cells); Solar collectors -> Thermal

Advantages of Solar Energy

No gaseous emissions, long lifespan, little maintenance, easily installed, plentiful, no fuel costs, renewable

Disadvantages of Solar Energy

Large amount of space required, photovoltaics require toxic metals, harvesting heavy metals could damage sea floors, more costly than conventional systems, each unit produces a small amount of energy, sunlight is intermittent and variable, conversion to electrical energy is not as efficient, cannot meet current energy demand, visual pollution, high cost of energy

Energy Conversions for Wind Turbines

Solar -> Gravitational potential (falling air masses create wind) -> Kinetic (wind) -> Kinetic (turbine) -> Electrical

Advantages of Wind Turbines

No gaseous emissions, many suitable sites available, renewable, land beneath a turbine can still be used for farming, no fuel costs, long lifespan for turbines with minimal operating costs, self-sufficient, land can also be used for agriculture, easily installed, perceived as environmentally friendly, permits individuals or smaller-scale facilities to generate power, is a means to reduce the emission of greenhouse gases

Disadvantages of Wind Turbines

Large amount of land required, danger to birds and bats, few ideal sites, more costly than conventional systems, wind is variable and intermittent, cannot meet current energy demand, visual or noise pollution, high cost of energy

Energy Conversions for Hydroelectric Dam

Solar -> Thermal -> Gravitational potential -> Kinetic (water) -> Kinetic (turbine) -> Electrical

Advantages of Hydroelectric Dam

No gaseous emissions in Canada, plentiful sites, renewable, no fuel costs, plants have a long lifespan, efficient process with large energy yield, cost per kilowatt-hour of energy produced is relatively low

Disadvantages of Hydroelectric Dam

Large amount of land is covered by reservoir, impacts aquatic ecosystem, can change chemical balance in waterways, increases erosion, changes water distribution patterns, methane and carbon dioxide can be produced as a result of decay of dying organisms caught in the dam, more costly than conventional systems, buildup of silt reduces longevity of power production, may involve displacement of people or loss of archeological sites and artifacts, visual pollution, development of projects is highly contentious

Fossil Fuels

Burned to release energy such as coal, gasoline, and natural gas

Energy Conversions for Fossil Fuel Power Plants

Solar + Chemical Potential -> Thermal -> Kinetic -> Electrical

Advantages of Fossil Fuels

Cheap, drives our economy, accessible

Disadvantages of Fossil Fuels

Inefficient, emissions (SOx, NOx, COx), non-renewable

Biomass

Fuel from plants

Energy Conversions for Biomass

Solar P.S. + Chemical Potential of living plants and processing -> Thermal -> Kinetic -> Electrical

Advantages of Biomass

Relatively renewable

Disadvantages of Biomass

Energy heavy process , still burning fuel, SOx, NOx, COx, if we chop down trees when plants decrease in number, lack of carbon sinks

Combustion reaction

A highly exothermic reaction when a fuel source reacts with oxygen to form the most common oxides of the atoms involved

Standard Heat of Combustion, ΔH

Amount of heat released when a substance undergoes combustion

Standard Molar Heat of Formation, ΔHf

Amount of energy absorbed or released when 1 mole of a substance is formed from its elements

Review of the nucleus of an atom

Every atom's nucleus contains protons and neutrons

Protons and neutrons

of protons = atomic #; #neutrons = mass # - atomic

Nuclear Reaction

A reaction that involves the nucleus of an atom

Types of nuclear reactions

Nuclear decay, nuclear fission and nuclear fusion

Nuclear Notation

Representation of an atom that lists the chemical symbol for the element, it's atomic number (number of protons) in subscript, and its mass number (total of the protons and neutrons in an atom) in superscript

Nuclear Radiation

Energy released as high speed charged particles or in the form of electromagnetic waves; ionizing radiation

Types of Nuclear Radiation

Alpha, Beta, Gamma

Alpha Radiation

Releases alpha particles (α), which are Helium, during nuclear decay or reactions; least penetrating of the three types of radiation

Beta Radiation

Release of beta particles (β), which are electrons, during nuclear decay or reactions

Gamma Radiation

A stream of gamma photons. Gamma photons are the most damaging of the three principal types of radiation

Radioactive Decay

Within an atom, an incredibly strong nuclear force attracts the protons to neutrons, neutrons to neutrons and even protons to protons

Nuclear Fusion

A reaction in which two small nuclei combine to form one larger, heavier nucleus, releasing enormous amounts of thermal energy

Nuclear Fission

Reaction in which a large nucleus is broken down into two smaller nuclei releasing energy

Energy Conversion of Nuclear Reaction

Potential (intranuclear) -> Thermal -> Kinetic (turbine) -> Electrical

Advantages of Nuclear Fission

No gaseous emissions other than water vapor, high energy-to-mass-of-fuel ratio, uranium reserves are more plentiful than fossil fuel in terms of stored energy content

Disadvantages of Nuclear Fission

Radioactive wastes, thermal pollution, risk of meltdown, non-renewable, plants are more costly to build than other thermal plants, danger to workers and public if radiation is not contained, perception that nuclear reactors pose a danger to society, nuclear materials can be used to develop nuclear weapons, risk of sabotage

Variables in Einsten's Formula: AE = Amc²

E = energy (J); m = mass (kg); C = 3.00 x 10^8 m/s

Geothermal Energy

Energy originating from radioactive decay in the Earth's core

Energy Conversions for Geothermal Energy

Potential (intranuclear) -> Thermal -> Kinetic (turbine) -> Electrical

Advantages of Geothermal Energy

Source is renewable, produces less pollution than fossil fuels, can be used to replace current methane-fueled furnaces, no fuel costs, long lifespan, can be less costly than conventional systems, perceived as environmentally friendly, is a means to reduce the emission of greenhouse gases

Disadvantages of Geothermal Energy

Some gaseous pollution (H2S (g) and CO2(g)), acids formed from emissions can cause corrosion of metals in facility and acid deposition, thermal pollution, disruption to wildlife, few ideal sites for an electrical-energy production facility, not all sites are renewable, hydrogen sulfide smell is often associated with development of sites

Tidal Energy

Gravitational and Kinetic energy associated with ocean tides

Energy Conversions for Tidal Energy

Gravitational -> Kinetic (turbine) -> Electrical

Advantages of Tidal Energy

Renewable, no gaseous emissions, no fuel costs

Disadvantages of Tidal Energy

More costly than conventional systems, few ideal sites, tidal energy is only available at certain times of the day, cannot meet current energy demands, visual pollution, high cost of energy is not popular with consumers

Hydrogen-Fuel Cells

Uses the formation of water from its elements, H2 and O2 to generate energy

Energy Conversions for Hydrogen-Fuel Cells

Chemical Potential -> Electrical

Advantages of Hydrogen-Fuel Cells

Only emission is pure distilled water

Disadvantages of Hydrogen-Fuel Cells

No infrastructure, hydrogen explodes, hard to contain