Unit 6: Energy Resources and Consumption

Comprehensive practice flashcards covering Unit 6 of AP Environmental Science, including renewable/nonrenewable classifications, fossil fuels, nuclear energy, biomass, solar, hydro, geothermal, hydrogen fuel cells, and energy conservation.

How are nonrenewable energy sources defined?

Sources that exist in a fixed amount and involve energy transformation that cannot be easily replaced or regenerated, such as fossil fuels and nuclear energy.

What is the difference between depletable and nondepletable renewable energy sources?

Depletable renewables can run out if overused (e.g., wood, charcoal, ethanol), while nondepletable renewables do not run out regardless of use (e.g., solar, wind, geothermal).

What is the primary trend in energy consumption for developing countries as they become more industrialized?

Their reliance on fossil fuels increases, and their energy use per person increases as residents achieve higher standards of living.

Which nation's residents use significantly more energy than the world average?

The average resident of the US uses $5$ times as much energy as the world average.

What are the three largest global sources of energy in order of use?

First is fossil fuels, second is hydroelectric energy, and third is nuclear energy.

List the three types of coal in order of increasing energy density and quality.

Lignite $ightarrow$ Bituminous $ightarrow$ Anthracite.

What is cogeneration (Combined Heat and Power)?

A process where a fuel source is used to generate both useful heat and electricity simultaneously, often achieving efficiencies close to $90\%$.

What is the primary chemical component of natural gas, and why is it considered the 'cleanest' fossil fuel?

It is mostly methane ($CH_4$) and produces about $\frac{1}{2}$ as much $CO_2$ as coal, virtually no particulate matter, and no mercury when burned.

Which countries hold the largest global reserves of coal, natural gas, and oil?

The US holds the largest coal reserves, Russia holds the largest natural gas reserves, and Venezuela holds the largest oil reserves.

What are tar sands and what is the specific form of petroleum recovered from them?

Tar sands are a combination of clay, sand, water, and bitumen. Bitumen is a thick, sticky, semi-solid form of petroleum.

What is the general process for generating electricity from fossil fuels?

Fuel combustion produces heat $\rightarrow$ heat turns water into steam $\rightarrow$ steam turns a turbine $\rightarrow$ the turbine powers a generator $\rightarrow$ the generator produces electricity.

What are the environmental consequences of hydraulic fracturing (fracking)?

It can cause groundwater contamination from fracking fluid or hydrocarbons, depletion of local water sources, and increased seismic activity (earthquakes).

How is nuclear power generated through fission?

A neutron strikes the nucleus of an atom of Uranium-235 ($U\text{-}235$), splitting it and releasing a large amount of heat, which is then used to generate steam for a turbine.

Define the term 'Radioactive Half-Life'.

The amount of time it takes for $50\%$ of a radioactive substance to decay or break down.

Why is thermal pollution a concern for nuclear power plants?

The release of hot water used for cooling back into surface waters can cause thermal shock, leading to decreased oxygen ($O_2$) levels and fish suffocation.

What is the difference between modern carbon and fossil carbon in the context of biomass burning?

Modern carbon is $CO_2$ that was recently sequestered from the atmosphere by plants (carbon neutral), while fossil carbon was stored for millions of years (increases atmospheric $CO_2$).

What are individual photovoltaic (PV) cells and what is their main drawback?

PV cells (solar panels) contain a semiconductor, usually silicon, that converts light energy directly into electricity; their main drawback is intermittency (they only work during the day).

What are the ecological impacts of water impoundment (dams)?

Impacts include flooding of ecosystems behind the dam, prevention of fish migration, and sedimentation (sediment buildup) that changes upstream and downstream water conditions.

How does a ground source heat pump differ from true geothermal heating?

A ground source heat pump uses the earth as a heat sink or source for air conditioning/heating ($50\text{-}60^\circ \text{F}$), whereas true geothermal heating uses heat from magma to warm water piped deep underground.

What are the inputs and outputs of a hydrogen fuel cell?

The inputs are hydrogen gas ($H_2$) and oxygen ($O_2$); the only waste product or emission is water ($H_2O$).

What is the difference between steam reforming and electrolysis for hydrogen production?

Steam reforming separates $H_2$ from methane ($CH_4$) using steam but emits $CO_2$; electrolysis uses an electrical current to split water ($H_2O$) into $O_2$ and $H_2$ without $CO_2$ emissions.

What are the common methods for conserving energy in a sustainable home design?

Methods include passive solar design (south-facing windows, roof overhangs), well-insulated walls, and using deciduous shade trees to block summer sun while allowing winter sun.

What are CAFE (Corporate Average Fuel Economy) standards?

Regulations in the US that require auto manufacturers to make cars that meet specific miles-per-gallon ($MPG$) standards to improve fuel economy.

What is 'peak demand' and how can it be managed?

Peak demand is the time when electricity use is highest; it can be managed by a variable price model where users pay a higher rate per $kWh$ during peak hours to discourage use.

What are fossil fuels?

Fossil fuels are natural substances formed from the decomposed remains of ancient plants and animals, primarily consisting of carbon and hydrocarbons. They include coal, oil, and natural gas.

What is the process of fossil fuel formation?

Fossil fuels form over millions of years through the burial and compression of organic material under layers of sediment, leading to chemical changes and releasing energy.

What is geothermal energy?

Geothermal energy is heat energy generated from the Earth's core, which can be harnessed for electricity and direct heating applications.

How does solar power work?

Solar power is generated by converting sunlight into electricity using photovoltaic cells or by concentrating solar power systems that harness thermal energy.

What is wind energy?

Wind energy is the process of converting wind kinetic energy into mechanical energy, typically through wind turbines, to generate electricity.

What are the benefits of renewable energy?

Benefits of renewable energy include reduced greenhouse gas emissions, decrease in air pollution, sustainability, and decreased reliance on fossil fuels.

What is bioenergy?

Bioenergy is energy derived from biological materials, such as plants and animal waste, which can be converted to biofuels or used directly for heating.

What is hydropower?

Hydropower is generated by utilizing the energy of flowing water, usually from rivers or dams, to produce electricity through turbines.

What role do batteries play in renewable energy systems?

Batteries store excess energy generated from renewable sources for later use, enhancing the reliability and stability of renewable energy systems.

What is energy efficiency?

Energy efficiency is the goal of using less energy to provide the same level of energy service, thereby reducing energy waste and costs.

What are the common challenges faced by renewable energy sources?

Challenges include intermittency in power generation, storage issues, initial high costs, and the need for updated infrastructure.

What are some technologies for energy storage?

Technologies include lithium-ion batteries, pumped hydro storage, compressed air energy storage, and flywheels.

How does energy consumption vary globally?

Energy consumption varies by region and development level, with developed countries typically consuming more per capita than developing nations.

What are energy policies?

Energy policies are laws and regulations set by governments to manage the production, distribution, and consumption of energy resources.

What is the significance of the Paris Agreement?

The Paris Agreement is an international treaty that aims to mitigate climate change by limiting global warming and fostering global cooperation on emissions reductions.

What are smart grids?

Smart grids are modernized electrical grids that use digital communications technology to monitor and manage the transport of electricity from all generation sources to meet varying electricity demands.

Define 'energy transition'.

Energy transition refers to the significant structural change in the energy system, transforming it from fossil fuel dependence to sustainable renewable energy.