second gk s

fossil fuels

Highly combustible substances formed from organisms 100-500 million years ago.

efficiency of fossil fuels

They are efficient to burn, ship, and store due to high energy content.

electricity

A secondary form of energy.

conditions forming coal

Organic matter compressed under high pressure in swamps.

highest coal reserves

The U.S. (28% of the world).

petroleum (crude oil) usage in the U.S.

Accounts for 40% of total energy use.

EROI

Energy Returned on Investment = Energy returned / Energy invested.

decreasing EROI for U.S. oil

Resources are harder to reach; more energy is needed for extraction.

cleanest burning fossil fuel

Natural gas.

EROI of oil today vs. past

Declined from 100:1 to 14:1.

fracking

To extract oil and reduce U.S. foreign dependence.

main coal mining techniques

Strip mining, mountaintop removal, underground mining.

Chernobyl incident

A nuclear reactor exploded, releasing radiation.

spent nuclear fuel storage

Wet storage for 5 years, then encased in steel and concrete.

passive solar energy

Sunlight is absorbed naturally through building design.

active solar energy

Technology used to focus, store, or move solar energy.

large solar project in California

Ivanpah Solar Tower.

drawback of solar energy

Intermittent sunlight, requires storage like batteries.

wind energy

Energy from air movement, an indirect form of solar energy.

EROI of wind energy (2023)

23:1.

NIMBY syndrome

Local opposition to wind turbines.

hydropower

Uses moving water to turn turbines and generate electricity.

run-of-river approach

Small dams generate power without heavily disrupting flow or fish.

tidal energy stations

They trap water and use outgoing tides to turn turbines.

wave energy challenges

Expensive to transmit electricity from deep ocean to shore.

geothermal heat cause

Radioactive decay under Earth's surface.

GSHP

Ground-source heat pump; transfers heat between buildings and soil.

biofuels

Liquid fuels from biomass used in transportation.

EROI of corn-based ethanol

About 1.5:1 (inefficient).

major biofuels besides ethanol

Biodiesel (from oils, fats), algae, and switchgrass.

hydrogen fuel cell

A device that uses hydrogen to produce electricity.

toxin

A poisonous substance produced by living organisms.

toxicant

A toxic substance from human activity.

toxicology

Effects of toxins and toxicants on organisms.

teratogen

A substance that causes birth defects.

neurotoxin

A toxin that damages or disrupts the nervous system.

carcinogen

A substance that causes cancer.

allergen

A substance causing allergic reactions.

endocrine system

Regulates hormones; endocrine disruptors interfere with this system.