exam 3

Dominant sources of energy in the US (decreasing order)

natural gas ≈ coal > petroleum > nuclear energy.

Energy consumption order in the US (decreasing consumption)

Transportation > electricity generation > industrial uses > residential and commercial uses.

Major use of Petroleum

More than half is used for a single application (transportation).

Major use of Coal

More than half is used for a single application (electricity generation).

Major use of Natural Gas

Used in multiple applications, no single application uses more than half.

Efficiency of electricity generation in the US

Over 90% of energy from fuel converted into electricity.

Inefficiencies in energy use

Amounts to about 50% of US energy use.

Dominant use of petroleum in the US

Transportation.

Transportability of Natural Gas globally

Natural gas is not easily transported globally.

Hydraulic fracturing (fracking)

A method of extracting natural gas from geological formations with high porosity.

Source rock

Geological formations where oil and gas are produced, often referred to in shale contexts.

Rapid growth of production of certain resources

Production first began around 2005, particularly in shale oil and gas.

Spacing of wells in shale oil and gas

Wells are spaced very close together.

Geological resources location

Located only in the United States.

Large scale production locations for oil and gas

Almost exclusively occurring in the United States.

Environmental impacts of shale gas and oil production

Include water quality, water quantity, seismicity, and greenhouse gas emissions.

Carbon intensity comparison of natural gas and coal

Natural gas has lower carbon intensity than coal.

Influence of carbon intensity on greenhouse gas impacts

Carbon intensity is not the only factor influencing greenhouse gas impacts.

Greenhouse gases and radiative forcing

Have a net positive radiative forcing with low uncertainty.

Aerosols and radiative forcing

Have a net negative radiative forcing with high uncertainty.

Historical temperature increase in the past century

Average global temperatures have increased by about one degree Centigrade.

Warming extent predictions for next century

Greatest over land.

Cost of inaction on climate change

Much more than the cost of acting.

Effects of anthropogenic emissions changes

Drive changes in planetary temperatures for hundreds of years.

IPCC warming summary exceptions

Cooling in the North Atlantic does not disprove global warming.

Average material use per person in the US

Currently hundreds of pounds per day.

Dominant materials used in the US

Sand, gravel (minerals) and fuels.

Stock accumulation in industrial economies

Typically more than half of total material flows.

Material reuse in the US

Most materials are used once and then thrown away.

Material use in industrial vs agrarian economies

Is much greater in industrial economies.

Kalundborg, Denmark

A city where industries use wastes as raw materials.

Life cycle of a product includes

All aspects including raw material extraction, manufacturing, use, and recycling.

Functional unit for a product defined as

Basis for comparing alternative products that perform the same function.

Renewable energy sources example

Solar power.

Global distribution of conventional oil and gas resources

Concentrated in a few regions globally.

Life Cycle Assessment (LCA) definition

Methodology for assessing environmental impacts across a product's life cycle.

Primary goal of Circular Economy

Keep resources in use for as long as possible and then recover products and materials.