WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF FOSSIL FUELS?

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF FOSSIL FUELS?

Fossil fuels supply most of our commercial energy

• Most commercial energy comes from extracting and burning nonrenewable energy resources obtained from the earth’s crust.

– 87% from carbon-containing fossil fuels (oil, natural gas, and coal).

– 6% from nuclear power.

– 8% from renewable energy resources—biomass, hydropower, geothermal, wind, and solar energy.

Energy use by source throughout the world and US in 2009

We depend heavily on oil

• Crude oil (petroleum), is a black, gooey liquid consisting of hundreds of different combustible hydrocarbons along with small amounts of sulfur, oxygen, and nitrogen impurities. – Also known as conventional oil and as light or

sweet crude oil. – Oil, coal, and natural gas are called fossil fuels

because they were formed from the decaying remains (fossils) of organisms that lived millions of years ago.

We depend heavily on oil

• Global peak production is the point in time when we reach the maximum overall rate of crude oil production for the whole world.

• After extraction, crude oil is transported to a refinery by pipeline, truck, or ship (oil tanker).

• Crude oil is heated to different boiling points in a complex process called refining to separate it into different layers, such as petrochemicals.

When crude oil is refined, many of its components are removed at various levels

How long might supplies of conventional crude oil last?

• Crude oil is now the single largest source of commercial energy in the world.

• Geologists project that known and projected global reserves of conventional crude oil will be 80% depleted sometime between 2050 and 2100. The remaining 20% will likely be too costly to remove.

OPEC controls most of the world’s crude oil supplies

• 13 countries make up the Organization of Petroleum Exporting Countries (OPEC).– In 2010, OPEC holds about 77% of the world’s proven

crude oil reserves. – OPEC’s members are Algeria, Angola, Ecuador,

Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates, and Venezuela.

• The U.S. has only about 2% of the world’s proven oil reserves. China has only 1.1%, India has 0.4%, and Japan has no oil reserves.

Crude oil use has advantages and disadvantages

Using crude oil has advantages and disadvantages

• Extraction, processing, and burning of nonrenewable oil and other fossil fuels have severe environmental impacts. – Land disruption.– Air pollution.– Greenhouse gas emissions.– Water pollution.– Loss of biodiversity.

Using crude oil has advantages and disadvantages

• Oil spills cause catastrophic damage.– In 2010, the BP Company’s Deepwater Horizon oil-

drilling rig exploded, spilling an estimated 679 million liters (180million gallons) of crude oil into U.S. Gulf Coast waters.

– In 1989, the oil tanker Exxon Valdez ran aground and spilled 42 million liters (11 million gallons) of oil into Alaskan waters.

– More than 2.5 times the estimated amount of crude oil spilled in the 2010 Gulf Coast disaster has been spilled from off the coast of Nigeria with little media attention.

Will heavy oil be a useful resource?

• Oil shale is rock that contains a solid combustible mixture of hydrocarbons called kerogen which can be processed to produce shale oil.

• Producing shale oil requires large amounts of water and has a low net energy and a very high environmental impact.

• Estimated potential global supplies of unconventional shale oil are about 240 times larger than estimated global supplies of conventional crude oil.

Shale oil can be extracted from oil shale rock

Natural gas is a useful and clean-burning fossil fuel

• Natural gas is a mixture of gases of which 50–90% is methane (CH4).

– Has high net energy.– Versatile fuel that can be burned to heat indoor

space and water, propel vehicles and produce electricity.

– Cleanest-burning among the fossil fuels, releasing much less CO2 per unit of energy than coal, crude oil, and synthetic crude oil from tar sands and oil shale.

Use of fracking to extract natural gas is controversial

• Hydraulic fracturing, or fracking, pumps water mixed with sand and some toxic chemicals underground to fracture deep rock and free up natural gas stored there. – The gas flows out, along with a toxic slurry of water,

salts, toxic heavy metals, and naturally occurring radioactive materials that is stored in tanks and holding ponds.

– Drillers maintain that fracking is necessary for exploiting this reserve at a reasonably low cost, and they argue that no groundwater contamination directly due to fracking has ever been recorded.

Coal is a plentiful but dirty fuel

• Coal is a solid fossil fuel formed from the remains of land plants that were buried 300–400 million years ago and exposed to intense heat and pressure over those millions of years.

• Coal is burned in power plants to generate about 42% of the world’s electricity, and burned in industrial plants to make steel, cement, and other products.

• The three largest coal-burning countries are China, the U.S., and India.

• Coal is plentiful and cheap.

Coal is a plentiful but dirty fuel

• Mining and burning coal have severe impacts on the earth’s air, water, land, climate, and human health.– Coal-burning power and industrial plants are among the

largest emitters of the greenhouse gas CO2.

– Coal burning emits trace amounts of toxic and radioactive materials.

– Burning coal produces a highly toxic ash that must be safely stored, essentially forever.

– China uses three times as much coal as the U.S. and it has become the world’s leading emitter of CO2 and of sulfur dioxide.

CO2 emissions vary with different energy resources

Coal is a plentiful but dirty fuel

– Coal is cheap but most of the harmful environmental and health costs are not included in the price.

– The clean coal campaign.• Powerful U.S. coal companies and utilities oppose

measures.• Publicity campaign built around the misleading

notion of clean coal. – Burn coal more cleanly by adding costly air pollution

control devices. – There is no such thing as clean coal.

Coal has advantages and disadvantages