Nonrenewable Energy

Ch 15

Nonrenewable Energy Resources

99% of the energy that heats the earth and our buildings comes from the sun, the remaining 1% comes mostly from burning fossil fuels.

78% of the commercial energy (sold in market) we use comes from nonrenewable fossil fuels

Burning fossil fuels causes more than 80% of US air pollution and more than 80% CO2 emissions.

Energy Considerations1. What is the net energy yield for the resource?

2. How much will it cost to develop or phase in and use?

3. What constructive subsidies will be used to promote R&D?

4. How will dependence on the resource affect national and global economic and military security?

5. How vulnerable is the resource to terrorism?

6. How will extracting, transporting, and using the resource affect (a) environment; (b) human health; (c) climate

7. Should true costing be considered?

Net EnergyNet energy is the amount of high-quality usable energy available from a resource after subtracting the energy needed to make it available for use.

Net energy ratio = useful energy produced : energy used to produce it

ie. 10:8 (10/8) for every 10 units of energy in oil we use, we waste 8 units of energy to produce it. The net energy ratio is 10/8 or 1.25. The higher the ratio, the greater the net energy.

When the ratio is less than 1, there is a net energy loss.

COALCoal is an abundant energy resource

that is burned mostly to produce electricity and steel.

Coal is the world’s most abundant fossil fuel.

Mostly in USA (25%), Russia (16%), and China (12%)

US coal reserves could last up to 300 years, but an increase of just 4% per year could reduce that to 64 years!

COAL FORMATION ~60% C >90% C~70% C

Advantages of Coal Abundant known world reserves (200

years at current world consumption rate)

Unidentified world reserves (1000 years at current consumption rate)

USA (300 years at current consumption rate)

High Net Energy Yield US subsidies keep prices low

Disadvantages of Coal 60 % surface mined (strip mining) in

USA 40 % subsurface mined Occupational hazards include “black

lung disease”, underground fires and collapse.

20% of coal becomes fly ash, boiler slag, and sludge. Releases mercury and radioactive particles into air.

Expensive to process and transport

Environmental Impacts From Coal

Releases CO into atmosphere Contributes 35% of all CO2 into

atmosphere (global warming) Contributes 70 % of all SO2 (acid

deposition) Contributes 30% of all NO and NO2 (acid

deposition) Produces more fly ash, toxic metals, and

radioactive particles than a nuclear power plant.

Partial Solutions Particle Emission Control Devices

1. Electrostatic Precipitator – utilized for fly ash reduction and to remove particulate emissions by treating air with an electrical charge to capture the suspended particles in the gas flow.

Electrostatic Precipitator

Partial Solutions2. Scrubbers (wet and dry) – are

used to trap particles from gaseous emissions from fossil-fuel-burning power plants especially. The scrubbers prevent most of these particles from entering the atmosphere, especially NOx and SOx, that lead to acid rain

Wet Scrubber

OILOil is a fossil fuel produced by decomposition

of deeply buried organic material such as plants under high temperatures and pressures for millions of years.

Crude oil (petroleum) is a thick liquid containing hydrocarbons that once extracted via drilling are separated into products through fractional distillation (gasoline, aviation fuel, heating oil, diesel oil, asphalt).

Oil Extraction & Processing

Crude oil and natural gas are trapped in porous rock beneath dome shaped structures (anticlines).

To extract oil, a well is drilled into the deposit. Then oil, drawn by gravity out of the rock pores and into the bottom of the well, is pumped to the surface.

Oil is then transported to a refinery by pipeline, truck, or oil tanker.

Oil RecoveryPrimary Oil Recovery – drilling a well and pumping

oil that flows by gravity into the bottom of a well.

Secondary Oil Recovery – After primary, water is injected into nearby wells to force some of the remaining oil to the surface.

Tertiary Oil Recovery (Enhanced Oil Recovery) – after primary and secondary, CO2 gas is used to force some of the heavy oil into the well cavity so it can be pumped to the surface.

OIL DRILLING

Distillation

Then it is distilled and separated into components with different boiling points.

Some of the products called petrochemicals are used as raw materials in industrial organic chemicals, pesticides, plastics, synthetic fibers, paints, and medicines.

Fractional Distillation

Aviation Fuel

Heating Oil

Who Has the World’s Oil?The oil industry is the world’s largest business!

Eleven OPEC Countries (Organization of Petroleum Exporting Countries) have 78% of the world’s crude oil reserves.

Saudi Arabia has the largest (25%)

Canada (oil sand) (15%)

Iraq (11%)

United Arab Emirates (9.3%)

Kuwait (9.2%)

OPEC Nations

How Long Will World Oil Supplies Last?

World reserves 80% depleted in 42-93 years.

US reserves 80% depleted in 10-48 years.

At current rate

Saudia Arabia could supply the entire world’s oil needs for 10 years.

Reserves under Alaska’s North Slope (Prudoe Bay) would meet current world demand for 6 months and US demand for 3 years.

Estimated reserves in ANWR would meet current oil demand for only 1-5 months and US oil demand for 7-24 months.

Advantages of OilRelatively inexpensive

Easily transported via pipelines, trucks and tankers.

High net energy yield

Ample supply for immediate future

Large US government subsidies in place.

Disadvantages of OilWorld oil reserves limited and declining.

Produces pollution SO2, NO, NO2, CO2

Drilling causes land disturbances which accelerates erosion.

Oil spills (Exxon Valdez, Deepwater Horizon)

Extraction releases contaminated wastewater and brine

Disruption to wildlife habitats (ANWR)

Artificially low prices encourage waste

Exxon Valdez Oil Spill (1989)

Exxon Valdez Oil SpillOne of worst man-made environmental disasters (until Deepwater Horizon…) but NOT even in the top 50 oil spills by volumeOil can STILL be found in Prince William Sound!Cost ~$2.1 billion in clean up

Alaska National Wildlife Refuge

ANWR

ANWREssentially unexplored/unknown amounts of oil? Natural gas? No one really knows…and estimates change constantlyBush – yesAlaskans – mostly yes (they receive a portion of proceeds)Obama – noUS DOE – not enough effect on world production to make it worthwhileHighly sensitive and fragile ecosystems

Oil SandOil sand (tar sand) is a mixture of clay, sand, water and

combustible bitumen (heavy oil with high sulfur content).

Dug up by giant shovels, mixed with large amounts of hot water and steam to extract the bitumen, and converted to a low-sulfur synthetic crude oil suitable for refining – VERY energy-intensive (most natural gas)

Exists mostly in Canada (70% known reserves)

Severe environmental degradation to air, water and land

Alberta’s strip mines are considered one of the most destructive projects on earth

Shale OilOil shales contain kerogen which can be extracted from crushed

oil shales by heating them to yield a distillate called shale oil.

Must be heated to increase its flow rate and processed to remove sulfur, nitrogen, and impurities.

Net energy loss

Tar Sand - bitumenShale Oil - kerogen

Natural GasNatural gas is a mixture of 50-90% by volume of methane (CH4)

and smaller amounts of ethane (C2H6), propane (C3H8), and butane (C4H10).

Conventional Natural Gas – lies above most reservoirs of crude oil, but can only be used if a pipeline is put in place. Many times it is considered waste and is burned off

Liquefied Petroleum Gas (LPG) propane and butane gases liquefied when a natural gas field is tapped. Stored in pressurized tanks for use in rural areas.

At very low temperatures LPG can be converted to Liquefied Natural Gas (LNG) can be shipped in refrigerated tankers.

Natural Gas DepositsRussia has 31 % of world’s gas reserves, followed by Iran (15%),

and Qatar (9%).

Known reserves and undiscovered potential reserves of conventional natural gas should last the world for 62-125 years.

United States is 1st/2nd largest natural gas producer with Russia

OK produces 1 billion McF (thousand cubic feet)/year - 4th in country (TX, LA, WY)

Advantages of Natural Gas

Relatively inexpensive and pipelines in place in USA

High net energy yield

Produces less air pollution than other fossil fuels

Extraction not as harmful as for oil and coal

Easily processed and inexpensive to transport

Can be used in fuel cells

Can be used in combine-cycle natrual gas systems (cogeneration)

Viewed as “transitionary fossil fuel” as world switches to alternative energy resources because of less air pollution

Disadvantages of Natural Gas

H2S and SO2 released during processing, and CO2 and hydrocarbons during burning.

LNG processing is expensive, dangerous, and results in lower net energy yield

Leakage of pipes and tanks (CH4) contributes to global warming

Extraction can release contaminated wastewater and brine

Land subsidence

Disruption to wildlife habitats (ANWR)

US Shale Plays

Fracking

http://www.youtube.com/watch?v=VY34PQUiwOQ

Uses water/sand/chemicals to extends and prop open fractures in rock to allow flow of oil and natural gas

Generally done thousands of feet below aquifers/drinking water so limited possibility for contamination

No proven connection to earthquakes! Oops…