Topics to be addressed:

• Energy sources that fuel our civilization • History of energy use • Patterns of energy production and consumption • Crude oil, coal, natural gas, and nuclear energy • Environmental, political, and social impacts of fossil fuel use

Energy sources used today

• Growth in coal has slowed, but oil and gas are still rising.

Figure 17.5

Canadians are the highest per-capita energy users on planet Earth !

Figure 17.3

•Hydrocarbons •Found in sedimentary rock •Remains of prehistoric animals, forests and sea floor life (FOSSIL FUELS) •Toxic to wildlife (spills) •Climate change •Air pollution and acid rain

Canadian production about 3 million barrels/day (ie., now red on map!)

Fossil fuels

• These are fossils in the sense that they are made of remnant decayed material from ancient organisms.

• Compressed tissues of plants (and some animals) from 100–500 million years ago store chemical energy from photosynthesis.

• This greatly concentrated energy is released when we burn coal, oil, or gas.

Fossil Fuels

•

Anaerobic

(without oxygen) decomposition is required for fossil fuel formation.

(

Aerobic

= decay in presence of oxygen) Anaerobic environments exist at the bottom of the ocean, in deep lakes, and in swamp sediments.

FOSSIL FUEL FORMATION

• • • • • Plants and animals die Organic material settles in anaerobic site and is partly decomposed Organic material is buried Heat and pressure alter chemical bonds Coal, gas, oil formed

Figure 17.6

•

Coal:

Compressed under high pressure to form dense carbon structures.

•

Natural gas:

Primarily methane, CH 4 , is produced: – By bacteria near surface – By heat and pressure deep below ground •

Crude oil:

Sludgelike mix of hundreds of types of hydrocarbon molecules. Forms at temperatures and pressures found 1.5–3 kilometers below ground.

The ANWR National Wildlife Reserve: Contentious US Issue

Alaska’s North Slope

Figure 17.1

Distribution of Conventional Fossil Fuel Reserves

Figure 17.8

Distribution of Conventional Fossil Fuel Reserves

• Saudi Arabia has the most oil.

• Russia has the most natural gas.

• The U.S. has the most coal.

Oil: Drilling

• Liquid oil exists in pores in rock deep underground.

• We must drill into rock and extract oil by using a pressure differential.

• The more oil is extracted, the harder it is to extract:

Refining Crude Oil

• Crude oil from the ground is a messy mix of hundreds of hydrocarbons.

• It is put through a

refining process

to segregate different components.

–Small-chain hydrocarbons boil at cooler temperatures in a distillation column, isolating lighter weight oils (

e.g., butane

).

–Long-chain hydrocarbons boil at hot temperatures, isolating heavier oils (

e.g., lubricating oils

).

Refining crude oil

Petroleum Products

• Refined components of crude oil are used to manufacture many of the material goods we use every day.

• Petroleum products include: •

Helmet, water bottle, sunglasses, clothing, sunscreen, gear and chain grease

Figure 17.11

Oil Conservation

• Although oil is a limited resource, prices have remained low enough that few people feel the need to conserve • Conservation measures taken in the 1970s resulting from fears of oil shortages were mostly abandoned, but recent price increases may cause history to repeat itself • As oil supplies dwindle, conservation will again become popular.

• Geologist M. King Hubbert predicted U.S. oil production would peak around 1970 and then decline.

• He was only a few years off.

Figure 17.15a

Depletion of Oil Reserves

• World oil reserves are a finite resource as well.

• Some observers predict they have peaked.

Figure 17.15b

Vehicle Fuel Efficiency

• Automobile fuel efficiency rose after the oil shocks of the 1970s, but has stagnated since then.

Figure 17.13

•

Clay, sand, water and bitumen

•

Black oil rich in sulphur

•

Oil sands must be heated and treated with steam to separate bitumen

•

Energy intensive

•

Sulphur dioxide emissions

•

Huge waste disposal ponds

•

Habitat fragmentation

•

Greenhouse gas emissions

Photos: Syncrude

•Most CO 2 and air pollution per unit energy •Sydney tar ponds - the most contaminated site in Canada

* New technology may present cleaner coal burning options (eg. improved boiler efficiency)

Illustration: Brooks Johnson, Ontario Clean Air Alliance

• Several types of coal exist, depending on the amount of heat and pressure that overlying sediments have exerted.

Figure 17.16

• Coal is mined either underground, in

subsurface mining

, or from the surface, in

strip mining

.

Figure 17.17

•Gaseous hydrocarbon mixture Primarily methane – CH 4 Also C 3 H 8 and C 4 H 10 •Now 45% of Canada’s energy production •Much cleaner and more efficient Problems: potent greenhouse gas, wildlife disruption, flaring & H 2 S

Natural Gas: History

• Seeps known for 2,000+ years • Used for street lighting in the 1800s • Became commonly used after WWII once pipeline technology became safer

Natural Gas Formation

•

Forms in two ways: Biogenic

gas = formed at shallow depths by anaerobic decomposition of organic matter by bacteria

Thermogenic

gas = formed at deep depths as geothermal heating separates hydrocarbons from organic material

(Formed directly OR from crude oil altered by heating. Thus gas deposits often occur with oil deposits.)

Gas Extraction

• Initially, gas comes out on its own from natural pressure.

• Later, it must be pumped out.

Horsehead pump to extract natural gas

Figure 17.18

15% of Canada’s electricity >50% of Ontario’s electricity

Nuclear Power

• 6.8% of world’s primary energy supply • 16.9% of world’s electricity production • Grew 15-fold since 1970 • Has stagnated due to safety concerns and economics

Nuclear energy

• • • Two ways to produce nuclear energy: Fission: used for power Fusion: not yet used commercially

Nuclear Energy

• Comes from the radioactive element

uranium

• The nuclear fuel cycle enriches forms of uranium to make it into usable fuel.

• Waste fuel is radioactive and must be specially disposed of.

Figure 17.24

Nuclear Energy: Fission

•

Fission

= energy is released by splitting apart uranium nuclei by bombarding them with neutrons.

• This is the process used in nuclear reactors and weapons.

Figure 17.25a

Nuclear Energy: Fission

• Note that several neutrons are produced from each reaction with one neutron.

• This means the reaction could be a runaway reaction, or explosion.

• In a commercial reactor, the reaction must be controlled.

• Metal rods are used to absorb the extra neutrons. Engineers move these

control rods

to regulate the reaction.

Figure 17.25a

Nuclear Reactor

• In a reactor, fission boils steam to turn a turbine and generate electricity

Figure 17.26

Nuclear Troubles

• Although nuclear power is clean, lacking the pollutants of fossil fuels, it has faltered, due to: – • Cost overruns – • Public fears of catastrophic accidents – Three Mile Island, 1979 – Chernobyl, 1986 • 450 nuclear plants remain operating today in the world; 100 have closed.

•No greenhouse gas emissions/air pollution (except mining) •Minimal land disturbance •High energy output with minimal environmental impact Problems: •Storage of nuclear waste (DGD in Canadian shield proposed) •Expensive •Public trust / meltdown risk (older systems)

Renewable Energy Sources

•

Biomass & Biogas:

from combustion of organic material •

Hydropower:

from water flowing through dams •

Solar:

from the sun’s rays •

Wind:

from the wind •

Geothermal:

ground from heat and heated water beneath the •

Ocean sources:

from the tides and from waves •

Hydrogen:

fuel and fuel cells that store renewable energy in usable form

GLOBAL ENERGY SUPPLY

SOURCES OF ELECTRICITY

Renewable Sources: Outlook

•

The outlook for renewable sources is good.

Growth should continue.

But will governments raise subsidies to the level offered to fossil fuels?

Will research and development proceed fast enough?

Will consumers choose alternative energy sources

Turbine generator inside dam

Hydro Power

•

12% of Canada’s energy

•

No air pollution

•

Downstream irrigation regulation

Pros and cons of hydroelectric

PROS

power

CONS

• Renewable as long as water is not overdrawn from river system • Clean: no greenhouse gas emissions • Dams cause numerous disruptive ecological effects to riparian environments • Dams bring a mix of impacts for people

Wind Power

• Takes kinetic energy of wind and converts it to electrical energy • Fastest growing power source today • Technology =

wind turbines

, machines with turning blades that convert energy of motion into electrical energy by spinning a generator

Windmills have been used for centuries.

First wind turbine for electricity: late 1800s

Source: Canadian Wind Energy Atlas

Annual average wind power

Wind power

Figure 18.12a

Wind Power: Wind Turbines

• Wind spins the blades, which turn the gearbox, which turns the generator to produce electricity.

Figure 18.9

Wind Power: Wind Turbines

•

Turbines are often located in groups (“wind farms”) at sites with exceptionally good wind conditions.

Wind Power

• Most wind power so far is concentrated in a few nations.

Figure 18.11

Wind Power

•

By surveying with anemometers that measure wind speed, people can determine sites that will be best for wind power production.

From The Science behind the Stories

•

Near zero environmental impact

•

Potential exists to reverse current level of impact from other sources

•

Each turbine powers at least 250 Alberta homes!

•

It’s windy here!

PROS

Pros and Cons of Wind Power

CONS

• Renewable, as long as wind blows • No emissions after equipment made, installed • Can allow local decentralized control over power, and local profit from electricity sales • Costs low after initial investment; costs dropping • Not everywhere is windy enough • Windy sites can be far from population centers • Blades kill birds, bats • High start-up costs

Biomass

Organic substances produced by recent photosynthesis (

unlike fossil fuels, products of ancient photosynthesis

)

More than 1 billion people burn fuelwood as their principal power source for cooking, heating, etc.

Biomass

•Wood, agricultural wastes, garbage 15% of world’s energy 6% of Canada’s energy Mainly in developing nations •Less emission of greenhouse gases if forest replacement exceeds removal (wood) •Biofuels for cars (ethanol - Brazil)

Problems:

land clearing and associated problems (wood)

Pros and Cons of Biomass

PROS:

• Renewable, as long as forests aren’t depleted • Usually inexpensive • Some waste can be used for energy • Capturing methane reduces that greenhouse gas

CONS:

• Does not always reduce CO 2 emission as much as other renewables • Cutting trees for fuelwood can lead to deforestation • Growing crops for fuel (e.g., corn for ethanol) is highly inefficient

Biogas Production from Manure

• • • •

Electricity Generation Gas for cooking Heat Utilized in Southern Alberta (eg. Iron Creek Hutterite Colony) Photos: Rokai Pig Farm, Kaunas, Lithuania http://www.folkecenter.dk/en/rokai/rokai.html

INLET OUTLET

Difficulties

•

Temperature optima maintenance

•

Acidity: pH sensitive anaerobic bacteria (lime required)

•

NH 3 toxicity (control input rate)

•

CH 4 won’t liquefy – difficult to store (must use or burn)

Geothermal Energy

• Radioactive decay of elements deep in Earth’s core creates heat that rises toward the surface.

• This heats magma of volcanoes, and also underground water.

• Sometimes water spurts through to the surface in

geysers

.

•

Geothermal power plants use the energy of naturally heated water to generate electricity.

Geothermal Energy

•

Underground heat warms water, and steam turns turbines and generators.

•

Condensed steam is reinjected into the aquifer to keep up pressure.

Figure 18.13a

Geothermal Energy

•

Iceland uses geothermal energy to heat water for 86% of its homes.

•

Heat pumps using surface heat can also be very efficient.

Figure 18.13b

Geothermal plant in Iceland

Pros and Cons of Geothermal Power

PROS CONS

• Renewable, as long as water is heated naturally • Much lower greenhouse gas emissions than fossil fuels • Can be inexpensive in areas where geothermal heating naturally occurs • Heated water may give out after a while—hotspot moves or aquifer pressure drops • Salts in water can corrode equipment, shorten lifespan • Limited to geographic areas where geothermal heating naturally occurs

Ocean Energy Sources

• Three sources from oceans:

Tidal power

: The twice-daily flow of tides (rising and falling of seas due to the moon’s gravitational pull) creates energy of motion that can be converted to electricity.

Wave power

: Motion of waves at ocean shores creates energy of motion that can be converted to electricity.

Tidal Energy

•

The LaRance power station in France is the world’s largest tidal generating station. Its turbines spin with both incoming and outgoing tides.

Figure 18.14b

Wave Energy

•

There are several designs for wave energy stations.

•

In this one, air is compressed in a chamber with each incoming wave, driving a turbine to spin a generator.

Figure 18.15

Pros and Cons of Ocean Power

PROS

• Renewable, as long as oceans behave as they always have • No greenhouse gas emissions

CONS

• Development could take up large portions of coastline valuable for other uses • Could interfere with ecology of estuaries and intertidal shorelines

Source: DOE, USA

Solar Energy

• Use of energy from the Sun •

Huge potential: Each day Earth receives enough sunlight to power human consumption for 27 years, if we could somehow capture it all.

Solar energy

•

Passive solar

= designs buildings to maximize capture of sunlight in winter, but keep buildings cool in summer

through window placement, absorbent materials

… •

Active solar

= uses technological devices to focus, move, or store solar energy –

Solar panels: dark heat-absorbing metal plates in glass covered boxes, often mounted on roofs

Solar energy: Active solar

•

Portable solar cookers focus sun’s rays onto a small area—here, boiling water in Nepal. These are becoming popular throughout the developing world.

Figure 18.6

•

Numerous mirrors focus sunlight on a receiver atop a “power tower” in the California desert. This facility was the first to generate much solar power commercially.

Application: Steel Production Facility Source: www.technologystudent.com/energy1/solar4.htm

Solar Energy: Active Solar

•

Gaviotas, Colombia, uses solar panels in homes and businesses for heating, cooling, and water purification

(This photo is from Bogotá)

Figure 18.5

Solar Energy: PV Cells

•

Photovoltaic cells (PV cells)

convert solar energy directly into electrical energy by making use of the

photoelectric effect

: • Sunlight strikes one of a pair of negatively-charged metal plates • Electrons migrate to opposing plates, and electric current is produced.

•

In PV cells, light strikes negatively charged phosphorus enriched silicon, and electrons migrate downward through silicon to positively charged boron-enriched silicon.

•

Solar Energy: PV Cells

Electrons move from the phosphorus side of the silicon plate to the boron side, creating electric current. PV cells are arranged in modules, panels, and arrays.

Figure 18.8

•

Solar Power

• Is little used, but fast growing

Currently only 0.04% of primary energy supply in the U.S.

•

Growing at 33% per year

Cheaper technologies are taking off in developing countries.

• More expensive technologies are growing more slowly in developed countries.

Pros and Cons of Solar Power

• PROS: • Renewable, as long as sun keeps on shining • Sun’s energy abundant, if technology can capture it • Allows for local decentralized control over power • No greenhouse gas emissions (although some are created in manufacture of technology) • CONS: • Not everywhere is sunny enough • Up-front investment cost is high; takes years to pay for itself

Photo: WIRED

Hydrogen

• Hydrogen = simplest and most abundant element in universe • Could potentially serve as basis for clean, safe, efficient energy system •

How it would work:

–

Electricity generated from intermittent renewable sources like wind or solar can be used to produce hydrogen.

–

Fuel cells can then use hydrogen to produce electrical energy for power.

Production of Hydrogen Fuel

• Hydrogen gas (H 2 ) does not exist freely on Earth.

• We need to make it.

•

Electrolysis

is the cleanest way: • Split water into hydrogen and oxygen:

2 H 2 O



2 H 2 + O 2

•

This can potentially be very clean, releasing no greenhouse gas emissions.

Production of Hydrogen Fuel

• However, cleanliness of hydrogen production depends on source of electricity for electrolysis!

• If the source of electricity needed for electrolysis is not clean (e.g., from coal), then greenhouse emissions will still occur.

• Besides electrolysis, hydrogen can also be produced from organic molecules like fossil fuels. This entails greenhouse emissions.

• H = 75% of the universe’s mass !

• Combustion engines can be fuelled by hydrogen (Ballard Power – Canadian company and leader in this field)

Fuel Cells

• In a fuel cell, hydrogen gas is used to produce electricity.

• The reaction is simply the opposite of electrolysis:

2 H 2 + O 2



2 H 2 O

• • •

How it works: Hydrogen molecules are stripped of electrons.

H + ions move through a membrane.

Electrons complete a circuit, creating electricity.

Fuel cells

Figure 18.16

O 2 + 4H + + 4e => 2H 2 O

2H 2 => 4H + + 4e NET REACTION: 2H 2 + O 2 => 2H 2 O

Pros and Cons of Hydrogen Power

• PROS: • We will never run out of hydrogen • Can be clean and non toxic, with no greenhouse gas emissions • Fuel cells potentially convenient, safe, and efficient • CONS: • Depending on way hydrogen is produced, it may not be environmentally clean