Alternative Fuels

Kimberly MurphyGEO 4333Dr. Hugli

Alternatives to Coal

Solar Power Hydroelectric Energy Wind Energy Geothermal Energy Nuclear Energy

Solar Power

Solar power is energy from the sun that is converted into thermal or electrical energy

Sunlight falls on a layer of semiconductor (silicon) panels and the jostles electrons, creating an electrical current

Advantages of Solar Power

Solar power is a free, abundant, and nonpolluting source of energy

Produces energy without any environmental hazards

Reduces dependence on fossil fuels

Disadvantages of Solar Power

Would take about 10,000 square miles of solar panels to satisfy all of the United States electricity needs

High construction and consumer costs Only a small percent of daily sunlight can be

captured– Only certain wavelengths of the UV spectrum

Sensitive to environmental changes– Won’t work on cloudy or rainy day

Leading Producers of Solar Power

Germany Japan United States Europe China India

Hydroelectric Power

What is hydroelectric power?

– The generation of electricity by using the motive power of water

Typical Hydrodam

Dam is built on a large river that has a large drop in elevation

Near the bottom of the dam there is a water intake

Gravity forces the water through the penstock and then turns a turbine connected to a metal shaft

Typical Hydrodam

The shaft of the turbines goes up into an electric generator and carries the electricity out via power lines

Wave Power

The wave rises into chamber and forces air out

The moving air spins a turbine, generating electricity

When the water falls it allows air back into the chamber, forcing turbine to spin and generating more electricity

(Other methods use the up and down motion of the wave to power a piston that moves up and down inside a cylinder)

Tidal Power

When tides come to shore they can be trapped in reservoirs behind dams

When the tide recedes, the water behind the dam can be let out just like in a regular hydroelectric power plant

– Note size of turbine

Ocean Thermal Energy

Uses temperature differences in warm surface water and cold deep water to produce electricity

Warm water is drawn from the surface layer into a heat exchanger (boiler) to vaporize a liquid

Ocean Thermal Energy

Vapor drives turbine attached to an electric generator

Vapor from turbine is condensed in a second heat exchanger, which is cooled by water pumped from the cold water source below

Benefits of Hydroelectric Energy

Reduces dependence on coal No carbon emissions Relatively low construction costs Low operating and consumer costs

Downfalls of Hydroelectric Energy

Requires 50 years to collect hydrological data Disruptive to surrounding aquatic life (fish

populations)– Dams block upwardly migrating fish such as Salmon – Fish are sucked into turbines and killed

Changes downstream river environment (sediment carried in currents)

Sensitive to environmental changes (weather patterns)

Ocean Thermal: Not very effective– Pumping water is a huge engineering problem

Leading Hydroelectric Producers

Canada 341,312 GWh

United States 319,484 GWh

Brazil 285,604 GWh

China 204,300 GWh

Russia 160,500 GWh

Norway 121,824 GWh

Japan 84,500 GWh

India 82,237 GWh

France 77,500 GWh

Sweden 70,823 GWh

Venezuela 60,600 GWh

Paraguay 51,910 GWh

Italy 47,054 GWh

Austria 41,727 GWh

Wind Energy

Power derived by wind– Wind strikes the blade of

the windmill causing it to turn

– This turns a shaft to rotate a generator and produce electricity

Depends on two factors:

– Area swept by the windmill blade

– Wind Speed

Wind Energy

Pros– Reduces dependence on

fossil fuels– No carbon emissions– No waste products– Low operating costs

Cons– Can only be used in

locations that have enough wind over an extended part of the day.

– Wind is weakest in summer and winter when the demand for power is greatest

– Unsightly and noisy– Blades kill migrating birds– High construction and

consumer costs– Sensitive to environmental

changes (weather patterns)

Leading Wind Energy Producers

Germany 12,247 MW

United States 16,818 MW

Spain 15,145 MW

India ~8,000 MW

China 6,050 MW

Geothermal Energy

Energy derived from the heat in the interior of the earth

Volcanoes, geysers, hot springs, steam vents and tectonic plate boundaries

3 methods for producing geothermal energy

– Vapor-dominated– Water-dominated– Binary cycle

3 Methods of Geothermal Energy

Vapor-Dominated– Steam from underground wells is carried by a pipes to a turbine

generator– The steam turns the turbine, generating electricity

Water-Dominated– Uses hot water flowing from wells– A fraction of the water is allowed to vaporize into steam at a

certain pressure – The steam then travels to a turbine, generating electricity

Binary Cycle– Brings geothermal water under high pressure from wells but does

not allow it to vaporize– Instead, hot water is used to heat a second fluid that has a lower

boiling point– The steam produced by the fluid powers the turbine and

afterwards cools and returns to its liquid state to be used again

3 Methods of Geothermal Energy

Geothermal Energy

In all three methods, used geothermal fluid is pumped back into the ground, both to preserve the environment and to maintain pressure in the reservoir

Advantages of Geothermal Energy

Reduces dependence on fossil fuels Renewable resource Little effect on the land used Unaffected by changing weather conditions

Disadvantages of Geothermal Energy

Can only be achieved in limited parts of the world

Releases gases such as hydrogen, sulfur, sulfur dioxide, and ammonia

Pollution of water by runoff of geothermal well

High construction and consumer costs Locations may cool down or lose pressure

– Debates on whether geothermal energy is renewable

Leading Producers of Geothermal Energy

United States 2,228 MWe

Philippines 1,909 MWe

Italy 785 MWe

Mexico 755 MWe

Indonesia 590 MWe

Japan 547 MWe

New Zealand 437 MWe

Iceland 170 MWe

El Salvador 161 MWe

Costa Rica 142 MWe

Nicaragua 70 MWe

Kenya 45 MWe

Nuclear Energy

Nuclear power is alternative energy source that can be obtained from either the splitting the nucleus of an atom (nuclear fission) or the combining of the nuclei of atoms (nuclear fusion)

Nuclear Energy

There are 15 different types of nuclear reactors Most common type is the boiling-water reactor

– A single cooling loop contains water at high pressures– Water is pumped into the reactor and as it flows through the core it

is heated by fission causing it to boil– Steam generated in the core region drives the turbine directly and

creates electricity

Nuclear Energy

Pros:– Relatively Safe (safety

record unparalleled by any other industry)

– Abundant– Reduces dependence on

fossil fuels– No carbon emissions– Low consumer costs

Cons:– High construction costs– Not a renewable resource– Nuclear waste management

Unsatisfactory methods of storing high-level wastes

– Risk of loss of coolant Melt down would release

radioactive particles to the rest of the plant and even possibly the outside environment

– Transportation Accidents Has never happened

– Nuclear Proliferation Terrorism

Leading Nuclear Power Producers

European Union 370,721 MW

United States 99,209 MW

France 63,363 MW

Japan 47,593 MW

Russia 21,743 MW

United Kingdom 11,852 MW

South Korea 16,810 MW

Canada 12,599 MW

Germany 20,339 MW

India 3,557 MW

Energy Cost Comparisons

Resource Type Average Cost (per kWh)Hydroelectric 2-5

Nuclear 3-4Coal 4-5

Natural Gas 4-5Wind 4-10

Geothermal 5-8Biomass 8-12Solar PV 15-32

Worldwide Energy Supply

Alternatives to Natural Gas

Alternatives to Natural Gas

Biomass– Ethanol– Biodiesel

Vehicles– Electric – Hybrid– Hydrogen

Ethanol

Ethanol holds the promise of reducing carbon emissions by recycling carbon in the atmosphere into presently growing plants (carbon neutral)

– Burning ethanol releases carbon from plants– Photosynthesis captures carbon in plants

By contrast, burning fossil fuels increases carbon emissions by releasing ancient carbon that was once locked within the earth

Ethanol

Ethanol is fuel derived from biomass

Ethanol can be made from:– Corn – Sugar Cane– Switchgrass– Wheat– Barley– CELLULOSE

(We will be discussing corn, sugar cane and cellulosic ethanol)

Corn Ethanol

Corn is ground into a fine powder, mixed with water, and heated Enzymes are added to convert the starch into sugars Yeast is added to ferment the sugars into alcohol Alcohol is then separated by distillation A small amount of gas is added to render the liquid undrinkable

ONLY 1% OF THE PLANT IS ACTUALLY USED– Byproducts are put back on the fields

Corn Ethanol

Would require more than 20 million acres of corn, or about one-quarter of the U.S. total corn acreage

Requires large doses of herbicide and nitrogen fertilizer

Causes more soil erosion and requires more water than any other crop

1:1.3 energy ratio 22% less emissions than gasoline

Sugarcane Ethanol

Unlike corn, in which the starch has to be broken into sugars, the entire sugarcane stalk is already 20% sugar and starts to ferment almost as soon as it is cut

Cane yields 600-800 gallons of ethanol an acre– Twice as much as corn

Sugarcane Ethanol

Fields are burned before harvest to kill snakes and make the cane easier to cut by hand

Harvest burns release methane and nitrous oxide into the atmosphere

Sugar cane is harvest by hand– Increase in labor costs– Cutters die of exhaustion every year

Does not require fossil fuels for distillation – Burn cane waste, known as bagasse, for heat and power

1:8 energy ratio 56% less emissions than gasoline

Pros of Ethanol

Ethanol is renewable Ethanol can be domestically produced Reduces dependence on foreign oil Ethanol burns cleaner than gas Eases pressure to drill in controversial and

environmentally sensitive areas at home

Cons of Ethanol

May be contributing to deforestation Sensitive to environmental changes Does not reduce carbon emissions

– Major controversy of ethanol Takes food from third world countries

– Prices of crops and crop based products would increase significantly

– Amount of crops need to sustain energy needs is equal to amount exported

Cons of Ethanol

Cannot be transported through a pipeline– Transported by trucks, trains, or barges– Increases emissions and cost

Is not cost competitive with natural gas Has two-thirds the energy value of gasoline

Major Controversy of Ethanol

Does the amount of the fossil fuel energy needed to make ethanol equal the energy it produces?

Controversy of Ethanol

Producing corn ethanol consumes as much fossil fuel as the ethanol itself replaces

Heavy use of diesel machinery required to harvest crops– increases emissions

Most ethanol plants burn natural gas or coal to create the steam that drives the distillation

– increases emissions Cannot be transported through pipeline

– Transported by trucks, trains, or barges which require fossil fuels– Increases emissions and price

Ethanol delivers 30% fewer miles to a gallon– Requires 1.4 times as much

Lower fuel economy= increased emissions

Cellulosic Ethanol

Cellulose is the tough chains of sugar molecules that make up plant cell walls

Finding a way to break down the cellulose chains would significantly increase our ethanol sources

Cellulosic Ethanol

Sources of cellulosic ethanol– Agricultural Residues

Leftover material from crops– Forestry wastes

Wood chips, sawdust, tree bark– Municipal solid wastes

Household garbage, paper products– Paper pulp– Fast growing plants that require less energy and

that can be grown on marginal land

Pros of Cellulosic Ethanol

Reduce dependence on foreign oil Cellulose is highly abundant Energy can be derived from organic waste

material– Saves the environmental and economic cost of

their disposal Does not compete with food crops 1:36 energy ratio (HUGE AMOUNT) 91% less emissions than gasoline

Con of Cellulosic Ethanol

More research is needed– Trying to develop a way to reproduce digestive

enzymes in the stomach of termites Only organism that can digest cellulose

We are years away from developing an effective economic process of producing cellulosic ethanol– Some of us may not even see it our lifetime

Biodiesel

Renewable fuel made from vegetable or animal fat

Sometimes mixed with conventional, petroleum-based diesel

Biodiesel

Pros– Reduces carbon

emissions 68% less than gasoline

– More energy than gasoline

Increases mileage– Can be used with any

diesel engine– 1:2.5 energy ratio

Cons– Fuel system problems at

low temperatures– Is not cost competitive

with gasoline

Electric Vehicles

Has an electric motor rather than gasoline engine

Consumes no energy at idle or coasting Regenerative braking Car itself produces zero emissions

Electric Vehicles

Electricity still has to come from coal-fired power plants

Electric vehicles only transfer the emissions source from the vehicle to the power plant

Energy is lost in process (20%) Ultimately there is an increase in carbon emissions

Hybrid Vehicles

At idle, hybrids’ computer automatically turns off the gasoline engine and restarts it once the driver starts accelerating.

Every time the driver brakes, the car recovers that momentum as electricity and stores it in a battery (Regenerative Braking)

Hybrid Vehicles

Pros– Delivers high fuel efficiency– Low emissions of tail pipe pollutants

Because of fuel efficiency and electric motor One tenth the pollution of conventional gasoline cars

Cons– Still dependent on natural gas and create carbon

emissions– Only good for stop and go traffic

Hybrid Vehicles

Only good for stop and go traffic, however:– 80% of driving is on interstate– Battery weighs approximately 600 lbs

– Scenario: You’ve been driving on the interstate and your still three hundred miles from home when your 600 lbs battery dies. What happens?

Decrease in fuel economy Ultimately increases emissions

Hydrogen Vehicles

Two Methods:– In combustion, the

hydrogen is burned in engines in fundamentally the same method as traditional gasoline cars.

– In fuel-cell conversion, the hydrogen is reacted with oxygen to produce water and electricity, the latter of which is used to power an electric traction motor.

Hydrogen Vehicles

The only emission from the vehicle itself is water However, refining hydrogen requires energy from fossil fuels Emissions source is merely transferred from the vehicles to the

smoke stack

Energy Content

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