• LEARNING OBJECTIVE:• Relate how hydroelectric power, geothermal

energy, and tidal power contribute to our energy resources.

• Evaluate wind power’s potential for providing energy in the future.

• Explain how nuclear power plants use nuclear fission to produce energy.

UNIT 4 ENERGY AND EARTH’S RESOURCES: Alternative Sources of

Energy

• Automotive & Truck (Transportation)– Electrical battery– Hydrogen– Solar & battery– Alternative sources of gasoline-type fuels

(ethanol based)– Alternative sources of diesel-type fuels (algae,

etc.)

Transportation Energy AlternativesAutomobiles I – Non-petroleum fuel

• Advantages of alternative energy vehicles:– Represents existing technology– 71% of petroleum used in U.S. is utilized for

gasoline, diesel & jet fuel.– Some alternative energy vehicles maybe

carbon neutral, and thus not produce CO2 as a waste

• Disadvantages:– Currently all non-combustion vehicles are more

expensive than their combustion counter-parts– There are infrastructure modifications

necessary to have many types of these cars usable nation-wide

– Two of the alternatives; hydrogen & battery vehicles have a number of technological issues to have them be cost-effective

Chrysler Envi

Battery powered cars themselves have zero emissions

However the source of the electricity can still be a problem regarding CO2 emissions and the global climate.

Utilizing nickel-hydride & lithium ion batteries has lightened weight of vehicle batteries, however battery-only cars probably still need to use heavier lead-acid batteries.

Nissan’s Leaf

Between battery powered cars & combustion are hybrid vehicles

Battery production does involve energy & other environmental impacts (including mining and disposal issues)

Honda FCX

Hydrogen vehicles by definition emit only water vapor.

Costs for hydrogen vehicles has remained relatively high, though technological innovation should bring this cost down.

GM Sequel

Current filling station infrastructure under consideration involves using natural gas as hydrogen source, rather than dissociation of water.

• There are a number of alternative fuel sources that are available as a alternative to petroleum fuels (or other fossil fuels; natural gas, etc.)

• These alternatives include following fuel sources– Corn, sugar cane or sugar beets to ethanol– Cellulosic fuel sources to ethanol (switch grass,

willow, etc.)– Algae and other lipid sources for diesel

• Not all of these sources are necessarily carbon neutral in terms of CO2 in atmosphere

• Usage may increase cost of food worldwide• Any increase in the amount of CO2 to

atmosphere is due to fossil fuel in producing fertilizer or to plant & harvest the crop

Alternative Sources of Energy

• Heating (homes & buildings)–Passive heating–Geothermal

Heating Energy AlternativesPassive Heating

Utilization of solar radiation to heat water, and heat or cool indoor space.

For domestic water heating this process is best suited for regions south of Pennsylvania.

Heating Energy AlternativesHomes/Buildings I

Thermal (passive) heating for buildings involves utilizing construction materials that store solar radiation, and thereby absorbing solar radiation

during the day and radiating that heat during night.

Involves increased construction costs that are off-set by lowering heating & cooling costs.

• Learning objectives: How do hydroelectric power, geothermal energy, and tidal power contribute to our energy resources.

Geothermal Energy Alternatives• Geothermal energy utilizes higher

temperatures within Earth to heat water to either heat buildings or generate electricity.

• Advantages of geothermal energy:– Represents an existing technology– Does not generate any CO2 as a waste– They are relatively cheap to operate (<½ coal)

Geothermal Energy Alternatives• Advantages of geothermal energy:– Represents an existing technology– Does not generate any CO2 as a waste– They are relatively cheap to operate (<½ coal)

• Disadvantages:– For large scale electricity generation it is

restricted to areas that are volcanically active– Geothermal facilities are relatively expensive to

build– Geothermal energy facilities are relatively large

and with their piping systems they can cover an even larger area

Geothermal Energy I

Large-scale geothermal plants have large ‘foot-prints’, and are located in regions that are volcanically active.

Countries with large-scale geothermal operations include; Iceland, New Zealand, Costa Rica, Kenya, El Salvador, & The Philippines. The largest group of plants are located in California (The Geysers).

Geothermal Energy II

Home heating applications utilize at heat exchanger that allows an exchange of warm or cold water (depending on the season) to preheat or cool water for home heating and air conditioning.

This type of system is very cost efficient to run

However installation costs (including drilling of closed-loop system in the ground) generally runs in the $20,000 to $30,000 range.

Alternative Sources of Energy• Electrical Energy–Hydroelectric (dams, turbines, tidal,

ocean currents, etc.)– Stored Energy–Nuclear Energy–Wind Energy– Solar (multiple sources)–Biomass/Algae

Electrical Energy AlternativesHydroelectric I - Dams

• Advantages of Dams – Existing form of energy production (2.4 % in the U.S.)– Have a very low relative cost to operate (<½ coal)– Do not produce hazardous by-products (waste or air

pollution)– Once built can have a very long life decades or longer– Reservoir can be used for recreation purposes &

irrigation– Stored water is a constant energy source

Electrical Energy AlternativesHydroelectric I - Dams

• Disadvantages of Dams– Expensive to build, especially if they are to last

(sediment issue)– Impact large area upstream (reservoir – people &

wildlife)– Jurisdiction issues on rivers between adjoining

states/nations– Rise of local water table is possible– Interruption of sediment flow on rivers– Impact on flushing of water pollution

Three-Rivers Gorge Dam, China

Sediment build-up behind this dam is of special concern

But it will produce electricity for 100 million people

Three-Rivers Gorge DamEnvironmental Impact

Baiji, Yangtze River Dolphin

Siberian Crane

Electrical Energy AlternativesHydroelectric II - Dams

• Of the 80,000 dams in the U.S. only ~3% are used to generate electricity.

• Though expensive to build, dams that generate electricity are relatively inexpensive to operate – therefore the U.S. is missing a large opportunity to use an already expensively built resource.

Electrical Energy Alternatives Stored Energy I – Pumped Stored Hydroelectricity

Due to energy losses in the turbines and during pumping this system is a net energy consumer, but if run correctly will run at a net profit.

Electrical Energy Alternatives Hydroelectric II - Tidal

• Usually involves creation of ‘tidal-dams’ or free standing turbines in estuaries to capture flow and drive turbines

• Advantages– Do not produce hazardous by-products (waste

or air pollution)– Located in areas that are otherwise not being

utilized

Electrical Energy Alternatives Hydroelectric II - Tidal

• Disadvantages– Relatively costly to build & cost to operate is

variable– Would be limited to coastal regions, and only

those with relatively large tidal fluctuations– Has intermittent energy production (though

this is completely predictable)– Can impact organisms that live in these areas

(especially those associated with estuaries – which generally have larger tidal effects)

Examples of Tidal Energy Production

Tidal energy dam in La Rance, France; 240 MW

Electrical Energy Alternatives Hydroelectric III – Ocean Currents

• A potentially very important source of electrical energy

• Currently it is only speculative in nature

Electrical Energy Alternatives Nuclear Energy I

• Existing form of electricity production, producing >8% of electricity for U.S.

• Advantages:– Existing form of energy production– Does not produce CO2, and therefore does not

increase our impact on Global Warming

Electrical Energy Alternatives Nuclear Energy I

• Disadvantages:– Extremely expensive (in many aspects)– Produces extremely toxic wastes that need to

be secured for (very) long periods of time– Requires very sophisticated and complex

operations– Accidents at these types of facilities can result

in widespread contamination by radioactive materials

Nuclear Energy III

Kashiwazaki, JapanWorld’s largest nuclear plant

Some other industrial countries depend heavily on nuclear power for their electrical generation.

Japan generates 34.5% of their electricity from nuclear power.

Nuclear Energy III

Paluel, France

France generates 78.8% of their electricity from nuclear power.

• Public confidence has also been shattered by the explosion at Chernobyl in 1986, worlds worst nuclear accident.

• A 19 mile “zone of alienation” has been formed around the reactor.• In 1979 an accident at Three Mile Island occurred in Pennsylvania.• This accident allowed radioactive steam to escape and resulted in the

partial core meltdown.• On march 11, 2011 the worlds second worst nuclear disaster occurred in

Fukushima, Japan after the 9.0 earthquake and associated tsunami.• There was a meltdown in three units and radioactive steam was released. • Highly radioactive water spilled into the ocean. • There have been a total of 98 accidents worldwide.

Electrical Energy Alternatives Wind Generation I

• Existing form of electricity production, producing <1% of electricity for U.S.

• Advantages:– Existing form of energy production– Does not produce CO2

– Though tall, wind turbines do not cover a large area

– Turbines come in a range of sizes and can be used for a number of applications both on & off the grid

Electrical Energy Alternatives Wind Generation I

• Disadvantages:– Has intermittent energy production (based on

the consistency of the wind)– The public may consider wind turbines to be

unsightly– Can be a hazard to bird (& migrating bird) and

bat populations

Electrical Energy Alternatives Wind Generation II

Relative costs for wind generation are a fifth of what they were in the 1980’s; and based on relatively conservative estimates are only 5% more then electricity from coal-fire power plants.

Electrical Energy Alternatives Wind Generation IV – Wind Strength

Locations of consistent wind generation in U.S.

Note locations in upstate New York; the Adirondacks, southern tier, and great lakes.

To distribute this power to market would especially require an integrated power grid.

Electrical Energy Alternatives Wind Generation V – Power Grid

NPR Story on Power Grid & Alt. Energy

To distribute electrical energy effectively from wind source areas to high-use regions (urban areas) requires a more integrated nation-wide power grid system

This is also a factor for other alternative energy sources like: nuclear power plants and large scale solar farms.

Electrical Energy Alternatives Power Grid Considerations II

The perception is that high voltage power lines are unhealthy. However several studies conducted in the 1990’s on the effects of electromagnetic fields (associated with power lines) concluded “that there was

no evidence that showed exposure to EMF from power lines presented a human health hazard.” Two of these studies were conducted with under the supervision of the National Academy of Science and by the National Cancer Institute.