Alternative energy and result

ENERGY OCEANSThree different approaches Harnessing the energy of waves Harnessing the energy of tides Ocean thermal energy conversion OTEC... Tidal-power generation uses flowing water to

ALTERNATIVE ENERGY

UNIVERSITY OF TECHNOLOGY

FALCUTY OF GEOLOGY & PETROLEUM ENGINEERING

CHAPTER 15

Member list:

Huynh Pham Quoc Anh 1410064

Dinh Nguyen Thuy Dung 1410530

Pham Thanh Hoa 1411347

Ngo Kieu Mi 1414914

Instructor: DR Bui Trong Vinh

Alternative energy sources for the future are

thus needed, both to supply essential energy

and to spare the environment as much

disruption as possible And this is true

worldwide, for globally, too, fossil fuels are

the primary energy source

I Nuclear power

1.Fission

2.Fusion

II Energy oceans

III Solar energy

 Fission is the splitting apart of atomic nuclei into smaller ones, with the release of energy.

 Very few isotopes - some 20 out of more than 250 naturally occurring isotopes - can undergo fission spontaneously, and do so in nature

 The fissionable nucleus of most interest in modern nuclear power reactors

is the isotope of uranium with 92 protons and 143 neutrons, uranium-235

1 Nuclear power – Fission

i Nuclear power

Nuclear fission and chain reaction involving uranium-235 (schematic) Neutron capture by uranium-235 causes fission into two smaller nuclei plus additional neutron

Nuclear Fission Diagrams

How the nuclear fission occur?

2 Nuclear power – Fusion

 Nuclear fusion is the opposite of fission As

noted earlier, fusion is the process by which two or more smaller atomic nuclei combine to form a larger one, with an accompanying release of energy.

 It is the process by which the sun generates its vast amounts of energy

 For technical reasons, fusion of the heavier hydrogen isotopes deuterium and tritium

 would be easier to achieve on earth.

Since fusion is a far “cleaner” form of nuclear power than fission, why not use it?

• To bring about a fusion reaction, the

reacting nuclear must be brought very close together at extremely high temperatures (millions of degrees at least)

• The natural tendency of hot gases is to

expand, not come together, and no known physical material could withstand such temperatures to contain the reacting nuclei.

We would have a new sun if we were careless!

The Geology of Uranium Deposits

Worldwide, 95% of known uranium

reserves are found in sedimentary or

metasedimentary rocks, distributed

mainly in Australia 21%, Kazakhstan

19%, Canada 10%, South Africa 8%,

USA 8%, Namibia 7%, Brazil 6%,

Russia 4%

Advantages and disadvantages of nuclear power

Generate a large amount of energy Green energy

Not pollute the air

Independent fuel

Radiant Develop nucle

ar weapons

Huge construc

tion costsNuclear waste

Accident nucle

ar power plantVS

Concerns Related to Nuclear Reactor Safety

1 Reactor protection system- RPS

2 Essential service water system- ESWS

3 Emergency core cooling system-ECCS

4 Emergency electrical system

5 Containment systems

6 Standby gas treatment-SBGT

7 Ventilation and radiation protection Three Mile Island near Harrisburg,

Pennsylvania; damaged reactor remains shut down, while others are still operative (© Doug Sherman/Geo file)

Fukushima incident

The Fukushima Daiichi nuclear disaster was an energy accident at the Fukushima I Nuclear Power Plant, initiated primarily by the tsunami that was triggered by the Tōhoku earthquake on 11 March 2011

Nuclear energy is increasing

And accounting for a large proportion of the world 's energy resources

II ENERGY OCEANS

Three different approaches

Harnessing

the energy of

waves

Harnessing the energy of

tides

Ocean thermal energy conversion (OTEC)

• Tides represent a great volume of shifting water

• A commercial tidal-power electricity-generating plant requires at least 5

meters difference between high and low tides for efficient generation of electricity and a bay or inlet with a narrow opening that could be

dammed to regulate the water flow in and out

1 Harnessing the energy of tides

Tidal-power generation uses flowing water to generate electricity, as with conventional hydropower.

2 Harnessing the energy of waves

The up-and-down motion of the water can be harnessed in various ways to generate electricity These systems too are clean and renewable However, appropriate sites are limited by concerns over the visual impact of the equipment in coastal areas, and over possible disruption of natural sediment-transport patterns These issues, together with relatively high costs, have so far prevented widespread development of wave energy.

Wave Profile Devices

3 Ocean thermal energy conversion (OTEC)

•Is another clean, renewable technology that is currently in the

developmental stages It exploits the temperature difference between warm surface water and the cold water at depth

•The temperature difference between warm and cold seawater must be at least 40°F (22°C) year-round, which is true only near the equator

G iven the thermal and other

requirements of OTEC, tropical

islands are likely to be the first

sites for its development (After

National Renewable Energy Lab)

• It does not produce green

house gases or waste

products.

• Doesn't require any fuels to

create

• Don’t require much

maintenance, and will last

longer than tradition power

• There are very few locations

to build these barrages.

• Intense waves may result in the damage of some

technologies used to create ocean energy.

III SOLAR ENERGY

• The earth intercepts only a small fraction of the energy radiated by the

sun Much of that energy is reflected or dissipated in the atmosphere

• The two areas in which solar energy can make the greatest immediate

contribution are in space heating and in the generation of electricity,

uses that together account for about two-thirds of U.S energy consumption

2014 Top 10 Solar States SEIA - Solar Energy

Industries

1.Solar heating

The simplest approach is passive-solar heating, which does not require

mechanical assistance These supply thermal mass that radiates heat

back when needed, in times of less (or no) sunshine

Basics of passive solar heating with

water or structural materials as

• Active-solar heating systems usually involve the mechanical

circulation of solar heated water

• The method can be as practical for urban row houses or office

buildings as for widely spaced country homes in the United States,

40 to 90% of most homes’ heating requirements could be supplied

by passive-solar heating systems, depending on location

• More economical to design

• Other features required can add tens of thousands of dollars to the cost of such homes

A common type of active-solar heating system with a pump

to circulate the water between the collector and the heat

exchanger/storage tank.

Solar heat can be used to make steam to

power turbines, as here in the

California desert

High in the mountains of Denali National Park, solar cells (right) power vital

communications equipment.

• Solar energy is free although there

is a cost in the building of

‘collectors’ and other equipment

require

• Solar energy does not cause

pollution

• Solar energy can be used in remote

areas where it is too expensive to

extend the electricity power grid

• Solar energy is infinite

• Solar energy can only be harnessed when it is daytime and sunny

• Solar collectors, panels and cells are relatively expensive

• In countries such as the UK, the unreliable climate means that solar energy is also unreliable

• Solar power is used to charge batteries

so that solar powered devices can be used at night They need replacing from time to time

IV WIND ENERGY

• Wind power has been utilized to some extent for more than two thousand years; the

windmills of the Netherlands are probably the best-known historic example  there is

considerable interest in making more extensive use of wind power for generating electricity.

The windmills of the Netherlands

• Windmill power generation increases as the cube

of wind speed So if wind velocity doubles,

power output increases by a factor of 8 (2 3 2 3

2).

• The newest wind turbines are available for some

power generation at least 95% of the time

•At one time, it was projected that the United States might produce 25 to 50% of its electricity from wind power by the year 2000

•In fact, in 2005, wind-powered electric generating facilities in the United States accounted for only about 1% of U.S generating capacity, and of actual electricity generation.

How wind turbin work?

Wind-turbine array near Palm Springs, California Different elements of the array can take advantage of various velocities of wind Some of the smaller turbines turn even in light wind, while the larger turbines require stronger winds to drive them

(© The McGraw-Hill Companies, Inc./Doug Sherman, photographer)

• The electricity can be

transmitted without excessive

loss in the power grid

• Interference with and deaths

of migrating birds and bats;

• The noise associated with a

large number of windmills

operating

*ADVANTAGE

• It is clean and, like sunshine, renewable indefinitely (at

least for 5 billion years or so)

• Erratic, highly variable in speed both regionally and locally

• Most of these fuels all into three broad categories: wood,

waste, and alcohol fuels Some are used alone, others

“cofred” (burned in combination with conventional fuels)

Truck dumping wood chips to be burned

at the Tracy Biomass Plant, an

electricity-generating plant in Tracy, CA.

Biomass is cofired with coal at the Northern Indiana Public Service Company generating station in Bailey, IN;

- Much of the wood burned as biomass fuel is also waste, especially from logging, lumber-milling, and similar operations

- Some waste-derived fuels are liquids

- Another waste-derived biomass fuel is biogas (CH4)

1 Waste – Derived Fuels

- Ethanol, butanol, propanol

- One biofuel that has received special attention is alcohol

- Recently, increasing numbers of vehicles have been designed to run on E85, a blend of

85% ethanol, 15% gasoline

- One important consideration is that to grow, harvest, and derive ethanol from corn or other starting plant material takes energy

2 Alcohol fuels

Alcohol pump in some countries

VI HYDROPOWER

• Hydroelectric power has consistently supplied a small percentage of U.S energy needs for several decades; it currently provides close to 3% of U.S energy (about 6% of U.S electricity)

• The requirement of plentiful surface water is reflected in large regional variations

in water use for hydropower generation

• Hydropower is using water to power machinery or make electricity Water

constantly moves through a vast global cycle, evaporating from lakes and oceans, forming clouds, precipitating as rain or snow, then flowing back down to the

ocean

Srisailam Dam (AndraPradesindia) Kerr Dam (Montana, USA)Kerr Dam

• When flowing water is captured and turned into electricity, it is called hydroelectric power or

Water use for hydropower generation in the United States is naturally concentrated where streamflow is plentiful.

• Conventional hydropower is also limited by the stationary nature of the

resource

• A western drought that began in 1999 dropped water levels in Lake Powell, the reservoir behind Glen Canyon Dam, by more than 100 feet, reducing water storage by more than 50%

Decline in water storage in the reservoir has both

hydropower and supply consequences

water-Water storage (vertical axis) in millions of acre- feet.

Hydropower is an important renewable energy source in the United States

• No pollutants!

• Say no to greenhouse gases

• Saving natural resources

• A predictable renewable source of energy

• Economical advantage

• Controllable source of energy

• Economical advantage

Three Gorges Dam Project, Wushan, Yangtze River, China 2002

VII GEOTHERMAL ENERGY

The earth contains a great deal of heat, some of it left over fromits early

history, some continually generated by decay of radioactive elements in the earth

Traditional Geothermal Energy Uses

Magma rising into the crust from the mantle brings unusually hot

material nearer the surface Heat from the cooling magma heats any ground water circulating nearby  the basis for extracting geothermal energy scale

Geothermal energy is utilized by tapping circulating warmed ground water

The magma-warmed waters may escape at the surface in geysers

and hot springs, signalling the existence of the shallow heat source

• High heat flow signals unusually high temperatures at shallow

depths

• High heat flow and recent (or even current) magmatic are most

often associated with plate boundaries

 most areas in which geothermal energy is being tapped extensively are along or near plate boundaries

Geothermal power plants worldwide (Source: Figure prepared by L J Patrick Muffler and Ellen Lougee, U.S Geological Survey)

Geothermal resources are more readily accessible:

•Above 20 (68 ) : direct ℃ (68 ℉) : direct ℉) : direct

uses like greenhouses,

aquaculture and district heating

•Above 75 (167 ) the water ℃ (68 ℉) : direct ℉) : direct

is hot enough to be used for

electricity generation using

binary cycle technology

•Above 160 (320 ) flash ℃ (68 ℉) : direct ℉) : direct

steam generation can be used to produce clean, renewable

electricity

Alternative Geothermal Sources

• The geothermal gradient is the rate of increase of temperature with

increasing depth in the earth

• Where geothermal gradients are at least 40°C/ kilometer, even in the

absence of much subsurface water, the region can be regarded as a

potential geothermal resource of the hot-dry-rock type.

• Most of the regions identified as possible hot-dry-rock geothermal fields

in the United States are in thinly populated western states with restricted water supplies

• The area east of the Rocky Mountains has

a geothermal gradient and surface heat flow typical of world average continental crust;

• The faster temperature increases with

depth, the closer to the surface are

usefully warm rocks, and—all else being equal—the greater the geothermal-energy potential.

Where most feasible, geothermal power is quite competitive economically with conventional methods of generating electricity The use of geothermal steam is also pollution-free

DISADVANTAGE

• only be used for a period of time—a few decades, on average— before the

rate of heat extraction is seriously reduced

• not only are geothermal power plants stationary, but so is the resource

itself  inefficient

• cannot contribute to such energy uses as transportation

• We find an almost bewildering variety of alternatives available

• Some of the already-viable have limited ultimate potential (e.g.,

hydropower, geothermal power)

• Nuclear fission produces minimal emissions but entails waste-disposal

problems, and concerns about reactor safety

• The fuel reprocessing necessary if fission-power use is greatly expanded

raises security concerns

• Solar and wind energy, though free and clean to use, are so diffuse, and so

variable over time and space

• Biofuels, like fossil fuels, yield carbon dioxide (and perhaps other pollutants

also), and may require substantial expansion of cropland