Renewabl;e Energy Ch 1 PowerPoint

Chapter 1INTRODUCTION TO

RENEWABLE ENERGY

Fundamentals of Renewable EnergyME 4490

Prof. E. Ilksoy

Renewable Energy 1

1Energy Sources

1-1 FOSSIL FUELS: OIL, COAL AND NATURAL GAS1-2 NUCLEAR ENERGY1-3 THE SOLAR RESOURCE1-4 THE WIND RESOURCE1-5 GEOTHERMAL RESOURCES1-6 HYDROELECTRIC RESOURCES1-7 BIOMASS AND BIOFUEL RESOURCES

Energy Consumption in US in 2012

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Energy Map by source and consumption

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Some Energy Statistics

• The US uses ¼ of the world’s energy

• The US pays more than $5 billion for imported oil each month

Present-day energy use:World energy supplies

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Global Energy Consumption over decades by Different Sources

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Energy Consumption of different sources by Regions

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Global Energy Consumption by Regions

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• Major fossil fuels are:• Coal

• Petroleum

• Natural Gas

All fossil fuels are considered to be non-renewable resources because they are being consumed at a much faster rate than they are replenished.

Fossil Fuels: oil, coal and natural gas

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Coal is a hydrocarbon that formed from ancient plant life that was buried and subjected to heat and pressure. It formed into a organic peat in a process called diagenesis.

Heating value

lignite subbituminous bituminous anthracite

Moisture content

Types of coal:


Natural gas is trapped underground in reservoirs. The primary constituent of natural gas is methane, the simplest hydrocarbon. The chemical formula for methane is CH4.The chemical reaction that occurs in burning methane is:

The equation shows that for one molecule of CH4, two molecules of O2 combine with it to form one molecule of CO2 and two molecules of water.

1-1 Fossil Fuels: oil, coal and natural gas

4 2 2 2CH 2O CO 2H O Energy

Petroleum (oil) was formed from organic sediments in a two step-process:

1. Compaction and heat into a waxy material known as kerogen and a black tar-like material called bitumen.

2. Further chemical and physical change in a process called catagenesis.

1-1 Fossil Fuels: oil, coal and natural gas


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• Release of CO2 and pollutants such as sulfur, arsenic, lead, and mercury

• Acidification of lakes and streams from sulfur dioxide

• Issues with obtaining fuels including spills and ash releases.

Environmental effects of fossil fuels are:

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Another environmental disaster that has not received much attention is coal seam fires. These underground fires have been started by both natural means and humans but are estimated to account for 3% of the world’s industrial carbon emissions may come from these fires.One fire in India has been burning since 1916 and has consumed an estimated 37 million tons of coal. Fires like this have a huge impact on pollution, land subsidence, and destruction of wildlife habitat.

© 2015 by Pearson Higher Education, Inc.

Problem & Opportunity

• Several ProblemsAir & water pollutionHealth effects of pollutionOil depletion/ importsGlobal warming from CO2

• One SolutionRenewable energy sources

cause minimal pollution, don’t cause global warming and are locally available

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ENERGY AND ENVIRONMENT• The conversion of energy from one form to another often affects the environment

and the air we breathe in many ways, and thus the study of energy is not complete without considering its impact on the environment.

• Pollutants emitted during the combustion of fossil fuels are responsible for smog, acid rain, and global warming.

• The environmental pollution has reached such high levels that it became a serious threat to vegetation, wild life, and human health.

Energy conversion processes are often accompanied by environmental pollution.

Motor vehicles are the largest source of air pollution.

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Ozone and Smog• Smog: Made up mostly of ground-level ozone (O3), but it also contains numerous other

chemicals, including carbon monoxide (CO), particulate matter such as soot and dust, volatile organic compounds (VOCs) such as benzene, butane, and other hydrocarbons.

• Hydrocarbons and nitrogen oxides react in the presence of sunlight on hot calm days to form ground-level ozone.

• Ozone irritates eyes and damages the air sacs in the lungs where oxygen and carbon dioxide are exchanged, causing eventual hardening of this soft and spongy tissue.

• It also causes shortness of breath, wheezing, fatigue, headaches, and nausea, and aggravates respiratory problems such as asthma.

Ground-level ozone, which is the primary component of smog, forms when HC and NOx react in the presence of sunlight in hot calm days.

• The other serious pollutant in smog is carbon monoxide, which is a colorless, odorless, poisonous gas.

• It is mostly emitted by motor vehicles. • It deprives the body’s organs from getting enough

oxygen by binding with the red blood cells that would otherwise carry oxygen. It is fatal at high levels.

• Suspended particulate matter such as dust and soot are emitted by vehicles and industrial facilities. Such particles irritate the eyes and the lungs.

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Acid Rain• The sulfur in the fuel reacts with oxygen to form sulfur dioxide (SO2), which is an

air pollutant. • The main source of SO2 is the electric power plants that burn high-sulfur coal.• Motor vehicles also contribute to SO2 emissions since gasoline and diesel fuel

also contain small amounts of sulfur.

Sulfuric acid and nitric acid are formed when sulfur oxides and nitric oxides react with water vapor and other chemicals high in the atmosphere in the presence of sunlight.

• The sulfur oxides and nitric oxides react with water vapor and other chemicals high in the atmosphere in the presence of sunlight to form sulfuric and nitric acids.

• The acids formed usually dissolve in the suspended water droplets in clouds or fog.

• These acid-laden droplets, which can be as acidic as lemon juice, are washed from the air on to the soil by rain or snow. This is known as acid rain.

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The Greenhouse Effect: Global Warming

• Greenhouse effect: Glass allows the solar radiation to enter freely but blocks the infrared radiation emitted by the interior surfaces. This causes a rise in the interior temperature as a result of the thermal energy buildup in a space (i.e., car).

• The surface of the earth, which warms up during the day as a result of the absorption of solar energy, cools down at night by radiating part of its energy into deep space as infrared radiation.

• Carbon dioxide (CO2), water vapor, and trace amounts of some other gases such as methane and nitrogen oxides act like a blanket and keep the earth warm at night by blocking the heat radiated from the earth. The result is global warming.

• These gases are called “greenhouse gases,” with CO2 being the primary component.

• CO2 is produced by the burning of fossil fuels such as coal, oil, and natural gas.

The greenhouse effect on earth.

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• A 1995 report: The earth has already warmed about 0.5°C during the last century, and they estimate that the earth’s temperature will rise another 2°C by the year 2100.

• A rise of this magnitude can cause severe changes in weather patterns with storms and heavy rains and flooding at some parts and drought in others, major floods due to the melting of ice at the poles, loss of wetlands and coastal areas due to rising sea levels, and other negative results.

• Improved energy efficiency, energy conservation, and using renewable energy sources help minimize global warming.

The average car produces several times its weight in CO2 every year (it is driven 20,000 km a year, consumes 2300 liters of gasoline, and produces 2.5 kg of CO2 per liter).

Renewable energies such as wind are called “green energy” since they emit no pollutants or greenhouse gases.

Carbon dioxide emission from fossil fuels over time

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Pollution

• US power plants emit 18 million tons of SOUS power plants emit 18 million tons of SO22 per year + per year +

NONOxx, particulates, carbon monoxide, mercury and lead, particulates, carbon monoxide, mercury and lead

• Energy production & use also contribute to Water Energy production & use also contribute to Water

pollutionpollution

• Some regions has been in violation of federal air quality Some regions has been in violation of federal air quality

standards since they began in the 1970’sstandards since they began in the 1970’s

Global Warming• Throughout history, the earth has been

much colder, and at times warmer, than it is nowBut climate change is occurring 100’s of times

faster than these natural changesCO2, CH4, N2O, O3 and soot all cause warming

• Global average air temperature has risen 1°F in the past 50 years

• But, this has already resulted in melting ice sheets, migration of animals and more severe weather

Fossil fuels and climate change

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Fossil fuels and climate change

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The Greenhouse EffectGlass has a transparent window in the wavelength range 0.3 m < < 3 m in which over 90% of solar radiation is emitted. The entire radiation emitted by surfaces at room temperature falls in the infrared region ( > 3 m). Glass allows the solar radiation to enter but does not allow the infrared radiation from the interior surfaces to escape. This causes a rise in the interior temperature as a result of the energy buildup in the car. This heating effect, which is due to the nongray characteristic of glass (or clear plastics), is known as the greenhouse effect.

Temperature increase over the years

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What’s the Alternative?And what’s the hold up?

• Renewable energy generally Renewable energy generally

cost more than conventional cost more than conventional

fossil fuel energy systemsfossil fuel energy systems

• Solar 11 - 40 Solar 11 - 40 ¢/kWh ¢/kWh

depending on the depending on the

technologytechnology

• Wind 5 - 15 ¢/kWh from Wind 5 - 15 ¢/kWh from

large wind turbineslarge wind turbines

But what if you consider the big picture?

Reasons for Renewable Energy

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Renewable energy sources

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Renewable energy sources

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Sustainable Energy

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There are lots of Alternatives

• Nuclear• Hydroelectric• Wind• Solar• Wave• Tidal• Geothermal• Bio-mass

Nuclear energy

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Currently, all reactors that produce useful energy use the fission process in which the release of neutrons keeps the process going in a chain reaction.

Nuclear Energy

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A basic pressurized water reactor (PWR) uses the standard Rankine cycle to convert heat energy to mechanical motion.

Nuclear Energy

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Fusion reactors offer promise for the future with unlimited fuel (from water) but have been notoriously difficult to build.

An artist rendition of a Tokamak reaction chamber

Nuclear Energy

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Nuclear Energy

Environmental effects for all fission reactors include potential and actual accidents and radioactive waste disposal requiring very long term storage.

Source: NREL

General

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General

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Solar Energy: Source of Sustainable Energy

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Passive Solar

• Uses sun angles, shading and thermal storage

• Daylighting is using natural sunlight instead of electric lights

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Solar Electric

• Solar Photovoltaic (PV)

panels generate electricity

directly from sunlight with

special materials

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Solar Thermal

• Heat from the sun can be used to heat water, houses, pools, in industry and to generate electricity

Solar Cookers

• Many different designs

• Can improve health & reduce deforestation in developing countries

Solar Cars?

• Hybrid and Electric cars are coming

• Why not solar charge them?

ATMOSPHERIC AND SOLAR RADIATIONAtmospheric radiation: The radiation energy emitted or reflected by the constituents of the atmosphere.

The energy of the sun is due to the continuous fusion reaction during which two hydrogen atoms fuse to form one atom of helium. Therefore, the sun is essentially a nuclear reactor, with temperatures as high as 40,000,000 K in its core region. The temperature drops to about 5800 K in the outer region of the sun, called the convective zone, as a result of the dissipation of this energy by radiation.

Total solar irradiance Gs: The solar energy reaching the earth’s atmosphere is called the

Solar constant: The total solar irradiance. It represents the rate at which solar energy is incident on a surface normal to the sun’s rays at the outer edge of the atmosphere when the earth is at its mean distance from the sun 52

The value of the total solar irradiance can be used to estimate the effective surface temperature of the sun from the requirement that

The sun can be treated as a blackbody at a temperature of 5780 K.

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Direct solar radiation GD: The part of solar radiation that reaches the earth’s surface without being scattered or absorbed by the atmosphere. Diffuse solar radiation Gd: The scattered radiation is assumed to reach the earth’s surface uniformly from all directions.The total solar energy incident on the unit area of a horizontal surface on the ground is

The solar energy incident on a surface on earth is considered to consist of direct and diffuse parts.

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it is found convenient in radiation calculations to treat the atmosphere as a blackbody at some lower fictitious temperature that emits an equivalent amount of radiation energy. This fictitious temperature is called the effective sky temperature Tsky.

The radiation emission from the atmosphere to the earth’s surface is

The value of Tsky depends on the atmospheric conditions. It ranges from about 230 K for cold, clear-sky conditions to about 285 K for warm, cloudy-sky conditions.

Net rate of radiation heat transfer to a surface exposed to solar and atmospheric radiation

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The absorption and emission of radiation by the elementary gases such as H2, O2, and N2 at moderate temperatures are negligible, and a medium filled with these gases can be treated as a vacuum in radiation analysis. The absorption and emission of gases with larger molecules such as H2O and CO2, however, can be significant and may need to be considered when considerable amounts of such gases are present in a medium. For example, a 1-m-thick layer of water vapor at 1 atm pressure and 100°C emits more than 50 percent of the energy that a blackbody would emit at the same temperature.

The radiation properties of surfaces are quite different for the incident and emitted radiation, and the surfaces cannot be assumed to be gray. Instead, the surfaces are assumed to have two sets of properties: one for solar radiation and another for infrared radiation at room temperature. 57

What we call renewable energy is usually nothing more than the manifestation of solar energy in different forms.

Such energy sources include wind energy, hydroelectric power, ocean thermal energy, ocean wave energy, and wood.

For example, no hydroelectric power plant can generate electricity year after year unless the water evaporates by absorbing solar energy and comes back as a rainfall to replenish the water source.

Although solar energy is sufficient to meet the entire energy needs of the world, currently it is not economical to do so because of the low concentration of solar energy on earth and the high capital cost of harnessing it.

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The solar spectrum includes a visible region and energy above and below the visible region.

At the top of the atmosphere, the spectrum is:

The Solar Resource

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The solar constant is the energy per square meter per day at the outer edge of the atmosphere. The amount that reaches the earth’s surface is less because some is absorbed and some is reflected.

The Solar Resource

1. Global horizontal irradiance (GHI) is the total amount of shortwave radiation received on a horizontal surface

2. Direct normal irradiance (DNI) is the portion of GHI that comes in a straight line from the sun

3. Diffuse horizontal irradiance (DHI) is that portion of radiation that arrives at the surface from indirect paths.

The GHI value includes both the direct and diffuse irradiance. Both direct radiation and diffuse irradiance is useful for solar applications like flat plate collectors, but only direct radiation can be focused using concentrating collectors.

The radiation reaching the earth's surface is given in three different ways:

The Solar Resource

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A map of the average annual solar resource for the U.S.:

The Solar Resource

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A map of the average annual solar resource for the world:

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The Solar Resource

Environmental effects of solar energy are:

• Manufacturing including certain hazardous materials• Disposal of panels when life of the product is over• Certain types of solar installations have water requirements• Land use issues• Effect on wildlife

Copyright © 2015 by Pearson Education, Inc.All Rights Reserved

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Wind

• Wind turbines – modern windmills Wind turbines – modern windmills

have become quite efficient and cost have become quite efficient and cost

effective in windy areaseffective in windy areas

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Global patterns of winds are driven by three primary air cells in each hemisphere: The tropical cell, the mid-latitude cell, and the polar cell.

When the earth’s rotation is taken into account, the winds are deflected by the Coriolis force that adds an east-west component to the movement of the air in the global air cells. In the U.S., the best wind resources are on the coasts, the Great Lakes and the Midwest as shown in the following slide:

The Wind Resource

The Wind Resource

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A map of the wind resource for the world:

The Wind Resource

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Offshore winds are generally higher because of the clear path free of buildings and land masses.

Some countries with the best offshore wind resources are the UK, Ireland, Italy, the Philippines, Japan, and parts of the United States.

The offshore resource is frequently near population centers, minimizing transmission issues.

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The Wind Resource

Environmental issues:

• Land use and visual “eyesore”• Structures may create hazard for small

aircraft• Noise• Bird strikes• Additional power line infrastructure

Geothermal & Bio-mass

Geothermal is heat generated within the earth primarily from radioactive decay. The best resources are along tectonic boundaries where it can be used for driving steam generators and provide baseline power.

Geothermal Resources

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Low quality geothermal heat is available in most parts of the world and can be used for geothermal heat pumps (GHP) to provide heat or air conditioning. These are systems that work on a basic refrigeration cycle using heat in the ground as a basic resource.


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Plate tectonics is a geological theory that explains how the earth’s surface moves and changes over time. The outer surface of the earth is divided into plates that form the lithosphere. The best spots for geothermal energy tend to be near plate boundaries.


In the U.S., the best geothermal sites tend to be in the west as shown on the geothermal resource map.


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Environmental effects of Geothermal plants


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• Low gaseous emissions including a small amount of CO2

• Can have high volume of water requirements

• Water injection into ground to replace ground water

• Very minor earthquakes (“micro-quakes”)

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Renewable Energy SystemsDavid Buchla | Thomas Kissell | Thomas Floyd


Biomass and Biofuel Resources

Biomass fuels are fuels derived from organic matterand they comprise the largest segment of the renewable energy sector. Examples of biofuels are:

• wood chips• waste from the paper industry• agricultural waste• organic and food waste• various crops grown for fuels

One use for biofuels is to co-fire it with coal in electrical power stations to alleviate some of their CO2 emissions.

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For the U.S., the crop residue resource map is:


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Liquid biofuels include ethanol, produced from grains such as corn. An ethanol plant:

An ethanol plant. Principle steps are:1) offloading 2) grinding3) treatment with sulfuric acid to decompose into sugars4) fermentation 5) storage of fuel

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Biodiesel is another biofuel made from vegetable oil, animal fat, or cooking grease that is combined with alcohol.

1-7 Biomass and Biofuel Resources


Environmental effects of energy crops:

• Reduced biodiversity and loss of wildlife habitat particularly as farmers plant more pristine lands for energy crops

• Increased water requirements for irrigation and processing, particularly with ethanol production

• Increased use of pesticides and fertilizers which has significantly increased nitrate levels in rivers and streams and affected drinking water

• Replacement of farmland that was used for food crops with production of ethanol.

There are some positive benefits for growing certain biofuels, especially with switch grass and tree farming,

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Renewable Energy SystemsDavid Buchla | Thomas Kissell | Thomas Floyd


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Water EnergyHydro-electric, wave, tide

Hydroelectric resources broadly covers any source that converts the energy in moving or falling water into electricity. As such, the water is considered to be a prime mover.

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Water is used to generate electricity primarily by trapping it behind dams and releasing it to turn turbines as it is needed. Flowing water in rivers, streams, and tides are also used to a smaller extent.

Hydroelectric Resources

Source: http://www.usbr.gov/mp/2010_accomp_rpt/highlights/index.html

The location of hydroelectric power plants in the U.S. principally is in mountainous regions.


In addition to large storage dams, there are dams used in rivers in systems called run of the river systems (ROR). In a few coastal locations, a tidal barrage dam is used to trap water from tides and generate power by releasing it through turbines.

Ocean waves and natural current from tides have been used to generate power in some areas, but overall have been a small part of the energy mix.


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There is a tremendous reservoir of low quality heat in the oceans. Warm surface waters can boil ammonia, which is condensed by deeper cold water to drive a turbine.

This technology is called Ocean Thermal Energy Conversion (OTEC) and there is interest in developing the technology.



Environmental issues with dams:

• Silting problems filling in reservoirs and depriving farmlands of the renewing effects of silt.

• Water quality and flow are affected• Loss of fish habitat and upsetting natural

migration patterns• Loss of scenic and wild rivers and loss of

useful land for reservoirs.

A Future Hydrogen Economy?

• Solar energy can split water into hydrogen & oxygen

• A fuel cell can make electricity from hydrogen and oxygen, making water

• A completely clean, renewable cycle

2 Last Thoughts

It has been estimated that we can improve the way we use energy by a factor of 4!

Selected Key Terms

Biomass

Catagenesis

Diagenesis

Diffuse horizontal irradiance

Organic material that is commonly used for fuels for heating, power generation or making liquid fuels useful in transportation

The cracking process that results in the conversion of kerogens into hydrocarbons including natural gas and oil.

The process of converting constituents to a different product through application of heat and pressure.

The portion of global horizontal irradiance that comes in a indirectly (scattered radiation) from the sun.

Selected Key Terms

Direct normal

irradiance

Ethanol

Kerogen

Solar constant

The portion of global horizontal irradiance that comes in a straight line from the sun.

The primary biofuel used as a gasoline additive and is a type of alcohol.

A mixture of organic chemical that are part of the organic matter in sedimentary rocks.

The power emitted by the sun that falls on 1 square meter. It is generally cited as 1368 W/m2.

true/false quiz

1. The primary use of coal is for industrial heat.

true/false quiz

2. The formation of coal into an organic peat is called diagenesis.

true/false quiz

3. Burning any fossil fuel releases CO2.

true/false quiz

4. The major issue with nuclear power is the large amount of cooling water required.

true/false quiz

5. The fuel for future fusion reactors is CO2.

true/false quiz

6. The solar spectrum refers only to visible light.

true/false quiz

7. The Coriolis force adds an east-west component to the movement of the air in the global air cells.

true/false quiz

8. Hydroelectric resources are concentrated in mountainous regions.

true/false quiz

9. Geothermal heat pumps cannot be used for cooling.

true/false quiz

10. Biomass burning can help electrical power stations to alleviate some of their CO2 emissions

true/false quiz

Answers:1.F2.T3.T4.F5.F

6.F7.T8.T9.F10. T

Basic Concepts

• Force, Energy, Power

• Energy Conservation: First Law of Thermodynamics

• Forms of Energy

• Conversion and efficiency

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Force, energy and power

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Force, energy and power

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Energy conservation: The First Law of Thermodynamics• Total quantity of energy remains constant during

transformation from one form to another.

• This principle is known as first law of thermodynamics.

• eg., energy transformation from potential (mgh) to kinetic (0.5mv^2)

• Thermal energy or internal energy that has to do with vibration of atoms (kinetic energy of atoms.

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Gravitational and electrical energy

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Thermal Radiation Carried by Electromagnetic Waves

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Conversion and efficiency

• When we convert energy from one form to another, the useful output is never as much as the input. The ratio of the useful output to the required input (usually expressed as a percentage) is called the efficiency of the process.

• The difference between the high and low conversion efficiencies is because the latter involve more wasted heat while generating mechanical or electric work.

• the essential message of the Second Law of Thermodynamics: that there is necessarily a limit to the efficiency of any heat engine (Carnot efficiency).

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Renewabl;e Energy Ch 1 PowerPoint