Some Basic Conceptsof Energy

Kenneth M. Klemow, Ph.D.Wilkes University

Prepared for FYF 101J - Alternative Energy

Overview of topics

Basic energy conceptsHistoric phases of energy production

and supplyTerminology pertaining to energy

Basic energy concepts

What is energy?

Ability to do work Physicists distinguish between kinetic and

potential energy Energy comes in different forms

Radiation Mechanical energy Chemical energy Atomic energy Electromagnetic energy Electrical energy Heat energy

How do we measure energy?

Force: Newton (N = kg x m / s²)Energy: Joule (J = N x m)Power: Watt (J / s)

www.sommarskog.se

Is a Joule a lot or a little?

The energy released when an apple falls one meter to the ground.

The energy released as heat by a person at rest, every hundredth of a second.

# one hundredth of the energy a person can receive by drinking a drop of beer.

Some conversion factors

1 calorie = 4.187 J 1 BTU = 1054 J 1 kilowatt hour = 3.60 x 106 J 1 barrel oil equivalent = 6.119 x 109 J 1 ton wood equivalent = 9.83 x 109 J 1 ton coal equivalent = 29.31 x 109 J 1 ton oil equivalent = 41.87 x 109 J 1 quad (PBtu) = 1.055 x 1018 J 1 horsepower = 735.49 W

Laws of Thermodyamics

First law: Energy cannot be created nor destroyed, can only be converted (conservation of energy)

Second law: No energy conversion is perfect; always get some loss as heat.

Energy and power

Power = energy / time 1 watt - 1 Joule / second

Energy = power x time

www.belmont.k12.ca.us

Why is living matter a source of energy?

CO2H2O C6H12O6

Carbon reduction

Energy

Energy

Carbon oxidation

Energy needs

Biblical times Move people and their possessions Agriculture and food processing Build cities Produce clothing Simple chemical transformations (e.g.

metallurgy) Heating

www.uncp.edu

Where did this energy come from?

Animate sources Humans Animals

Low head hydropowerBiomass (woody tissue)

www.uncp.edu

Energy needs

Industrial revolution times Mechanized food production /

consumption Centralized heating Transportation Lighting Textile manufacturing More complex chemical

processes (e.g., glass manufacturing)

mhslibrary.org/

Where did this energy come from?

Animate sources (mainly animals)Low head hydropowerBiomass (woody tissue)CoalPetroleumLow capacity wind

mhslibrary.org/

Why we need energyModern

Transportation (personal vehicles, commercial vehicles, aviation)

Automated production of goods Transport of goods Centralized heating and air

conditioning Lighting Highly complex chemical

processes

content.answers.com

Where does this energy come from?

Coal Petroleum Natural gas Nuclear fission High and low head hydropower Biomass (woody and

herbaceous tissue) Animate sources (mainly

animals) Low capacity and industrial wind Geothermal Solar collection

content.answers.com

Terminology pertaining to modern energy

Renewable vs nonrenewableTraditional vs new energyCommercialized vs non-

commercializedCentralized vs distributed generationOn-grid vs off-grid

Stages of energy flowfrom http://www.fao.org/docrep/u2246e/u2246e02.htm

Primary energy is the energy as it is available in the natural environment, i.e. the primary source of energy.

Secondary energy is the energy ready for transport or transmission.

Final energy is the energy which the consumer buys or receives.

Useful energy is the energy which is an input in an end-use application.

Stages of energy flowfrom http://www.fao.org/docrep/u2246e/u2246e02.htm

energy technology examples

Primary coal, wood, hydro, dung, oil

Conversion power plant, kiln, refinery, digester

Secondary refined oil, electricity, biogas

Transport/transmission

trucks, pipes, wires

Final diesel oil, charcoal, electricity, biogas

Conversion motors, heaters, stoves

Useful shaft power, heat