8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

1/16

ME 413: Energy and Environment

1

Dr. Md. Ashiqur Rahman

 Assistant Professor, ME, BUET

Sustainable Energy 

Lecture: 4

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

2/16

ME 413: Energy and Environment

2

Recap 

Energy use Quality of life, economic development

Great disparity globally in levels of energy use

Prosperity, health, political power ………….. 

Wealthy, developing, rest of the world

 All affect environment in a certain way

More people and more development Higher future need of

energy

Can this be achieved in a sustainable

manner??

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

3/16

ME 413: Energy and Environment

3

We need a solid understanding of technological, geopolitical,environmental, and economic impacts of energy use and abuse

Recap 

Bottom-line: Energy affects all people and every aspect of

human endeavor

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

4/16

ME 413: Energy and Environment

4

Sustainable Energy Technology:

• If their net effect  on the ecology do not significantly 

degrade its capabilities to support existing species in

their current abundance and diversity.

What is Sustainable Energy 

Sustainability is subjective –

 reflects human value 

In the most naive way: “  Sustainable energy is that whichcan be provided without any change to earth’s ecology”  

Now vs.  Future; Individual vs.  National vs.  Global

interests; Time-frame for reform; economic opportunity

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

5/16

ME 413: Energy and Environment

5

A Better Definition:

“A dynamic harmony between the equitable availability of energy-

intensive goods and services to all people and preservation of

the earth for future generations.” 

There is no easy or unique roadmap

What is Sustainable Energy 

That meets the need of the present without

compromising the ability of future generations

to meet their own need

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

6/16

ME 413: Energy and Environment

6

Green Growth:

To be sustainable development + No degradation

of natural or environmental stocks

In rich countries, may make sense to cut CO2 

emissions sharply by conservation, shifts to

gas, etc.

“Green growth” in the developing world is muchtougher

What is Sustainable Energy 

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

7/16

ME 413: Energy and Environment

7

Increase efficiency of energy production

Increase efficiency of energy end-use

Reduce consumption

New renewable energy technologies

Public awareness

Use fossil-fuels in a climate-friendly way

Future Energy Needs: Can it be Achieved in

a Sustainable Manner?

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

8/16

ME 413: Energy and Environment

8

Why is energy use increasing? 

Human efficiency is very low.

Power produced by Human at hard work: 0.1 kW

Human work efficiency: 18%

Human body is only 10% efficient in converting food to fatand muscle tissues that can be converted to useful work 

Human work efficiency: 18% 1.8%

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

9/16

ME 413: Energy and Environment

9

Environmental and Other Hazards of

Energy Supply Technologies

Extraction

Refining

Transportation

Production

Pollution of air, water, land etc.

Waste

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

10/16

ME 413: Energy and Environment

10

Sustainability and Alternative Proposals

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

11/16

ME 413: Energy and Environment

11

Sustainability and Alternative Proposals

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

12/16

ME 413: Energy and Environment

12

Energy Efficiency of Automobiles

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

13/16

ME 413: Energy and Environment

13

Mathematical Representation of Sustainability

Sustainability is difficult to measure and describe quantitatively,

as it has many subjective factors

How to quantify human life, health and welfare;diversity etc.?

The different measurement approaches of sustainability

assume that the sustainability of a technology reflects:

How many people use that technologyThe role of that technology in the economy

Some measure of the resource consumption or environmental

degradation caused by that technology

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

14/16

ME 413: Energy and Environment

14

Algorithm 01:

SI = (P)  X (GDP/P) X (E/GDP) (i)

Where

SI = Sustainability Impact

P = Population

(GDP/P) = Per capita Gross Domestic Product

(E/GDP) = Energy consumption per GDP

Suggests the outcome that

SI = E

Total energy consumption is a measure of sustainability, that is,

energy use only benefits sustainability

Mathematical Representation of Sustainability

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

15/16

ME 413: Energy and Environment

15

Algorithm 02:

SI = (P)  X (GDP/P) X (E/GDP) X (CO 2 /E) (ii)

Where

CO2/E = Amount of carbon dioxide emitted per unit ofenergy used

Takes into account the adverse impacts of energy use

Suggests the outcome that

SI = CO 2

Total carbon dioxide emission is a measure of sustainability

Mathematical Representation of Sustainability

8/16/2019 Lec 4_ME 413_15 Sept 2015.pdf

16/16

ME 413: Energy and Environment

16