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There can be no doubt of the rising trends, and there are disturbing signs of systematic change in other indicators as well ( Arndt, et al., 2010 ). The short-term extension of these trends can be estimated by extrapolation. Prediction beyond thirty or so years requires developing scenarios based on assumptions about the population, social behavior, economy, energy use and technology advances that will take place during this time. Because trends in these quantities are frequently punctuated by unexpected developments such as the recession of 2008 or the Fukushima nuclear disaster of 2011, the pace of carbon emissions, global warming and climate change over a century or more cannot be accurately predicted. To compensate for this uncertainty, predictions are normally based on a range of scenarios with aggressive and conservative assumptions about the degrees of population and economic growth, energy use patterns and technology advances. Although the hundred year predictions of such models differ in magnitude, the common theme is clear: continued reliance on fossil fuel combustion for 85 percent of global energy will accelerate global warming and increase the threat of climate change.

The present reliance on fossil fuels developed over time scales of decades to centuries. Figure Primary Energy Consumption by Source, 1775-2009 shows the pattern of fuel use in the United States since 1775.

Primary Energy Consumption by Source, 1775-2009
Primary Energy Consumption by Source, 1775-2009 Graph shows the pattern of fuel use in the United States since 1775. Source: U.S. Energy Information Administration, Annual Review, 2009, p. xx (Aug. 2010)

Wood was dominant for a century until the 1880s, when more plentiful, higher energy density and less expensive coal became king. It dominated until the 1950s when oil for transportation became the leading fuel, with natural gas for heating a close second. Coal is now in its second growth phase, spurred by the popularity of electricity as an energy carrier in the second half of the 20 th Century. These long time scales are built into the energy system. Uses such as oil and its gasoline derivative for personal transportation in cars or the widespread use of electricity take time to establish themselves, and once established provide social and infrastructural inertia against change.

The historical changes to the energy system have been driven by several factors, including price and supply challenges of wood, the easy availability and drop-in replaceability of coal for wood, the discovery of abundant supplies of oil that enabled widespread use of the internal combustion engine    , and the discovery of abundant natural gas that is cleaner and more transportable in pipelines than coal. These drivers of change are based on economics, convenience or new functionality; the resulting changes in our energy system provided new value to our energy mix.

The energy motivations we face now are of a different character. Instead of adding value, the motivation is to avert "doomsday" scenarios of diminishing value: increasing environmental degradation, fuel shortages, insecure supplies and climate change. The alternatives to fossil fuel are more expensive and harder to implement, not cheaper and easier than the status quo. The historical motivations for change leading to greater value and functionality are reversed. We now face the prospect that changing the energy system to reduce our dependence on fossil fuels will increase the cost and reduce the convenience of energy.

Summary

Continued use of fossil fuels that now supply 85 percent of our energy needs leads to challenges of environmental degradation, diminishing energy resources, insecure energy supply, and accelerated global warming. Changing to alternate sources of energy requires decades, to develop new technologies and, once developed, to replace the existing energy infrastructure. Unlike the historical change to fossil fuel that provided increased supply, convenience and functionality, the transition to alternative energy sources is likely to be more expensive and less convenient. In this chapter you will learn about the environmental challenges of energy use, strategies for mitigating greenhouse gas emissions and climate change, electricity as a clean, efficient and versatile energy carrier, the new challenges that electricity faces in capacity, reliability and communication, the challenge of transitioning from traditional fossil to nuclear and renewable fuels for electricity production. You will also learn about the promise of biofuels from cellulose and algae as alternatives to oil, heating buildings and water with solar thermal and geothermal energy, and the efficiency advantages of combining heat and power in a single generation system. Lastly, you will learn about the benefits, challenges and outlook for electric vehicles, and the sustainable energy practices that will reduce the negative impact of energy production and use on the environment and human health.

Review questions

Fossil fuels have become a mainstay of global energy supply over the last 150 years. Why is the use of fossil fuels so widespread?

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Fossil fuels present four challenges for long-term sustainability. What are they, and how do they compare in the severity of their impact and cost of their mitigation strategies?

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The dominant global energy supply has changed from wood to coal to oil since the 1700s. How long did each of these energy transitions take to occur, and how long might a transition to alternate energy supplies require?

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References

Arndt, D. S., Baringer, M. O.,&Johnson, M. R. (eds.). (2010). State of the Climate in 2009. Bull. Amer. Meteor. Soc ., 91 , S1–S224, (External Link)

Hirsch, R.L., Bezdek, R.,&Wendling, R. (2006). Peaking of World Oil Production and Its Mitigation. AIChE Journal , 52 , 2 – 8. doi: 10.1002/aic.10747

Owen, N.A., Inderwildi, O.R.,&King, D.A. (2010). The status of conventional world oil reserves – Hype or cause for concern? Energy Policy, 38 , 4743 – 4749. doi: 10.1016/j.enpol.2010.02.026

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Sustainability: a comprehensive foundation. OpenStax CNX. Nov 11, 2013 Download for free at http://legacy.cnx.org/content/col11325/1.43
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