HAS222d

2009 Intro to Energy and Environment: Lecture 13:

Global energy: national profiles, local

solutions

We want to look into the global use of energy by humans, estimated at 4 x 1020

J/year. This is the number which, divided by the global population and the number of seconds per year gives about 2 kW of rate-of-use of energy per global citizen, with the US consumption being ¼ of this (10 or 11 kW per person, by only 1/20 of the global population).

Contrasting national energy profiles: US and Tanzania ..next 2 slides.

B. Lomborg, Skeptical Environmentalist

We have talked about the 1/10 solution…living with 1/10 our present energyuse in the US (thus, about1.1 kilowatts per person ratherthan 11 kilowatts).

It’s too radicalperhaps for the near term butnot out of the question in comingdecades (when home heatingand transportation could be vastly more efficient).

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The next figure looks frighteningly complex, yet it is a gold-mine of insight into US energy flow. The ‘pipes’ show many aspects

of energy sources, consistent with the previous slide, and uses and losses. For example, electricity is not an energy ‘source’ but a mode of delivery; you can see it at roughly 40% of the energy stream, and largely generated by burning coal. The numbers are exaJoules…1018

J, but note that our total energy use is close to 100 of these….that is, 1020 J per year, about ¼ of the global energy use.

So, you can read the numbers as % of the US energy flow as well.

Knowing that energy is conserved among all its forms, it is useful to look at the ‘rejected’ energy losses and contemplate how much of this you might scavange

and use; for example the enormous heat billowing into the atmosphere over an electrical power generating station, or the ‘waste’ natural gas burnt off at the head of an oil well.

Energy losses amount poor ‘efficiency’ (just as in the Stirling

heat engine, we get mechanical work out which is only a part of the throughflow

of heat). We estimated the efficiency of the automobile at about 20% in converting gasoline to mechanical energy. But…is

it useful energy that is produced? Amory Lovins

suggests that as a people-mover it is much less efficient…most of the kinetic energy is in the car, not the solitary driver. So multipy

20% by mass of driver/mass of car and you get about

1% efficiency.

This is useful when you then calulate

the efficiency of a bicycle, for example.

This 1999 data (source: Los Alamos National Laboratory) is very close to 2002 data shown as an inset.

60% of oil supply is imported

•

1 barrel of oil:–

42 US gallons

•

which yields ~ ½ as (19.5 gallons) gasoline–

136 kg

–

317 CO2

produced–

6.19 GJ

(6.19 x 109

Joules)

•

US use: 20.7 M barrels oil per day (source: EIA

http://www.eia.doe.gov/basics/quickoil.html

)

•

US imports: 12.0 M barrels per day (58%)

Ashok

Gadgil

and Jon Koomey, of Lawrence Berkeley National Laboratory, and Paul Craig, Professor Emeritus of Engineering at the University of California at Davis,

published in the 2002 Annual Review of Energy and the Environment,

energy forecasts made between 1950 and 1980 systematically overestimated energy demand (neglecting increased efficiency) (and, there is evidence that estimates of oil and coal reserves are far in excess of what is there: Smildisagrees)http://www.lbl.gov/Science-Articles/Archive/EETD-energy-forecasting.html

//arts.bev.net/roperldavid/minerals

Oil and gas production estimates; these hinge on how much oil and gas is in the ground…our reserves. There is much uncertainty, with some persuasive arguments that

the reserves are smaller than now estimated (see e.g. Roberts, The End of Oil). Here again we argue that uncertainty should dictate cautious behavior in the immediate

future. That advice runs through the entire story of energy and environment.

30

www.asponews.org/ ASPO.newsletter.030.php

Gb/yr

1930 20502000

http://earthtrends.wrf.org

UN’s human development index vs. electricity use

Benka, S.G., Physics Today, April 2002

yet another energy unit: the quad (1018

Joules): global

use of marketable energy by type, and production/consumption of oil by country

up to 0.55 M tonnes

of oil capacity: tankers move 2 B tonnes

of oil per year 1300 feet (400m) long ..at a cost of about $0.02 per gallon at the pump 4M bbl

atmospheric CO2

…the Keeling curve. Human burning of fossil fuels and forests is adding about 7 Gtons..7x1012

kg… of carbon per year, and 44/12 times this amount of CO2

. About ½ of this carbon input is absorbed by the biosphere, and the other ½ raises the atmospheric concentration by roughly 2

ppm

…parts per million..per

year.

source: Wikipedia ‘carbon’

Pacala & SocolowStabilization Wedges, Science 2004

If carbon dioxide concentration inthe atmosphere can be kept below500 ppm (it is now (2009) 385, it was 280 before human intervention), the climate changes will be far smallerthan with unrestrained growth (1000 ppm or more). Remember,Venus is a run-away greenhousewith mostly CO2 atmosphere andsurface temperature of 7000C

upper curve is 1.5% carbon releaseincrease per year which is typical offorecasts for industrialgrowth Each of 7 ‘wedges’ is an increasing savingreaching 1 gigaton

per yearreduction in carbon emissions in 2059 (50yrs);altogether they could keep atmosphericCO2

below 500 parts per million

•

. Some of the wedges:•

efficient vehicles,•

reduced vehicle use,•

efficient buildings,•

efficient coal fired electricity plants,•

more natural gas•

elec. plants,•

remove CO2 from smokestack and bury it, •

wind•

solar,•

biomass energy sources

•

..others??•

The problem implicit here is that since 2004 when the ‘wedges of

stabilization’ were first describe, we have lost 5 years in the time-line, during which atmospheric CO2

has increased about 10 parts per million ….there is not time to waste.

Alternative energies and optimism: we have looked at solar and wind power in some detail. In Lomborg’s

(The Skeptical Environmentalist) book-keeping they represent roughly

0.04% wind 0.009% solar 0.04% biomass

0.12% geothermal 6.6% hydropower

6.4% ‘traditional’ fuel wood and charcoal

•

While these are small fractions of the 4 x 1020

Joules per year(i.e. divide by seconds-per-year, π

x 107, and then 1000 to get an equivalent expression,

1.3 x 1010

kilowatts) for the 6.5 x 109

residents of Earth…

2 Kw

per person, 24/7,

hydropower and fuel woods are significant and the others are growing very rapidly. Allegedly wind power installations are now cheaper

in long term cost than the fossil fuel power generation plants that dominate our electricity production.

Remember that electricity represents about 40% of our energy use, and that electric motors are vastly more efficient (~90%) than gasoline engines (~20% or less). But if the electricity is generated at ~33% efficiency in the coal-

or oil fired plants, and transmitted to you at 70% efficiency, then on the face of it, your electric motor may be as poor environmentally as you gasoline engine. But one hopes to improve the 33% greatly or at least its environmental impact by scrubbing out the CO2

at the smokestack. By localizing the fossil fuel use, the net effect on

the environment could be very good. ‘Efficiency’ needs to include the loss of, and damage to, natural capital and the (I would say huge) damage to human capital, the cost of overcrowded roads, noise, health effects of too many cars.

We see above that burning wood for cooking and purifying water is a big part of global energy use even today (~6.3%). Much of this occurs in the tropics where sunshine can be abundant. Solar box cookers

are a ‘soft technology’ that can entirely replace wood burning, except in

rainy seasons that accompany tropical monsoons. This is a potentially radical improvement developing nations’ household energetics

Another aspect of alternative energy: radically improving developing nations’ household energetics; Solar cookers in Bolivia and Nepal…a soft technology that bakes bread, cooks meals and purifies water, replacing the need for fuel wood burning (or..yak

dung in Tibet), wherever it’s sunny www.solarcooking.org

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We have argued that an important test of environmental ideas and

trends can be made a few years after a book or research paper has been published. Check the predictions! This needs to be done widely.

–

Lomborg

in 2000 quotes the US Energy Agency in predicting a price for oil at about $20 to $22 per barrel through roughly 2010. The price in May 2007 ranged from $50 to $75. Then it surged above $140 per barrel before retreating (temporarily) due

to the global recession. So much for ‘no problems with oil supplies’

–

Lovins

in 1999 quotes the CEO of Daimler-Benz as ‘pledging’ 100,000 of their car production to be hydrogen fuel cell powered by 2005. There are no such cars. Toyota in 1998 revealed plans to market fuel-cell cars ‘well before 2002 (later slipped to 2003)’. Only a token, trial vehicle has been developed. He quotes the president of Toyota as predicting 1/3d of the world automobile fleet to be electric/gasoline hybrids by 2005! In fact Toyota is the dominant producer and is doing very well, but the number of hybrid Toyota’s produced in 2004 was 200,000 (of a world new car production of ….0.3% are hybrids). So much for instant environmental solutions with new technologies.

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Paul Ehrlich, in his books The Population Bomb and The Population Explosianfollowed the tradition of a 1970s book The Limits to Growth in sounding the environmental alarm with numbers that were too pessimistic in some areas. Depletion of energy supplies, metals and minerals has not happened as quickly as predicted. Yet, the basic message is much more important than prediction of the exact year that oil will be gone.

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Slide #12 showed how far off predictions of global energy demand

were back in the 1950s-

1980s: virtually everyone predicted more energy demand, neglecting increased efficiencies.