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David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 1
April 1, 2008
A Sustainable Energy Future?
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 2
April 1, 2008
We should start by asking what we
mean by sustainable energy?
We need energy sources that
won’t run out.
We need energy sources that
won’t degrade our planetary
environment.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 3
April 1, 2008
We need energy sources that
won’t run out.
• The prosperous economies of developed
countries are built on a foundation of abundant
energy from fossil fuels.
• Developing countries like China and India,
with the world’s largest populations, are
following the same route.
• Demand for fossil fuels keeps rising, but……
Earth’s supplies of fossil
fuels are finite and eventually
they will be used up.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 4
April 1, 2008
People talk a lot about Peak Oil, the time when world
oil production reaches its highest point and then
declines further and further each year…..
When will it happen? What will its consequences be?
Little consensus among experts on exact timing, but most
predict sometime in the next couple of decades….
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 5
April 1, 2008
Perhaps more relevant is
when demand starts to
exceed supply….
• The developing
economies of Asia have
rapidly growing demand
for oil.
• World production rates
are straining to keep pace.
This is reflected in the
dramatic increases in the
price of a barrel of oil in
recent years.
The price of a barrel of crude oil has
increased by a factor of 5 over the last
decade.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 6
April 1, 2008
• We can no longer count on cheap & abundant
oil in the future.
• Natural gas supplies are similarly strained.
• Coal supplies are much more abundant, but
cannot be used as simply for transportation.
Need for energy
alternatives…
We need energy sources that
won’t degrade our planetary
environment.
The decline of fossil fuel supplies dovetails with another important area
of concern….
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 7
April 1, 2008
The 2007 Nobel Peace Prize was awarded to the IPCC and Al
Gore for their work documenting and bringing attention to the
issues of global warming and climate change.
The International Panel on Climate Change is the U.N. sponsored
organization of scientists that has carefully studied evidence
establishing that ….
• Earth’s atmosphere is warming
• Rising levels of greenhouse gasses (like CO2) that result from
burning fossil fuels play a major role
• Many aspects of Earth’s climate will change in response to
warming
• The impact on human societies and other forms of plant and
animal life may be severe
How severe these effects will be depends on how much
higher GHG levels rise.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 8
April 1, 2008
Burning fossil fuels releases CO2 and other GHG’s into the
atmosphere. How much higher GHG levels go depends in large
part how fast the world can move away from reliance on fossil
fuels….
Trillions of
kilograms of
Carbon emitted
from burning
fossil fuels each
year.
Again this strongly points to the need for energy alternatives…
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 9
April 1, 2008
Source: Energy Information Agency, 2007 International Energy Outlook
http://www.eia.doe.gov/oiaf/ieo/pdf/world.pdf
The U.S. Energy
Information Agency
makes predictions for
the future based on
current data and trends.
Total world energy
usage by source, with
EIA projections through
2030.
EIA shows fossil fuels
increasing more rapidly
than renewables.
Unfortunately, all the trends are pointing in the wrong
direction…
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 10
April 1, 2008
Let’s make an inventory of our future energy options and try
to understand their future prospects….
• Fossil Fuels
• Nuclear
• Wind
• Solar
• Biofuels
• The Hydrogen economy?
• Hydroelectric, Geothermal, Waves, Tides, …
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 11
April 1, 2008
Fossil Fuels….. Even with oil and natural gas
running low, we shouldn’t think
that fossil fuels will soon become
irrelevant.
What is on the horizon for fossil fuels?
• Non-conventional crude oil - heavy oil, tar sands & shale oil.
• “Clean” coal.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 12
April 1, 2008
Non-conventional crude oil - heavy oil, tar sands & shale oil.
As oil prices rise, some more costly to exploit petroleum-like
substances will become profitable.
• Total world oil reserves 1300 Billion bbl
• Athabasca Oil Sands 1700 Billion bbl
• Orinoco Heavy Oil 1200 Billion bbl
• Green River Oil Shale 2000 Billion bbl
How much non-conventional oil is
economically recoverable is
unclear….
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 13
April 1, 2008
When you think coal, think electricity…
• 50% of U.S. electricity comes from coal fired
power plants.
• Over 90% of coal mined is used to produce
electricity.
• U.S. coal reserves are estimated at 250 years
at current production rates.
Extremely attractive to the electric
power industry and to politicians
interested in energy security.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 14
April 1, 2008
Why Clean Coal?
• Coal is the dirtiest way to generate electricity.
• Burning coal produces the pollutants SO2, NO and
NO2 that cause acid rain.
• Burning coal produces more CO2 than other fossil
fuels relative to the amount of energy released.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 15
April 1, 2008
The U.S. Department of Energy, the coal industry and power
companies are working together on implementing “clean coal”
technologies through the prototype FutureGen power plant.
The FutureGen plan includes…
• The coal is first “gasified” allowing pollutants to be removed and the
CO2 to be separated, leaving H2 as a fuel for clean electricity generation.
• The CO2 will be sequestered in an underground geological formation.
In the meantime, non-clean coal power plants are being built at a
rapid pace both in the U.S. and worldwide…
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 16
April 1, 2008
Nuclear Power
• The U.S. has 104 nuclear power plants
generating 20% of our electricity.
• No new nuclear power plants have been
approved since 1978, the year before the 3
Mile Island accident.
• However, with concerns over GHG
emissions and economic encouragement
from the Energy Policy Act of 2005, new
applications are beginning to roll into the
Nuclear Regulatory Commission.
• The NRC received 4 applications for new
nuclear plants last year and is expecting 15
more in the coming year.
• The industry talks about a nuclear
renaissance.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 17
April 1, 2008
Renewable energy…..
Earth gets a very nice allowance of energy from the sun every day, but
can we learn how to make better use of it?
• Solar Power
• Wind Power
• Biofuels
There is reason to be optimistic,
but technologies have a long way
to go to be economically
competitive with fossil fuels.
Of course, government policies can have great
effect in leveling or tilting the playing field!
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 18
April 1, 2008
Solar Power….
There are many ways to make use of the Sun’s energy. Let’s focus
on how we can use solar energy to generate electricity.
Two main ways.
Photovoltaics (PV)
• A solar cell is basically an LED light working in
reverse. An LED is a silicon device that procudes
light from electricity. A solar cell is a silicon
device that makes electricity from light…..
• Rooftop solar panels supply houses and other
buildings with electricity. In grid-tied systems,
the electricity flows into the power grid when
excess electricity is generated & your meter turns
backwards.
One vision of the future for electricity is many small scale producers…
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 19
April 1, 2008
The big issue with solar panels is cost.
• The price for a new coal fired power plant is
about $1000 per kilowatt of capacity. To put
solar panels on your roof costs about $7500 per
kilowatt. The operating costs are zero, but the
payback time is still long.
• Big efforts are going into lowering the costs
of solar panels. Silicon is abundant, but the
pure silicon crystals used in solar cells are
expensive.
• 1366 Technologies (a very recent MIT based
startup) is one of many companies aiming at
using innovative technologies to match the
$1000 per kilowatt cost benchmark for solar
cells,
1366 Watts per square
meter is known as the
Solar Constant - the
amount of solar power
hitting the Earth.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 20
April 1, 2008
For large scale power plants, the
choice is solar thermal power….
• Mirrors are used to concentrate the
Sun’s rays on a heat transfer material
used to make steam which drives a
turbine generator.
• One dramatic scheme is the solar
power tower.
• Another is a system of parabolic
troughs with oil piped through tubes
at the center.
• Feb. 2008, Arizona Public Service
contracted with the Spanish company
Abengoa Solar to build the world’s
largest solar power plant (280 MW),
covering 3 square miles.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 21
April 1, 2008
Wind power…..
• Winds come from the differential heating of the
atmosphere by the Sun, so wind power is another
form of solar energy.
• Wind power is much closer to being cost
competitive with coal and is growing in the U.S.
at over 25% annually.
• Texas has
become the U.S.
leader in wind
power.
• Cape Wind in
Nantucket Sound
is the the first
offshore wind
farm proposed in
the U.S.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 22
April 1, 2008
Intermittency…
One major problem with solar and wind power is that they
fluctuate with the sun and winds.
Electricity is difficult to store. For solar & wind to become
major components of our energy infrastructure, this
problem needs to be solved.
Hydrogen is one possible energy storage solution.
• Hydrogen can be made from water using electricity. It can then be
burned as needed to produce electricity.
• Companies are hard at work linking solar, wind and hydrogen
technologies.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 23
April 1, 2008
Biofuels….
The major player is ethanol, which is
the basic alcohol that we drink. It is
produced from sugars by fermentation.
There are many ways of going from
plant matter to ethanol….
C2H6 Ethane
C2H5OH Ethanol
The easiest way is to start with sugar cane, as
they do in Brazil, where ethanol accounts for
about 40% of automobile fuel.
In the U.S., most ethanol is currently made
from corn.
Before fermentation, the carbohydrates in the
corn kernels must be converted to simple
sugars. This is itself an energy intensive
process.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 24
April 1, 2008
Corn based ethanol has a number of
serious drawbacks…
• The energy gain relative to the energy
input is at most a modest 30%.
• Savings in GHG emissions are even
smaller.
• Using corn for ethanol displaces land
from food production.
• If 100% of the U.S. corn crop went to
ethanol, it would replace only 12% of
gasoline.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 25
April 1, 2008
An alternative route that holds great promise is
cellulosic ethanol…
Cellulose is the primary structural component of
green plants.
One advantage is the ability to use agricultural
waste products, such as corn stalks, industrial
waste, such as paper making sludge, or crops
such as switchgrass that can grow in poor soils
with little fossil fuel input.
Another advantage is that biomass is typically
used as a fuel in the conversion of cellulose into
sugars, greatly reducing CO2 emissions.
The challenge is in converting the cellulose into
sugars for fermentation into ethanol. Many
biotech firms are working on developing
biological agents tailored to this task ….
is a local start-up company founded in the
summer of 2007 by UMass Microbiology
Professor Susan Leschine
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 26
April 1, 2008
Should we be optimistic about a
sustainable energy future?A couple of random examples…
Although the federal government has not shown much
leadership on climate change, individual states are
stepping forward.
• Massachusetts vs. EPA (2007) - The Supreme Court
ruled that the EPA must either regulate CO2 emissions,
or give a scientific justification for not doing so.
• Kansas recently turned down an application for two
new non-clean coal fired power plants based solely on
their GHG impact. Governor Sibelius recently vetoed
an attempt by the Kansas Legislature to reverse this
decision.
David Kastor
Physics Department
A Sustainable Energy Future?
Sustainable Living
Slide - 27
April 1, 2008
And if government won’t listen, we can always turn to…
