Clean Coal
Clean Coal is almost an
oxymoron, however America is the Saudi Arabia of coal which means there is
a tremendous amount of energy stored right here within our borders, if
only we choose to extract the energy from coal wisely. Converting just 5
percent of the U.S. coal reserves to liquid fuels for aviation would
equate to the existing U.S. crude reserves of 29 billion barrels.
Coal to Natural Gas
Coal is quite willing to
give up its energy bearing hydrocarbons and allow them to be converted
into gases. Most Coal to Gas technologies produce syngas, but a number of
groups are working on producing natural gas from coal. These developments,
if commercialized, would allow the huge US reserves of coal to be
converted into natural gas in an environmentally friendly manner.
In-Situ Coal Gasification
Mining coal has a tremendous
environmental impact, so extracting the energy out of coal while it still
is in the ground makes a lot of sense. Underground Coal Gasification (UCG)
or the use of geo-reactors offers tremendous potential to clean up coal energy and enable economic
access to stranded coal deposits.
The Coal to Gas Advantage
This emerging Coal to Gas
technology tantalizes us with the promise of extracting the energy from
coal:
- cleanly and in a
carbon free manner.
- at the place of
extraction and then being able to pipe that gas to the point of
consumption.
- without ever having to
mine the coal out of the ground and by extracting coal's energy in-situ
saves us from having to take whole mountains down with open cast mining
techniques.
Piping Gas is much more
Efficient than Hauling Coal
Piping gas around the
country can be done using the existing natural gas infrastructure and
piping the gas moves the energy to precisely where it is needed for use in
your home or business.
This is a much more
efficient conversion system than hauling coal by freight train to a
emissions belching power plant and then loosing massive amounts of energy
transmitting that electricity to homes and businesses via the national
grid.
Electric Cars and Burning
Coal to Charge Them
In the US there is
sufficient idling capacity available overnight to recharge 75% of the US
auto fleet if it were converted to electric drive today. Burning coal would enable the US to generate the
huge amounts of electricity that would be required to power the 280
million vehicles in the American private transportation fleet.
The
problem is burning that amount of coal at existing coal fired electric
power plants to provide the required electricity for an all electric
vehicle fleet would produce about 4 times the amount of CO2 than an
equivalent gasoline burning vehicle fleet.
Using the Tesla Electric Car
on a 100 mile trip as an example, approximately 65 pounds of coal would
have to be burned at an electric power plant to provide the electricity
for that journey. Burning 65 pounds of coal would release nearly 250
pounds of carbon dioxide into the atmosphere.
In comparison, powering the
Tesla with a gasoline engine instead would consume approximately three
gallons of gasoline. Burning 3 gallons of gasoline would release
approximately 60 pounds of carbon dioxide in to the air.
This means that the coal
fired electricity used by the Tesla on that 100 mile trip causes four
times as much carbon dioxide to be dumped into the atmosphere as the
equivalent gasoline powered Tesla would on the same trip.
Clean Coal and Fuel Cells
offer a pathway to an all Electric Vehicle Fleet
The possibility of converting the US's tremendous reserves of
coal into clean electricity does however offer a tantalizing prospect of
an all electric vehicle fleet without creating a CO2 nightmare:
This would need to be
tackled in two simultaneous technology rollouts:
-
Coal to Gas technology
offers us a way to get at the energy stored in the massive US reserves of
coal in an efficient and environmentally friendly manner.
- Installing large
numbers of distributed, small scale
Fuel Cell
Combined Heat and Power systems (CHP) could then take that natural gas
and produce the electricity and heat we need for our transportation and
housing needs.
Coal to
Gas, combined with the Fuel Cell over comes the "long tail pipe"
and "CO2" argument
against electric cars
and offers the path away from liquid fuels and the internal
combustion engine.
(There is sufficient coal in
the US for the next 250 years, so coal would give us just about enough
time to figure
out fission and its promise of unlimited energy)
Hydrogen Fuel Cell
Technology still on the horizon
Hydrogen Fuel Cells have
been held out as the silver bullet solution for powering our
transportation needs in the future. The problem with hydrogen and its
associated fuel cells is how to generate the hydrogen in the first place
and then get that hydrogen to the fuel cell.
Solutions to these two
problems are at best many years out, however natural gas is an excellent
hydrogen carrier technology and the infrastructure is in place today.
Natural Gas and Fuel
Cells
The natural gas produced by
this emerging coal gasification technology could be converted directly into heat and electricity using
a fuel cell.
Graphic
courtesy of Plug Power
The neat thing about a fuel
cell is that it is able to convert the energy in natural gas at conversion
efficiencies close to 80% for a combined heat and power installation, plus
do so in a virtually emission free manner.
The Dangers and
Possibilities of Nuclear
Energy
There is a lot of talk about
Nuclear Energy as it is a carbon free energy source, however the horrific
memory of the Chernobyl disaster seems to be forgotten in this rush to
re-kick start the US nuclear program. We still have not solved the waste
storage problem and burying material in the ground that decays in
millennia rather than weeks, seems a very hazardous and wasteful undertaking.
The sheer scale of the
"going nuclear" undertaking is mind boggling as the US would need to build
approximately 250 new nuclear power plants in addition to the existing 104
to enable us to shut down all coal fired plants. France has a very successful, large
scale nuclear program, but this example aside I am very leery of the safety
of conventional nuclear power and think it wise not to attempt to restart the US
nuclear program in its conventional form.
We could use pebble bed
nuclear reactors to replace coal fired stations and get a lot of
electricity in CO2 neutral manner. Koeberg outside Cape Town, South Africa
is just such an example of a pebble bed reactor and these designs of
reactors are "walk away safe" as they are an inherently, passive safe
design. These reactors are designed so high temperatures reduce power
output by doppler broadening of the fuel's neutron cross-section. In
addition, they use ceramic fuels so its safe operating temperatures exceed
the power-reduction temperature range.
Ideally you would want to
retro fit America's coal fired power stations with pebble bed reactors as
all the associated electricity infrastructure is already in place at the
coal fired sites. Combining Pebble Bed Reactors with solid state heat
conversion technology is as close to "safe nuclear" as we are likely to
see in the 21st century.
Nuclear Coal?
The irony of all this
nuclear discussion is that there is more than enough uranium sitting
around in coal fired power station slag heaps to build a lot of nuclear
weaponry. This is all the more reason to use the energy of coal in-situ
rather than bringing it to the surface and burning it in a coal fired
power station.
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Clean Coal
Carbon Sequestration
Heat to Electric
Walk Away Safe Nuclear
Energy
