This item addresses the apparent
natural persistence of the coal based energy economy and is an eye opener as
far as it goes. Coal is our cheapest way
to deliver variable base load power with a secure price structure. Thus China and India are building as is every
other developing economy.
My problem with this thesis is
that two game changers are either in place or at least on the horizon and they
eliminate the dependency on fuel. One is
the advent of superconducting cable. It
exists and is going into mass production and will soon allow power to be
shifted easily around the continent.
This innovation will allow new conventional geothermal power in Nevada
to be readily exported with no loss throughout the USA. This combination will eventually be much cheaper
than coal.
The other is the advent of fusion
based thermal heat engines either now happening or about to be happening that
we know can be delivered shortly. This
technology will not wait because it can be retro fitted into any plant near you
that needs it at a scale to fit the customer. This is where mass production
will swallow the whole power industry in as little as a decade, in quite the
same way as computer technology has transformed the communications and media
industry.
I presently can make sound
arguments to support the early outright demise of all but a small fraction of
the carbon based economy inside of less than fifty years. Everything is in place and already invented
with the exception of superior battery technologies. Actual roll-out will still take a little time
to reach critical mass but it will reach critical mass.
This is a Perspective for the
article 2012 Environ. Res. Lett. 7 014019
Myhrvold and Caldeira worked
out the climate consequences of various ways in which the world's current fleet
of coal power plants could evolve into something different [1].
They imagined one-fortieth of
the world's coal plants being closed down each year for 40 years. Two
limiting cases are (1) nothing is built to take the place of this power,
because efficiency gains have made them unnecessary, and (2) coal plants
exactly like those now running take their place. Since coal power is the most
carbon-intensive form of power, all other options fall between these limits.
They looked at six single-technology alternatives: taking over from coal as we
know it are coal with carbon dioxide capture and storage, natural gas, nuclear
power and three forms of intermittent renewables (presented as baseload
options). Moreover, whatever the alternative, it remains in place unchanged
from year 40 through year 100.
Results are presented as
100 yr trajectories for the increment in the average global surface
temperature due only to this power production. For the coal-for-coal scenario,
the surface temperature increase is about 0.13 °C in 40 yr and 0.31 °C in
100 yr. For the efficiency-for-coal scenario, the rise is 0.07 °C in
40 yr and 0.06 °C in 100 yr. Clearly, temperature rise is
approximately proportional to emissions and these are self-consistent answers.
For example, after 40 yr efficiency-for-coal has brought approximately
half the temperature rise of coal-for-coal, and there have been exactly half
the emissions. The efficiency-for-coal trajectory falls ever so slightly
between years 40 and 100, because once CO2 enters the atmosphere it
lingers.
As for the absolute magnitude
of the coal-to-coal trajectory, today's global coal power production
(8300 TWh in 2008) is almost exactly what would be produced from one
thousand one-gigawatt coal plants running flat out (8760 TWh), which is
the coal power production assumed by Myhrvold and Caldeira. From table S1 of
their paper, each GW-year of coal power production is accompanied by
6.59 Mt of CO2 emissions. Thus, a century of this coal will emit 659
billion tons of CO2. A rule of thumb recently promoted associates each trillion
tons of carbon emissions (each 3.7 trillion tons of CO2 emissions)
with a long-term temperature rise whose fifth and 95th per cent confidence
intervals are 1.0 and 2.1 °C [2]. With this rule of thumb, the long-term
temperature rise should fall between 0.18 and 0.38 °C, so the estimated rise of
0.31 °C agrees with the rule of thumb.
Much of the paper is about
estimates of the emissions for the alternatives to coal and efficiency.
Emissions are estimated for building the physical stock as well as running it.
The authors cite a high and a low value for each alternative, and the lower
limits, with one exception, are close to what most analysis assumes. (The
exception is natural gas, whose lower limit is 60% of the value for coal, even
though values of 50% or lower are widely claimed.) The high limits are
unorthodox and are already creating consternation. The high limit for
hydropower reflects large emissions of methane from the lakes that form behind
dams. In the cases of nuclear power, solar electric power, solar thermal power
and wind power, the high limits can be attributed to emissions during
construction. One suspects that these high values are straw men, avoidable with
care.
It is illuminating to compare
the Myhrvold–Caldeira partial emissions scenarios with the two full blown
scenarios of the International Energy Agency (IEA)—the Current Policy Scenario
and the 450 Scenario, presented in World Energy Outlook 2010 [3]. Both IEA
scenarios go only to 2035. In the Current Policies Scenario, coal emissions
approximately double by 2035 (to 16 500 TWh); Myhrvold and Caldeira
actually do not tell us that this is where global coal power is heading, in the
absence of new policies and priorities.
As for the IEA's 450 Scenario,
it provides insight into the 40 yr phase-out for global coal power chosen
by Myhrvold and Caldeira as their base case. In the 450 Scenario, global coal
power falls to 5600 TWh in 2035, down one third from its 2008 value. By
contrast, the pace for coal phase-out explored in the Myhrvold and Caldeira
paper is about twice as fast: if their 40 yr phase-out had started in
2008, by 2035—27 yr later—global coal production would have fallen by
about two thirds. I think one can view the 450 Scenario as capturing the IEA's
judgment about the fastest achievable decarbonization of the world energy
system. It is sobering to realize that allowing 40 yr for the closing out
of world coal power production, which might strike some readers as relaxed, is
actually so intense as to stretch credibility.
The IEA 450 Scenario also
sheds light on the small fraction of the potential change in the future of the
global energy system that the Myhrvold–Caldeira paper captures. The
2700 TWh reduction in coal power production between 2008 and 2035 in the
450 Scenario is smaller in magnitude than the increases in wind power
(3900 TWh), nuclear power (3700 TWh), and hydropower (2800 TWh)
in the same interval. Myhrvold and Caldeira present a textbook exercise, not to
be confused with an exploration of the full range of possible futures.
I would not recommend this
paper for its insight into energy systems. Rather, I would recommend it,
strongly, as one of the rare papers that adequately confronts both of the
sources of inertia that characterize our world: the inertia of the climate
system epitomized by the durability of atmospheric CO2 and the inertia
of the energy system epitomized by the durability of our capital stock.
Confronting this inertia can lead us to despair that what we can change for the
better each year matters so little. Or it can inspire us, because what we do
each year that points in the wrong direction will take so long to undo.
References
[1] Myhrvold N P and Caldeira
K 2012 Greenhouse gases, climate change and the transition from coal to
low-carbon electricityEnviron. Res. Lett. 7 014019
[2] Matthews H D, Gillett N P,
Stott P A and Zickfeld K 2009 Nature 459 829
[3] IEA 2010 World Energy
Outlook 2010 (Paris: IEA)
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