This article received some main-stream press coverage, including
in The New
as well as a large number of more local outlets, with different
aspects of the report emphasized to varying degrees. It's not clear
the primary message has gotten through though: we're not ready to
replace fossil fuels yet, and we should be spending an awful lot
more money (Manhattan or Apollo-project sized) on research into the
long-term alternatives, so we can be ready in time.
As the article states, Kyoto is paradoxically both "too weak and
too strong: Too strong because the initial cuts are perceived as
too much of an economic burden by some (the US ...); too weak
because much greater emission reductions will be needed, and we lack
the technology to make them."
What are the technology alternatives available now? Improved efficiency
is the maxim of the environmental advocates - a lot can be done there,
both with improved technology and altered lifestyle choices (if that's
acceptable in a democracy). But as the authors point out, the limited
potential effects of improved efficiency (at best a factor of 2 or so)
in the Western countries would be overwhelmed by increased
energy requirements in China and India. Efficiency improvements are
worth doing, but will only delay the inevitable, unless other
measures are taken.
On the technocrat side (exemplified by the position of such US agencies
as the Department of Energy) the
long-favored solution has been power from nuclear fission. Surprisingly,
this is as much a limited resource as oil, which the article estimates
at 6 to 30 years-worth of reserves of land-based uranium, if
used to sustain 100% of world energy usage. More uranium is available
from seawater, but the authors point out extracting sufficient uranium
to power the world would require processing seawater at a rate at
least five times the total outflow of the world's rivers to the ocean.
Fission power can be stretched through production of plutonium in
breeder reactors, but most of the world has decided that is an unsafe
course to follow.
Use of hydrogen as a fuel does not directly help since hydrogen is not
available in raw form in sufficient quantities to serve as a major fuel:
original energy of some other form is needed to produce it. Hydrogen may help
in relocation of the CO2 production from end-users to central
power plants, however. A recent set of large-scale engineering proposals
involves "sequestration" of carbon dioxide; capture and removal to the deep
ocean, or underground in old oil fields, etc. This will likely be a
valuable short-term measure, but if nothing else is done the
sequestration rates required to stablize global CO2 levels
will be enormous, and we will run out of places to store it all safely.
That pretty much leaves the renewables, and fusion. With renewable energy
sources, by definition, we will not run out (at least while the Sun still
shines), so they definitely provide a long-term CO2-free solution.
All renewables, however, suffer from low power density: you need to
occupy a lot of land area to capture the 3-10 TW (electric) estimated needed.
For example, with solar photovoltaic panels the land area needed would
be 200-600,000 square kilometres (100-250,000 sq. miles) or up to 7% of
the land area of the United States. Using biomass (green plants and
incinerator/generators doing the work of the solar panels) even 3 TW
would require as much land area as is currently used by human agriculture.
The most intriguing renewable option is space-based solar power. Due
to the direct exposure to the sun and ability to produce energy
24 hours a day, a space-based solar option would require
only 1/4 the area of one on Earth's surface (after accounting for
microwave transmission losses). The technology was researched
in the 1970's with a plan for large satellites ("the size of Manhattan",
i.e. each about 20-30 square miles) in geosynchronous orbit; on the
order of 1000 of these would meet the space-based area requirements
for 3 TW electric worldwide power supply. The Earth-based land area
requirements for receiving this energy via microwave beams would be
substantial, but less than for land-based photovoltaic, and would
allow dual-use (for example as range land) where land paved with
photovoltaic cells would be difficult to use for anything else.
Alternatives to geosynchronous orbit may be economically
more attractive, particularly use of the Moon as suggested
by David Criswell in a number of articles recently, notably
in the April issue
of The Industrial Physicist,
Space solar power has the advantage over fusion that no real
fundamental further research is needed to figure out how to do it -
the primary challenges are those of large-scale space engineering.
Criswell has estimated the start-up costs for his lunar solar
power system would be on the order of $150 billion before the system
would start to pay for its continued expansion - a substantial
(Apollo-project-level) investment, but given the scale of the problem
facing the world and the expected cost of most other solutions,
not an impossible figure.
One other space-based option for climate change mitigation is
to directly block the sun with a mirror, placed at the L1 semi-stable
point between Earth and Sun. A mirror the size of the United States
would block about 2% of solar energy, roughly compensating for a doubling
of atmospheric CO2. Of course the sun would appear to
have a permanent spot right in the middle!
Fusion research has progressed over the years, and several
major new test reactors are in development, most prominent
among them being the International Thermonuclear Experimental Reactor
(ITER), with construction costs estimated at about $10 billion. The
next major milestone, aside from understanding the engineering challenges
with confining large, hot, plasmas, is to demonstrate net electric power
production from a self-sustaining fusion reaction. The authors of this
study find it unlikely that fusion could be relied on to help with the
CO2 problem before 2050 or so, but continued research
on this long-term option is very important.
The world has a serious problem here. We're clearly not ready to
deal with it. Whether on the space engineering or fusion
physics/engineering side of things, a massive investment in research
and development funding will be needed to get these long-term
energy projects moving. Tragically, in the recently declared US
national energy policy,
only one of the more than one hundred recommendations even mentions
fusion energy, and that recommendation also suggests promoting hydrogen
and fuel cell use (confusing given that hydrogen cannot be a primary
energy source). Solar energy and other renewables (along with conservation
and other short-term measures) are mentioned in quite a few recommendations;
however the possibility of large scale space-engineered systems is completely
overlooked. Further evidence of a lack of thought for the future can
be found in the 2002 budget
for the US Department of Energy; $2 billion over 10 years for "clean coal",
$1.4 billion over 10 years for "weatherization assistance", solar
and renewable technology money contingent on ANWR approval, and overall
a $700 million cut from the previous year's budget. The request for the
2003 fiscal year
(still not yet passed by Congress) doesn't look any better, with actual
dollar cuts in the (already small) levels requested for renewable and
nuclear energy research.
Is there any real hope for such massive R&D projects? Are we,
the democratic western societies, still capable of such things? The
somewhat aimless International Space Station has been beset by
funding troubles, but the cost involved is a few times less than total
costs for new energy solution R&D would be. But we did succeed
with the Apollo project, roughly $100 billion in cost, at a time when
US GDP was less than 1/4 its present size (in constant current dollars).
And the cost scale is not so far out of the range of current major power
systems: a typical multi-GW modern power plant costs several billion
dollars, and hydropower plants already involve engineering on an
enormous scale here on Earth - for example China's Three Gorges Dam
is estimated will cost over $20 billion to build, with a reservoir 370
miles long, and the concrete dam itself 1.2 miles across and about
600 feet high. And even that can only provide a small fraction of China's
future energy needs.
Personally I'm an optimist; I think most people just don't yet realize the
scale of the problem or of the research effort needed to overcome it.
When this is widely understood the world will surely
rise to meet the challenge. Won't it?