16 Apr, 2009 08:17 am
The recent start-up of the latest large-scale nuclear fusion experiment, the National Ignition Facility at the Lawrence Livermore National Laboratory, was greeted with the customary mix of fanfare and skepticism that has accompanied the quest for practical fusion power for as long as I have followed it, starting as a seriously nerdy child.
The answer may lie in the generally-assumed characteristics of a successful commercial nuclear fusion reactor technology, providing cheap, reliable and concentrated energy from a fuel that is as ubiquitous as it is limitless, using a process that creates large amounts of power but essentially no harmful waste. Is that a realistic expectation, or merely the aggregated antonyms of the shortcomings of every existing energy source? Consider the alternatives:
fuels are finite, and their production and use release a variety of
unwanted byproducts, including greenhouse gases implicated in climate
change. Their reserves are also unevenly distributed, giving rise to
worrying levels of rent-seeking, resource nationalism, and geopolitical
instability and insecurity.
- Wind power is intermittent,
unpredictable and unsightly, requiring extensive adaptation of the
power grid, ample fossil-fueled back-up, expensive energy storage or
all of these to contribute reliably on a large scale.
power is more predictable than wind but still expensive, inefficient
and cyclical, delivering less than a quarter of a day's peak output
even in optimum locations. It takes well over 3,000 MW of solar
installations to generate the same amount of energy as one 1,000 MW
coal-fired power plant.
- Geothermal power is reliable and
relatively cheap. However, the "hydrothermal" reservoirs--natural
deposits of steam and very hot water--that it taps are unevenly
distributed and often far from markets. Enhanced, or "dry rock"
geothermal offers greater promise and flexibility, though it is still
in its infancy and might also cause earthquakes.
power taps waves, tides or temperature gradients, offering enormous
potential while sharing many of the drawbacks of wind, solar and
geothermal. It is also decades behind them in development.
necessary shift away from unsustainable food-based feedstocks depends
on unproven or expensive technology. Truly large-scale biofuel
production entails harvesting and hauling vast quantities of bulky
materials with low energy densities, raising serious questions about
whether it can ever create a sufficient energy surplus for the rest of
the economy. This limitation also applies to electricity generated from
- Perhaps fusion's first cousin, fission, comes closest to its ideal, providing large amounts of cheap kWhs on demand, around the clock and with very low emissions. Unfortunately, it's hobbled by the high construction cost of new reactors and concerns about safety, security, proliferation, and waste. Some of these are legitimate while others seem overblown, but the technology is no one's free lunch.
I don't know what form fusion's unexpected drawbacks will take, should the NIF testing pave the way for commercial fusion power plants a decade or two from now. I do know we need a serious debate about the sorts of trade-offs we're willing to accept from any energy source we promote as part of the solution to our dual challenges of climate change and energy insecurity. At a minimum, we must move beyond the mindset in which no current technology can compete with the presumed perfection of those that are still on the drawing board or have yet to be deployed on a scale at which their flaws might become apparent. Our future energy diet will most probably be a messy mix of "all of the above", just as our current one is. Perfect energy remains an April Fool's story.
Originally published on Energy Outlook