Justifying $15 Trillion for Renewables

Yesterday I received a joint press release from a group of renewable energy trade associations. It touted a new report from the UN Intergovernmental Panel on Climate Change (IPCC) on the potential growth of renewable energy by 2050. The report has already garnered an impressive array of headlines, such as "Renewable Energy Can Power the World" and "Renewable Energy Key to Solving Climate Change". The headline from the Financial Times was characteristically more concrete, "World faces $15,000 bn renewable energy bill." Unfortunately, although the final report, rumored to run 1,000 pages, might support all of those conclusions when it is issued at the end of the month, the 25-page "Summary for Policymakers" falls far short of inspiring such confidence. Heaven help those policymakers if the summary is all they actually read.

I'm not even sure if "read" is even the correct verb to apply to this document. Once I got beyond the introductory paragraphs it seemed to degenerate into jargon and bureaucratese that was very hard to parse into plain meaning. The report's genesis as the product of pure consensus is readily apparent. Or as Andy Revkin of the New York Times' Dot Earth blog kindly put it, "it doesn't take readers much beyond what is already well established." That's a shame, because we don't need yet another report telling us that we are swimming in enough renewable energy to power our civilization umpteen times over, if we can merely muster the willpower to reach out and tap it. What we urgently need is a roadmap that describes a path--or preferably several possible paths--through the brambles that separate the energy status quo of 2011 from its ideal low-carbon state of 2050.

For example, we need to understand just how renewables will supplant the petroleum that currently provides around 94% of all transportation energy, at least in the US. That demand might be met by biofuels, although the report points out that the first-generation biofuels that supply nearly 3% of global road transport fuel today, but are still the only kind available on a commercial scale, have serious shortcomings. Closing the gap between 3% and 94% would require a true revolution in next-generation biofuels from sources such as cellulose and algae, yet after reading the Summary for Policymakers we are no wiser about when and how this will occur. I might note that such developments are rarely amenable to precise timetables, as the EPA is learning to its chagrin.

Alternatively, or in combination with biofuels, renewables might replace petroleum in transportation via the potentially more robust pathway of vehicle electrification, matching improved batteries with rapidly expanding supplies of intermittent renewables (wind, solar, tidal, etc.) delivered via increasingly intelligent power grids. But if that's the scenario, its crucial details are barely hinted at here.

The basic message of the summary appears to be that with enough investment, supported by the right policies, the currently identified renewable energy sources could expand by enough that in the very best case (out of 164 scenarios they considered) they could supply roughly as much energy by mid-century as we currently get from fossil fuels. That corresponds to 77% of total expected energy consumption in 2050 and may be the source of the headlines I saw. Of course the median level of those 164 scenarios is quite a bit lower, and the determination of the share of renewables in total energy relies on a projection implying that total global energy consumption will grow by an average of just 0.25% per year over the next 40 years. That suggests either a massive energy efficiency effort or minimal further economic uplift in the developing world. On a more reasonable track of 1% annual energy growth, the top scenario in the scatter chart on page 19 would meet 58% of total 2050 demand, while the median result would cover just a third of global energy needs. That's still impressive, compared to where we are today, but not quite as headline-grabbing.

I will be keenly interested to see what sort of scenarios the IPCC looked at in putting together the report on which this summary is based. Something tells me that they are likelier to fall into the category of what I would call projections or "cases" than true scenarios, which dig deeply into underlying trends and uncertainties and are not merely the output of a mechanistic model. That's not just a technical quibble, because I'm not aware of a single model-type forecast from 1970 that accurately projected the economic and sociopolitical conditions in which we find ourselves today. The intervening improvements in computing power and econometric sophistication still seem insufficient to conquer the fundamental unpredictability of looking that far into the future. But then the IPCC has a built-in bias to accept the results of such work, since long-term climate models underpin its entire effort. I hope I'm not alone in thinking that the expenditure of up to $15 trillion requires a much more rigorous justification than anything provided in this document. Whether or not Saint-Exupery really said it, a goal without a plan is just a wish.

If it seems that I'm being overly critical of a 1,000 page report that I haven't even seen on the basis of the horse-by-committee summary that I have seen, I plead guilty. But isn't that the same sin that the journalists and industry spokespeople are committing when they use this summary as the basis of glowing claims about the potential of renewables? And then there are the politicians and bureaucrats who will attempt to commit vast sums without ever reading any more than summaries such as this--at best--and without questioning the host of assumptions that went into them. If anything, this Summary for Policymakers reinforces my concern that the UN climate process has become so unwieldy and unresponsive that we must look elsewhere for leadership on this complex challenge. Meanwhile, we deserve a clearer articulation of how renewables can overcome the considerable obstacles that stand between their recent impressive performance and the achievement of the milestones this report suggests lie ahead.

Perfect Energy

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. MIT's Technology Review does a good job of describing the new facility, which will use high-powered lasers to attempt to create useful amounts of nuclear energy. But rather than focusing on the stupendous potential of fusion energy and whether this device might finally be the one to deliver on it, I'm more interested in what our dogged pursuit of this technology through decades of frustratingly slow progress says about our collective view of our current energy sources. How much of the search for fusion springs from its inherent value, and how much from our dissatisfaction with every other long-term energy option we possess?

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:

• Fossil 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.
  
• Solar 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.
  
• Ocean 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.
  
• Biofuels' 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 biomass.
  
• 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.

Don't get me wrong; I have always loved big science, and nothing would please me more than if the NIF performed exactly as advertised and heralded the dawn of a new era of energy abundance. However, given the long history of drawbacks and unintended consequences from all other energy sources, it seems unrealistic to suppose that any new source, including fusion, is capable of living up to all of its pre-deployment expectations. Fusion is perfect on paper, but then so is my favorite long-term energy option, space-based solar power--until the public becomes anxious about beaming megawatts of power to earth from space, or rogue nations develop anti-satellite capabilities that could hold our orbital energy supplies hostage.

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.

Catching the Flow

Of all the different technologies for producing energy, I've probably devoted the least space in this blog to those that extract energy from flowing water. Large hydroelectric dams are hardly novel; they generate about 7% of our electricity. But at least in the US, most of the attractive locations for large-scale hydropower have already been dammed or determined to be too pristine to exploit. "Mini-hydro", in the form of small dams or "run of river" installations is an interesting alternative, and it looks a lot more palatable than its larger cousin. The other day I ran across a link to a video report on a project that has fascinated me since I first heard about it in the late 1990s. It is a hybrid of hydropower and tidal power, tapping the tidal energy of the East River alongside Manhattan with turbines installed on the riverbed.

The initial size of this project is tiny; it will only power a supermarket and parking garage, when it runs, but the developers hope to scale up to 10 MW--still a lot smaller than the typical power plant or wind farm. This kind of tidal power application falls somewhere in the middle of the spectrum of renewable electricity sources: much more predictable than wind, but less reliable than geothermal or conventional hydro. Where it shines is in its unobtrusiveness, which might enable it to fly under the NIMBY radar in a way that wind turbines can't.

For that matter, the turbines used in the East River ought to work just as well in a river flowing due to gravity, like the St. Laurence, instead of one that reverses flow when the tide changes direction. It could provide a useful alternative to the standard approach to mini-hydro, which avoids large dams and reservoirs, but still entails diverting and empounding a portion of the flowing river. The reliability and environmental impact of "kinetic hydropower" remains to be determined, however. I will be watching the East River project with interest to see whether this emerges as a viable competitor or ends up as another interesting, but not very practical energy idea.