A friend and I have started writing a blog at contraposition.org on these issues (this post is cross-posted there).  Our “about” page, which reads as follows, might be a good starting point for this discussion:

We’ve noticed that much of the sustainability/green/environmental community likes to reason in only one direction:(1) If we’re going to maintain the current economy (p), then we’ll need alternative fuels that meet current energy needs (q).

But why not contrapose?

(2) If we can’t get alternative fuels to meet current energy needs (~q), then we won’t be able to maintain the current economy (~p).

It seems we need to flesh out part of this argument: the part that discusses why “we can’t get alternative fuels to meet current energy needs.”  That is, we need to discuss what possible alternative sources of energy might be, and whether they are likely or unlikely to meet current or extrapolated energy demand.I think it’s possible that the sustainability/green movement sees this from a practical, marketing perspective.  That is, it’s thought to be hard to sell people on an austere life, so instead we should sell people on alternatives that will let them keep their current life.  But that’s entirely a question of marketing, not of whether it’s achievable.

What I’d like to address is whether it’s possible for the world to seamlessly transition to alternative energy.  There are a few dimensions to this question:

  1. What are the compounding constraints that will limit our choices?
  2. How much alternative energy would we need to build?
  3. What are we likely to be able to build?

Before I try to address each question, I want to add a disclaimer.  One of the difficulties in writing about the challenges of alternative energy is that it can easily be mistaken as coming from a very different perspective: the kind put forward by science-denying “skeptics”.  Recently, to get a sense of what they’ve been writing, I wandered over to Reason and CATO, and was greeted by a number of posts arguing against environmental regulation, alternative energy, or saving energy.  They’re arguing against even trying to develop alternative energy, and generally disagree with the notion that “if we’re going to maintain the current economy, then we’ll need alternative fuels that meet current energy needs.”  My contention here is quite different – I believe that we need to switch to alternatives, but it’s likely that alternatives will not deliver enough energy to replace today’s sources so we need to factor that shortfall into our plans.What are the compounding constraints that will limit our choices?

The two primary reasons to develop alternative energy sources sooner rather than later are peak oil and climate change (though in the longer term we’ll have to switch to alternatives simply because our primary energy sources today are finite).

For climate change, scientists today generally agree that 2 degrees Celsius of warming (over pre-industrial) is the threshold at which positive feedbacks (such as the melting of the permafrost) become severe.  Therefore our aim should be to keep the climate from exceeding that threshold, which translates to a max of 450 ppm of CO2 in the atmosphere.  Global emissions currently increase CO2 in the atmosphere by about 2.5 ppm per year, giving us a little over two decades to bring emissions to zero.  (This is crucial to ensure the health of the oceans too.)

We’re within a couple of years of the peak of global oil production (depending on how you calculate “oil”), and the Hirsch report estimated that it’d take a minimum of two decades to achieve a successful mitigation of peak oil.  (The mitigation they suggest doesn’t take into account environmental or climate impacts – they consider switching to coal-to-liquids, etc. – so it may actually be harder to achieve than they suggest.)

The combination of these factors indicates that our energy transition needs to occur within two decades.

How much alternative energy would we need to build?

Saul Griffith performed a number of calculations to answer this question in his talk Climate Change Recalculated.  To produce enough energy to replace the fossil fuels we use today, within two decades, we need to build (the sustained rate for 20 years):

  1. 100 m2 of solar panels / sec = 2 TW of solar photovoltaic
  2. 50 m2 of solar mirrors / sec = 2 TW of solar thermal
  3. 12 x 100m wind turbines / hour = 2 TW of wind
  4. 3 x 1GW plants / week = 3 TW of nuclear
  5. 3 x 100MW turbines / day = 2 TW of geothermal
  6. 1250 m2 oil algae / sec = 0.5 TW of biofuel

The scale is daunting, and brings us to our next question.What are we likely to be able to build?

It’s hard to get good data to answer this question, so I looked at industry press releases (which are generally optimistic) where available, and then overestimated to determine what, in a best-case scenario, we might be able to build and install:

  1. 20 m2 of solar panels / sec (vs. 100 m2 /sec required)
  2. > 50 m2 of solar mirrors (vs. 50 m2 / sec required)
  3. 6 x 100m turbines / hour (vs. 12 turbines / hour required)
  4. 0.5 x 1GW plants / week (vs. 3 plants / week required)
  5. 1.5 x 100MW turbines / day (vs. 3 turbines / day required)
  6. negligible (vs. 1250 m2 oil algae / sec required)

Summed up, this will yield, after 20 years, about 7 of the 15 TW we use today, so it would be a replacement for at most about half of current energy demand.  The rates of production I’ve listed here require all-out manufacturing (i.e. making the production of alternative energy a priority in the way making bombers was a priority during World War II).What does this mean?

First, knowing that it’s unlikely we’ll be able to build alternatives fast enough helps confirm the notion that alternatives will not be able to power the economy in the way we do today.  But more than that, it’s a reminder that we can’t just focus on keeping our industrial society running the way it is – we’re all going to have to use a lot less energy.  This, I think, is the central issue we should focus our attention on.

Compounding the problem, alternatives face many deployment issues as we try to scale them up, as I surveyed in the Nine Pitfalls of Alternative Energy.  A consequence of the likely shortfall in energy (any any sort) is that we are likely at or near the end of economic growth as we currently measure it.  As a result, economic challenges will make it harder still to build up alternative energy capacity.  This is an issue that I plan to continue to write about in more detail, but for now, here’s a summary:

  1. Our economy depends upon fossil fuels, particularly oil.
  2. Oil and fossil fuels are finite.
  3. In the production of all finite resources, production must reach a peak at some time.
  4. Discoveries must precede production.
  5. Discoveries of oil are well past their peak and current geological  studies indicate we are near or at the peak of oil production.
  6. Fossil fuels more generally must be phased out due to their impacts on our climate.
  7. No alternatives can substitute for oil or fossil fuels in scale, malleability, or cost.
  8. The decline in oil production and energy availability has a direct, negative impact on industrial economies.
  9. Therefore we’re at the end of economic growth as we currently measure it.

Until next time…