Solar power – can we get enough of it?
Over recent days, I have promoted and engaged in – but mainly observed – online discussions regarding the feasibility of modern civilisation meeting its projected energy needs from renewables alone. Some say we can (and must) do this; whereas others say we might need (but cannot possibly hope) to do so… I remain confused and hope that, by posting this, I may facilitate some polite discussion of the issues by people whose knowledge of the subject is better than my own. First of all, however, some context:
A few weeks ago, I posted an item on my blog that included a video of an old Nova programme (originally broadcast in 2007), which featured Dr Amory Lovins of the Rocky Mountain Institute (RMI) – who has proposed a 40 year plan to decarbonise the USA’s power generation systems without resorting to nuclear power (i.e. renewables alone). However, when I asked fellow blogger Schalk Cloete to review this, he declared himself thoroughly sceptical; and referred me to a piece he had written on the subject of the Second Law of Thermodynamics, which includes the following assertions:
On average, the surface of the earth receives about 180 W/m2 over a 24 hour period, but, because energy does not like to be concentrated, we can only get access to small amounts of this solar energy influx. More specifically; solar panels made from common materials which are sufficiently abundant for mass production typically manage to convert about 10% of the incoming solar radiation to useful electricity and solar thermal is even worse. When considered relative to the solar radiation falling on the total plant area, a large solar thermal power plant produces electricity at an efficiency of less than 3%.
Solar panels therefore can generate about 18 W/m2 of electricity on average while solar thermal is restricted to about 5 W/m2. This implies that you would need 5.5 m2 of solar panels or 20 m2 of solar thermal power plant to power a single traditional 100 W light bulb 24/7 (if you have the energy storage capacity to smooth out the intermittent nature of solar power of course).
In an attempt to promote discussion of this, I posted a link to it on Peter Sinclair’s Climate Denial Crock of the Week (with some interesting results). Schalk has also prompted further discussion by commenting on a more recent post (although Peter Sinclair now appears to be ignoring him).
Schalk has since provided me with a more carefully considered critique of the Lovins plan (as detailed in his book Reinventing Fire – see RMI website link above), which he has kindly granted me permission to publish here:
I spent some time on Youtube and the internet in general to get more informed about Dr. Lovins’ ideas. His strong emphasis on demand reduction through efficiency is definitely a step in the right direction and I strongly support that. The profit-driven private enterprise route also makes a lot of sense and, if green business practices can in fact give an obvious competitive advantage, it will definitely be adopted very rapidly. However, I can still see many challenges, the most important of which I summarize below:
- The enormous scale of this challenge. The requirements in terms of energy, capital, materials and specialized human labor needed to revamp all of our buildings and industry, our entire transport fleet and, most importantly, our entire energy industry is truly colossal and I still think that it will require many decades to get the job done.
- The gradual unraveling of our great Ponzi scheme economy will make innovation very challenging through greater uncertainty, tight credit markets and increasing social welfare demands.
- Some success with demand reduction will once again make fossil fuels dirt cheap. For example, we just need to cut our oil use by about 10% in order to get off unconventional oil and slash crude prices by a factor of five.
- Putting theory into practice in the real world is always harder than it seems. For example, Dr. Lovins has been working on these ideas since 1976 already and, although he has been doing excellent work for almost four decades, his impact is hardly earth-shattering.
That being said, however, I definitely think his ideas are a lot more feasible than others advocating a massive government-sponsored renewable energy revolution. In essence, he goes one level down from government to private enterprise for the purpose of increasing the efficiency of this great transition. Personally, I think we need to go another level down from there to the individual consumer in order to get access to loads of environmental, economic and societal benefits that do not require any energy, capital or natural resources. I don’t see how we can get through this transition unscathed without liberally tapping into these totally free benefits.
Therefore, since I remain completely bemused by all this, I invite anybody who can reconcile Schalk’s assertions (i.e. quoted and/or linked to above) with the infographic image (below) to which I have been referred by Roger Lambert (i.e. a contributor to the recent discussion linked to above).
To me, Schalk’s assertions regarding the low energy-conversion efficiency of all forms of renewable power generation (compared to burning fossil fuels, nuclear power, and even photosynthesis) are incontrovertible facts; facts which do not appear to accord with the information on the above infographic. Furthermore, in light of the agreement of people like Dr Samuel Alexander of the Simplicity Institute (e.g. as seen here in this part of a serialisation of his Alexander’s paper on Learning from Dogs), I would also like to know what our chances are of replacing fossil fuel use with renewable power generation in the timescale that climate scientists say we need to act (i.e. years not decades).
As things stand, my provisional conclusion is as stated on Learning from Dogs:
…Dr Alexander provides the solution to the conundrum that has been troubling me: He too acknowledges that we have no way (neither renewables or nuclear) to power anticipated economic or population growth but says that we must also get off fossil fuels as quickly as possible… His solution is not just energy efficiency or even self-sufficiency (i.e. independence) – it is far more radical. What scares me, however, is that this too is impossible: In 1968, Garrett Hardin (Tragedy of the Commons) said that solving the problem would require mutual restraint to be exercised by all of us, but this is never going to happen. Therefore, I think I know how the story will end… Humanity will refuse to change and therefore William Ophuls will be proven correct – If we fail to heed the warning signs, like an aeroplane landing on the deck of an aircraft carrier is brought to rest by a steel cable, nature will intervene (to re-establish a balance between supply and demand).
I am, however, not an expert on renewable energy; and I would like to know who is mistaken here because – one things seems clear – someone definitely is.