Remember when the news was that the IPCC had announced that renewables could power the world by 2050? 

There has been a bizzaro controversy over this.  Prominent voices from across the spectrum of opinion on climate science weighed in on the same side.   A world class odd couple, Steve McIntyre and Mark Lynas, agreed that the IPCC blew it and Andy Revkin wrote it up for the NYTimes.  This provoked a response from the IPCC.   

(McIntyre is famous for being such a thorn in the side of the East Anglia Climate Research Unit he was mentioned in more than 100 of the hacked emails of “climategate”.   One email was written by a scientist who wrote McIntyre was a “bozo”.  Lynas is McIntyre’s opposite.  Lynas wrote Six Degrees:  Our Future on a Hotter Planet.  He is a contributor to The Guardian newspaper among others, etc.  Revkin has been a science reporter deeply immerised in the issue of climate change for more than twenty years.)

But, as Edenhofer, the IPCC front man for PR for the report, pointed out in his comment on Dot Earth, “the criticisms of McIntyre and Lynas relate to the headline of the press release….” 

The IPCC allowed a press release to come out in advance of the publication of the report. 

The first line of that press release contained these words: “close to 80% of the world’s energy supply could be met by renewables…”   This was taken by many to be the conclusion of the main report and trumpeted worldwide.   Yet the statement wasn't a conclusion at all:  it was one scenario, 1 of 164 scenarios with different "what if" assumptions, that the IPCC authors reviewed as they explored what the potential of renewable power is.  

In his comment posted to Dot Earth, the IPCC front man pointed out that if anyone read further into the press release, things would have been made clear to them. 

Sure enough, deeply buried in the press release, the significance of the study trumpeted in its first line is explained: “Over 160 existing scientific scenarios on the possible penetration of renewables by 2050… have been reviewed with four analysed in depth.  These four were chosen in order to represent the full range.  Scenarios are used to explore possible future worlds….”  

So one "possible future world" out of very many, a possible world where it was assumed that conditions would exist that would produce the most massive deployment of renewables possible, was served up as the first sentence in a press release for the media to seize on and run with saying this is some sort of IPCC delusion conclusion about renewable power.  

The scenario doesn't seem to be a very possible world.  In it, a presumably spooked civilization outlaws all nuclear power globally AND carbon capture is never deployed, but it decides to mount an all out effort to eliminate the use of fossil fuels.  The possibility that public opinion, once it became unified enough that climate was a threat, might change its perception of the risks of nuclear or educate itself about the possibilities of carbon capture was ignored.  Oh, AND "a comprehensive energy efficiency strategy across all sectors" is simultaneously imposed. Given all this, what is incredible is they didn't find that renewables could supply 100% of all power.  The scenario finds that some people keep burning fossil fuels.  The scenario was taken from this published study.  The lead author is from Greenpeace.   

A more appropriate headline for this is: "Greenpeace admits renewables can't do it all".  

Gerbils running on treadmills powering generators could be used supply all the world’s electricity, if all other sources of power were outlawed, and the world didn’t care how much electricity was generated or what it would cost…  

Throwing a scenario like this into a review with 163 more realistic scenarios to give policy makers an idea what the extreme end of renewables deployment in a world without other options would look like is one thing, but this press release is a blunder for the IPCC.  

Greenpeace hijacked this press release.  Why did the IPCC allow it?  

 Now I have heard that when a major report like this comes out few bother to read further than a bit of the Summary For Policy Makers.  But in this case it looks like few got past the first sentence in the press release.  

For those who would like a bit more detail:

Here’s Edenhofer explaining it in a 3 minute video hosted on the IPCC website. 

He says the IPCC did the report  “to explore" how renewable energy (RE) can contribute to mitigation of climate change.  The mandate of the IPCC, he reminds everyone, is to provide "policy relevant" advice "without being policy prescriptive".  He emphasized:  "renewables are not the only option" and stated that they concluded:  "without dedicated national energy policies we will not see an increasing deployment of renewables".   At no time does he make a statement about how the IPCC decided that 80% of the world’s energy could come from renewables by 2050. 

The Summary for Policy Makers  section of the report fleshes out what Edenhofer said in the video.

On page 3 it says "there are multiple options for lowering GHG", i.e. conservation and efficiency, fossil fuel switching, renewables, nuclear, and carbon capture and storage.  "A comprehensive evaluation of any portfolio of mitigation options" would take cost, scalability, and sustainability into account.  "This report will concentrate on the role that the deployment of RE technologies can play within such a portfolio of mitigation options."

On page 7 the summary clarifies what they mean when they say that the “technical potential” of renewable power is not what would limit its use, i.e. there is more than enough to power civilization at the size it will be in 2050:  this is true as long as there is “no explicit reference to costs”.   

On page 14 the summary acknowledges that cost increases as the share of RE increases:  "The costs and challenges of integrating increasing shares of RE into an existing energy supply system depend on the current share of RE"

And on page 15 they acknowledge that  the actual penetration of RE will depend on what it costs:  "the actual rate of integration and the resulting shares of RE will be influenced by factors such as costs, policies, environmental issues and social aspects"

The Technical Summary. page 143 and 144, is clear about what will ultimately constrain RE deployment:  "energy demand growth and the competition with other options to reduce CO2 emissions (primarily nuclear energy and fossil energy with CCS)" 

They pointed out that:  "the cost, performance and availability of the competing supply side options—nuclear energy and fossil energy with CCS—is also uncertain", and that factors other than cost can affect nuclear and carbon capture:  "If the option to deploy these other supply-side mitigation technologies is constrained—because of cost and performance, but also potentially due to environmental, social or national security barriers—then, all things being equal, RE deployment levels will be higher"

And they point out that many studies find that costs are lower if all options are on the table:  Technical Summary, page 145 " A number of studies have pursued scenario sensitivities that assume constraints on the deployment of individual mitigation options, including RE as well as nuclear energy and fossil energy with CCS (Figures TS.10.6 and TS.10.7). These studies indicate that mitigation costs are higher when options, including RE, are not available. Indeed, the cost penalty for limits on RE is often at least of the same order of magnitude as the cost penalty for limits on nuclear energy and fossil energy with CCS"

The full report can be accessed here. 

Both images from Wikipedia Commons.