How Solar PV Can NOT Power A Carbon-Free Energy Revolution, In 4 Charts

30 10 2014

Once again, the internet proves how nobody understands NETT ENERGY.  A friend pointed me to this article titled “How Solar PV Can Power A Carbon-Free Energy Revolution, In 4 Charts” which I quickly glanced at (I’m busy making cheese right now!) and thought ‘is this for real?’  I then emailed the link to our resident professor, Dave Kimble who cobbled a response together that I will attempt to parse here correctly…….

Dave first pointed out that the “Inputs and outputs for a whole industry” ‘chart’ is not a chart at all, it is a diagram.  it is also not a chart resulting from calculations.  It has the right shape, but its timeframe is all wrong.

inputs~outputs-for-PVsIt should actually look more like this:

real-inputs~outputs-for-PVsThe article also states “the EPBT for PV systems in regions with high amounts of sunlight (high solar insolation), such as the U.S. Southwest, is now under one year.” EPBT stands for Energy Pay Back Time.  I’d missed that one, and when Dave pointed it out to me, I was gobsmacked……  because such a short energy return implies an ERoEI of 25:1, when in fact Pedro Prieto and Charles Hall recently calculated that it was more like 2.5:1, but what’s one order of magnitude among friends….?

.To me it makes absolute sense that as the ERoEI of the fossil fuels used to make PVs drops, the ERoEI of PVs should also drop……  there is no free lunch here, this is the energy trap we are looking at…..

Then Dave pointed out that the ERoEI is critical to how long the EPBT actually is.  Here is a chart from his own website:

“If the industry grows faster than a critical amount” says Dave, “then the fossil energy subsidy grows bigger and bigger:  The limit is given by (ERoEI/Lifetime)*100 % per year, so if the ERoEI is 25, you can grow at 100%, but if it is 2.5 you can only grow the industry at 10% – anything above that can never be energy positive.”

The article then states:

They projected that “the payback year has a 50 percent likelihood of occurring between 2012 and 2015.” In other words, there’s a good chance the cumulative solar energy generated by every PV system in use as of today equals the cumulative electricity consumed in producing those system to date.

This is “largely due to steadily declining energy inputs required to manufacture and install PV systems.”

How can there be steadily declining energy inputs when all the ore grades for the materials involved are getting worse, and the ERoEI of the fossil fuels is going down too, and may not be available within 10 years?  As usual, it’s what you leave out of the EI part of ERoEI that matters, and I doubt Pedro would have left anything out, because he’s run solar farms in Spain, and knows full well what goes IN to make them work…..  For instance, the article gloats over the fact that the cost of PVs has dropped 99% over the past 25 years (from $10/W to $1/W now), but that’s mostly because robots are now making them instead of people.  How much energy went into build the robots and the factories where they are being built?  ALL made with low ERoEI fossil fuels?  And their numbers must grow to keep up with production growth too…..

Can you tell I’m still sceptical?




15 responses

30 10 2014
Chris Harries

The author of the ‘4 Charts’ article is Joe Romm, a very good climate campaigner. One of the best.

I guess Joe has to exude Hope, because his mission is to say that fossil fuels are killing the world and if that’s correct then there are only two answers: 1. Collapse (do nothing and wait for it) or 2. Renewable energy.

He’s not alone. That’s the dilemma facing the whole environmental lobby, and they nearly all come to the same conclusion as Joe does, even arguing that dealing with climate change will hardly dent the economy at all. Some actually earnestly believe that.

Others argue that this course of persuasion, even if it is not logically sustainable, is pretty well harmless because the renewable energy path has to happen anyway, and whilst going down that path we (society) will belatedly be forced by circumstance to arrive at a conclusion that we also have to radically change our whole culture and all of our behaviours. That’s far too of a negative message to give out right now, so that bit is rarely mentioned as part of the package. Again we come to the perceived need to deliver Hope, even at the expense of bending or hiding the truth.

And so…. we find most of our colleagues do exactly what Joe Romm does.

Why are we (a very small minority) driven to be devil’s advocates? Why do we feel the need to kill off the Hope that everyone wishes for? For me it just boils down to not wishing to tell a lie. I can choose to say nothing, or I can say what’s real. I go either way, depending on the audience. At the same time I’m conscious of all the well meaning people out there who are totally enamoured by the prospect of a glorious, prosperous solar future and I don’t like to be a spoiler.

30 10 2014
John Weber

Solar and wind capturing devices are not alternative energy sources. For the physical devices – for wind, photovoltaices, solar hot water, hot air panels – the sun and wind are there, are green, are sustained. The devices that are used to capture the sun and wind’s energy are an extension of the fossil fuel supply system.

There is a massive infrastructure of mining, processing, manufacturing, fabricating, installation, transportation and the associated environmental assaults. There would be no sun or wind capturing devices with out this infrastructure. This infrastructure is not green, sustainable, or renewable. The making of these devices inadvertently but directly supports fracking, tar sands and deep ocean drilling because of the need for this infrastructure.

In addition, the Energy Returned on Energy Invested (ERoEI) is very marginal for all solar devices. It takes years if ever to repay the energy it took to make, install, and maintenance these devices.

I invite anyone cheerleading for solar to view these essays.
This essay has diagrams and pictures of how we get copper, aluminum, glass, black chrome – the chemicals, heavy machinery, and industrial processes that are necessary to make the devices to capture the energy of the sun and wind.

31 10 2014

Squashing the y-axis on the ‘diagram’ doesn’t change the timeframe at all. Scaling either axis doesn’t change the relationship between the two variables (time and nett power).

31 10 2014

Actually……… I stretched the x axis! I realise that when the two images are scaled by the publishing software to fit in the same area it might look like I squashed the y axis.

5 11 2014

Not sure what you mean, but what’s published here is a squashed y-axis in the 2nd image… the whole image is shorter than the 1st one. Their widths (x-axis) is the same.

Either way, the point of the diagram is that there’s a cross-over point (where the curve crosses the x-axis) where the solar has paid back its energy subsidy and starts producing a nett energy surplus.

Scaling doesn’t change that. Hey, everybody loves maths teachers, right? 🙂

5 11 2014

No…… if you look at the type even, you will see it’s stretched. Once stretched, the x axis was, obviously, longer, so, to allow it to still fit on the page, the computer shrank the whole image, and you are seeing a squashed y axis.

The reason I stretched it was to move how far along the crossover happens…..

31 10 2014

Let’s not rubbish the green cheerleading of the article’s author when in fact these are Stanford researchers making the original claims.

Here’s a presentation by the lead author of the paper cited (which is behind a paywall):

Anybody want to pony up $35 for 48 hours of access to the actual paper?

Also, I found the lead author’s email address. Here’s what I’m proposing to email him. Before I bother him, any suggestions for phrasing/content?

“Dear Mr Dale blah blah. In your paper “blah blah”, your analysis includes energy used in the manufacture and installation of PV, but this is not the more accurate holistic energy figures determined by other researchers. Wouldn’t using the entire energy that goes into PV manufacture and deployment in analysis show that PV’s growth is actually severely limited? The difference is large – those figures indicate an EROEI of X, rather than the Y that your papers do.”

31 10 2014

Go for it! Make sure you give them a link to the Prieto/Hall study. I’d love to know what they say!!

1 11 2014
Susan Krumdieck

Mik was my PhD student back in the day… He is meticulous in his research methods. I have reviewed the paper. Scientific papers are pieces of precise work. This paper has a tight focus on looking at the energy flow balance over time of a particular industry. Mik’s work is about gathering huge amounts of data and analysing it in rigorous ways. If you want to draw policy or social or lifestyle planning inferences from the results, then they would be like this –
Any kind of energy conversion industry necessarily has an “energy drag” on the economy. Some energy and embedded energy is used in building and running the energy conversion industry that could have otherwise been used for other things in the economy. Since the ONLY purpose of the energy conversion industry is to produce energy for consumption by other sectors, building up of this sector necessarily competes with the other energy end uses. If there is surplus consumer energy capacity at that time, then the economy will not be affected by the build up of the energy sector, (as in the past) and as the conversion plant comes on line, the surplus increases and growth can occur.

There has not really been an energy conversion industry that has had such a large and prolonged drag on the energy to the economy. Solar PV so far has been more like “green bling” for roof-tops. It’s like any other consumer product that requires energy and materials that people purchase for whatever purpose, like IKEA furniture. The economy may not have noticed the energy drag effect because the amount of solar PV built hasn’t been significant compared to manufacturing cars or building highways. The economy will also not notice a big energy surplus – and in fact, if the engineering of the solar systems so that they are well-matched with on-site loads has not been done well (as in Germany) then the economy will definitely notice increased costs and loss of fidelity of the electricity distribution system.

The punchline of the story, based on the data and analysis is this:

We are not in the midst of a revolutionary energy transition from fossil fuel to solar PV.

1 11 2014

Wow……. thanks for that great input Susan, always appreciated…

6 11 2014
6 11 2014

What do I think? When I see “This is truly “game changing” in that unlike shale gas or tight oil, solar capacity has virtually no limits”, I immediately dismiss the writer for obviously having no understanding of limits!

EVERYTHING has limits. In particular, the size of the Earth! And of course, the author makes the classic mistake of measuring solar’s worth in dollars, instead of NETT ENERGY.

To plagiarise Bill Clinton, it’s the nett energy, stupid…… Absolutely everything built around us is built with excess energy. It’s that simple, really. Run the world on solar, and you’ll cut excess energy by at least 80%. And you’ll be working your arse off in the process of running the world on 20% of the energy we currently take for granted. Because most of the nett energy from solar will be expended to just make more solar, instead of more airplanes, more highways, more hospitals, more schools, more food, more………..

6 11 2014

And don’t forget, there’s no solar powered solar panel factory. Sure, they can put PV on the roof to power the lights, but the actual industrial process making panels requires massive amounts of energy and high temperatures.

Put another way, not all Joules are the same. Some store better, transport better, have better energy density, flow faster, or are available at high amounts more easily. Oil rules. Really, PV is petrol-powered.

6 11 2014

Indeed. Solar is merely an extender of fossil fuels. it can help keep FFs last a little longer, at an emissions cost at that, but it cannot replace them.

10 11 2014

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