Germany’s gamble on P2G: Expensive electricity to expensive methane to expensive storage


There isn’t much good news about Germany’s failing Energiewende. Because they have boxed themselves into a corner by eliminating their nuclear portfolio, they are facing the physical realities of trying to deploy unreliable wind and solar far beyond their appropriate penetration levels. According to the research by Lion Hirth (Vattenfall Europe AG) appropriate penetration would be 7% wind for today’s Germany, perhaps as much 25% in a future Germany optimized for VRE [PDF]. Germany is abusing neighboring grids by dumping excess generation while exploiting the neighboring grids to supply power when the sun doesn’t shine and the wind doesn’t blow.

To push VRE to meet their 80% commitment Germany obviously needs abundant cheap storage. Unfortunately they don’t have the enviable volume of hydro that Sweden and Norway have. So, as  Quirin Schiermeier writes in Nature Renewable power: Germany’s energy gamble, Germany is making a big bet on P2G:

P2G, however, could provide a vast amount of new storage capacity and Germany is leading the way. The plant in Stuttgart has 250 kilowatts of electrolysis stacks, which use electricity from renewables to produce hydrogen from water. To make methane, the hydrogen is reacted with CO2 from decomposing sewage and agricultural waste at a nearby biogas plant. Other P2G plants could scrub CO2 from the air.

But P2G is still an immature technology, with high upfront costs and an efficiency of only about 50% in converting electricity to methane. Synthetic methane plants have also struggled with the purity of their product. At the ZSW facility, the main goal is to routinely produce gas with low oxygen and hydrogen content.

For transport fuels, the P2G concept might make some economic sense IF powered by nuclear electricity. But Germany is trying to use this process to fix the serious grid instability problems they have created for themselves. Adding the high cost of variable renewable electricity to the high cost of the P2G conversion – this is good for the economy? How prudent is it to base an industrial economy on advanced proton-exchange membranes for electrolysis?

Catastrophic Arctic methane release feedback?

NewImageThere is high concern in some quarters about the possibility of near-term catastrophic Arctic methane release. Example: the Arctic Methane Emergency Group which promotes videos such as Arctic Methane: Why the Sea Ice Matters. I’ve reviewed the recent peer-reviewed publications via Google Scholar, concluding that near-term (decades) disaster is extremely unlikely. The potential for long-term (centuries) feedback remains one of many climate change risks that we just don’t know much about. The current climate forcing is so much faster than anything seen in the geologic record — we are definitely exploring new territory.

A good summary of what I’ve learned can be found in this post at the Arctic Methane blog by Prof. Euan Nisbet. Here’s a brief excerpt that addresses the recent media-frenzy prompted by the Guardian articles (which stemmed from the Whiteman paper).

Is Godzilla about to arise? Is there a methane monster?

In the 25th July issue of Nature this year, Whiteman et al. suggested a monster methane release is about to occur in the Arctic. They modelled a release of 50 Giga-tons of methane from Arctic hydrate, at 5 Gt a year over 10 years from 2015 to 2025. One Giga-ton is 1000 million tons, or 10^15 grams. To put this in context, the total amount of methane in the world’s air now is about 5 Gt, and the annual input is about 0.5 Gt, so this would double the methane in the air within the first year. They based this number on a ‘single stage blowout’ scenario from another paper by Shakhova et al, (2010). The Whiteman et al. paper had immediate press interest, from newspapers as prestigious the Guardian and the New York Times to a wide range of blogs.

Contrary voices were also heard, in particular from researchers on methane and hydrates (including the present author). They were widely sceptical of such large releases. Responses were both published later in Nature, and also a posted comment that is accessible by scrolling far down the page on:

The full text is on:

There’s clearly a great deal of methane hydrate in the Arctic, and much of it is likely to be destabilised by Arctic warming. But is it going to come out as a great sudden burst in a few years? Or is it going to dribble out as a chronic release, as suggested in 2008 by David Archer, a recognised hydrate expert? Remember also that the northern wetland methane emissions respond very fast to warming. There’s much evidence that at the end of the last glaciation it was not primarily the hydrates but the wetland response that drove the very rapid increase in methane.

Archer, et al (2008) Ocean methane hydrates as a slow tipping point in the global carbon cycle, Proc. Natl. Acad. Sci. 106, 20596–20601

Nisbet, E.G. and Chappellaz, J., (2009) Shifting gear, quickly. Science 324, 477-8

The scepticism of Arctic researchers about the 50 Gt blowout scenario was initially dismissed by an influential Guardian blog as “narrow arguments of scientists out of touch with cutting edge developments in the Arctic.”

However, later the comment was modified:

The answers to these puzzles is what we’re trying to find out….

Dr. Nisbet’s post is written for the lay public – highly recommended. To repeat, Dr. Nisbet and colleagues wrote a detailed response in Nature to the Whiteman et al paper. Nisbet mentions this in his blog post — so politely that it may not to be noticed.