Here is further email exchange with Professor Richard Sears, following on from a previous web log post.
From: Richard A. Sears
Date: 24 February 2014
To: Jo Abbess
Subject: Question from your TED talk
I was looking back over older emails and saw that I had never responded to your note. It arrived as I was headed to MIT to teach for a week and then it got lost. Sorry about that.
Some interesting questions. I don’t know anybody working specifically on wind power to gas options. At one time Shell had a project in Iceland using geothermal to make hydrogen. Don’t know what its status is but if you search on hydrogen and Iceland on the Shell website I’m sure there’s something. If the Germans have power to gas as a real policy option I’d poke around the web for information on who their research partners are for this.
Here are a couple of high level thoughts. Not to discourage you because real progress comes from asking new questions, but there are some physical fundamentals that are important.
Direct air capture of anything using current technology is prohibitively expensive to do at scale for energy. More energy will be expended in capture and synthesis than the fuels would yield.
Gaseous fuels are problematic on their own. Gas doesn’t travel well and is difficult to contain at high energy densities as that means compressing or liquefying it. That doesn’t make anything impossible, but it raises many questions about infrastructure and energy balance. If we take the energy content of a barrel of oil as 1.0, then a barrel of liquefied natural gas is about 0.6, compressed natural gas which is typically at about 3600psi is around 0.3, and a barrel (as a measure of volume equal to 42 US gallons) of natural gas at room temperature and pressure is about 0.0015 (+/-). Also there’s a real challenge in storing and transporting gasses as fuel at scale, particularly motor fuel to replace gasoline and diesel.
While there is some spare wind power potential that doesn’t get utilized because of how the grid must be managed, I expect it is a modest amount of energy compared to what we use today in liquid fuels. I think what that means is that while possible, it’s more likely to happen in niche local markets and applications rather than at national or global scales.
If you haven’t seen it, a nice reference on the potential of various forms of sustainable energy is available free and online here. http://www.withouthotair.com/
Hope some of this helps.
Richard A. Sears
Department of Energy Resources Engineering
From: Jo Abbess
Date: 24 February 2014
To: Richard A. Sears
Many thanks for getting back to me. Responses are nice – even if they
are months late. As they say – better late than never, although with
climate change, late action will definitely be unwise, according to an
increasing number of people.
I have indeed seen the website, and bought and spilled coffee on the
book of Professor David MacKay’s “Sustainable Energy Without The Hot
Air” project. It is legendary. However, I have checked and he has only
covered alternative gas in a couple of paragraphs – in notes. By
contrast, he spent a long chapter discussing how to filter uranium out
of seawater and other nuclear pursuits.
Yet as a colleague of mine, who knows David better than I do, said to
me this morning, his fascination with nuclear power is rather naive,
and his belief in the success of Generation III and Generation IV
lacks evidence. Plus, if we get several large carbon dioxide
sequestration projects working in the UK – Carbon Capture and Storage
(CCS) – such as the Drax pipeline (which other companies will also
join) and the Shell Peterhead demonstration, announced today, then we
won’t need new nuclear power to meet our 4th Carbon Budget – and maybe
not even the 5th, either (to be negotiated in 2016, I hear) :-
We don’t need to bury this carbon, however; we just need to recycle
it. And the number of ways to make Renewable Hydrogen, and
energy-efficiently methanate carbon monoxide and carbon dioxide with
hydrogen, is increasing. People are already making calculations on how
much “curtailed” or spare wind power is likely to be available for
making gas in 10 years’ time, and if solar power in the UK is
cranked/ramped up, then there will be lots of juicy cost-free power
ours for the taking – especially during summer nights.
Direct Air Capture of carbon dioxide is a nonsensical proposition.
Besides being wrong in terms of the arrow of entropy, it also has the
knock-on effect of causing carbon dioxide to come back out of the
ocean to re-equilibrate. I recently read a paper by climate scientists
that estimated that whatever carbon dioxide you take out of the air,
you will need to do almost all of it again.
Instead of uranium, we should be harvesting carbon dioxide from the
oceans, and using it to make gaseous and liquid fuels.
Gaseous fuels and electricity complement each other very well –
particularly in storage and grid balancing terms – there are many
provisions for the twins of gas and power in standards, laws, policies
and elsewhere. Regardless of the limitations of gas, there is a huge
infrastructure already in place that can store, pipe and use it, plus
it is multi-functional – you can make power, heat, other fuels and
chemicals from gas. In addition, you can make gas from a range of
resources and feedstocks and processing streams – the key quartet of
chemical gas species keep turning up : hydrogen, methane, carbon
monoxide and carbon dioxide – whether you are looking at the exhaust
from combustion, Natural Gas, industrial furnace producer gas,
biological decomposition, just about everywhere – the same four gases.
Energy transition must include large amounts of renewable electricity
– because wind and solar power are quick to build yet long nuclear
power lead times might get extended in poor economic conditions. The
sun does not always shine and the wind does not always blow (and the
tide is not always in high flux). Since demand profiles will never be
able to match supply profiles exactly, there will always be spare
power capacity that grids cannot use. So Power to Gas becomes the
optimal solution. At least until there are ways to produce Renewable
Hydrogen at plants that use process heat from other parts of the
Renewable Gas toolkit. So the aims are to recycle carbon dioxide from
gas combustion to make more gas, and recycle gas production process
heat to make hydrogen to use in the gas production process, and make
the whole lot as thermally balanced as possible. Yes. We can do that.
Lower the inputs of fresh carbon of any form, and lower the energy
requirements to make manufactured gas.
I met somebody working with Jacobs who was involved in the Carbon
Recycling project in Iceland. Intriguing, but an order of magnitude
smaller than I think is possible.
ITM Power in the UK are doing a Hydrogen-to-gas-grid and methanation
project in Germany with one of the regions. They have done several
projects with Kiwa and Shell on gas options in Europe. I know of the
existence of feasibility reports on the production of synthetic
methane, but I have not had the opportunity to read them yet…
I feel quite encouraged that Renewable Gas is already happening. It’s
a bit patchy, but it’s inevitable, because the narrative of
unconventional fossil fuels has many flaws. I have been looking at
issues with reserves growth and unconventionals are not really
commensurate with conventional resources. There may be a lot of shale
gas in the ground, but getting it out could be a long process, so
production volumes might never be very good. In the USA you’ve had
lots of shale gas – but that’s only been supported by massive drilling
programmes – is this sustainable ?
BP have just finished building lots of dollars of kit at Whiting to
process sour Natural Gas. If they had installed Renewable Gas kit
instead of the usual acid gas and sulfur processing, they could have
been preparing for the future. As I understand it, it is possible to
methanate carbon dioxide without first removing it from the rest of
the gas it comes in – so methanating sour gas to uprate it is a viable
option as far as I can see. The hydrogen sulfide would still need to
be washed out, but the carbon dioxide needn’t be wasted – it can be
made part of the fuel. And when the sour gas eventually thins out,
those now methanating sour gas can instead start manufacturing gas
from low carbon emissions feedstocks and recycled carbon.
I’m thinking very big.