13th July 2024

Prior to now three years, one other nonsensical thought has sprung as much as by some means permit delivery of molecules for power. The premise is that liquified pure gasoline (LNG) goes in a single path and liquified CO2 (l-CO2) will get put in the identical tanks and goes the opposite manner. It sounds so apparent!

The premise is that CO2 from pure gasoline needs to be captured, after which has to go someplace. And the ships that convey pure gasoline in liquid kind from its origin to its vacation spot must sail residence empty, which has no financial benefit. And the gasoline fields like to put CO2 underground, even when solely to get extra oil.

That is, after all, being proposed by school members on the College of Houston, and solely for methane extracted from underground with CO2 returned to the oil fields for enhanced oil restoration. Given the excessive upstream and downstream methane leakages within the US system, and enhanced oil restoration’s premise of injecting CO2 underground to get extra crude oil out which when used as directed creates extra CO2 than injected, this can be a exceptional thought in any occasion. It’s half and parcel of the shell sport that’s carbon seize and sequestration within the fossil gas business, the place CO2 is extracted from underground in a single place and put again underground in one other for enhanced oil restoration and claimed as a win whereas nonetheless remaining a tiny fraction of ExxonMobil’s annual emissions.

However Fortescue, an Australian useful resource extraction firm making an attempt to make exported Australian inexperienced hydrogen an power supply for the world regardless of the realities of economics and thermodynamics, is contemplating going a lot additional down the entropic rabbit gap. They’re proposing changing inexperienced hydrogen to extra manageable however excessive international warming potential methane, then liquify the methane into LNG, then ship the LNG to power markets, after which re-use the LNG tankers to return the CO2 for reuse within the inexperienced methane manufacturing course of.

Let’s begin with whether or not that is even attainable, and the reply is sure. Economically possible? Deeply unlikely. A local weather answer? Clearly not.

Let’s begin with simply making methane from inexperienced hydrogen. As I and lots of others have identified, hydrogen may be inexperienced, however it may possibly’t be low-cost. There are capex and opex elements to the argument. The capex half is that scaled electrolysis crops are main capital property and electrolyzers are solely one among maybe 28 main elements. The remainder of the elements are already commoditized, so the whole capex isn’t going to break down to nothing. That implies that the plant should be operated as near 24/7/365 as attainable to pay for the capital prices. Meaning it requires firmed electrical energy 24/7/365, and firmed at all times on electrical energy is grid electrical energy, or costlier than grid electrical energy.

Table showing costs of CO2, hydrogen and processing them into methanol.

Desk displaying prices of CO2, hydrogen and processing them into methanol by Michael Barnard, Chief Strategist, TFIE Technique Inc.

Hydrogen is the costliest enter to any artificial gas like inexperienced methane, as I revealed in my evaluation of the thermodynamically illiterate Carbon Engineering a number of years in the past. No low-cost hydrogen, no low-cost methane. However it’s a must to supply CO2 and hydrogen and push them collectively in one other power intensive course of to get methane. The desk above supplies a pathway to low-cost methanol, one other different, and provides a way of the power and price balances. Methane gained’t be far off.

Throw away a bunch of inexperienced electrical energy whereas making hydrogen and eliminating extra moisture in it. That loses about 30%. Eliminate extra power getting the CO2, particularly in the event you tanker it the world over. Eliminate extra power by combining the 2 into methane. You is perhaps fortunate to be seeing 50% of the power embodied within the methane, and we aren’t finished but.

After that, it’s a must to liquify the methane, which takes so much much less power than hydrogen, however nonetheless so much. Then it’s a must to ship it throughout an ocean and get it to the place the place it burns. Maybe 40% of the power arrives?

Then you definately burn it in a contemporary pure gasoline mixed cycle plant with an effectivity of 50%, so solely 20% of the inexperienced electrical energy in Australia turns into electrical energy in Germany, for instance.

Then you’ve got seize the CO2 from burning it, one thing that causes parasitic hundreds within the vary of 20-30% even in line with the at all times CCS-positive World Carbon Seize and Storage Institute, a fossil gas lobbying group that loves to provide CCS each good thing about the doubt conceivable. So you might be really maybe 15% of the photo voltaic and wind from Australia really entering into the vacation spot grid.

As famous, the electrolysis plant would require firmed grid-quality electrical energy, so which means most likely $100 / MWh, so it’s most likely within the vary of $600 / MWh wholesale delivered electrical energy in Europe or Asia. In the meantime, new wind and photo voltaic onshore are $30 / MWh, or 20 instances cheaper. Who precisely goes to pay for this deeply costly power?

Oh, however wait, there’s extra silliness to this concept. One among many provisos to Fortescue Future Industries‘ plan is that the mass of CO2 generated from burning methane ends in 20% higher quantity in liquified CO2 than LNG, so a bunch of it must be left behind the place it was burned.

That CO2 could be 2.1 instances as heavy for a similar quantity within the ship. CO2 won’t liquefy until it’s compressed to a minimal of 5.18 bar. LNG is transported at ambient stress. Will probably be a lot hotter for the CO2 cargo than the LNG cargo and have to undergo a ~100C thermal cycle at every finish of the voyage. In order that’s a bunch extra capital value at every finish for thermal administration.

After all, most methane-powered ships are LNG tankers utilizing boil-off from the LNG, and if you’re transporting l-CO2, you haven’t any LNG to boil off, so it’s a must to specifically inventory methane to drive the ship, or extra doubtless simply use a very totally different gas.

No current LNG ship is able to this use case, in different phrases. They must be specifically constructed for it, with important design and financial compromises. To do that, it is advisable engineer a complete ship from the keel up for this function.

All so that top international warming potential gases may be manufactured and put right into a provide chain that leaks them to the ambiance alongside the way in which.

The premise that LNG amenities and ships may be reused to ship CO2 within the different path doesn’t stand as much as the slightest engineering scrutiny. The top-to-end value of delivering power as inexperienced LNG doesn’t stand as much as the slightest financial scrutiny. It’s exceptional that individuals who can do basic math give any of this credence, which is a testomony to the mixed energy of lobbying and hope.


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