Tom Powell and Tim Jones – Coal Action Network Aotearoa
This is how technology advisor Michael Liebreich recently described hydrogen in Threadreader.
In some renewable energy circles, green hydrogen is all the rage. It can be made from ordinary water and electricity. It can be burned like fossil gas but without the greenhouse gas emissions. And, it can be used in fuel cells to make electricity again. What is there not to like? Quite a lot, it turns out.
The usual argument against using green hydrogen for energy is the abysmally poor efficiency of turning electricity into hydrogen and then turning it back into useful energy. Presently, a hydrogen fuel cell vehicle gets back only about 30% of the electrical energy used to make the green hydrogen in powering the vehicle. A typical battery electric vehicle gets back around 80% of the electrical energy used to charge its batteries.
The Parliamentary Commissioner for the Environment, in a December letter to Megan Woods, criticised proposals to use wind power to make green hydrogen at Taranaki, store it underground until needed then burn it to make electricity again, due to the lifecycle efficiency of only 20%. By comparison, pumped hydro storage has a lifecycle efficiency of about 75%. There are better ways to store energy than converting electricity to green hydrogen.
Like the petroleum fuels we have grown to know and love, hydrogen’s best attribute is that it is a flammable fuel that can be moved around and stored. But, what about the other properties of this weird and wonderful new fuel?
Let’s first talk about “escapey”. Hydrogen is a very small molecule and being small, it can squeeze through most materials. It leaks through ordinary carbon steel, which is what most fossil gas pipelines are made of. Along the way, it can cause “hydrogen embrittlement” which further weakens the steel. So, here we have a flammable gas that needs careful containment in special materials.
Now, let’s talk about “explodey”. Hydrogen is flammable in air with a wide range of concentration, 4% to 74% by volume. By comparison, fossil gas is flammable in air with a concentration range of 4.4% to 17%. Hydrogen burns with a flame invisible in daylight – when it is burning, you can’t see it.
It also has a very low ignition energy – a spark of static electricity is reportedly enough to set it off. And, it is known to ignite for unknown reasons when suddenly decompressed, as with the rupture of a high pressure fuel tank.
Add to this the fact that when it leaks, you won’t be able to smell it, like you can fossil gas. Hydrogen has to be very pure in order to work in automobile fuel cells, so perfume can’t be added. Sophisticated sensors are needed to detect leaking hydrogen.
There have been a number of recent accidents due to hydrogen explosions: one in South Korea in 2019 and one in Norway, also in 2019.
And, what’s this about “expanded polystyrene”? Hydrogen is much lighter than air, which is why it was used to lift early dirigible air ships, at least until the 1937 Hindenburg disaster. Being so light, it is still pretty light when compressed or liquefied. Hydrogen compressed to the NZ standard storage pressure of 350 bar (5,000 psi –14 times the pressure in an LPG tank and 2 times the pressure in a SCUBA tank) has a density of only 23 kg per cubic metre – about the same as expanded polystyrene used for home insulation. So, although it holds about 3 times more energy per kilogram than gasoline, the same amount of energy requires roughly 12 times the volume. Fuel tanks for trucks or aeroplanes would need to be many times larger, and many times stronger, than petrol tanks, in order to drive or fly the same distance.
The upshot of all this is that hydrogen is not an easy or efficient fuel to work with. We will need special materials to store and transport it – materials that keep it from leaking out, as well as hold it at very high pressure. We’ll also need lots of sensors to make sure it doesn’t leak and explode.
Green hydrogen is not all bad, however. It has a role in reducing emissions in the manufacture of steel and fertiliser, for instance, but that is very different than using it as a transport fuel.
When you add to this the poor round trip efficiency of turning electricity to green hydrogen and back to useful energy again, requiring abundant renewable electricity that Aotearoa New Zealand doesn’t have at the moment, we can only hope that somebody comes up with a better renewable fuel than hydrogen. Otherwise, I am afraid we are in for an “escapey, explodey, expanded polystyrene” future.
Twenty years ago, on 20 March 2003, the US and its few allies brought “shock and awe” to Baghdad, starting the Iraq war. At the time, I was an under-employed consultant / house husband in Windsor, California, taking the kids to school and back, cooking dinners, and volunteering in the regional parks and with the local search and rescue team. So safe and so secure, the war was still to change my life.
Having narrowly avoided the military draft during the Viet Nam war, learning of its horrors through correspondence with my older brother who was drafted and served two tours, and living with the sad carnage of the war’s aftermath, I was against the Iraq war, and the invasion of Afghanistan before it. I joined thousands of others demonstrating against these wars in their build-up, in Santa Rosa and in San Francisco, but to no avail.
Americans were still angry about the 9/11 attacks in 2001 and wanted retribution. Comprehending the history, politics and lies that the Iraq war was based upon seemed to be the least of their concern. Even seemingly rational newspaper columnists echoed the ridiculously unrealistic talking points of Bush-Chaney-Rumsfield neo-conservatives. America could build a liberal democracy in the heart of the Middle East – what were they smoking?
Now, at this anniversary, we get to relive that sad, disgusting and ultimately pointless episode of history. Weapons of mass destruction, Abu Ghraib, IEDs, Guantanamo Bay, drone warfare, Islamic State.
I recall opening the local newspaper in the mornings, to be confronted by the photos of the young military men and women who’d died in Iraq the week before, smiling proudly in their dress uniforms. Thankfully, we were spared pictures and home towns of the untold hundreds and thousands of dead Iraqis – the collateral damage – but we knew they were there. And it was all just heart breaking.
I would meet my neighbour in the street in the mornings, collecting the mail or putting out the rubbish and we would work ourselves into a near frenzy of anger at our government, its lies, its disregard for international law, its abdication of its own founding principles. How could they do this, so soon after the great folly and atrocity of the Viet Nam war?
When a consulting job in New Zealand came up, I jumped at it. Here was a quiet country, not at war with anyone, least of all with itself, like America was. The news was about traffic accidents and maybe the occasional murder, often just a coroner’s report from a crime committed years ago. A progressive country, seemingly interested only in bettering itself and the lives of its people.
When that consulting work turned into a job offer, I jumped at it again, leaving my adult sons at home and moving Hamilton. My wife moved back after 6 months of home sickness and I began a new life alone. That was 20 years ago. Since then I’ve shifted towns, found new loves and become a citizen.
I still follow American politics, but mostly for its entertainment value. No one, it seems, can out-do Americans when it comes to “man bites dog” stories or its mad roller coaster of electoral politics. Happily, I don’t feel that same anger anymore.
But I do still feel a tinge of sadness for the betrayal of national ideals that America’s recent wars represent, and how they appear to have changed the discourse of its democracy. There are still prisoners at Guantanamo bay. Drones are still conducting extrajudicial executions. If anything, the number of outlandish lies rattling around in the highest halls of government seems to be increasing.
Can it ever recover its dignity enough to be trusted again?
I’m sad to say that 20 years ago I gave up on trusting my home country and decided to join a new one. It’s been a good decision. But with this decision, comes a sense of vigilance – we cannot let the same thing happen here. Without fear or favour, we must always hold our political leaders to account. We need to trust that they will tell us the truth.
These are a collection of opinion articles principally written by CKM member Tom Powell for the Marlborough Express. Tom is a retired geologist who came to New Zealand in 2004 to work in the geothermal industry on the North Island, is a New Zealand citizen and now lives in Blenheim. Some articles have been written by other CKM members, and their names appear with those articles.