| | | Speaking of EROEI .
<<<< Hydrogen, carried in a tank like a gas cylinder, can last much longer and be refuelled quickly. This makes it suitable for long distance vehicles like buses and articulated trucks carrying containers. Switzerland produces green hydrogen using hydro power and is extending its fleet of hydrogen fuel cell-powered trucks.
So far so good. The big picture is way more complicated. Stored hydrogen is highly flammable and vulnerable in hot conditions. The hydrogen molecule is minute (as far as molecules go) and 1 percent is said to escape with every day it’s stored.
Hydrogen is an energy carrier, not a primary energy source in itself. This means that it requires outside energy at each step – for its production, then for its compression or liquefaction when it’s stored, and for its delivery and ultimate use.
Moreover, energy is lost when the gas is converted to electricity by fuel cells. This voracious appetite
has been aptly named the “parasitic” energy needs of hydrogen.
This aspect is made clear when the viability of energy is calculated according to the system used widely to compare the benefits and disadvantages of energy sources. This calculation is known by the acronyms EROEI, or more usually the shorter EROI. The former expresses the Energy Return On the amount of Energy expended, or Invested, in order to produce energy in its usable form. EROI can sometimes be interpreted to refer only to the financial investment – Energy Return On Investment.
Both values vary according to how they are calculated and what they take into account.
The EROI for fossil fuels has decreased as the availability of oil, coal, gas has reduced and the cost of production increased. Fracking for oil or gas (as has been done in Taranaki for years) is expensive and polluting. Extracting oil from the tar sands in northern Canada is a similarly destructive process. So, what was an EROI of 100:1 last century is now sometimes little more than 10:1.
Hydroelectricity has the highest value at 84:1, compared with wind at 18:1 and solar lower according to whether battery storage costs are included.
For hydrogen the EROI is 1:4 or 1:5. In other words, it’s demonstrably negative.
Nevertheless, it has its proponents, some of whom promote it as a more efficient way of storing electricity than lithium batteries. Others propose producing it in the down-time of electricity demand, in between the morning and night peak usage – the so-called “curtailment” time.
Still others foresee it as God’s gift to the airline industry but initial proposals grapple with the enormous storage tanks needed, which make relatively short distances only possible, and the problems of airport facilities for refuelling.
I fail to see how hydrogen can have a role in a future that is genuinely sustainable. Exporting it to Japan will do little for New Zealand except lock us in to a cycle of producing electricity from wind turbines for the benefit of Japan. Emissions-free FCEVs are not the answer to reducing our transport emissions. If we thought more carefully about the stuff we buy, where it comes from, how it’s made we would perhaps use less and what we do need could be transported on a massively increased electrified railway network. This would be to hubs from where goods could be collected by smaller, battery-electric vehicles.
A so-called “hydrogen economy” assumes we can produce renewable electricity inexhaustibly and
thus, emissions-free, continue to lead our resource-depleting lifestyles. This is not the future we want.
Our decision-makers in business and government need to come to terms with the issue of net energy
– the amount that is left after the costs of production. Renewables are not a simple substitute for
fossil fuels.>>>>
newsroom.co.nz
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