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largolagrande | 3 years ago
Hydrogen is the most abundant element in the universe and is found in great abundance in all galaxies. It is particularly present in the Sun, which is problematic because it is not very accessible to us :) On Earth, there is also a lot of hydrogen in water and in hydrocarbons. However, it does not exist in free form, i.e. just hydrogen. It is always associated with something else, for example with oxygen in water, or with carbon in hydrocarbons.
There are, however, small sources of native hydrogen in the earth underground, but the quantities are nowhere near what we would need to use if we wanted to do anything significant with it. At least not beyond what we are already doing, because hydrogen is already used a lot these days. Nearly 100 million metric tonnes of this element are produced in the world every year.
To be transported, hydrogen must be kept under high pressure or extremely low temperature. This should already raises some question about the feasibility :)
Half of this production is used to de-sulphurize fuels and the other half to make fertilizers (Haber-Bosch process). Thus, hydrogen is already used extensively in the world, but there is a small problem: it is made from hydrocarbons, fossil natural gas, oil or coal, which represents 10 to 30 (metric) tonnes of CO2 per metric ton of hydrogen.
With the way it is made, should we go even further towards this fuel despite global warming? We could then imagine making hydrogen for other applications that do not exist today. For example, like you imagine, to power vehicles with hydrogen fuel cells or to make steel without emitting CO2.
There is a process for making iron with blast furnaces that do not emit CO2. There are also plans by steelmakers to make steel without emitting CO2 by converting iron ore into iron with hydrogen. The hydrogen then removes the oxygen from the iron ore, which is released into the atmosphere as water vapor. To do this, large quantities of hydrogen are needed and, for example, to replace a blast furnace, a nuclear plant is needed to generate the electricity that will enable the water to be electrolyzed, which is the only way to make "clean" hydrogen without emitting CO2. Something like a thousand wind turbines would be needed to replace a nuclear plant (and remember: wind turbines does not work all the time)
When you see the amount of electricity it would take to be able to produce carbon-free hydrogen in large quantities, you realize that there will never be much of it in transport. Not all the world's aircraft will be replaced by hydrogen-powered aircraft, for example. The applications that could then be made with carbon-free hydrogen would be to keep the production of fertilizers and carbon-free steel. Achieving this would already be a big step.
Gwypaas|3 years ago
Your calibration is off by quite a few years. The current off-shore turbines being built are 15 MW with capacity factors of around 60%.[1] So lets do 50% for wind and 90% for nuclear.
Wind: 1,000 * 15 MW * 0.5 = 7.5 GW
Nuclear: 1 * 1650 MW (EPR) * 0.9 = 1.485 GW
The HYBRIT plant, a pilot project for fossil free steel is going to utilize an over sized green hydrogen production side to enable it to work as a smart consumer and therefore balance the grid. Thus it is completely dependent on cheap renewables to operate and enables deeper penetration of renewables.
> The HYBRIT initiative was launched in 2016 by the three owners; SSAB, LKAB and Vattenfall. The hydrogen storage facility will play a very important role in the overall value chain for fossil-free iron and steel production. Production can take place without a storage facility, but storage provides the opportunity to vary the demand for electricity and ensure stable production. By producing hydrogen gas when there is a lot of electricity, for example when there is a lot of wind, and using stored hydrogen gas when the electricity system is under strain, will ensure production.
> “The hydrogen storage facility has a stabilising effect on the electrical system. It reduces the risk of the system overloading. We want to develop HYBRIT technology so that it is in line with the future electricity system with more weather-dependent electricity generation,” says Mikael Nordlander, Development Manager for Vattenfall’s industrial partnerships.
https://www.hybritdevelopment.se/en/hybrit-a-unique-hydrogen...
[1]: https://www.vestas.com/en/products/offshore/V236-15MW/V236-1...
natmaka|3 years ago
mytailorisrich|3 years ago
I'm thinking a key metric is the efficiency of it all.