With more states increasing their RES, the curtailment is inescapable. With curtailment comes opportunities for H2 - the major cost component. Progress made with PEM Electrolyzers are also part of the equation.

so the point about curtailment is good, but it's a slightly one sided perspective on the question and the question about financial viability rather depends on the market that you are looking at. Where there is the vehicle demand, people are already beginning to install renewables to support the electrolysers, not electrolyses to catch the constrained power from installed renewables.
In the natural gas/heating and industrial processes, it's a way off competitive because of the extreme low price of natural gas, however policies that reward carbon reduction are starting to motivate companies like Shell and Phillips 66 to install electrolyses rather than using traditional SMR hydrogen in some parts of their supply chain. so it's expensive but there is so much of the final cost of the fuel made up by tax, motorists won't notice.
In the pure road transport sector it's possibly a bit closer, their it's up against a much higher comparable cost (petrol and diesel) and specifically in things like captive fleets a cost of U$7/kg is about the point where it becomes the same operational cost as diesel (because of the high energy density). But in these fleets, it needs the fleet in the first place to get to the scale to hit that price.
So on the transport side the restricting factor is really the vehicles, preferably large ones that use a lot, which is fortunately what hydrogen is best at. Enough density of busses/trucks/taxis in an area and locally hydrogen can hit diesel parity in 5-10 years, once it does that in one location it'll start spreading.
Where there is the vehicle demand, people are already installing renewables to support the electrolyses.
industrial heat, maybe 15-20 years, but if it takes off in transport more quickly this will likely shorten as the electrolyser producer ramp up to scale and make gains on the learning curve, which will likely be faster than we currently see on batteries in the first instance as most of the PEM manufacturers are effectively hand building at the moment.

The investments various governments put in as a part of COVID recovery could shorten these time scales down to closer to the 5 years slot, but not really any closer and then only for the environments where hydrogen is up against high value or high energy density alternatives.


there isn't really a single source on hydrogen better than the report you found but maybe look here for a very UK based set of analyses:
CCC review
hydrogen in a low carbon economy
Heavy duty transport

Gareth
Hydrogen is a feedstock for many applications, including renewable aviation fuel. Long Haul heavy duty transportation electrification is looking better with H2. We have to prime the pump with something...

indeed, I focus on transport because the price difference between renewable hydrogen and the incumbents are not so bad. in industrial chemicals, fertiliser and steel, it's a bigger difference.
if the demand side is primed the supply will follow. but it is a somewhat circular argument at the moment.

This article in Forbes quotes the Hydrogen Council as saying that the, "cost to produce and distribute hydrogen from clean energy sources will fall by as much as 50% over the next decade." However, it also says that, "If the hydrogen economy is to advance, it must receive investment support of $70 billion by 2030."

I’d just caution that the hydrogen council is an industry association in a lobbying position so a pinch of salt needed. Though it is possible they are even under stating potential, however very much looking for production support as you point out

Many thanks to everyone who has replied so far!

Today, I read this story claiming that liquid hydrogen is a viable fuel for international shipping.

The ICCT study found that 99% of the transpacific voyages made in 2015 could have been powered by hydrogen and fuel cells, with more than half of those requiring either minor changes to fuel capacity — by replacing 5% of cargo space with extra storage for the clean fuel, or by adding an additional port of call to refuel. About 43% of the voyages could have taken place without any such changes.

An interesting company to look at is ITM power. They seem to be at the forefront of some of the enabling technologies for Hydrogen conversion.

Ben Bailey - You might be interested in this story which says, "Australian researchers have claimed a new world efficiency record for solar panels that can directly split water using sunlight, in an achievement that opens up a new pathway to low-cost renewable hydrogen."

Here's a recent story about the debate in the EU on whether to allow "blue hydrogen" under its long-term hydrogen strategy.