OK stepping out into my legal designation for a moment.

My only concern with one of these is the legal issues boilers for power generation require construction to ASME codes everywhere in North America. Most places also require a license to operate them and lastly the rules for annual inspection are even stricter.

So to build one of these and operate it legally.
You would need a licensed ASME shop to fabricate it.
A steam ticket to operate it, depending on the state or province the level of license and experience required would vary.
Lastly in all of North America you would need it inspected by someone with an NB23 designation, in Alberta or Saskatchewan there is an additional license also required.

Lastly Steam Boilers pack a lot of explosive force into a very little space. Everyone is supprised by the extreme amount of potential energy that a 1 cubic foot steam vessel with 50 PSI can hold.

Ok now that I fullfilled my required duty, if you are going to build one yourself, I have a few tips on being safe.
1)look into having it in an outbuilding.
2) Install a thermal PSV.
3) keep combustible material at least 10 feet away.

I'd just like to point out that steam power never left us at any point in the past century, at least in regards to power generation for the grid:

♦Nuclear: Uses heat of splitting atoms to boil water to make steam to run a generator.

♦Coal: Same technology they were using in the industrial revolution, boil some water, make some steam, etc.

♦Solar: Most major solar plants do not use photovoltaic cells to just collect energy, they use mirrors to focus heat on pipes of oil, which is then used to boil water, make steam, etc.

♦Geothermal: Boil water, make steam, run a generator.

Really, the only two power generation methods that Don't rely on steam engine principles to generate power are Run of the River Hydroelectric, and Wind Turbines. Shocking, but true.

And here we all thought nuclear harnessed some esoteric energy when the atom split