Everyone has blood, the bigger issue is the vampires. Do you think big engine will be happy with wild sourced vampires or do you think they will start farm raising them? Because capitalism will require an infinite growth of vampires.
Yeah when people talk about their hypothetical zombie survival plans, mine is just stay at home and eat the food I have. Realistically zombies would starve before I do because they don't know how to use can openers.
It bothers me more that gasoline never goes bad in these things. Things like 28 days later it's fine, but Walking Dead and Last of Us where it's years later... yeah those cars aren't going anywhere anymore. I don't expect these things to be realistic, but it would be more interesting to see people have to adapt to these kinds of problems.
This reminds me of the Superman comic where they tell him if he truly wants to help all of mankind and solve things like crime and war, he needs to provide almost limitless free energy to the planet. So they put him on a crank and make him generate energy. Mankind prospers until after a long long time Superman is all dried up and has nothing left to give. But before he's empty he's replaced by a new energy source and made obsolete.
The only fear I have with this is that I'm not going to be able to bless the holy water quickly enough to make up for the volume lost. Also, there will be certain animal rights concerns that will need addressing before blood can be sourced.
Holy water can be mixed with non holy water and it fully becomes holy water. Simply having a holy water tank that refills whether it becomes 2/3rds full gives you an infinite source of holy water.
Surelly using the rotational energy of corpses turning in their graves at what's done in their name/by their family/just done somewhere, would be easier.
For one, they're way easier to procure than vampires plus the raw material requirements are lower (in some cases merelly saying certain things is enough to induce rotation).
There are some downsides, however, such as how they have to be in graves for it to actually work (so it's probably a method best used for bulk generation using existing graveyards, plus there are some engineering challenges in connecting the actual corpses in situ to the turbines for energy generation, which are not present in a system made from the ground up for energy generation such as the vampire piston) and, of course, as the corpses age and decompose they become more brittle and it's easier to get catastrophical failure if the turbine offers too much resistance, which means energy production decreases over time or, to avoid turbine replacement later, from the get go a less powerful turbine has to be connected to a pristine condition corpse.
As I mentioned, merelly saying certain things is enough.
For example, going to a Christian cemitery and shouting "God is dead!" is probably enough to get lots of them going. I wouldn't at all be surprised if with the right setup merely reading pretty much anything by Nietzsche out loud could yield several gigawatts-hour worth of electrical energy production.
Unfortunately, in some cases, this would create negative feedback which would affect efficiency. As an example, Rudolf Diesel is currently rotating in his grave at approximately 2e6 RPM at the current implementation of the diesel engine, his invention. For context at his posthumous displeasure, the when tuned used properly, the diesel engine is the singular most efficient internal combustion engine. That proper use: steady, consistent operation at an invariant rotation running on a waste byproduct of the gasoline refinement process. What it is unquestioningly not designed for: operating devices which turn on and off frequently and require a variation in output power to operate, you know, like a motor vehicle.
So, with all that in mind, attaching a rotational corpse drive to him would generate immense amounts of power initially and push the vehicle and shipping markets towards EVs even faster, but as that happens, his ire will abate and he will begin to slow his rotation until it eventually comes to a peaceful rest, but the power deficit created by that would definitely cause economic and social problems.
You could probably use the diluted blood exhaust to feed baby vampires. You would obviously need to farm more vampires for your power plant and this would reduce overheads.