[Wavytone]

He also has no understanding of the hazards associated with storing large amount of energy - in any form - in a small space and I'll bet he's either un-insured, or hasn't read the fine print in his home insurance policy.

Any of those go pear-shaped and its all going up in smoke - probably along with his house.

And he's added more fuel (plywood) just to make sure.

Whether the energy is mechanical (flywheels), chemical (battery), water (pumped storage dam), compressed air (air cylinders)... the stored energy significant hazards and frequently sufficient to guarantee the house will be destroyed, one way or another.

This is why IMHO the most appropriate way to store energy - if done with batteries - is on the scale of a suburb, with a "big box" building built for the purpose roughly the size of a Bunnings, with all the protection equipment.

But not in domestic homes.

The other problem is the industrial waste when batteries have had it. If we all did this the planet would be poisoned several times over. This is why hybrid and electric cars are really only a stop-gap until we find a better solution - vehicles with large batteries are not a long-term solution environmentally.

And the last problem is energy density - to date there is still no viable solution for aircraft or heavy haulage vehicles (truck, diesel locomotives or farm machinery) apart from jet fuel and diesel.