well look at it this way, buy a generator that can power one furnace at a time.. plus some lights and other critical things.

not for this simulated disaster but any time power fails..

you could promote your idea of a generator as a investment for your community.

if the power fails someday your church would have enough power to be a shelter for the neighborhood and or your members, besides protecting your valuable investment your building.

later you could suggest some emergency food. MREs or shelf stable stuff that can be rotated out for the needy before they get too old.

and dont forget bottled water.