It has been 2 days of blackout in my area and our tank got empty last night.
If power is not restored by evening, I may be forced to buy petrol of 1,060 naira for 2 liters which is higher than what we usually spend.

I have been thinking of how economical it would be to replace the electric water pump with manual pump, so we don't have to spend any kobo on petrol for pumping water.

One thing is certain about the petrol subsidy removal, the petrol demand and consumption will surely decline by close to forty percent. Some people will start using their initially abandoned diesel machines. Some people will develop alternative ways to get their problems solved just as the @op just stated. Don't forget about conversion of some vehicles from petrol to gas. The petrolatum marketers in this forum should not play with this thread. If the exorbitant price of petrol is a selfish step to milk the people dry, they are going to experience the adverse effects when the people stop buying the products. They should act fast to save their business by ensuring that the price is moderate.