From https://en.wikipedia.org/wiki/Electricity_pricing

> 3.1[US cents/kWh] at Official exchange rate ( 13.50 Bs/US$) or 0.48 [US cents/kWh] at unofficial exchange rate (1.095 Bs/US$)

(This may have changed due to high inflation.)

For comparison, in the same table the price in continental USA is between 8 and 17 [US cents/kWh].

They were exchanging it for money or stuff in Colombia, so they were getting an effective price similar to using the black market bolivar/US$ exchange rate, i.e. 0.48 [US cents/kWh]