Electricity in Botswana, Kenya, Namibia, South Africa, Tanzania, Zambia, Zimbabwe and in most of the continent is 220/240 volts.
Most safari lodges and camps are not connected to an electrical supply. Solar lighting (backed up by batteries) is common, with many lodges having a generator, which runs part of the day (morning and late evening when guests are out on their activities).
Lanterns also provide light at night. In many camps running on solar power, you will not be able to use a hairdryer.