NO they are down in Mutoko. YES they are affected by Power cuts just like anyone else but sometimes they do have backup inverters and generators on some of their base stations / access points and repeaters across the country.
It looks like they won't be covering Mutoko anytime soon. According to the planned coverage blue print for CDMA "wireless internet" Mutoko is out of scope.
See map details herein on the link below http://www.powertel.co.zw/images/maps/PLANNED%20COVERAGE.png
Even under VPN mutoko is not covered now or any-time soon see map below
Again so their mobile network only spans like the great dyke but still misses Mutoko area as well. See map below
However don't despair about Powertel's absence in Mutoko i am sure you can still get WWW access via Econet / Netone or Telelcel depending on your choice and WWW requirements. As of heavy downloads then you have to look for another option such as a VSAT but it's costly and might make you lose an arm and a leg to foot the costs.
A usb dongle configured for any of the three mobile networks should be sufficient to get you to WWW and check emails, a couple of FB statuses etc etc "end of thinking capacity".