Sovereign defaults by both Zambia and Zimbabwe have escalated the Batoka Gorge hydro-electric project cost, with the estimated price climbing 23% to almost $5-billion. The plan, which is being developed by General Electric and Power Construction Corporation of China, needs credit support, the Zambezi River Authority said in an emailed response to questions. This may be raised through development bank guarantees, government guarantees or partial credit and risk guarantees, the agency, which is overseeing the construction of the project, said.