Angolan President Joao Lourenco (L) greets U.N. Secretary-General Antonio Guterres (R) during the 9th Tokyo International Conference on African Development in Yokohama. Africa has everything it takes to become a "renewable superpower," U.N. head Antonio Guterres said Thursday, as he called for greater investment in green energy across the resource-rich continent. Guterres spoke at a three-day development conference in Japan attended by African leaders, where Tokyo is offering itself as an alternative to China as African nations reel from a debt crisis exacerbated by Western aid cuts, conflict and climate change. "We must mobilize finance and technology, so that Africa's…