Emerging economies are expected to account for more than 90% of the global net-energy-demand growth to 2035. Intensive use of renewable energy by emerging economies is inevitable to solve the problem of global warming. In this paper, we propose a grid comprising distributed small solar energy systems without electric wires, called a «virtual grid,» where lithium-ion batteries, solar panels, and appliances are wirelessly networked and the batteries are shared between users to improve the efficiency of battery usage. The states of health (SOH) of batteries are monitored and the batteries are used beyond the SOH deterioration limit defined by the makers as far as the batteries are evaluated as safe, which results in extension of the battery lifetime to more than twice. The virtual grid is projected to reach grid parity for emerging economies around 2030, assuming continued cost reduction of lithium-ion, or other high-energy-density batteries.