Tethered Solar Power Satellite (Tethered-SPS) has been proposed as a feasible and practical Solar Power Satellite. It consists of a power generation/transmission panel suspended by tether wires deployed from single or multiple bus satellite. Especially, the multi-bus Tethered-SPS, recently invented, is highly flexible and expandable. It can be constructed by integrating perfectly equivalent units of miniature Tethered-SPS connected to each other. Each unit folded up is transported from the ground to the geo-stationary orbit and deployed automatically. This concept enables phased construction approach, evolutional development scenario, and coexixtence with other geostationary satellites.