How StratoSolar stores energy at a low cost

• Low cost buoyant support platform in the stratosphere
• Off the shelf motor generator and winch technology
• Weight on cable stores 54Wh/kg at 20km altitude
• Fast response time for load following and peaking
• better than 85% round trip efficiency
• Long life exceeding 15,000 cycles or thirty years without degradation
• No dependence on geography. Hills or caverns are not required
• Scale-able from 1MW to many GW in increments
• Same buoyant platform elements can provide PV generation for a complete dispatch-able electricity solution
• Capital cost less than $100/kWh and/or $1/W in production