Presented at the International Space Development Conference, Huntsville, AL, USA, May 2011 1A US-INDIA POWER EXCHANGE TOWARDS A SPACE POWER GRID Brendan Dessanti, Nicholas Picon, Carlos Rios, Shaan Shah, Narayanan Komerath Daniel Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0150 [email protected] Abstract— The Space Power Grid (SPG) architecture described in papers from our group since 2006, is an evolutionary approach to realizing the global dream of Space Solar Power (SSP). SPG first concentrates on helping terrestrial power plants become viable, aligning with public policy priorities. It enables a real-time power exchange through Space to help locate new plants at ideal but remote sites, smooth supply fluctuations, reach high-valued markets, and achieve baseload status. With retail cost kept to moderate levels, a constellation grows in 17 years to 100 power relay satellites at 2000 km sun-synchronous and equatorial orbits and 250 terrestrial plants, exchanging beamed power at 220GHz. In another 23 years, power collection satellites replacing the initial constellation will convert sunlight focused from ultralight collectors in high orbits and add it to the beamed power infrastructure, growing SSP to nearly 4 TWe with wholesale and retail delivery. The SPG-based SSP system can break even at a healthy return on investment, modest development funding, and realistic launch costs. The immense launch cost risk in GEO-based SSP architectures is exchanged for the moderate risk in developing efficient millimeter wave technology and dynamic beam pointing in the next decade. A US-India space-based power exchange demonstration would constitute a rational first step towards a global SPG. We discuss two options to achieve near-24-hour power exchange: 1) 4 to 6 satellites at 5500km near-equatorial orbits, with ground stations in the USA, India, Australia and Egypt. 2) 6 satellites in 5500 km orbits, with ground stations only in the US and India. TABLE OF CONTENTS A US-INDIA POWER EXCHANGE TOWARDS A SPACE POWER GRID........................................................................ 11. INTRODUCTION ................................................................ 12. SSP IS AN OLD DREAM .................................................... 13. SSP IS HARD..................................................................... 24. THE SPACE POWER GRID................................................ 35. ARCHITECTURE RESULTS ............................................... 46. THE INDIA-US STRATEGIC PARTNERSHIP OPPORTUNITY...................................................................... 67. CONCLUSIONS .................................................................. 88. ACKNOWLEDGEMENTS.................................................... 88. REFERENCES.................................................................... 81. INTRODUCTION Much of humanity today does not enjoy the $0.10/KWhe, uninterrupted delivery of electric power that is taken for granted in urban industrialized societies. In regions that are not wired for power, residents pay exorbitant costs for a few watts or watt-hours and suffer lack of basic amenities and opportunities. Thus the first point to make is that competing with the efficient, reliable terrestrial utility and power grid, is not the only purpose of a Space-based electric power resource. The ability to reach all parts of the world at any time is a very significant characteristic, beyond being worth a high price. On the other hand, it is entirely possible that the price commanded by terrestrial utilities will keep rising beyond the level where we can make SSP viable even in this market. In this paper, we will start by pointing out that SSP is an old dream, not a new idea. It has not been realized, because SSP is hard. There is no short-term viable prospect for SSP as a significant source of power except for some very special and high-valued markets. The periodic spikes of media interest in SSP through the past six decades correlate with drives to develop something else, where large scale construction in Space for SSP was advanced as a popular civilian justification. We argue for a strategy where SSP helps, rather than competes, with terrestrial renewable energy initiatives, as a way to establish the technology and the infrastructure to exchange power between markets. In other words, Space is a venue for power exchange rather than just generation, and as such we call our architecture the Space Power Grid (SPG). This approach will also buy time to develop the best technological options for the Gigawatt-level SSP satellites that will replace the first-generation relay satellites. We have shown in recent work that such a strategy can lead to an economically viable infrastructure with a continuing revenue stream. This will help develop the massive satellites needed to expand SSP to the 4 Terawatt level of today’s fossil-based primary power supply. The US-India Strategic Partnership initiative was announced during the tenures of President Clinton and Prime Minister Vajpayee, and expanded under the tenures of Presidents Bush and Obama, and Prime Ministers Vajpayee and Manmohan Singh. This provides a special near-term opportunity to start demonstration experiments leading to the Space Power Grid architecture. The formidable technological obstacles are discussed, but seen to be within reach of focused research. 2. SSP IS AN OLD DREAM Arthur C. Clarke [1] pointed out in 1945 that the unique properties of the Geostationary Earth Orbit (GEO) suited it to locate a power relay system. Several periods of heightened interest in SSP are listed in Table 1, along with major initiatives or policy concerns existing in those periods. The large GEO SSP microwave platform idea isPresented at the International Space Development Conference, Huntsville, AL, USA, May 2011 2credited to Peter Glaser [2], then a Vice President of the Arthur D. Little Company, renowned for its strategic planning expertise. The massive number of launches required to construct such a platform probably helped to convince the US Congress to fund the Space Shuttle Transportation System, projecting that the launch cost would come down to $100 per lb ($220/kg) in routine, mass production operation. NASA and the DOE studied the concept, with DOE given development responsibility [3,4]. Interest appears to have waned until