Space-based solar power varun.pptx ppppp

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1. AMC ENGINEERING COLLEGE 18KM BANNERGHATTA MAIN ROAD , BANGALORE 560083 DEPARTMENT OF AERONAUTICAL ENGINEERING Technical Seminar on SPACE BASED SOLAR POWER Submitted by N P Varun Achar 1AM21AE401 UNDER THE GUIDENCE OF LAKAPPA MATI Assistant Professor Aeronautical Engineering

2. Space-Based solar power (SBSP)

3. Trends of Concern

4. Future Energy Options Must Be…

5. Introduction Space-based solar power (SBSP) is the concept of collecting solar power in space (using an "SPS", that is, a " solar-power satellite " or a "satellite power system") for use on Earth. It has been in research since the early 1970s.

6. How it would differ SBSP would differ from current solar collection methods in that the means used to collect energy would reside on an orbiting satellite instead of on Earth's surface. Higher collection rate and a longer collection period due to the lack of a diffusing atmosphere and nighttime in space Solar Intensity 1,366 W/m 2 No Night Min Weather Solar Intensity 1,000 W/m 2 Night Loss Weather Loss Space Solar Ground Solar

7. Basic Concept Part of the solar energy is lost on its way through the atmosphere by the effects of reflection and absorption. Space-based solar power systems convert sunlight to microwaves or Laser beam outside the atmosphere, avoiding these losses, and the downtime (and cosine losses, for fixed flat-plate collectors) due to the Earth's rotation.

8. History Originally known as satellite solar-power system (SSPS), was first described in November 1968. In 1973 Peter Glaser was granted U.S. patent for his method of transmitting power over long distances using microwaves from a very large antenna (up to one square kilometer) on the satellite to a much larger one, now known as a  rectenna , on the ground. Between 1978 and 1981, the US Congress authorized the Department of Energy (DoE) and NASA to jointly investigate the concept. In 1997 NASA conducted its "Fresh Look" study to examine the modern state of SBSP feasibility. On Nov 2, 2012, China proposed space collaboration with India in SBSP

9. Requirements for Space Solar Power Low-cost, environmentally-friendly launch vehicles . Large scale in-orbit construction and operations : To gather massive quantities of energy, solar power satellites must be large, far larger than the International Space Station (ISS). Power transmission : To transmit power from satellites to the Earth’s surface with minimal environmental impact.

10. Design Space-based solar power essentially consists of three elements: a means of collecting solar power in space , for example via solar concentrators, solar cells or a heat engine. a means of transmitting power to earth , for example via microwave or laser. a means of receiving power on earth , for example via a microwave antenna (rectenna).

11. Microwave power transmission Power transmission via radio waves can be made more directional, allowing longer distance power beaming, with shorter wavelengths of electromagnetic radiation, typically in the microwave range. A  rectenna  may be used to convert the microwave energy back into electricity.  NASA Study of solar power satellites required a 1-km diameter transmitting antenna, and a 10 km diameter receiving rectenna, for a microwave beam at 2.45 GHz. Experiments in the tens of kilowatts have been performed . Conversion efficiency under experimental conditions was measured to be around 54% efficient.

12. Laser power beaming Power can be transmitted by converting electricity into a laser beam that is then pointed at a photovoltaic cell. Compared to other wireless methods: Collimated monochromatic wavefront propagation allows narrow beam cross-section area for transmission over large distances. Compact size: solid state lasers fit into small products. No radio-frequency interference to existing radio communication such as Wi-Fi and cell phones. Access control: only receivers hit by the laser receive power.

13. Earth-based receiver The Earth-based rectenna would likely consist of many short dipole antennas connected via diodes. Microwave broadcasts from the satellite would be received in the dipoles with about 85% efficiency. Rectennas would likely be several kilometers across.

14. Rectenna

15. Challenges The most significant technical challenges are the development of Low-cost re-usable space access Dealing with launch costs Demonstration of space-to-Earth power beaming Efficient and light space-qualified solar arrays Space Assembly, Maintenance and Servicing, and Large in-space structures

16. Conclusion The solar energy available in space is literally billions of times greater than we use today. Space solar power is by far the largest potential energy source available, dwarfing all others combined. This technology on a larger scale, combined with already demonstrated wireless power transmission can supply nearly all the electrical needs of our planet. Space solar power can completely solve our energy problems long term. The sooner we start and the harder we work, the shorter "long term" will be.

17. References http://www.nss.org/settlement/ssp/ http://martianchronicles.wordpress.com/2010/06/20/our-burning-need-for-energ/ http://en.wikipedia.org/wiki/Space-based_solar_power#Microwave_power_transmission http://spacesolarpower.files.wordpress.com