Friday, July 31, 2009

Timeline

  • 1968: Dr. Peter Glaser introduces the concept of a large solar power satellite system of square miles of solar collectors in high geosynchronous orbit (GEO is an orbit 36,000 km above the equator), for collection and conversion of sun's energy into an electromagnetic microwave beam to transmit usable energy to large receiving antennas (rectennas) on earth for distribution on the national electric power grid.
  • 1973: Dr. Peter Glaser was granted U.S. patent number 3,781,647 for his method of transmitting power over long distances (eg, from an SPS to the Earth's surface) using microwaves from a very large (up to one square kilometer) antenna on the satellite to a much larger one on the ground, now known as a rectenna.[3]
  • 1995–1997: NASA conducts a “Fresh Look” study of space solar power (SSP) concepts and technologies.
  • 1998: Space Solar Power Concept Definition Study (CDS) identifies commercially viable SSP concepts which are credible, with technical and programmatic risks identified.
  • 2000: John Mankins of NASA testifies in the U.S. House "Large-scale SSP is a very complex integrated system of systems that requires numerous significant advances in current technology and capabilities. A technology roadmap has been developed that lays out potential paths for achieving all needed advances — albeit over several decades.[4]
  • 2001: Dr. Neville Marzwell of NASA states "We now have the technology to convert the sun's energy at the rate of 42 to 56 percent... We have made tremendous progress. ...If you can concentrate the sun's rays through the use of large mirrors or lenses you get more for your money because most of the cost is in the PV arrays... There is a risk element but you can reduce it... You can put these small receivers in the desert or in the mountains away from populated areas. ...We believe that in 15 to 25 years we can lower that cost to 7 to 10 cents per kilowatt hour. ...We offer an advantage. You don't need cables, pipes, gas or copper wires. We can send it to you like a cell phone call—where you want it and when you want it, in real time."[5]
  • 2001: NASDA (Japan's national space agency) announced plans to perform additional research and prototyping by launching an experimental satellite of capacity between 10 kilowatts and 1 megawatt of power.[6][7]
  • 2007: The Pentagon's National Security Space Office (NSSO) issued a report[8] on October 10, 2007 that states they intend to collect solar energy from space for use on Earth to help the United States' ongoing relationship with the Middle East and the battle for oil. The International Space Station is most likely to be the first test ground for this new idea, even though it is in a low-earth orbit.
  • 2007: In May 2007 a workshop was held at MIT to review the current state of the market and technology.[9]
  • 2009: A new company, Space Energy, Inc., plans to provide space-based solar power commercially. They say they have developed a "rock-solid business platform" and should be able to provide space-based solar power within a decade.[10]
  • 2009: Pacific Gas and Electric (PG&E) announces it is seeking regulatory approval for an agreement with Solaren to buy 200 MW of solar power, starting in 2016. PG&E spokesman Jonathan Marshall stated that "We've been very careful not to bear risk in this."[11][12][13]
  • 2009: PowerSat Corporation files a patent concerning ganging multiple power satellites to form a single coherent microwave beam, and a mechanism to use the solar array to power ion thrusters to lift a power satellite from LEO to GEO. [14]

[edit] History

The SPS concept, originally known as Satellite Solar Power System ("SSPS") was first described in November 1968 [15]. In 1973 Peter Glaser was granted U.S. patent number 3,781,647 for his method of transmitting power over long distances (eg, from an SPS to the Earth's surface) using microwaves from a very large (up to one square kilometer) antenna on the satellite to a much larger one on the ground, now known as a rectenna.[16]

Glaser then worked at Arthur D. Little, Inc., as a vice-president. NASA signed a contract with ADL to lead four other companies in a broader study in 1974. They found that, while the concept had several major problems—chiefly the expense of putting the required materials in orbit and the lack of experience on projects of this scale in space, it showed enough promise to merit further investigation and research [17].

Between 1978 and 1981 the US Congress authorized DOE and NASA to jointly investigate. They organized the Satellite Power System Concept Development and Evaluation Program [18][19]. The study remains the most extensive performed to date. Several reports were published investigating possible problems with such an engineering project. They include:

  • Resource Requirements (Critical Materials, Energy, and Land)[20]
  • Financial/Management Scenarios[21][22]
  • Public Acceptance[23]
  • State and Local Regulations as Applied to Satellite Power System Microwave Receiving Antenna Facilities[24]
  • Student Participation[25]
  • Potential of Laser for SPS Power Transmission[26]
  • International Agreements[27][28]
  • Centralization/Decentralization[29]
  • Mapping of Exclusion Areas For Rectenna Sites[30]
  • Economic and Demographic Issues Related to Deployment[31]
  • Some Questions and Answers[32]
  • Meteorological Effects on Laser Beam Propagation and Direct Solar Pumped Lasers[33]
  • Public Outreach Experiment[34]
  • Power Transmission and Reception Technical Summary and Assessment [35]
  • Space Transportation[36]

The Office of Technology Assessment[37] concluded

Too little is currently known about the technical, economic, and environmental aspects of SPS to make a sound decision whether to proceed with its development and deployment. In addition, without further research an SPS demonstration or systems-engineering verification program would be a high-risk venture.

More recently, the SPS concept has again become interesting, due to increased energy demand, increased energy costs, and emission implications, starting in 1997 with the NASA "Fresh Look"[38]. In assessing "What has changed" since the DOE study, this study asserts that

Another important change has occurred at the US national policy level. US National Space Policy now calls for NASA to make significant investments in technology (not a particular vehicle) to drive the costs of ETO [Earth to Orbit] transportation down dramatically. This is, of course, an absolute requirement of space solar power.

[edit] SERT

In 1999 NASA's Space Solar Power Exploratory Research and Technology program (SERT) was initiated for the following purpose:

  • Perform design studies of selected flight demonstration concepts;
  • Evaluate studies of the general feasibility, design, and requirements.
  • Create conceptual designs of subsystems that make use of advanced SSP technologies to benefit future space or terrestrial applications.
  • Formulate a preliminary plan of action for the U.S. (working with international partners) to undertake an aggressive technology initiative.
  • Construct technology development and demonstration roadmaps for critical Space Solar Power (SSP) elements.

It was to develop a solar power satellite (SPS) concept for a future gigawatt space power systems to provide electrical power by converting the Sun’s energy and beaming it to the Earth's surface. It was also to provide a developmental path to solutions for current space power architectures. Subject to studies it proposed an inflatable photovoltaic gossamer structure with concentrator lenses or solar dynamic engines to convert solar flux into electricity. Collection systems were assumed to be in sun-synchronous orbit.

Some of SERT's conclusions include the following:

  • The increasing global energy demand is likely to continue for many decades resulting in new power plants of all sizes being built.
  • The environmental impact of those plants and their impact on world energy supplies and geopolitical relationships can be problematic.
  • Renewable energy is a compelling approach, both philosophically and in engineering terms.
  • Many renewable energy sources are limited in their ability to affordably provide the base load power required for global industrial development and prosperity, because of inherent land and water requirements.
  • Based on their Concept Definition Study, space solar power concepts may be ready to reenter the discussion.
  • Solar power satellites should no longer be envisioned as requiring unimaginably large initial investments in fixed infrastructure before the emplacement of productive power plants can begin.
  • Space solar power systems appear to possess many significant environmental advantages when compared to alternative approaches.
  • The economic viability of space solar power systems depends on many factors and the successful development of various new technologies (not least of which is the availability of exceptionally low cost access to space) however, the same can be said of many other advanced power technologies options.
  • Space solar power may well emerge as a serious candidate among the options for meeting the energy demands of the 21st century.
Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)