Professor Stephen Sweeney writes on the latest developments of space-based solar power

[bananas]

A short non-technical article written by one of the lead scientists.

http://news.pv-insider.com/photovoltaics/beaming-solar-power-space

Beaming solar power from space

Jul 11, 2011

Space platforms using lasers to beam solar energy back to Earth is no longer stuff of science fiction. Professor Stephen Sweeney, Head of Photonics at the University of Surrey, writes on the latest developments of space-based solar power.

By Dr Stephen Sweeney, University of Surrey

Science fiction becoming a reality

It's the stuff of science fiction - space platforms using lasers to beam solar energy back to Earth - but the reality of a solar power satellite system has become much closer.

In an Astrium-led project, trials have begun at the Advanced Technology Institute at the University of Surrey working closely with space technology giant Astrium. The technological approach has the potential to be scaled up to become a major and long-term source of energy - 'clean', inexhaustible and accessible for any area of the planet.

<snip>

Once proven, a first stage would be to set up a multi-satellite system capable of beaming power to people in isolated areas with no access to electricity power grids. These kind of ‘off-grid’ power sources would then be operational in advance of the development of the real goal, the very large scale Mega- and Giga-watt orbiting solar power stations which could provide significant supplies of power to grids, not necessarily as a single solution to energy needs, but as an important part of a suite of renewable energy sources.

<snip>

Initial ground based trials are in progress and a first prototype is expected to be launched into space in 2016 to beam low levels of energy, and the technology scaled up to the point where many megawatts of power will stream into energy grids.

[PoliticAverse]

1. How is this in any way cost-effective? n/t

[bananas]

2. We're approaching the power-to-mass ratio which makes it cost-effective.

http://blog.nss.org/?p=2807

Space Solar Power May Be within Our Grasp

According to National Space Society Director Al Globus, the development of thin-film solar cells may bring the reality of space solar power closer than ever.

<snip>

Space solar power using crystalline photovoltaics is expensive because the mass is high and launch costs tend to dominate. Industry people measure the effectiveness of a solar cell by its specific power, or output per weight. The unit of measurement is Watts per Kilogram (W/kg). The goal is to achieve 1000 W/kg. Recently, thin-film photovoltaics have exceeded this critical point. Very thin (10-25 micrometers) metallic substrates can achieve and exceed the required specific power targets.

According to Globus, this may bring space solar power within our grasp. Thin-film solar cells currently in use in space on the Ikaros solar sail achieve approximately 1,250 W/kg for power generation. However, this does not include the rest of the system (power beaming, ground receivers, etc.). Using current day technology, a thin-film based PowerSat could probably achieve around 275 W/kg. If we assume a reasonable R&D program to develop the basic technologies, it appears that 1,380 W/kg can be achieved in a reasonable time scale.

<snip>

[OKIsItJustMe]

3. I thought the Solaren patent from 2009 took a very interesting approach, using inflatable elements

http://www.patentgenius.com/patent/7612284.html

In this case, the proposal was to use mirrors (perhaps inflatable) to focus the light onto high-efficiency receivers.

Using inflatable elements certainly cuts down a lot on the necessary weight.

[LongTomH]

4. Bananas, thanks for posting these updates!

I was involved with the old L-5 Society back in the 70s and 80s. SBSP (Space Based Solar Power), AKA SPS (Solar Power from Space or Solar Power Satellites.). I've been meaning to post something myself; looks like you beat me to it.

Edited to add: When we were talking about SPS in the 70s and 80s, we were looking at orbiting platforms like the one below. A Manhattan-island sized photovoltaic array delivering from 5 - 10 gigawatts (a gigawatt is a billion watts!) to the earth-based rectenna.



We did get some really pretty pictures of the projects:



I used to have a whole carousel of slides like this and gave slide shows to civic groups who would listen. Of course nothing ever came of it!