On August 13, 1968, at the Intersociety Energy Conversion Engineering Conference ( IECEC) in Boulder, Colorado, Dr. Peter Glaser of the US Solar Energy Society presented the idea of collecting solar energy in orbit and delivering it as radio wave energy to receivers on Earth 24/7.

In those days solar energy was still a relatively new idea. Solar cells had been manufactured for less than a decade, and annual output was barely kilowatts. But visionaries such as Peter Glaser understood the enormous potential of this new, "photo-voltaic" technology: solar cell production is now approaching 5 GW/year, and still growing fast, about 30 square kilometres/year of solar panels – or about 20 acres every day. This has been achieved with very little government support by comparison with fossil fuels or nuclear energy.

Since 1968 research has showed that a solar power satellite ( SPS) system could generate about 20 times the energy per square kilometre as terrestrial solar energy and could supply power to most places on the Earth, unaffected by climatic conditions. Because of the sharp rise in oil prices in the 1970s, the US Department of Energy (DoE) spent $20 million investigating it from 1976 through 1981.

The DoE concluded that an SPS system was feasible and likely to be environmentally benign, but it was far too expensive. They suggested that the idea should be revisited in 15 years. This happened in 1995 when Congress gave NASA $15 million for the "Fresh Look" study. The study found that, as might be expected, many related technologies had advanced considerably since 1980, and the project was considerably more attractive than before. However, neither DoE nor NASA, nor similar organisations in other countries, have provided any significant funding to advance the project since then.

By contrast, during the 40 years since SPS was proposed, nuclear fusion has received about $40 billion, and conventional nuclear power has received about $200 billion in Japan alone – while space agencies have spent the best part of $1 trillion.

So why hasn't SPS secured the few billion dollars needed to test out a prototype?

One reason is that space agencies claim, "Energy is not our responsibility," while energy ministers say, "We know nothing about space." For still-unstated reasons, governments have agreed not to investigate SPS, as they have chosen not to develop low-cost launch systems.

But this policy failure applies to space as a whole, where the US federal government has now allowed NASA to eliminate Americans' ability to get to space at all, when the space shuttle fleet is decommissioned 2010. This is such a stunning failure that we must hope that the American public will finally be shocked into action. They need to do whatever is necessary to get their government to start doing its job again – namely working for the benefit of the general public rather than for special interests.

In the case of NASA this would mean forcing it to “...encourage, to the maximum extent possible, the fullest commercial use of space," as federal law states. This is very clear and simple: if implemented, it would immediately lead to NASA funding a range of companies developing passenger-carrying launch vehicles, since this is by far the most promising commercial activity in space, as NASA reports have admitted. And one of the great beneficiaries of this would be SPS, which needs low launch costs in order to compete with terrestrial energy sources.

Unfortunately there is as yet no sign of such an improvement in the US government’s behaviour. And it's an open guess when Americans will next get to orbit after the last space shuttle flight. Would anyone like to bet on it?

There is also no sign that the world's space agencies intend to change their collective policy of "no SPS and no space tourism." They seem resolutely determined not to use their $20 billion/year funding to develop any services that taxpayers might want to buy.

However, the development of passenger space travel may throw a lifeline to SPS. As orbital travel services grow to millions of passengers/year – which is easy to foresee within a few decades once serious investment starts – this industry will use tens of gigawatts of power. Although small within a global energy industry at that time of several thousand GW, it will also be growing rapidly. Although Virgin Galactic currently publicises the low environmental impact of its planned sub-orbital flight services, a diplomatic business plan might consider generating this power independently.

So this leads to the nicely "heretical" idea that SPS may be developed, not for terrestrial energy supply, but in order to power the space tourism industry independently of the terrestrial energy industry.

It has been clear for some time that SPS needs space tourism in order to reduce launch costs. But maybe space tourism will also need SPS? And if costs fall low enough, SPS may then grow beyond just powering the passenger launch business to supply a share of the Earth's energy supply. Moreover, the development of massive power plants in orbit will stimulate all sorts of spin-off space businesses, in addition to those stimulated by the hotels that will mushroom in a range of Earth and lunar orbits.

Encouragingly, there has recently been a flurry of interest in organisations other than space agencies - notably Welsom Inc, Space Island Group and NSSO - in developing an orbiting SPS demonstrator. Peter Glaser must be very disappointed not to have seen an SPS demonstrator in 40 years, but in the long run his 1968 vision of a large-scale, space-based solar energy industry may well turn out to have been correct.