Energy From Space

Depiction of a solar satellite that transmits electric energy by microwave
Picture by NASA

What then does the future hold for energy options that are both sustainable and climate friendly? To address this question, we may have to stretch our imagination, and look toward the sky for an answer. 

Faced with the problem of competition for land for solar farms, scientists have been studying the feasibility of setting up solar power satellites (SPS) that can transmit electric energy to Earth via electromagnetic beam. 

The concept was invented in 1968 by Peter Glaser (McSpadden and Mankins 2002). SPS benefit from an eightfold increase in solar flux experienced in space, compared to the flux received on earth's cloudy surface. Landis (2004) proposed that SPS could be positioned such that it has a constant view of the night side of the Earth, so as to supplement daytime ground solar power by providing night power.

Brown (1992) suggested that beamed microwave power transmission could have a theoretical efficiency of 76% and experimentally achieved 54% efficiency. Although the efficiency may appear low compared to the 7% losses on traditional transmission and distribution (T&D) lines estimated by the US Energy Information Administration (EIA), one should also consider the vast distances that can be covered via satellite technology. Access to remotely located, environmentally sound, renewable resources, and transmission across sensitive areas could become possible with satellite technology, when traditional transmission lines would have faced challenges (Woodell and Schupp, 1996).

Although early studies succeeded in establishing technical feasibility, government funding in the United States came to an abrupt halt in the 1970s given the enormous costs in excess of US$100 billion needed to realise the project (Mankins, 1996)

Nonetheless, Matsumoto (2002) argued that microwave power transmission remains as one of the new technological frontiers, and the SPS had been the central attraction of space and energy technology, which could potentially achieve 80% efficiency for both transmitting and receiving systems. In this regard, Hoffert et al (2002) opined that SPS could potentially be demonstrated in 15 to 20 years and deliver electricity to global markets by the latter half of the 21st century

A reader had commented in an earlier post on wind power that due to supply and demand issues, technologies such as wind and solar may still need to be completed by traditional sources of fossil energy to ensure adequate supply of electrical power. 

To address this supply and demand dilemma, the future could see use of power relay satellites (PRS) to transmit power from regions where the energy is generated, to other regions on the globe where the energy supply is needed. Glaser (1994) suggested that a global PRS network can help to supply energy worldwide with wireless power transmitted from generation sites on Earth, to satellites in geosynchronous orbit, which then reflect the energy to load receiving stations interfacing with terrestrial power transmission networks. 

In particular, Bockris (2010) painted the scenario where regions that receive massive amounts of sunshine such as Australia, North Africa and Saudi Arabia could act as generation centres, and the PRS could beam the energy to a country needing energy through a load receiving station. 

However, even with technical feasibility, implementation of SPS and PRS may not be straightforward. Dickinson (2002) suggested that given the likelihood of interception of power beams by aircraft and spacecraft flying through the beams, there may need to be robust space policy to assure safety given the high-power flux densities required. 

The SPS and PRS may sound like technologies from a science-fiction novel today. But who knows? Maybe the ideas can be realised commercially within the next few decades, serving as a sustainable and climate-friendly energy solution.