The Hindu Business Line : Scientists look to Space for energy source

DEMANDS of the digital economy on power quality, concerns on pollution levels flowing from raised generation and fears over depleting fossil fuel reserves are forcing engineers to turn to the Creator for an assured and sustainable source of energy.

Space holds the key to an inexhaustible and non-polluting energy supply, according to Mr N.T. Nair, Technical Advisor to the Energy Management Division of CMS Computers, Thiruvananthapuram.

Presenting a paper at a session organised here recently by the KSEB (Kerala State Electricity Board) Post-Graduate Engineers Association, Mr Nair said the Space-Solar Power (SSP), a constellation of orbiting satellites serving as hi-tech space dams could in the foreseeable future catch the flood of energy flowing relentlessly from the Sun and then pump it to Earth via laser or microwave beam using a rectifier-antenna (Rectenna).

On Earth, it would be converted into electricity and fed into power grids to be tapped by terrestrial customers. SSP would employ satellites in geostationary orbit (22,300 miles or 35,800 km) or on the surface of the moon, fitted with efficient solar cells.

New challenges: The ever-increasing demand for quality power is posing several new challenges to the power sector today. Power quality requirements to support the multitude of critical digital systems - assets and processes - in use in businesses and industries, specify a reliability level as high as 99.9999 per cent.

Demand for power by all sections of society, especially in the most developing nations fast marching towards a "developed" status with improved quality of life, has been straining the generation sector currently serviced through hydro, thermal and nuclear inputs. Any addition to generating capacity based on these traditional methods will be to the dislike of environmental protection groups.

The threat of impending fossil fuel shortage is yet another matter of concern, leave alone the environmental hazards their increased usage will bring about.

Limits reached: All these pose new challenges, threats and opportunities to the engineering community as the allowable limits in many of the related areas have already been reached. Fortunately, scientists and engineers are already on high alert and are in action to find ways and alternatives to meet them with.

Solar power from Space is one such. There are compelling arguments why it could be looked at as a possible option in the foreseeable future. For one, photo-voltaic (PV) arrays in space would receive, on an average, eight times the sunlight compared to Earth. They are also unaffected by cloud cover, atmospheric dust or by the day-night cycle of the Earth. PV technology has achieved a conversion efficiency of 42-56 per cent (as against 7-9 per cent earlier).

Lasers are also under consideration for beaming, in place of microwaves, but prevented only by a treaty between the US and Russia.

Cost factor: Using today's technology, it is estimated that SSP power would cost 60-80 cents per kWh, compared to a ruling market price of 5-6 cents. But, in 15-25 years' time, the same could be supplied at 7-10 cents, Mr Nair said.

There are some issues that militate against exercising the SSP option - such as the very large size of antennas required, international legal, political and social acceptability, health and environmental hazards from laser or microwave beams broadcast from Space and very high initial costs. But efforts are already on to deal with these engineering and economical challenges one by one.

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