Indian, Israeli experts tap sun for hybrid power plants

Avi Kribus inked the project with S. Iniyan in October last year to study how solar energy can further augment power output.

Updated: Feb 14, 2012, 17:01 PM IST

New Delhi: The success of hybrid cars is inspiring yet another way of going green but on a more ambitious scale -- harnessing solar energy to drive hybrid power plants under an India-Israel project.
Avi Kribus, professor of mechanical engineering at Tel Aviv University in Israel, inked the project with S. Iniyan, professor and director, Institute of Energy Studies, Anna University, Chennai, in October last year to study how solar energy can further augment power output.

This collaboration is the outcome of a call for proposals for developing alternative energy sources by the Indian government`s department of science and technology and is being funded by both the countries.

"Sunlight is the most abundant and environmentally benign source of energy, which can provide power and heat in amounts far surpassing all of humanity`s needs, but the prohibitively high production cost limits its use worldwide," said Iniyan from Chennai.

Production of solar-powered electricity "is still two to three times costlier than with fossil fuels such as coal, thanks partly to equipment made from expensive metals", said Iniyan, a mechanical engineering professor.

"This cost can be brought (down) to competitive levels if the conversion efficiency from sunlight to electricity is boosted and made available in a reliable way, not dependent on the intermittent availability of sunlight," he added.

In this context, the solar-powered steam injected gas turbine (STIG), a promising technology developed by Kribus, works with much lower steam pressures and temperatures than those required by conventional coal-fired plants.

The proposed STIG cycle, which permits the solar part to use cheaper metals and low-cost solar collectors, can cut fossil fuel use by 25 to 50 percent, bringing down production costs.

It will drive hybrid power plants of tomorrow, which will be as competitive as coal-fired ones, according to Iniyan.

Elaborating on the new concept, Kribus explained: "We combine a gas turbine, which works on hot air, and not steam, and inject the solar-produced steam into the process."

"We still need to burn fuel to heat the air, but we add steam from low-temperature solar energy, approximately 200 degrees centigrade," added the Israeli scientist.

Both teams, with diverse experience in various areas of renewable energy, including solar technologies and combined power generation, are pooling their expertise and working out the details of integrating solar energy with power plants for low cost, clean and green energy.

Given the fact that thermal power plants generate nearly 70 percent of power consumed in India, the potential to cut costs and reduce carbon dioxide emissions is enormous.

"The collaboration includes sharing of parallel tasks, joint tasks to develop analysis tools, run simulations and compare results, and frequent meetings and communication to keep the project synchronised and consistent.

"Our research is also tasked with defining and investigating a conversion method for solar radiation, energy storage for robust energy supply and lower cost of energy for increased competitiveness against fossil fuels," said Iniyan.

Bringing together these areas of expertise, which are partly overlapping and partly complementary, will provide an opportunity for mutual enrichment and support, he said.

"Besides, both the countries have identified a large amount of natural gas resources, which is preferred to other fossil fuels due to its much lower environmental impact," Iniyan added.

It is a stepping stone that will help introduce solar energy into the industry in an accessible and affordable way, concluded Kribus.