Solar energy becoming competitive

By Dewi Anggraeni

MELBOURNE (JP): The world community is becoming increasingly aware of the need to maintain the ecological balance of the environment we live in. However, this awareness rarely chimes with our ever increasing thirst for energy. So the challenge for this era is to keep quenching this thirst while avoiding further degradation.

In energy conferences, environmental issues are always hovering in the background like apparitions, if they are not actually brought into the foreground. At the APEC Energy Ministers Meeting, and the Business Council of Australia's International Energy and Environment Conference, Aug. 26 until Aug. 30 in Sydney, businesses were falling over each other trying to prove how environmentally conscious they were. Even giant mining companies now make a point that they do not only dig out minerals, they also reprocess and recycle their waste into new energy sources.

Purnomo Yusgiantoro, energy advisor to the Indonesian minister of mining and energy, pointed to some negative impacts of fossil fuels such as coal. "Coal utilization tends to produce greenhouse gases such as CO2, SOx and NOx," he said. Yet the technology needed to reduce the impact is very costly and often beyond the financial reach of developing countries.

Solar, wind, geo-thermal and other renewable energy sources are still grossly under-used, considering their abundant supply and ecological advantages.

While sunlight is free, converting it into energy is not. Solar energy is undoubtedly environmentally friendly, yet fossil and hydro-fuels still dominate global use. The photovoltaic technology that converts sunlight into energy sources was in fact invented late last century, yet its reliance on daylight and the initial costs of installing the photovoltaic cells remain drawbacks.

These drawbacks naturally are a disincentive for consumers to use it. In areas served by conventional electricity grids, it is naturally cheaper and more convenient to take advantage of the available service.

Research continues, nonetheless, and photovoltaic technology has improved and been refined enormously, resulting in lower prices. But it is still dearer than grid electricity.

Solar energy is utilized in remote places not served by electricity grids. The reason is clear. It would cost more to build grids and extend connection than bulk-buy photovoltaic cells. Australia's giant telecommunication company, Telstra, makes uses of solar energy for its transmitters and receptors in the deserts of Central Australia. In Indonesia, this renewable energy source is also used in gridless eastern regions.

In this era of commercialization and privatization, it is near impossible to obtain a funding commitment from the private sector for a research project that could take years, without a perceived guarantee of success. The commitment last year of A$64 million to the team headed by Professors Martin Green and Paul Basore, and their business partners, may thus mean that the project will not take long, and that it has a guarantee of success. The team members claim that both is true. They began research some ten years ago, and with what they had achieved, they approached Pacific Power and Unisearch (the commercial arm of the University of New South Wales). Pacific Solar, their own company, was founded with $45 million working capital provided by Pacific Power, and the rest was made up by share purchases.

The breakthrough in the technology developed by Pacific Solar lies in their success in producing a much cheaper photovoltaic cell that makes it viable for use in urban areas, not merely in remote, gridless places. The cell produced will be able to generate electricity for a very competitive $0.10 per kHh. It is equipped with an in-built converter to allow easy connection to existing grids. Householders can then sell their own generated solar electricity into the power grid in their area, to be sold to those who need more than they themselves generate. When recently a Sydney electricity company announced that it would allow householders to make money selling their own solar generated electricity, using solar energy became much more feasible, even sensible.

"Our cell will be much cheaper, because we use a great deal less silicon that the conventional photovoltaic cells. We use 10 to 20 microns-thick silicon wafers in our modules, compared to the 300 to 400 microns used in conventional cells," said David Hogg, Managing Director of Pacific Solar. Since silicon wafer is the biggest cost of the module, the massive reduction in silicon use means a reduction in price as well.

The new technology involves four steps. The first step is to clean the glass support, then place on it a multilayer stack by a technique known as chemical vapor deposition. The first layer is a dielectric barrier such as silicon oxynitride/nitride followed by several layers of silicon of alternating doping polarity. Then a silicon oxynitride/nitride layer is deposited on the top surface as a capping layer. The second step is to form set of grooves of one type of polarity (for example, n-type). After grooving with a laser and cleaning, the walls of the grooves are doped. The third step is to form a second set of grooves with the walls doped with the opposite polarity (p-type). The final step is to fill in the grooves with metal to form fingers which act as conventional grids for current collection, and connect adjacent cells.

Peter Lawley, the company's Business Development Manager, expects the product to be ready to be mass-marketed by the year 2000. They are currently developing the technology to mass- produce the cells, tailoring the size to specific market needs.

With global demand for energy continuing to escalate, and our awareness of the necessity for clean environment also increasing, this product should do well.