Glaring truth!

Energy consumption continues to grow. The costs of generation and transmission of energy must come down for the increased consumption to be sustainable. Energy must be generated without depleting resources, without causing pollution, and without incurring waste. Transmission of energy too must be efficient. Big challenge. But experts insist it can be an easy solution - onsite generation of electricity using the photovoltaic (PV) method of converting solar energy directly into electrical energy.

Nothing new in that but more and more scientists are focusing on the advantages of solar PV instead of the disadvantages like intermittency, storage, etc. For instance, silicon is the second most abundant element in the earth’s crust. Then consider the power saved. The creation of local DC power grids can save power being lost in the transmission and unnecessary conversion from DC to alternating current (AC) and then back to DC. Most electronic appliances and electric loads operate on DC and by transmitting and converting AC power to DC about 30% of the total power generated is lost.

The use of thin films of semiconductors such as cadmium telluride, amorphous silicon and copper indium gallium arsenide is still to make a major commercial impact. PV modules comprising organic and dye-sensitized solar cells shall not play a role in bulk power generation, without fundamental breakthroughs in material synthesis and performance.

Researchers at Penn University have proposed a new multi-terminal multi-junction architecture for inexpensive PV electricity generation. Efficiency will exceed the currently feasible 25%. The proposed architecture is based on the use of currently commercial crystalline solar cells and thin-film solar cells made of materials (such as copper oxide) that are abundant in Earth's crust. However, the additional manufacturing costs to be incurred thereby remain unknown, according to the researchers.

Empa scientists have developed a new technique for manufacturing high-efficiency, flexible, thin film solar cells from CIGS (copper indium gallium di-selenide) semiconductors. This has enabled them to achieve an efficiency of 20.4% for the conversion of sunlight into electrical energy. As the solar cells are deposited onto plastic foils, they could be produced on an industrial scale using cost-effective roll-to-roll manufacturing. The researchers are presenting a new manufacturing technique for CIGS solar cells, in which tiny quantities of sodium and potassium are incorporated into the CIGS layer.

All the research points to the sun as the future source of energy. More reason why we should be thinking of local micro grids rather than centrally generated power with potential for huge losses in transmission!