portfolio item6

Portfolio Item 6:

Being an energy source, solar power can provide much more energy than other commercial energy that humans use on the planet. Although the solar electricity generation and industries are growing, its share of total energy market remains rather small. However, in the long term, solar power will be an excellent alternative as it is environmentally clean, and its energy is transmitted from the sun to the Earth free of charge. However, there are some obstacles for engineers to tackle before widespreading solar power generation. Fortunately, those technologies used to address these issues are already in hand. However, current silicon based commercial solar cells are not efficient enough, only10% to 20%. Therefore, in order to make solar economically competitive, engineers must find ways to improve the efficiency of the cells and lower their manufacturing costs. These can be done by arranging the silicon material in a novel way or using nanocrystals, which is made from lead and selenium. Theoretically, the nanocrystal approach could reach efficiencies of 60 percent or higher, though it may be smaller in practice. Thus, engineering advances will be required to find ways of integrating such nanocrystal cells into a system that can transmit the energy into a circuit. However, current solar cells are expensive because impurities block the flow of electric charge. This can be improved by using nanorods. Another way is to combine dye molecules to absorb sunlight with titanium dioxide molecules to collect electric charges. However, large improvement in efficiency is necessary for this system to be more competitive. Another concern is that how to store the solar energy in order to make it available during nighttime darkness and cloudy weather. There are many technologies that can make this happen, such as pumping water, large banks of batteries, capacitors, superconducting magnets, or flyweels , and photosynthesis in plants. If the engineering challenges can be met for improving solar cells, reducing their costs, and providing efficient ways to use their electricity to create storable fuel, solar power will assert its superiority to fossil fuels as a sustainable motive force for civilization’s continued prosperity.a

Originial Passage:
http://www.engineeringchallenges.org/cms/8996/9082.aspx