Coal Age

APR 2018

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Page 27 of 51

26 April 2018 renewable energy continued ing plants. The solar pundits try to hide this problem by quoting maximum pow- er density instead of levelized use. Solar, and other intermittent energy sources, must be regularized to compete with and supplement existing power generating schemes. Merely stating a peak power availability (overhead sun, low angle of incidence, clear sky, low ambient tem- perature) is meaningless. That condition, is at best, only realizable for 2-4 hours a day. With storage and regeneration, the peak number equates to more than eight times the normalized power. This is smoke-and-mirrors designed to hide the poor economies of solar power. Electric power is usually sold by the kilowatt hour, the product of power in kilowatts multiplied by running time in hours. Typically, solar farms do not pro- vide a rating in commercial power units. They merely provide a watt rating, which is 1 joule of energy per second. It is obvious that they cannot compete with conven- tional power generators. Manufacturing Considerations Manufacturing a solar panel is an energy and resource consuming process, which will eventually lead to scarcity. To gener- ate photovoltaics capable of producing 1 mw of power from solar source, 13 tons of solar grade polysilicon is used. This equates to, roughly, 20 tons of silicon quartz before processing to PV grade sil- icon. Other more specialized materials are also used in the manufacture. Some are process materials that do not actually find their way into the device itself. Met- als, including rare earths are major con- siderations as well. Demand for energy consumption to manufacture solar panels continuously increases. A 1-MW — peak power — solar plant uses nearly 3,240 solar panels with the average panel area at about 1.626 m 2 . The total area of solar cells required to provide a 1-MW capacity is 5,268 m 2 . Approximately 0.25 MW hours of pow- er is required to produce a 1-m 2 panel. This is a total of 1,317 MW-hours to pro- duce the panels for one megawatt of solar. Assuming other forms of energy support the production process it is ap- parent that the carbon footprint is not minimal in solar energy's life cycle. To repay this manufacturing energy debt, the solar farm would have to operate continuously for a year. Adding in the installation energy and ancillary equip- ment necessary to operate the farm, the energy payback time budget easily ex- ceeds 3 years. Solar energy is harvested using solar panels. Solar panels are not available free- ly, they must be manufactured — just like any other electronic device. This involves a dirty and energy consuming process. Firstly, raw materials must be mined to re- move quartz sand for silicon cells. A series of chemical stages are carried out to make silicon as a semiconductor which can con- duct electricity. Finally, upgraded materi- als must be manufactured into solar cells and assembled into modules. All these processes produce air pollu- tion, emissions of heavy metals, consume energy, and encompass environmental impacts like land deterioration, loss of bio- diversity, pollution, logistical infrastruc- tural damages, deterioration of ground water and natural drainage system. Assembling individual solar cells typically needs to be soldered with cop- per wire coated with tin. Some manu- factures use lead and other toxic mate- rials. This results in release of harmful The Levelized Cost of Energy (LCOE) projected for 2020 using heuristic date from 2010-2016. As notated in the above chart (which uses averaged data from the U.S., France, Japan and Germany), Solar and Offshore Wind are outliers for the most expensive power production. While Advanced Cycle Natural Gas, Onshore Wind, and Geothermal represent the other end of the cost spectrum. Yes, solar energy is green, clean and emission free but at what cost? Problems associated with solar energy are vast and mostly blindfolded.

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