To finance building and running the solar PV panel plant, the municipality would issue medium- or long-term general revenue bonds to get the factory up and running and hire, train and retain employees. There are numerous other possibilities.
Here’s the really neat economic/financial aspect of Kernahan’s business model: the bonds would be repaid as a result of local consumers saving on their electricity bills. Some of that, likely most, would be spent and reinvested in the local economy.
The competitive advantages and economic and social benefits this public-private business model for expanding use of residential and commercial solar power are numerous and varied.
It could generate a virtuous circle: residents obtain a long-term means of generating some of their electricity through clean, renewable solar power, good, sustainable jobs would be created providing income and security to the local workers hired, and the municipality’s revenue would grow as result of the added local jobs, income and increased tax receipts.
Technological Innovation: Solving the Reverse Bias-Hotspot Problem
The competitive advantages Ideal PV and Locally Grown Power bring to the table are based on the technological breakthroughs Kernahan has made regarding enhancing the performance, safety and reliability of solar PV cells and panels.
With his latest innovations, Kernahan believes he’s developed a means for direct current (DC) to reclaim its ascendancy over alternating current (AC), at least when it comes to making use of electricity produced from solar PV.
A lot of time, effort and money is going into developing smaller, more efficient and more reliable inverters that convert the DC coming from solar panels into grid-ready AC. In fact, Kernahan’s the array converter technology Kernahan invented that’s being used by ArrayPower is designed to do just that.
Now, Kernahan’s invented, and filed patents, detailing a way to solve a critical safety and performance problem that plagues the solar power industry: the reverse bias or “hotspot” problem.
Solar cells are designed to operate with electrical current flowing forwards and backwards. They’re required to operate backwards at about 20-times their normal forward voltages, Kernahan explained.
The design of solar cells and panels, particularly in combination with imperfections in their manufacture or their weathering over time, can result in the development of micro-cracks and the formation of “hotspots” – areas on the modules where temperatures can reach anywhere from 200-1350 degrees Celsius.
The cracking or fracturing that results can destroy a solar panel; it could even compromise an entire array of solar panels.
“The most popular solar module configuration is three strings of 20 solar cells,” Kernahan explained. “When you partially shade one cell, the other 19 can power it [the shaded cell],” but the heat has to be dissipated.
Solar PV modules have so-called bypass diodes built-in to limit the amount of reverse bias of the solar cell and its silicon substrate to “only” 20-times the forward voltage in order to attempt to limit hotspot formation to “only” 200 degrees C if there is no breakdown. “If everything works exactly right and the cells don’t break down, they just dissipate the power from the other cells,” according to Kernahan.
Occasionally, the bypass diodes themselves fail, however. “If they break down before the bypass diodes can act, the temperature can reach as high as 1350 degrees Celsius and burn right through the module. This is referred to as pinholes or wormholes,” he explained.
“They’re relatively small, millimeter-sized holes that extend right through the module. The solar panel quickly fails; you look to see why and you find the holes. As a result of the intense heat, the front-side glass cracks, water gets in and destroys the panel.”
Significantly, “this can only happen from reverse-bias,” he continued. “If you had some electronics between the inverter and the solar cells, you could prevent this problem, and that’s what we have done.”
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On to page 3: Technological Innovation #2 & Locally Grown Power