Solar Builder

SEP-OCT 2018

Solar Builder focuses on the installation/construction of solar PV systems. We cover the latest PV technology (modules, mounting, inverters, storage, BOS) and equip installers/contractors with tips and tools to make informed purchasing decisions.

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SOLARBUILDERMAG.COM | 9 Path of disruption Starting in 1995, lithium-ion battery costs dropped 14 percent per year for 15 years. From 2010 to 2014, they started dropping 16 percent per year. From 2014 to now? 20 percent drop per year. There is every reason to believe this will continue to accelerate because the build out of Li-ion manufacturing capacity has increased by more than 6x in the last three years alone. "By 2020, the average American household could have one full day of storage for $1 a day," Seba says. "But you don't need a full day of storage, you just need 4 hours. This will cost $6 per month." Right now solar is still only 2 percent of the generation mix, so how could it get to 100 percent ever? Solar has come down in cost 11.5 percent per year since 1970 (300x). Every other generating source has gone up in price 6x to 16x from 1970. Since 1990, the market has grown 40 percent per year and doubled every two years. So, extend the trendline (doubling every two years) and you get to more than 100 percent in 12 years. "Solar right now is cheaper than what we buy from the utility in 80 percent of the world," Seba says. GOD parity Adding the storage story to the solar story and you hit what Seba has coined GOD parity, or generation on demand, and the money quote: "At some point soon rooftop solar + batteries will be cheaper than the cost of transmission," Seba said. "So even if the utilities generate at zero, when you add cost of transmission, it will still be more expensive than unsubsidized solar + storage. At that point it's in everyone's best economic self-interest to add solar + storage." Seba notes this is already happening. In Australia, solar is 7 cents, transmis- sion is 12 cents, and residential solar is 25 percent of the market in Australia. By 2021, Seba says it will be similar in all large markets. Large sources of generation will still be needed, but Seba notes solar is already at 1.8 cents per kWh in places around the world, unsubsidized, today. Here in the U.S., Tucson Electric just signed a solar + storage PPA at 4.5 cents per kWh (100 MW solar, 30 MW / 120 MWh battery storage system). Seba showed an example of an Xcel Energy RFP for wind + storage + solar that had a median result of 3 cents per kWh, with another company reporting an offer of 2 cents per kWh. "There is no excuse to build a new coal plant, gas plant or nuke. None," he concluded. "This is not just cheaper than any other form of energy, this is cheaper than the cost to operate any other source of energy." Insert mic drop sound here. Chris Crowell is the managing editor of Solar Builder. At some point soon rooftop solar + batteries will be cheaper than the cost of transmission. "

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