● PV proponents note that if you hook enough PV together over a large enough area, the intermittence issue goes away since it’s u sually sunny somewhere. The problem there lies in the cost of creating new continent-spanning two-way energy-transmission systems, as the current infrastructure is mostly one-way. ● The extreme version of this would be to have PV located around the world in sunny spots, all tied together with two-way high-voltage power lines, so the sun would always be shining somewhere and a person in Wisconsin could get their solar power from Egypt in real time. Cool. However, this would be VERY costly in complexity and energy (and money, of course), would involve the world’s power being concentrated in relatively long and vulnerable cable systems, and would require degrees of international cooperation and stability not easy to achieve. (The even-more-extreme version of th is is “Solar in Space,” in which huge power stations would collect solar energy and beam it to earth via microwaves. This is flat-out unaffordable and impractical, as noted elsewhere.) ● Current PV technology lasts roughly 20 years before it must be replaced, although this is slowly improving. Its inverters (devices converting DC to usable AC power) must generally be replaced more often, as it is controlling circuitry, batteries, and other support infrastructure. None of that is “renewable” per se; it requir es energy and materials to build from scratch, though some degree of recycling would be possible for a few parts, like the aluminum framing and lead in batteries. ● PV can exist quite well on rooftops, but existing grids are not made to accommodate a signi ficant percent of PV due to solar’s inherent intermittence and “night.” The higher percent of PV in a system, the more complex and expensive it becomes, if baseload is to be maintained. Many utilities get a lot of grief from people not understanding that they are simultaneously demanding two entirely different things: 100% solar energy and reliable baseload.
● The embodied energy of the entire SYSTEM associated with PV has quite a carbon footprint these days, and PV won’t work without those other system par ts. That’s one reason the EROEI number varies so
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