Can we light our cities with PV?

January 2nd, 2012

ThinkTech Hawaii

Can we light our cities with PV, or is that just Myth Number Three. (Myth Number One is that every island can go on its own, and Myth Number Two is that renewables cost less.) Today let’s talk Three.

Everybody loves PV, but PV needs daylight and can’t light our cities at night. Even if every one of us got PV we’d still need firm power to light out cities. You can sell all the PV you want to the utility, but overnight storage systems have not yet come of age and it’s of no use to them after dark.

Sure there are more PV jobs out there these days and they’re doing more work. It’s a great business to be in, although margins are thinner with all the new entries. Assuming the tax credits stay in place and the PUC finishes the job on on-bill financing, we’ll be pushing new PV records again in 2012.

Although homeowners and PV installers will consider it good times, what about the long-term effects? The utility can accept and pay for only so much daytime PV. There’s got to be a breaking point when additional PV is of no use to either the homeowner or the utility.

You can cut the cord, forget about 5-0 and get more sleep, or you can pay the minimum connection charge to the utility with a view to giving them power during the daytime and taking power from them at night in hopes of coming out even. But given the rise in PV, this will not be sustainable.

Whatever happens, the utility has to maintain its generator and distribution infrastructure to keep the lights on at night. The PV basic connection ratepayers don’t pay for that, but the rest of us do. When everyone but you has PV, you’ll be the last man standing. Just imagine what your rates will be.

In the end, something has to change. The connection rate has to go up, the rate the utility pays you for PV power has to go down, and/or the price it charges PV customers for night time power has to go up, or maybe all three. It won’t be pretty, but it won’t be as ugly as laying it all on the last man standing.

Of course, it won’t go that far. Somewhere along the line, there will be some serious adjustment before we get to that point, right? So when you look forward, and plan your own rooftop, be sure to check your assumptions on how these things will work when the whole world finds out it’s in love.

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One Response to “Can we light our cities with PV?”

  1. zzzzzz:

    Sopogy's technology ( could help here. Because their products don't directly convert light to electricity, there's a delay that naturally pushes some of their electricity generation into the peak use hours of early evening, and their technology has the possibility of storing thermal energy for later conversion to electricity.

    Wind power has a complementary issue--peak wind generation is overnight, when demand is at its lowest.

    Clearly, there's also a need to move at least some of our electricity consumption from demand-based to availability-based. Ice storage AC is one step in that direction. Widespread use of plug-in electric vehicles, along with a smarter grid that can deliver power to their batteries based on availability, would also be a huge step in making both PV and wind more viable for a larger percentage of our electricity production.

    In the meantime, time of day metering could push us to smooth out our demand, and match our electricity use better to its availability.

    One good thing about PV is that, apparently, many PV installers are pushing their customers to make sure they have solar water heaters before installing PV. Solar water heating has a much quicker payback (and might not be subject to myth #2) and also has inherent energy storage that helps HECO smooth out its demand.