On Jan 9, 2015, at 8:29 AM, EVDL Administrator via EV <[email protected]> wrote:
> I'm no expert, but I suppose it might come to pass if PV efficiency jumps > and cost tumbles, PV efficiency is already plenty. The insolation on the average single-family home's roof at today's efficiency is virtually always some multiple, generally some very significant multiple, of the home's electricity use. And said multiple is again virtually always more than adequate to charge a vehicle. And materials are and for some time have been the cheapest component of a PV installation. What costs all the money is first and foremost the labor; qualified electricians aren't cheap, especially those who both have experience with high voltage DC and are competent roofers. And, many places, the legal paperwork -- all the permits and inspections and utility company writeoffs and what-not -- winds up costing more than the bill of materials. The key ingredients we really need are twofold: solar roofing installations that can take the place of and be installed by today's low-skill roofing laborers (perhaps with an electrician just for the final run from the roof to the breaker box) and less-expensive battery technology. The former exists in various prototypes that keep getting mentioned in press releases, and the latter is something well known to the EV crowd. > "Aargh, no clean underwear, and I can't do laundry because we're at 7% and I > still have to charge the car. I wonder if the car has enough charge left > for a trip to the store to buy some." That just means the system is under-sized. In such a case, either you should have spent more for a bigger system, or you knew what you were getting into and therefore budget your energy use accordingly. Low income households already face similar problems...do I pay the electric bill with the last $50 remaining on this credit card's limit, or do I use the money to buy groceries for the kids? > "Sorry, boss, I can't come in to work until this afternoon. Joe ran the > house flat with his welder last night, and I won't have enough juice to > charge my car until the sun comes up." If Joe's a contractor, he should be showing up with his own power supply (such as one of the many industrial EVs we've seen Bruce mention with their own power plugs) to run the welder in this future -- or, otherwise, first making sure that the site he's visiting has the spare capacity to power the welder. And if Joe lives in the home, it's his own damned fault. > Also, the cost of storage (lithium battery? what?) It's a big question today, but I suspect we'll have a clear winner in the next several years at the most. Nickel-iron batteries live longer than people but cost more than any other type of battery. Lead acids are pretty cheap but die after a few years and cost significantly more over a lifetime. But there may well be a market in EV batteries old enough to be less than optimal for vehicular use but still with plenty left in them for an off-grid system. I could see leasing / renting of battery systems becoming popular, with the company that owns the batteries responsible for ensuring a minimum kWh capacity of the pack in exchange for whatever fees they charge, similar to what we've speculated Tesla might offer with their car battery swaps. > would have to decline by, oh, I dunno, say, 90%? Nowhere near as much. In many parts of the country, the payback time for a complete off-grid solution is better than the payback time for money market funds and other financial instruments. That is, if you're invested in the stock market or especially your bank, you'll be wealthier at the end of a decade or three if you pull the money out and put it into an off-grid system. But that requires a significant amount (to most people) of available capital. But it also means that a business -- such as Solar City -- can afford to invest its own capital (or borrowed funds) to install such a system and become an ad-hoc utility and still make a marginal profit. That's with today's technology...and it's only getting better. > I have no idea whether such a quantum leap in PV and energy storage tech is > on the horizon. Absent one, though, I suspect your estimate of "ten to > twenty years" is probably a bit optimistic. But that's just it. It's doable _and_economical_ today, if you have the capital to invest. No more revolutionary breakthroughs are required to bring it to the masses; only gradual refinements of the types we regularly see and expect, perhaps coupled with some entrepreneurial innovation. Cheers, b& -------------- next part -------------- A non-text attachment was scrubbed... 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