4 ms·
The issue is not power electronics, but power supply. You might have a 60 Amps grid supply, or even a 100Amps split phase 120/240V as is typical for newer US ho
by yholio 6y ago
The issue is not power electronics, but power supply. You might have a 60 Amps grid supply, or even a 100Amps split phase 120/240V as is typical for newer US homes, which allows drawing 24KW from the grid at full power. Your neighbor might have the same.
But that doesn't mean everybody in your neighborhood can draw 24KW all night long. Those are maximal currents for intermittent loads like heaters, clothes driers etc. You might have a single 100KVA polemount transformer suppling a whole street and a single 15KV / 300Amp line servicing a whole neighborhood.
When everybody attempts to draw even 5-10KW in the air-conditioning season, you get circuit breaks because the main feed is incapable of supplying sufficient power. The upgrading will be done but it will take a decade or more, especially considering the push from local municipalities towards buried power feeds which are very expensive.
- adrianN 6y agoElectric cars consume about 20kWh/100km. If your whole neighborhood needs to draw double digit kilowatts for 10h a night, you live in a neighborhood of long distance truck drivers.
- im3w1l 6y agoMaybe it doesn't happen every night, but only some nights. Say when everyone comes home from thanksgiving with empty batteries.
- adrianN 6y agoIf everyone wants to fill up their tank at once, the gas stations run out of gas. This doesn't happen with any regularity, which I take as an indicator that the scenario you're describing is very rare.
- im3w1l 6y agoThe gas system has buffering and slack at many levels. Cars store more mileage. Gas stations have a buffer. Gas stations can request more trucks come refill much easier than a grid can be upgraded. I don't think you proved anything.
- adrianN 6y agoAnd yet runs on gas stations happen during crisis times and they do in fact run out of gas.
- yholio 6y agoPrecisely, even with that significant slack, it still happens. How frequent will be the overloads in a system with no energy storage capacity, which is sized to handle the existing load peaks and already has infrequent overloads? The average commute in the US is 50 Km per day and if that is the average it is reasonable to assume some communities will be highly correlated above average, for example if they are 40-50 Km away from a large economic hub, a large proportion of residents will drive the 100Km roundtrip per working day. The lower price of electric comute will prompt many residences to have two electric cars driving the average every working day, for a total, again, of 100Km = 20KWh. So double digit is not exceptional, it will be the average, an extra 3KW of power for each household for the entire night, assuming an outstandingly smart grid that can perfectly level off demand. Combine that with rare events like hot nights and large movements, psychological reactions like panic, and you have an unreliable local supply that might trip every few months without expensive upgrades.
- Reason077 6y agoGenerally speaking, you don't need massive upgrades of local grid infrastructure to support electric vehicles. There is plenty of capacity available, provided charging is spread out over the night and not concentrated at peak demand periods. You just need chargers that are smart enough to ensure this happens.