Slashdot Mirror
The Myth of Going Off the Power Grid
Lasrick writes: Dawn Stover uses Elon Musk's announcement that Tesla will soon be unveiling plans for a battery that could power your home as a starting point to explore the idea that "going off the grid" is going to solve climate change. "The kind of in-house energy storage he is proposing could help make renewables a bigger part of the global supply. But headlines announcing that a Tesla battery 'could take your home off the grid' spread misconceptions about what it takes to be self-sufficient — and stop global warming." Stover worries that shifting responsibility for solutions to climate change from governments to individuals creates an 'every-man-for-himself' culture that actually works against energy solutions and does little to reduce overall greenhouse gas emissions. Instead, "smart grid" technology would be much more efficient: "With a smarter grid, excess electricity generated by solar panels and wind turbines could be distributed to a network of on-the-grid home and car batteries. Some utilities have also experimented with using home water heaters as an economical substitute for batteries."
The problem is that many utilities pay far less per kWh than they charge you. As a result, you're generating most of your power when you don't need it (during the day when you're at work), getting almost nothing for it, and then you're consuming most of your power when you're not generating it, paying full price for it.
The result? You end up saving very little.
It starts to make sense to have batteries to let you use the power you generated, giving you a much greater return. The only issue here is the cost of the batteries... which Tesla is trying to drive down as much as they can.
Vastly more efficient than battery, I'll grant, but let's try to stay accurate.
Modern Li-ion batteries have a round-trip efficiency of about 85%. Grid transmission has losses of about 7% from the power station to you, but will likely be higher if it is peer-to-peer. They are actually in the same ballpark.
But TFA is just stupid. The tiny handful of first-world survivalist kooks trying to go off the grid are not what is causing global warming. The massive expansion of coal burning in India is a somewhat bigger problem, by many orders of magnitude. Maybe we should focus on that instead. Solar-to-battery would be a good solution to many Indian and African villages that are not on the grid at all.
You're only proving my point, Coward. Why should I pay out of my own pocket to generate solar, and then pay the utility some more the utility to take my excess energy?
If I can't make my own home efficient enough to stand on it's own, I'm not spending the money. If the local power company wants solar, they can do it on their dime, I'll stick to my utility fees, TYVM.
If a neighborhood/city decided to invest in it's own smart grid, and treat every electricity source on equal-footing, that'd be interesting. If I can generate more power than I'm using, and the electric co *doesn't* own the distribution ...it's a free(er) market.
I'm sure anyone who tried that would probably be lobbied away, probably by someone like you.
Why can't all fpga/microcontroller manufacturers just release free optimizing compilers???
What I was trying to show is that in order to solve an engineering problem you have to have sound engineering principles. If you're talking about energy you use words like "watt" and numbers like Kilowatt Hours and maybe even joules and other terms that the author is probably unfamiliar with.
For example, If I equip my home with 5,000 watts (peak) solar panels that generate 35 kwh of energy. 15 kwh which I use immediately that leaves 20 kwh excess which I can store. If my storage system is 75% efficient I can then use another 15 kwh at night which will make me capable of being off grid. What's wrong with that?
The "grid" doesn't store energy, it delivers it -- and nowhere near 100% efficiency either. Power is generated "on demand". While there are spots around the country/globe where utilities experiment with storing excess production -- flywheels, exotic batteries, thermal wells, etc., it is a very rare exception.