241–250 of 341 posts
I was pleasantly surprised to see prices quoted in £GBP - the Powerwall is available in the UK! But, we don't have enough sunlight here to run a typical house off-grid year-round, do we?
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Hm for that price I can install a natural-gas generator. Have power for days if necessary, full power on all circuits.
Which still ties you to the 'grid' insofar as you need the natgas supply chain, even if you have a huge reservoir you'll eventually run out. Having said that, batteries and solar panels don't have an unlimited life span either. I'm looking at buying a petrol powered generator for reasons other than home power generation, but it will be reassuring to know we have backup power at home, but I don't think I'm allowed to…
So even though I am rural, I don't have to buy liquid propane to heat my house. I'm tapped into a 100,000 home supply line. Its been depressurized maybe twice for maintenance in 50 years.
Not a solution for everybody. But a pretty good one for me! And everybody else on the line.
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If you use a laptop a ups can power your router and modem for quite a long time. Or you can buy a huge ups for a lot less than 3000 and power a desktop machine too.
What's the running cost of a huge ups?
A lot of people buy prebuilt sheds and if it only cost $x extra and you could start lowering your electric bill.
@elonmusk Just a thought. How about A prebuilt shed built with these shingles might make a good product. A lot of people buy prebuilt sheds and if it only cost $x extra and you could start lowering your electric bill.
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There is quite a bit of work being done on solar powered airconditioning. I experimented myself with this about 10 years ago using two back-to-back Stirling engines with the first powered by the sun and the second being run in reverse to cool a working fluid. It's an interesting field, you'll learn more about Carnot cycles and thermodynamics than you ever wanted to :)
A climatization using DC current from capacitors charged with solar panels might be more interesting in mild hot regions. If I understood well AC is optimized for carrying current on long distance with minimal loss. But most electric devices use DC. They need an AC to DC convertor with some energy loss. Solar panels produce DC and is usualy converted to AC with some loss. Then, in most electronic devices, this AC is…
Most devices which operate on DC (e.g. computers, TV) have a switching power supply, which is around 90% efficient. So for a computer drawing 100W, only about 10W is lost in the conversion of AC to DC.
Larger appliances such as microwaves, ovens, and air conditioners will use AC directly without conversion to DC (except maybe to power the control electronics).
> But most electric devices use DC.
Yes, but no national grids are DC. There is a lot of interest in using high voltage DC (HVDC) for long distance transmission (and wind farms), since you don't have to expend energy to generate and maintain the sine wave (and your collector field electronics are simpler), but the customer connection is always AC.
With the insane amount of money invested in delivery to homes as 110/220VAC, no one is going to start selling DC devices. Even in regions where this is no electricity and people use off-grid systems, the economies of scale mean that DC appliances such as refrigerators are often 200-400% more expensive than their AC counterparts.
A lot of research has been put into DC distribution, but the main issues are:
- Devices still require a DC/DC converter to step up or down the distribution voltage to their operating voltage. This converter is again not 100% efficient
- High voltage DC is deadly (your muscles will contract instead of releasing, so if you touch a cable you're dead)
- Low voltage DC requires thicker wires, meaning higher cost for distribution
Source: work for a utility company
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> The big difference is because of air conditioning and baseboard heating (...) Which makes you wonder why there is not as much high-profile attention on A/C (and to a lesser extent electrical heating) as being a problem worthy of rethinking by Silicon Valley (perhaps even ahead of solar, in North America).
It might be (it is) anecdotal, but as someone from Europe it struck me odd how much Americans love their A/C. Too much, in fact. Almost everywhere I went it was too cold. Somewhat like in SE Asia. That might be the answer to high energy use.
@elonmusk Just a thought. How about A prebuilt shed built with these shingles might make a good product. A lot of people buy prebuilt sheds and if it only cost $x extra and you could start lowering your electric bill.
You also need the inverter etc etc. So unless it was a big shed, maybe its not viable?
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You also need the inverter etc etc. So unless it was a big shed, maybe its not viable?
Good point. I'd imagine you could charge an electric car without an inverter. Perhaps it could be just for that purpose. Bury a line running to your garage.
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> The big difference is because of air conditioning and baseboard heating (...) Which makes you wonder why there is not as much high-profile attention on A/C (and to a lesser extent electrical heating) as being a problem worthy of rethinking by Silicon Valley (perhaps even ahead of solar, in North America).
It might be (it is) anecdotal, but as someone from Europe it struck me odd how much Americans love their A/C. Too much, in fact. Almost everywhere I went it was too cold. Somewhat like in SE Asia. That might be the answer to high energy use.