Over the last 5 years, the price of new wind power in the US has dropped 58% and the price of new solar power has dropped 78%. Utility-scale solar in the West and Southwest is now at times cheaper than new natural gas plants. Even after removing the federal solar Investment Tax Credit of 30%, a recent New Mexico solar deal is priced at 6 cents / kwh. By contrast, new natural gas electricity plants have costs between 6.4 to 9 cents per kwh, according to the EIA.
(Score: 5, Informative) by deimtee on Monday May 25 2015, @05:47AM
Just as an aside, there is an important reason why homes are wired with AC instead of DC. To get usable power with reasonable wiring you need minimum 100 volts.
If you break a contact on a circuit drawing several amps at >100 volts DC there is a pretty good chance you will get a sustained arc. This is dangerous.
AC arcs are self extinguishing as soon as the voltage crosses zero.
Yes, you can use anti-arcing switches but that still means that when a wire breaks, instead of a circuit going dead, you burn down the house.
200 million years is actually quite a long time.
(Score: 2) by kaszz on Tuesday May 26 2015, @12:43AM
Yes, arcing etc is an issue. And low voltage makes it necessary to compensate with current. The issue is that once the hard dependence on the grid is cut. How power is distributed inside households may very well change. The other issue I really had in mind was that it's a lot simpler to design a good DC/DC converter than DC/AC etc. Issues like efficiency, active/reactive/complex/apparent, phase of volt vs current, THD, EMI etc all make generating AC at high power with semiconductors tricky and usually expensive. As for voltage, circa 100 V permits the use of pretty standard power semiconductors.
(Score: 2) by deimtee on Tuesday May 26 2015, @04:17AM
It's not just the fixed wiring and the pristine new installations with anti-arc switches.
Power leads and extension cords are often flexed until they go dead. If they go dead while operating, your house burns down.
Radiators and other resistive loads don't care whether it is AC or DC. If you have DC at the same voltage as AC you are going to get semi-knowledgeable idiots converting them over. In most cases it will be as simple as swapping a plug. They will even work for a while until they burn the house down.
In theory it could work. In practice high voltage DC in an average home environment is a bad idea. It will burn the house down.
200 million years is actually quite a long time.