OrionWorks wrote:
But then, I wonder if it might still be better than the reported 60%
loss through transmission lines just to get the electricity from the
average power plant to my wall socket.
It is nowhere near as large as that. In 1990 PG&E estimated 8% losses
for 500 miles. Other estimates for T&D (transmission and
distribution) are around 5%. See:
http://lenr-canr.org/acrobat/NRELenergyover.pdf
Of course, this is assuming strategic deployment of these Double
Decker sized sodium sulfur batteries will eventually enable shorter
transmission line distances.
How can they do that?!? Distances are not changed. The batteries do
not bring the customer any closer to the generation plant. The peak
capacity of transmission lines is reduced, reducing the size of the lines.
This would make wind turbines more viable, but wind turbines are not
close to most customers. I do not think they reduce T&D costs.
OTOH, looking at the PHEV angle where you would have to plug in 1000
hybrid cars to match the power of one of a single Double Decker sized
sodium sulfur battery sounds more like a feel-good publicity stunt.
1000 cars would be something of a stunt. 100 million cars would
probably be enough to buffer the entire U.S. power system with 50%
intermittent wind or daylight only solar generation. (Present systems
can work with ~20% wind.) It would not solve the problem of supplying
electricity to places without wind or solar resources, but HTSC power
lines would.
Note that there are 240 million registered cars in the U.S.
The estimate in this article comes to 7 kWH storage per car, which is
in line with the EV and PHEV literature. 100 million cars = 100,000
MW buffer for 7 hours per day, very roughly 1/8 of the U.S. capacity.
I think you need peak power buffering for about 4 hours per day, even
with wind. The only problem would be making sure most cars were
plugged in at around 3 p.m. on a summer afternoon. It is likely they
would be, since this is not rush hour.
Places like EPRI apparently take this concept seriously. Here is an
interesting table from U. Delaware:
www.mast.udel.edu/628/Lect10b-wk-V2G.pdf
"How Much Power?
Column headings: Australia, UK, USA
Electric Capacity (GW): 45, 80, 811
Light vehicles (10E6): 13, 22, 176
Vehicle GW (if electric drive @ 15 kW each): 195, 330, 2,640
... 4x more power in cars [than electric generating systems]"
Remember that's power, not net energy output. Cars do not run most
hours of the day.
- Jed
