Environment & Energy
In reply to the discussion: This is the state of politics in our country [View all]Fumesucker
(45,851 posts)I'm sorry that my personal experience matches SDG&E "talking points" but I have witnessed batteries catching on fire with my own eyes and I have cleaned up the damage to my personal property from fires caused by malfunctioning electronics combined with quite small batteries.
Going total solar implies some form of storage for those hours when the sun is not shining, it's unavoidable.
Another major problem with battery storage is that batteries all have a distinctly finite lifespan, both in terms of usage and just time in service, they start degrading as soon as they are manufactured and using them only accelerates the degradation process.
Flywheel motor/generators running in vacuum are one possible storage option that has a near infinite service life but research in that area seems to be lacking although Porsche has a successful hybrid race car out that uses electric flywheel energy storage.
http://www.popularmechanics.com/cars/alternative-fuel/hybrids/porsche-911-gt3r-hybrid-flywheel
At full speed the 16-inch diameter flywheel has a capacity of 0.2 kilowatt-hours, which pales in comparison to the 1.7 kwh available from the battery in the Cayenne hybrid. But the flywheel can release 163 horsepower for up to six seconds of boostone of the performance characteristics that make it more like an ultracapacitor than a flywheel. An ultracapacitor with equivalent oomph would be substantially heavier: the flywheel and its support structure weigh in at 103 pounds. The whole mechanism is mounted in a carbon fiber box where the passenger seat would normally be in the 911.
Under the extreme power charge/discharge cycles of racing, even a lithium ion battery would face durability issues. Kristen estimates that a battery would have to be replaced three times during a race like the 24 Hours of Nurburgring, where the 911 nearly won in May 2010, after leading for over eight hours. The best current lithium ion batteries will last for a claimed 20,000-plus charge cycles, and hybrid batteries are typically only partially charged and discharged, which maximizes their life-span. Kristen claims the flywheel will last over one million cycles.
In its current form, the 911 hybrid is about 230 pounds heavier than the 911 GT3 RSRs run by the Flying Lizards team in the American Le Mans Series GT class. At its Nurburgring debut, the hybrid didn't have the outright speed of the conventional 911s, but it spent more of its time on the track thanks to its ability to achieve 25 percent better fuel efficiency. The use of so much regenerative braking, thanks to the flywheel's ability to absorb power quickly, also reduced brake wear. The brake pads on the hybrid only had to be changed once in the 24-hour race, compared to 2-3 changes for the regular version. The hybrid's on-demand all-wheel-drive should also give it a handling advantage in wet conditions.
