99% of the worlds grid storage is pumped hydro because nothing else works out. Pumped storage is 70% to 85% efficient, can come online within 15 seconds, and works at scale.
The reservoir can provide about 13 GW·h of stored gravitational potential energy (convertible to electricity at about 80% efficiency), or about 2% of China's daily electricity consumption. https://en.wikipedia.org/wiki/Tianhuangping_Pumped_Storage_P...
Construction cost: $900 million USD maintenance costs are also minimal.
PS: ~14 GWh for 1 billion ~= 14 MWh for 1 million = ~14 kwh for 1000$. http://www.teslamotors.com/powerwall = 7 kWh for 3k or 2.3kwh per 1,000$ and much shorter lifetime.
The problem is that we have very limited amount of natural reservoirs. Practically every natural reservoir out there already has power plant, is on a desert or belongs to natural reserve.
With tesla solution the problem is going to be limited amount of lithium. There is maybe enough lithium to get a powerwall to every household in U.S. and EU. But rest of the world is fucked.
Granted, this would be a significant retrofit, but it's significantly cheaper than starting from scratch. And, assuming the net daily change is ~0 it's not going you don't lose existing power generation capacity or add significant environmental impact.
Also, you don't need very many. China can shift ~2% of it's daily power needs with just one location. Get into the 10-15% range and your done.
You can run the numbers for thermal storage. It's not fantastic. Probably a 60-70% return on input + plus waste heat. However thermal storage are very compact. Rough estimate I get; 100MW for 10 hours with a 2.5 acre footprint. One also gets about 40MW of waste heat which could be used for commercial or industrial heating.
Currently though, complaining about storage has a cart before the horse aspect. Since for the immediate future photo voltaic plants are competing with gas fired peaking plants not nuclear or coal fired base load plants. (If you ever wonder why the Koch brothers really don't like Solar plants it's because solar cuts into the market for natural gas)
Don't forget Li your down capacity after just 3 years and you might get 15 years total. Pumped storage is good for 50 years before a refit and the reservoir is probably good hundreds if not thousands of years.
That dam failed when 1 year's worth of rain fell over 24 hours if it had not been there a lot of people would have died anyway.
On net Dams have saved far more than 170,000 lives in china alone. Flood control is more or less a necessity in the modern world adding energy generation on top of that is a minimal risk. ex: From 1998 https://en.wikipedia.org/wiki/1998_China_floods loss of 4150 people, and 180 million people were affected.
PS: Direct deaths where ~26,000 people. The 145,000 died during subsequent epidemics and famine which where blamed on the dam, but that was a convenient excuse and far from the root cause.
Yes, poor word choice. I was comparing 26,000 from a failure in 1975 to 4,150 in 1998 even with lot's of flood control.
Even with lot's of flood control floods still kill some people. But, dams prevent many floods, reduce severity, and generally give significant warning time when there not going to be enough. So, most deaths are from small rivers that feed major ones instead of major rivers overflowing.
The reservoir can provide about 13 GW·h of stored gravitational potential energy (convertible to electricity at about 80% efficiency), or about 2% of China's daily electricity consumption. https://en.wikipedia.org/wiki/Tianhuangping_Pumped_Storage_P...
Construction cost: $900 million USD maintenance costs are also minimal.
PS: ~14 GWh for 1 billion ~= 14 MWh for 1 million = ~14 kwh for 1000$. http://www.teslamotors.com/powerwall = 7 kWh for 3k or 2.3kwh per 1,000$ and much shorter lifetime.