Redox and other unique battery solutions

[fastline]

We are working on some design ideas to hopefully eventually get our shop and home off the grid with independent power. We are in one of the best locations for wind generation but energy storage becomes an issue and a grid tie system is simply impractical and will not obtain our goals.

the largest obstacle here is the energy storage solutions. We have looked at many solutions but all seem to drive us back towards batteries. We have a facility and the electrical experience to build the systems but some things you just cannot cheat on. for instance, we were considering making our own lead acid battery bank but even doing that, we are limited to either melting our own Lead and machining the plates or buy bulk plate and machining from that. In any case, the system we would need would weight about 50k lbs and cost double that.

I guess we are looking for thoughts and ideas regarding mass energy storage. Size and energy density is NOT an issue, only actual retained energy. We will likely work with some systems to directly use the power as it comes in so we are not left storing as much but will still ultimately have to design for an entire week of no power in an industrial type shop building which needs a decent level of power.

 

[Drakkith]

Honestly, I would vastly scale back your battery power and simply invest in some emergency generators or something. I know it doesn't exactly fit your goal, but it is so much easier and cheaper than manufacturing or buying huge amounts of batteries.

Here is a list of common energy densities of fuels and storage methods: http://en.wikipedia.org/wiki/Energy_density
That might help you determine the size/weight of whatever you need. (Even though you said it wasn't an issue, trust me, it will be)
Also you can look here for different methods of storage: http://en.wikipedia.org/wiki/Energy_storage

Have you looked into things such as large flywheels? Use the power generated to spin it up, and when you need the power back you just take it out of the flywheel.

I suppose you could also use hydrogen generated by electrolysis, however it is VERY VERY dangerous unless used 100% correctly and safely.

 

[fastline]

here is a short list of options we have considered.

Ethanol production from the heat energy from wind
Hydrogen production from the electric through electrolysis
Direct battery storage
Hydro pumping (not practical in flat ground)
Bio diesel


lots of options but the battery just makes the most sense. The problem is the wind does not blow every day. Running a gas generator at 40% eff even for 1 day/month would totally offset any savings. The shop will maintain a grid connection for alt power but the home will not and the more energy storage we have, the better chance we have of staying off the grid.

From what I gather, power companies buy back power at less than 10% of what they charge so that is a sweet deal for them, not so much for me. I would rather use the extra power to run well pumps or other creative ways to use it.

is the Redox batt not anything close to a DIY project? I noticed a guy building them on ebay in China so I am on a guess that it is doable. I know lead acid is within our reach but they require very careful charge/discharge rates, ambient temps, and have a very limited life. i don't mind setting up our shop for a production run of parts to build batteries if it will be worth while.

 

[Drakkith]

Yeah, I looked into grid tie systems for my house and was going to sell excess back, but when I read the agreement online it turns out that they have fees and such fcosting at least 75% of what I would have made otherwise, and that is during summer with the highest production amount. The other seasons I would still be paying them lol.

I can't really help you on the details of your system, as I do not know enough about them. Just crunch the numbers and see what you need compared with the size and cost of producing the required amount of batteries.