Alternatives to TBE buffer for denaturing polyacrylamide gel electrophoresis of DNA and RNA?
You can try SB (sodium boric acid), LA (lithum acetate) or LB (lithium boric acid) buffers. Thex generate must less heat then TAE or TBE buffers and can be run on much higher voltages and are much cheaper than TAE or TBE. Also they do not interfere with standard applications such as band excision and they last longer.

For more info try this sites:

http://www.fasterbettermedia.com/products.html
http://ddgehelp.blogspot.com/2008/01/alternative-electrophoresis-buffer-to.html