Is two phase electric power possible?

Yes, it is possible and was in common use during the early 20th century. In a two phase system the phases are 90 degrees apart. It is important to note the difference between the 3 wire single phase common in North American homes and true two phase power. As far as I know, there are few, if any two phase systems still in use.

See

http://en.wikipedia.org/wiki/Two-phase_electric_power

for more information.