Can direct current data center power systems get real-world enough to become a realistic way to curb energy waste? Swiss power gear giant ABB is giving it a try, announcing Thursday that it’s taking an ownership stake in U.S. startup Validus DC Systems, one of the new entrants in the world of using direct current in buildings. While the companies didn’t disclose the value of the transaction, I’ve been told it was a $22 million stake, which would give ABB a majority ownership as compared to the $14 million in equity the Brookfield, Conn.-based company has raised to date. Validus makes power conversion and distribution modules that take AC grid power and step it down into DC at different voltage levels for distribution to the servers and other IT equipment that use DC anyway. Saving on the multiple AC-to-DC, and back again, conversions can save on both power lost in the process and for the cooling needed to manage that power lost in the form of heat. Of course, they also require a major rethinking of the way power delivery and management is built into data center designs. Other companies, such as Google-backed Transphorm, are tackling the efficiency losses associated with AC-to-DC conversion via their high-efficiency gallium nitride power conversion systems. Building technology that matches today’s way of doing things with AC power might be an easier bet — though nothing about electricity is set in stone.