Sunday 6 May 2012

The Historical cycle of the AC/DC Battle



How history repeats itself with no one being the wiser.

Back in the beginning, line losses resulting from low voltage Direct Current (DC) generation being transmitted over long distances and disinterest in building distributed generation infrastructure resulted in the development of the infrastructure we have today i.e., the Alternating Current (AC) electricity grid.  Without going into technical detail, AC is what comes out of the plugs in buildings, while DC is what comes out of batteries, including your car battery.
Over a century later, many countries are pursuing the development of distributed generation infrastructure based on renewable fuel sources.  Some of these fuel sources e.g., solar energy through solar PV technology, produce DC.  For countries with an AC-based electrical grid and an AC dependent appliance infrastructure in place, this DC electricity needs to be convert to AC for introduction into the existing grid.

Unfortunately, most of our 'gadgets', including cell phones, PDAs, laptops, PCs, Monitors, LCDs, Printers, etc. operate on DC.  For those not well versed in AC/DC outside of the Rock band: Any device that has a power cord that includes a box-like device, is a DC device.  The heat you feel when you touch the box-like section is an indication of how inefficient AC to DC conversion actually is.  Heat = wasted electrical energy.

So now we are building locally-based, distributed generation stations that won't need to transmit electricity over great distances.  But, instead of line losses, we are now hampered by conversion losses since we are generating DC, converting it to AC, only to convert it back to DC.  I suggest that we consider separate, co-existing, AC on-grid and DC off-grid development.
Are we witnessing the rebirth of the DC era?  Perhaps losses incurred through DC/AC/DC conversion are equivalent to the line losses once feared if we had chosen a DC-based system?

But the bigger challenge probably lies in the fact that we all have numerous AC powered appliances and tools.  While fridges, stoves, and other appliances exist in the DC world for use by mobile home and boat dwellers, I have yet to hear about the mobile home version of acompound mitre saw.  But, then again, I haven't researched this yet ;)

And so the AC/DC battle wages on.