About a year ago, I came across some startling information concerning the nuclear power industry. It seems that in the early 1950s, President Eisenhower (being a “likable” war-hero) made a fatefully historic decision. As a part of his “Atoms for Peace” program, he chose to use Uranium instead of Thorium as the fuel for nuclear reactors. The main rationale was that a byproduct of the Uranium reaction was Plutonium, which was deemed of strategic value to the U.S. defense industry in an increasingly hostile world. Of course, at the time, no mention was made (or did anyone really know?) of the side-effects of his decision. As it turns out, even though Thorium is more plentiful, Thorium fission produces no long-lived fissionable atoms like Plutonium. Additionally the products of thorium fission are less radioactive and less toxic than those of the Uranium fuel cycle. Wouldn’tFukushimaandThree Mile Islandhave looked different if we had been using Thorium? I think those two events would have ranked high on the ho-hum scale and we would be powering our cars on small Thorium-based nuclear batteries by now.
More recently, I tripped over a startling article in Wikipedia. According to the article, Thomas Edison and George Westinghouse were waging a “War of Currents” in the 1880s. The deal was that Edison had invented a direct current (DC) transmission system that would deliver electricity for up to 2.4 km from the point of generation. His system included other inventions such as huge battery banks that gave the system a built in uninterruptible power supply (UPS) capability that could ride through any “normal” (is there such a thing?) power outages. During that era, and even today, items such as subways, railroads, elevators, fans, pumps and even cars ran on DC.
Westinghouse countered Edison by showing that alternating current, (AC), a technology created by Nikola Tesla, could be transmitted over vastly greater distances with much less energy loss. Furthermore, if one needed to utilize DC in an application, an AC motor shaft (a system called a motor-generator set) could be connected to that of a DC generator to satisfy the demand. Always the great inventor, Edison fought back by inventing the “electric chair” to portray AC’s greater lethality as a smear tactic. Then, to advertise his point, he went around the country “executing” animals including, in one case, an elephant that had been convicted of homicide. I guess we know who won the war, but maybe we all lost because high voltage direct current (HVDC) transmission was belatedly perfected in 1950.
Today we are dealing with an energy system that requires conversion of voltages, often from AC to DC several times before it reaches us or our appliances (think digital). The real downside is that each energy conversion is accompanied by an energy loss. In these days of increasingly more costly energy, losses are something to be avoided at all costs. With that in mind, let’s look at our typical data center (or, in most cases, our “computer rooms”). Typically, electricity is supplied by the local power utility as AC, but since we want to have uninterrupted computations it is converted to DC for storage batteries. Then, once the power goes out for some unforeseen reason, the batteries’ DC is converted by an “inverter” into AC to be transmitted to our server(s). But, guess what? Our server’s electronics are run on DC! Therefore, it’s obvious that AC must be converted back to DC one more time before it gets used. I think you can see that there is a lot of inherent loss in this system. (I may have lost count of how many conversions were made, which should excuse the fact that I may have missed some). For this reason, some major data centers are currently examining the possibility of running their whole operation on DC alone (that is, once the outside AC power has been converted). As novel as that may sound, this system has been in place in laptops, notebook and tablet PCs for some time now.
Yes, things would have been different had several decisions been different. We would have had more that 50 percent of our power generation from nuclear, more “fuel” efficient transportation and lower energy bills instead of the threat of nuclear terrorism, radioactive pollution and excessive carbon emissions. Similar technological decisions can have far reaching effects; therefore it is wise to seek the council of the trained sales and engineering professionals employed by SOVRAN.
Written by: Harley Stauffer, Systems Engineer