Educate yourself before you doubt.
High-efficiency plasma lighting is the class of plasma lamps that have system efficiencies of 90 lumens per watt or more. Lamps in this class are potentially the most energy-efficient light source for outdoor, commercial and industrial lighting. This is due not only to their high system efficiency but also to the small light source they present enabling very high luminaire efficiency.
Luminaire Efficacy Rating (LER) is the single figure of merit the National Electrical Manufacturers Association has defined to help address problems with lighting manufacturers' efficiency claims [5] and is designed to allow robust comparison between lighting types. It is given by the product of luminaire efficiency (EFF) times total rated lamp output in lumens (TLL) times ballast factor (BF), divided by the input power in watts (IP):
LER = EFF × TLL × BF / IP
The "system efficiency" for a High Efficiency Plasma lamp is given by the last three variables, that is, it excludes the luminaire efficiency. Though plasma lamps do not have a ballast, they have an RF power supply that fulfills the equivalent function. In electrodeless lamps, the inclusion of the electrical losses, or "ballast factor", in lumens per watt claimed can be particularly significant as conversion of electrical power to radio frequency (RF) power can be a highly inefficient process.
Many modern plasma lamps, such as those manufactured by Ceravision and Luxim, have very small light sources—far smaller than HID bulbs or fluorescent tubes—leading to much higher luminaire efficiencies also. High intensity discharge lamps have typical luminaire efficiencies of 55%, and fluorescent lamps of 70%. Plasma lamps typically have luminaire efficiencies exceeding 90%.
Source:
http://en.wikipedia.org/wiki/Plasma_lamp
Also included in the list of the Nikola Tesla's many inventions may be found a variety of novel electric lamps, all of which were designed to operate in conjunction with specially designed high frequency power supply units. Some of these lamps were the forerunners of our present day fluorescent tubes.* In fact, not long ago a small Californian company announced the development of a high frequency electronically powered fluorescent bulb, dubbed the E-Lamp, which bears a striking resemblance to a bulb that Tesla designed and built nearly one hundred years ago.* The principal upon which they both work is identical.* Another type of lamp was essentially the same as the slender neon filled tubes that are now commonly bent into the shapes of letters and used in storefront advertising.* A third type of electric lamp that Tesla designed, known as the incandescent carbon button lamp, was capable of producing light at high levels of efficiency.* A variation on the design of this lamp is embodied in the popular Plasma Globe novelty item.* Another lamp that he patented in 1891 under the name "Electric Incandescent Lamp" has recently been adopted by the United States Armed Forces as part of a portable high intensity lighting system.* The lamp itself consists of a spark gap enclosed within a small gas filled glass bulb.
Source:
http://www.teslascience.org/pages/tesla.htm#lamp
