To manage the impact of the growing popularity of digital electronics, the California Public Utilities Commission and smart-grid researchers are assessing strategies to increase their efficiency. Electronics represent about 15 percent of electricity demand and their use is growing by up to 4 percent a year, Richard Brown, Lawrence Berkeley National Laboratory scientist, told the CPUC at a May 14 meeting on energy efficiency. Electricity demand at so-called data centers - banks of computer servers that hold content for Internet sites and other on-line data banks - is expected to double in the next five years, said Brown. The problem is that digital devices need direct current, not the alternating current that traditional analog stereos, televisions, and radios have required. To use alternating current from the grid, digital devices must have rectifiers. These devices convert the fluctuating AC current to a steady DC current. However, as Richard Karn points out in an article entitled "Electrifying Change" in the May 9 edition of the Emerging Trends Report, the rectifiers convert about half the AC current that flows into them into waste heat, which requires ventilation. The resulting energy use - particularly at the nation's five largest Internet search engine companies, which use an estimated 2 million computer servers - is inefficient. One approach to increasing the efficiency of digital devices is to make more efficient rectifiers and devices. Another tack, however, is to deliver high-quality digital-grade power, according to Karn. This will mean creating a "smart grid" that employs extensive monitoring and control systems that smooth fluctuations and increase the reliability of the existing alternating current. Variations in AC current increase energy waste in digital equipment. Utilities such as Southern California Edison are working on installing controls (Circuit, May 11, 2007). Continued smart-grid investment will be increasingly crucial to meeting energy-efficiency goals because the power demand of digital devices is expected to grow from about 10 percent of the electricity consumed today to between 30 and 50 percent by 2020, according to Karn.