The dc building power market is projected to grow significantly over the next several years, and among the driving forces is the need to improve efficiency and reduce electricity costs in several areas. According to the US Environmental Protection Agency (EPA), in 2006, data centres and servers in the United States accounted for approximately 1.5% of the nation’s total electricity consumption. To put this in perspective, the EPA stated that this total exceeded the electricity consumed by the entire nation’s colour televisions, and is similar to the amount of electricity consumed by approximately 5.8 million average TV households. In addition, energy consumption in data centres in the US is projected to continue to grow, and double every five years.
Traditionally, large data centres and telecommunications facilities have consumed large amounts of electricity without much regard for energy efficiency. Due to the continuous need for energy production, it has been an acceptable practice to trade off energy efficiency and operating costs for the sake of system reliability. However, in recent years a number of factors have emerged that may change that practice. Now, a debate is taking place on how to cope with the growing need for electricity to power these facilities. Data centre managers and other data centre professionals are looking to dc power as an alternative solution to traditional ac power. Proponents of dc power claim that it has the potential to eliminate the biggest sources of energy loss and waste in traditional ac systems: the multiple back and forth transformations and conditioning needed to step voltage down for use by IT equipment.
One of the pressing needs for the further expansion of dc power was the establishment of dc voltage standards. In light of this need, two new dc power distribution standards for facilities were developed over the past year, one for high-voltage (380Vdc) applications and another for low-voltage (24Vdc) applications. The development of theses standards is significant and is expected to contribute to the further expansion of dc power. The 380Vdc standard was developed by the Electric Power Research Institute (EPRI) along with Lawrence Berkeley National Laboratories and is designed for data centres and other critical facilities. EPRI has developed the first dc voltage tolerance envelope plotting voltage variations versus time for 380-Vdc powered equipment. The new dc voltage tolerance envelope provides the technical details of the electrical operating environment, including allowable voltage surges and sags that could enable engineers to design power converters for use with 380-Vdc distribution systems for next-generation data centre equipment.
The 24Vdc standard was developed by EMerge and is expected to play an important role in the expansion of dc power in commercial, industrial and residential buildings. The new EMerge Alliance standard is described as the first roadmap for the utilization of safe, low-voltage direct current power in commercial interiors. The EMerge Alliance Standard 1.0 establishes a more efficient means of powering the rapidly increasing number of digital, dc-powered devices, such as sensors, lighting and IT equipment found in today’s workplaces. It creates an integrated, open platform for power, interior infrastructures, controls and a wide variety of peripheral devices to facilitate the hybrid use of ac and dc power within buildings.
As the emergence of the EMerge Alliance standard suggests, dc power can be used to improve efficiency at the lower-voltage levels. The addition of dc power delivery systems to homes, office building and commercial facilities offers the potential for significant improvements in energy delivery efficiency, reliability, power quality and cost of operation. Most of these facilities are currently dominated by fixed overhead lighting, and a variety of electrical devices that are typically wired for the building’s lifetime rather than the occupant or residents evolving needs. In fact, although opportunities exist in both new installations and retrofits, according to the EMerge Alliance, 80% of the market opportunities are in the updating and retrofitting of commercial buildings. Actually, the ability to distribute low-voltage dc power within common infrastructures is already present in most commercial interiors
Lighting presents one of the major opportunities for the further development of dc power. According to a recent study funded by the U.S. Department of Energys Energy Efficiency and Renewable Energy Office (DOE EERE), lighting accounts for 22% of all electricity consumed in the United States. Commercial businesses consume 20% to 30% of their total energy just for lighting. And, 50% or more of that lighting-related energy may be wasted by obsolete equipment, inadequate maintenance or inefficient use. Upgrading lighting systems is one of the best energy efficiency investments available to a commercial facility. Since linear fluorescent light accounts for the majority of a commercial building's lighting energy use, improving the efficiency of these systems can save significant amounts of energy and money.
In addition to advances in dc power for data centres, new advances in solid-state lighting (SSL) are among the market forces expected to drive the dc power market over the next several years. The era SSL will be arriving soon, primarily powered by ultra-high-efficiency light emitting diodes (LEDs) and to a lesser extent by organic light emitting diodes (OLEDs). Used in large high-definition signs, architectural lighting, stadiums, billboards and other applications, modern LEDs represent the latest lighting devices based on dc power. In fact, current economic conditions are just right for the emerging LED replacement market. Several factors cited for this include “dramatic” improvements in commercially available LED performance, significant cost reduction, government regulations, and energy savings.
Other applications contributing to the advancement of dc power include common consumer electronics devices, which operate on dc power and require conversion from dc sources. These devices are common in every household and include televisions, computers, set top boxes and many others. (All microprocessors require direct current and many devices operate on direct power because it can be precisely regulated for sensitive components.) In fact, many of the smaller electronic devices such as mobile phones, notebook computers and personal digital assistants (PDAs) use ac-dc adapters, which also result in power loss during conversion. In aggregate, the millions of ac-dc conversions performed for the operation of these electronic devices extract a huge loss in energy during conversion.
In addition to the applications and trends driving the industry, the market for dc power is strongly influenced by a number of technological and regulatory factors. These factors vary from application to application and represent both opportunities and threats. They include the growth of dc power used in alternative energy systems, the availability of UL rated equipment and experienced personnel, the further development of both UPS technology, the expansion and development of a number of organizations and alliances the already-mentioned importance of increased efficiency and the further development of regulatory standards and policies.
Among the areas examined in this report are the technology and architecture trends affecting the industry, as well as a thorough discussion of new and emerging products and materials, potential threats and the latest regulatory developments and standards. Over 35 tables are presented depicting a variety of power system schematics and comparisons, architectural standards, product introductions, packaging solutions, efficiency standards and other relevant information. The focus of this comprehensive analysis provides decision makers with an insightful look into the current and future opportunities and threats available in the dc building power supply market.
- Current Areas of Development
- Additional Applications and Drivers of DC Power
- Organizations and Alliances Involved in DC Power
- DC Power and Alternative Energy Systems
- Barriers, Challenges and Threats to the Adoption of DC Power
- Architectural and Technology Trends and Developments
- Cost Dynamics of DC Power
- Policy and Regulatory Framework for Development
- Recent Developments and Products