While technological progress has improved the quality of our lives, it has significantly increased global energy consumption, from 7 billion toe (tonne of oil equivalent) in 1980 to 12 billion in 2007*. With the increasing levels of greenhouse gases in the atmosphere and the dwindling of traditional energy resources, a key change in the world’s approach to power is needed: instead of simply generating more electrical power to satisfy the growing demand, we must use energy more efficiently.

For many years, ST has been committed to developing products and technologies that enable an increasingly efficient power supply chain; from generation to consumption across the broad spectrum of microelectronics applications.  Essentially, there are two complementary approaches that we follow: reduce energy consumption in the chip itself and contribute to energy savings in the end application, such as home appliances or lighting. To achieve these objectives, a significant amount of ST’s total R&D investment is spent on energy efficiency-related technologies.

Power electronics holds the key to more efficient utilization of energy. As much as 90% of the energy currently used in TVs can be saved through efficient standby-power management; a 30-40% decrease in energy consumption can be achieved using intelligent compressor control in air-conditioning systems and by using inverters in home-appliance electric motors; and the use of electronic ballasts in compact fluorescent lamps as well as the use of induction instead of oven in cooking can cut energy use by 25%.

An ST internal analysis has shown that using end products built around ST’s energy-saving technologies and products can cut the residential energy consumption by a third. For example, a 4-person household with an annual power consumption of 3.36 MWh can save about 1 MWh a year - the equivalent of almost two barrels of oil – reducing both the electricity bill and environmental impact of power generation.

A good example of reducing energy at the chip level is ST’s MDmesh™ power MOSFET technology, which can cut the energy losses during the device conduction time by 80% compared with other power MOSFET technologies. Even in a device as conceptually simple as a rectifier, aiming to minimize power consumption in the end application can yield significant benefits. 

Another promising approach is the use of alternative semiconductor materials and technologies such as Silicon Carbide (SiC). SiC devices demonstrate better static and dynamic characteristics, bringing improved efficiency and thermal performance to the final applications. ST is actively engaged in the development of SiC devices and first SiC Schottky diodes are already available from ST.

Lighting
15% of all electricity in the world is used for lighting. Experts have calculated that replacing traditional incandescent lamps with fluorescent lamps, such as Compact Fluorescent Lamps and Tube Lamps, would cut energy use by a factor of five. Moreover, switching from conventional control techniques to electronic ballasts, which are devices that limit the amount of current needed to drive the tube, can save an additional 25% of energy.

As a leading provider of complete lighting solutions with smart lamp management and high levels of protection against lamp disconnection, aging of lamp gas and cathodes or fault ignition, STMicroelectronics supports the shift to electronic ballasts for energy-efficient lamps. ST offers an extensive portfolio of discrete power semiconductors, application-specific chips and microcontrollers combining all the functions to generate more light from less energy. These products ensure longer lifetime for the lamps and full compliance with safety and power consumption regulations.

Considerable savings can also be achieved with daylight-dependent dimming solutions that can cut energy consumption of lighting by as much as 80%. For instance, one 300W bulb that is on for two hours a day, dimmed by a phase-control technique to a 75% dim level saves 54 kWh of the full-light annual consumption of 219 kWh. ST’s dimmers provide smooth up-and-down light adjustments and memory presets. They can be combined with ST’s innovative peripherals for remote control, including RF and infrared, and networking capability.

White goods
Most domestic appliances, from heating and air-conditioning systems to “white goods” contain an electric motor. Due to the variable-speed capability, new motor-control systems can optimize the motor speed to the load needs, thus reducing the energy used. Using advanced motor-control technologies increases energy efficiency, ensures higher reliability, and delivers smaller physical dimensions and silent operation in a variety of end-user devices around the home.

The most integrated system in its category, ST’s patented sensorless motor controller with inverter driving allows a microcontroller to control the frequency and voltage of the power supplied to the motor. In white-goods appliances and air-conditioning systems, this approach delivers real-world savings of 30% compared to existing solutions.

Efficient motor driving, together with temperature control, can reduce energy consumption in refrigerators, washing machines and dryersby as much as 40%. In addition to improving energy efficiency, new electronic solutions also extend the lifetime of an appliance and increase its reliability and user convenience.

ST’s dedicated solution for refrigerators integrates full digital temperature regulation that helps maintain the internal temperature of the refrigerator more accurately for better food preservation while saving power. The electronic thermostat also optimizes defrosting cycles based on the current temperature in the cabinet.  

Typical annual power consumption of a fridge or a washing machine can be reduced almost 60%, from 600 kWh to 250 kWh. If all refrigerators in Europe used ST’s technology for power management and thermal control, the continent would save 1500 MW (an equivalent of two nuclear power units) and would reduce its production of CO2 by about 1.2 million tons a year.

Stand-by power
Nowadays, the majority of entertainment appliances, such as TVs, set-top boxes, DVD and CD players, can be operated by remote control. The devices operate in stand-by mode for 20 hours a day, waiting for signals from the remote. ST’s power-supply units for stand-by systems use innovative technologies such as BCD (Bipolar-CMOS-DMOS) in smart products including VIPer (Vertical Intelligent Power Enhanced Regulator) to reduce power consumption below 1W. In a model household with two TV sets, one set-top box, one video recorder, one radio and one PC, low-power stand-by systems can reduce energy consumption by 77%, from 203 kWh to 45 kWh a year.

Moreover, ST’s has estimated that its innovative solutions for stand-by management and the improvement of efficiency in mains-plugged systems saved around 1250 GWh in 2006 and 20% more in 2007. Other derivative benefits these solutions deliver include a 20% reduction in power supply weight and dimensions, a 15% reduction in the use of difficult-to-recycle materials and chemicals, and around 10% less heat generated on critical power components. All in all, ST believes these efforts reduce the cost of ownership by 30% and extend the lifetime of the equipment by 20-25%.

Emerging trends
At the vanguard of technology research and development, ST is constantly looking for new ways to further improve energy efficiency in the end applications. These emerging technologies include LED-based lighting.

Experts believe that Light Emitting Diodes (LEDs) are on track to become a new standard source of illumination for the 21st century. LEDs offer longer lifetimes (up to 100 000 hours), a wide color spectrum, small size, design flexibility and increased safety. They turn on instantly and operate silently. Most importantly, LEDs can save a lot of energy compared with standard lighting sources. Osram, a leading lighting manufacturer, has estimated that the replacement of 5% of all incandescent bulbs in the world (12.5B/year) with LED-based lighting would save 60 GWh of electricity, which is equivalent to saving the about 4 thousand barrels of oil needed to generate this energy,) and 23.4 Gt of CO2 a year.**

All these advantages are closely related to the performance of the LED’s driving electronics. Today, ST has one of the industry’s largest portfolios of compact and efficient LED drivers, including the recently introduced high-brightness LED drivers with auto-power-saving features.

*based on the US Energy Information Administration’s International Energy Outlook 2008
** Source: Osram GmbH; evg-spot 1/2007