(This page expands on the introductory blog post)
We live in an era where saving energy is a topic that receives considerable attention. For design engineers, there are many different motivations for saving energy from your company being able to claim your newest gizmo has longer battery life than any of its competitors to conserving natural resources to reducing the air pollution and greenhouse gas emissions associated with generating electricity. Until recently, reducing energy usage in electronic circuit designs was primarily a concern for designers of battery power products. Today, legislative restrictions on energy usage are covering more and more types of products and the marketplace pressures for reducing energy usage are impacting nearly all types of electronic products from consumer electronics to IT equipment and even industrial and manufacturing equipment. In our “instant on” world where few things are ever really turned completely off, the energy a device uses when it is doing nothing is becoming more important than the energy it uses while operating. These so called phantom loads drive megawatts of electricity generation daily and are squarely in the sights of legislators writing energy efficiency regulations.
Low power design is becoming pervasive through out nearly all types of electrical and electronic product design:
- Battery powered products
- The global market for battery powered products was $410B in 2011 and is expected to grow to $611B in 2016. The majority of the products to be sold in 2015 and 2016 have not even been designed yet.
- Manufacturers of these products are constantly challenged by their customers to deliver more features in smaller packages while also providing longer battery life.
- There are over 800 million devices with rechargeable batteries in the U.S. alone. The amount of electricity generated (along with the associated air pollution and greenhouse gas emissions) for battery charging has drawn the attention of legislators around the world. Battery charger efficiency legislation is already in place in the U.S. and other industrialized countries. This is the “low hanging fruit”, legislation similar to that in place for standby current levels for TVs and certain household appliances can be expected for cell phones and other polpular types of consumer electronics.
- Low-power AC powered products
- Energy efficiency has become a chief deciding factors in the purchase of many types of AC line powered products.
- A 2012 study by Deloitte of 600 companies indicated 42% of the companies surveyed are replacing equipment prior to end of life with more efficient equipment to reduce electricity expenses.
- Electricity is one of the highest operating expenses for IT equipment, the EPA created an Energy Star program for servers and other IT equipment in 2009 claiming 30% energy reduction for Energy Star compliant servers.
- U.S. federal energy efficiency standards cover about 55 product types (mostly appliances).
- The California Energy Commission is expected to recommend energy efficiency regulations this year for 15 types of home electronics products not covered by federal standards. If the recommendations are adopted into legislation it is likely that federal legislation will follow within a few years.
- Self Powered products based on energy harvesting
- Energy harvesting “absorbs” energy from movement or the environment around a device to create self-powered, battery-less devices. Applications range from implantable medical devices to wireless industrial sensors.
- Energy harvesting technology has emerged from the lab and into commercialized products such as tire pressure sensors powered by road vibrations.
- The M2M (machine to machine) segment of the Internet of Things is reliant on energy harvesting for self-powered, truly wireless sensors to monitor and communicate the health of equipment in industrial processes and manufacturing plants.
- As an example of what can be done with energy harvesting technology, a new building complex in Spain was outfitted with 4,200 wireless and battery-less “smart” light switches, occupancy sensors and daylight sensors all powered off ambient light in the buildings. This system automatically controls lighting in the buildings and saves an estimated 40% annually on energy costs and eliminated the need for 20 miles of wiring or replacing 42,000 batteries over a 25 year span.
The manufacturers of electronics components and sub-assemblies used in these products are highly involved with low power design since the power consumption of their products can often be the critical deciding factor in component selection for the end product.
As an engineer, you should consider learning low power design a requirement. It may help your current employer, it will make you a more marketable engineer. Low power design is also responsible engineering. The 800 million rechargeable battery devices in the U.S. alone require an estimated 70 billion killowatt/hours annually for charging, also emitting 73.5 billion pounds of CO2. Regardless of your stance on climate change, the impact of electricity generation on natural resources and both air and water pollution are well documented. Designing with low power techniques is your opportunity to make a positive impact on our world.