Our complacency about energy supplies in the United States was jolted at the beginning of 2001 by sudden, soaring prices for natural gas and home heating oil. Prices at the gas pumps soon followed suit. Then Californians discovered that electricity shortages would plunge most of the state into rolling blackouts when air conditioning season cranked up.
Energy — its cost and our consumption — is in the news and on our minds. But not enough, perhaps, to make us change our ways without a little help from technology.
“The U.S. is not energy conscious yet,” says Fred Lee, discussing the fact that people in Europe and Japan, where energy costs are much higher, are more willing to pay higher prices for appliances and other devices that consume less energy.
Lee, a university distinguished professor of electrical and computer engineering at Virginia Tech, is founding director of the Center for Power Electronic Systems (CPES), the first National Science Foundation (NSF) Engineering Research Center established in Virginia.
“The major goal of CPES research is development of power electronics technology
that we hope will increase U.S. competitiveness and lead to as much
as a 30 percent savings in energy consumption,” Lee says. “Total
energy consumption is growing at an exponential rate due to the rapid
expansion of industry. We can never actually reduce current energy
consumption in the US by that much, but we can achieve a savings in
future consumption of 30 percent.”
Realizing the need to bolster research in power electronics (PE), the NSF invested
$12.35 million in CPES in 1998 after a lengthy national review of
several PE center proposals. The Commonwealth of Virginia pledged
another $1.5 million in support of the Virginia Tech proposal, which
also received the endorsement of more than 100 industrial allies.
CPES is a consortium; Virginia Tech is the lead engineering school
and its partners are the University of Wisconsin-Madison, Rensselaer
Polytechnic Institute, University of Puerto Rico-Mayaguez, and North
Carolina A&T State University.
During the three years since CPES was founded, research conducted by the
center’s associates has resulted in at least 12 patents and more than 40 invention disclosures. Much of this work has been done in collaboration with the center’s 115 industry partners.
So, what would the prices people are willing to pay for appliances have to do with energy savings?
“Let’s look at the ‘energy pie’,” Lee says. The use of electricity constitutes about 40 percent of total US energy consumption. As much as 50 percent of our electricity is used to operate motor drives,
which power air conditioners, heat pumps, compressors, household appliances,
electric cars, and most manufacturing equipment. Another 20 percent
of electricity is consumed by lighting, and another 10 to 15 percent
by computers, communication, and Internet infrastructure.
Consider
motor drives, which consume up to 20 percent of all US energy output.
“A major issue with motor drives in this country is that they
are inefficient,” Lee remarks. “For example, all residential
air conditioning units and heat pumps have constant-speed drives,
which are either on or off. We need to develop variable-speed drives,
which could result in a savings of about 30 percent in the energy
consumed.”
Consider also the incredible growth in the use of energy-consuming
appliances in the United States. For example, in the early 1950s,
few homes had the luxury of air conditioning. By the end of the century,
more than 80 percent of US homes were cooled by window units or central
air.
In Europe and Japan, people do buy air conditioners and heat pumps with variable-speed
drives. Why don’t we use them in the United States? “Because
the initial costs are higher,” Lee says. Variable-speed drives
are controlled by PE devices, which cost more to produce than parts
for constant-speed drives. That is because the labor costs are higher
to produce PE devices — which is because PE devices are not standardized
for automated manufacturing.
“People
in Europe and Japan are willing to pay more for energy-efficient appliances
because their electric power costs considerably more than in the US,”
Lee says. “So their payoff for buying variable-speed appliances
comes in only about two years, whereas in the US the payoff can take
at least four years.”
CPES researchers are developing PE controls for motor drives as single
modules, says Dushan Boroyevich, deputy director of CPES and a professor
of electrical engineering at Virginia Tech. “Single, standardized
PE modules can be manufactured in high volumes by batch processing,”
Boroyevich notes. One factor CPES is working on is reducing the number
of PE semiconductor switches needed to operate motor drives. “Our
electrical engineering researchers are developing simpler electronic
solutions,” he says. Simplification and standardization also
can improve the reliability of PE devices.
A major area of CPES research and development is the Integrated Power Electronics
Module (IPEM) approach toward manufacturing PE devices for motor drives
and numerous other energy-consuming products.
“Currently,
PE products are custom designed and manufactured using nonstandard
parts,” Lee explains. “This results in labor-intensive manufacturing
with high costs and poor reliability.” The CPES goal is to develop
an integrated systems approach to standardize components — circuits,
controls, sensors, and actuators — and packaging techniques suitable
for automation and mass production.
“Automation
of PE production could be compared to the revolution brought about
by Very-Large-Scale Integrated (VLSI) circuit technology, which enabled
rapid advancement in computer and telecommunications equipment,”
Lee says.
Improving
the production and reducing the costs of variable motor drives is
just one aim of IPEM research at CPES. “The computer and telecommunications
industries have a critical need for reduced costs and improved reliability,”
Boroyevich says. “They are looking for high-power, low-cost,
reliable energy supplies, and IPEM is the answer.”
“People
haven’t given much thought to how much energy computers use,”
Lee comments. Currently, the Internet operates through “server
farms.” Each farm serves one small area, such as a town, and
can use as much as 10 to 30 megawatts of power per day. In fact, Lee
notes, California has stopped building new server farms because of
the state’s energy shortages.
“PE
technology hasn’t kept up with rapid information technology development
and its energy requirements,” Boroyevich says. “Power supply
problems are major roadblocks for the information technology industry.
CPES is developing new ways to deliver power for that industry.”
For example, CPES researchers are working on new types of power converters
for new generations of electronic processors.
“With
computers and other information technology devices, the problem often
is not how much energy is consumed but how it is consumed,” Boroyevich
notes. One patent recently issued to Lee and some of his colleagues
is for a circuit that will enable computers and telecommunications
equipment to draw “clean power.” Electrical equipment draws
energy in “dirty” — or inefficient — ways, which
wastes electricity and wears out supply lines more quickly, Boroyevich
explains. Europe and Japan have mandated the use of clean power devices,
which will help save electrical infrastructure costs. Once again,
these clean power devices are more expensive to manufacture. The circuit
developed through CPES will enable manufacturers to reduce production
costs by up to 10 percent.
Lighting,
which consumes about 20 percent of the electricity used in the United
States, is another energy savings priority for CPES. Fluorescent lighting,
which already is 40 percent more energy efficient than conventional
incandescent lighting, can be made even more efficient. Standard fluorescent
light ballasts — the devices that provide starting voltage and
limit current — are magnetic; electronic ballasts can reduce
energy consumption by as much as 30 percent, Lee says.
In addition,
electronic ballasts greatly increase the life of fluorescent lights.
Conventional fluorescent lights with magnetic ballasts aren’t
typically used in industrial settings or street lights because they
would have to be replaced too often.
“Widespread
use of fluorescent lights with electronic ballasts could result in
significant energy savings,” Lee notes, “but the cost of
manufacturing electronic ballasts is too high.” CPES researchers
are working in this area, and last year Lee and others obtained a
patent for a cost-effective electronic ballast.
CPES
research and development extends into several other energy-use areas.
One of Lee’s specialties, for example, is distributed power systems,
which can improve the reliability of electrical power supplies by
efficiently drawing energy from multiple sources. CPES also is attracting
support for development of low-cost automotive power electronics that
can be mass produced.
CPES efforts to develop PE technologies are aimed at another major goal in addition to savings in energy consumption. “By 2010, about 80 percent of electrical energy will be processed through PE devices,” Lee says. “As recently as 1980, almost 100 percent of all PE devices were built in the US Today, only about 30 percent are built here because of the high labor costs of manufacturing PE devices without automation.
“CPES is working to develop an integrated PE solution,” Lee notes,
“which can be adopted in an automated cost effective manufacturing
process that will enable US manufacturers to once again be the leaders in PE production.”
