POWER January 2012 - 48

RESEARCH & DEVELOPMENT
generated, making the electric sector the second-largest
electric-consuming industry.
The application of new technologies may
have the potential to reduce electricity use in
electric utilities by 10% to 15%. Even a 10%
reduction is enough electricity to power 3.9 million
homes. EPRI has identified technology options
and changes in operating methods that can
improve overall efficiency.
In power production, duty-cycle or capacity
factor is the key driver that influences internal
power use relative to unit output. In coal-fired
power plants, the average internal power use
across the sample used in EPRI's analysis was
7.6%. In nuclear power plants, the average was
4.1%. Opportunities to reduce electricity use
in power production may include advances in
control systems for auxiliary power devices and
the use of adjustable-speed drive (ASD) mechanisms.
In addition, ASD installations often reduce
CO2
emissions.
Electricity losses in power delivery total approximately
6.3%. In the distribution system,
the use of efficient transformers, improved voltage
control, phase balancing, and balancing of
reactive power needs could substantially reduce
electricity use. In the transmission system, opportunities
include extra-high-voltage overlays,
and transformer and line efficiency. In addition,
there are a couple of other " discoveries " worth
highlighting:
■ Newer power plants are not necessarily
more efficient than older plants, due principally
to environmental requirements.
■ Non-baseload operating plants have a particularly
high potential for improvement
by the application of ASDs on motors.
Other EPRI research shows that shifting
loads from peak to off-peak hours provides
significant improvement by reducing
load flows on the T&D system during peak
periods when losses are exacerbated, while
also reducing cycling operation for selected
generation units. Use of alternative energy
sources close to load centers to supply energy
requirements during peak periods also
can significantly reduce T&D losses during
the most challenging periods of operation.
Given the intensity of energy consumption in
the industry's own physical infrastructure, efficiency
measures undertaken at a finite number
of power plants or in the power delivery grid
can potentially yield energy savings and carbon
emission reductions more cost-effectively than
traditional end-use programs targeted at buildings,
residential users, and other industries.
Improve Data Center Energy Efficiency.
Typical data center power delivery designs use
alternating current (AC) power, typically distributed
within the facility at 480V AC. This
power goes through several conversions from
48
AC to DC and back again. The power losses
due to the use of inefficient power conversion
devices from both outside and within equipment
result in a large loss of useful electrical power.
They also directly increase the energy required
to remove the heat produced. Though estimates
and actual measurements vary, the power utilization
by information technology (IT) loads
can sometimes be 50% or less of the total input
power consumption.
Duke Energy and EPRI are working together
in a demonstration project that focuses on DC
conversion at the data center (or facility) level.
The approach will convert the facility's 480V
AC into 380V DC and deliver it to the equipment
racks via a 380V DC bus. The very best
AC equipment can be deployed to improve
power distribution efficiency, but that approach
only squeezes some of the losses out of each
component. The DC approach eliminates those
losses completely, through the removal of the
less-efficient AC components.
DC power distribution is an alternative approach
to a conventional data center AC power
scheme. Most data center server racks are not
currently powered using DC, but the servers
and storage arrays can operate with either AC
or DC. Typical servers and storage arrays inherently
convert an AC power source to DC within
each power supply, which adds an additional
power conversion loss. Using the DC powering
approach, extra power conversion steps are
eliminated, lowering losses, increasing reliability,
reducing cooling needs and square footage
requirements for data centers, and simplifying
power supplies.
Testing of a DC power system at a Duke Energy
data center in Charlotte, N.C., has revealed
preliminary results that the system uses 15%
less energy than a typical double-conversion
UPS AC power system.
Smart Grid
The " smart grid " concept combines information
and communications technologies with
the electricity grid to increase performance
and provide new capabilities.
Increasing use of variable generation and
controllable loads, combined with an aging
infrastructure, is a scenario where conveying
actionable information to and from interactive
markets, or monitoring asset health, will
require greater use of information and communication
technologies. Each utility will
create its own smart grid through investments
made in back office systems, communications
networks, and intelligent electric devices.
Smart grid functional requirements, interoperability,
and cyber security standards
are still evolving, and premature technology
obsolescence could strand some investments
as transitional technologies need to be replaced
before their expected end of life.
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This strategic issue requires a holistic vision
with end-to-end system considerations including
transmission, distribution, and end use.
Launch " Protect the Grid " Initiative. The
increasing interconnectedness, automation, and
communication capabilities of the power grid
pose several significant cyber security, resiliency,
and privacy challenges. Security threats
to the grid could come from deliberate attacks
by terrorists and hackers as well as inadvertent
user errors and equipment failures. Additionally,
the dramatic increase in the granularity of data
about end-user behavior raises several new privacy
concerns. To achieve a secure and resilient
grid, advances must be made in assessing and
monitoring risk, architectures to support end-toend
security, legacy systems security, approaches
for managing incidents, and technology to
support privacy.
EPRI has launched the Security and Privacy
Initiative, a collaborative effort to investigate cyber
security standards, business processes, and
technologies that can address these issues. This
project, which will expand to become the Cyber
Security and Privacy Program in 2012, also will
develop technologies, best practices, and controls
on data privacy.
EPRI also has partnered with the DOE to
conduct cyber security research and analysis to
support the National Electric Sector Cyber Security
Organization. As part of this three-year
public/private partnership, EPRI will determine
how to mitigate risks from impending threats,
harmonize cyber security requirements, and assess
cyber security standards and technologies.
Assessing and monitoring the cyber security
posture for energy delivery systems is
vital to understanding and managing cyber security
risk. As part of its R&D, EPRI is working
with advanced metering infrastructure
5. Low exposure. An EPRI researcher
takes data on radio-frequency exposure from
smart meters. These meters are typically part
of a wireless mesh network consisting of approximately
500 to 750 home meters connected
through a " cell relay " meter to local utility
via a cellular wireless wide area network. The
cell relay meter operates at a nominal power
level of 1 watt. Courtesy: EPRI
POWER | January 2012
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POWER January 2012

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