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There is a new reason to like the “smart” grid.
Its
advocates have long talked up the energy-saving opportunities.
Upgrading U.S. electricity transmission all along the wires with the
capability to better manage the flow of power through information
technology will make innovations like demand response and field
intelligence possible. It will also increase the power system's
capacity to manage the coming plug-in vehicle revolution. The Smart Grid: An Estimation of the Energy and CO2 Benefits,
from the Pacific Northwest National Laboratory (PNNL) of the U.S.
Department of Energy (DOE), documents how those innovations and the
energy savings they allow mean significant greenhouse gas emissions
(GhG) reductions. The PNNL report finds a smart grid will cut GhGs at
least 12% by 2030.
The
paper investigates 9 mechanisms in the generation and delivery of
electricity through which a smart grid could impact energy consumption
and GhGs. A smart grid, it shows, will have both direct and indirect
impacts on emissions. New technologies will increase control of the
flow of power and increase efficient energy use in businesses and
homes. These will directly reduce the consumption of energy and,
therefore, the emissions produced from it. Smart technology will
indirectly cut emissions by making the use of more emissions-free New
Energy possible by more readily integrating New Energy into the
transmission system in a variety of different ways.
The 9 mechanisms:
(1) Conservation Effect of Consumer Information and Feedback Systems
(2) Joint Marketing of Energy Efficiency and Demand Response Programs
(3) Deployment of Diagnostics in Residential and Small/Medium Commercial Buildings
(4) Measurement & Verification (M&V) for Energy Efficiency Programs
(5) Shifting Load to More Efficient Generation
(6) Support Additional Electric Vehicles and Plug-In Hybrid Electric Vehicles
(7) Conservation Voltage Reduction and Advanced Voltage Control
(8) Support Penetration of Renewable Solar Generation (25% renewable portfolio standard [RPS])
(9) Support Penetration of Renewable Wind Generation (25% renewable portfolio standard [RPS])
The
PNNL study is one of the first to bring together the fields of
emissions research and smart grid research. It demonstrates that such a
combined approach warrants further development by smart grid investors
and utilities.
COMMENTARY
Fully
utilizing a smart grid could prevent 442 million metric tons of GhGs
yearly. That’s the equivalent of 66 typical coal power plants’ spew.
Primary Assets of the smart grid:
(1)
Demand response (DR), a 2-way communication-and-control of end-use
business and home devices and systems by grid operators to manage
electricity demand as it varies through days and seasons;
(2)
Distributed generation (DG), all small-scale power from small engines,
generators, wind turbines, solar systems, etc., connected to the grid
to add extra capapcity;
(3) Distributed storage (DS), all
batteries, flywheels, super-conducting magnetic storage, and other
electric and thermal storage technologies connected to the grid to
provide dispatchable power;
(4) Distribution automation/feeder
automation (DA/FA), the automation in substations and into grid feeders
with remote switches for reconfiguring transmission with advanced
protective relays and control abilities and sophisticated electronic
component management systems to make responses in power suppy
transmission more generally automatic, more malleable when necessary
and always more efficient;
(5) Transmission wide-area
visualization and control, the systems that sense and quickly respond
to changes along the wires; and
(6) Electric and plug-in
electric hybrid vehicles (EVs/PHEVs), the fleet of vehicles with
batteries that can be both a new type of load and, as a source of
distributed storage, a new type of load management.
click to enlarge
Enabling Assets (cross-cutting technologies necessary to support the primary assets) of the smart grid:
(1) Wide-area communications networks, servers, gateways and other interconnections;
(2)
Smart meters, the basic advanced metering infrastructure (AMI)
technology as well as even smarter meters that respond to DR and DG
controls more quickly and subtly for peak load management, including
full 2-way communication with business and home networks (including
smart thermostats and appliances);
(3) Local-area home,
commercial building, and industrial energy management and control
systems (EMCS) and networks that allow grid operators to manage energy
consumption;
(4) Consumer information interfaces and decision
support tools such as personal computer dashboards that give business
and homeowners opportunities to streamline their energy consumption;
(5) Utility back-office systems, including billing systems, that enhance consumer engagement in efficiency measures;
(6)
Other key embedded technical enabling assets: (a) Cyber-security
technologies to protect the many 2-way communication systems, and (b)
Interoperability standards and protocols that allow the 2-way
communications to take place seamlessly.
click to enlarge
Operational
Objectives, the categories of benefits or applications of the smart
grid that improve cost effectiveness, reliability, and energy
efficiency:
(1) Managing peak load capacity for generation, transmission, and distribution;
(2) Cutting the costs of wholesale generation, transmission, and distribution operations;
(3) Enhanced reliability at reduced cost;
(4) Making ancillary services available;
(5) Cutting the cost of New Energy integrations; and
(6) Using the transmission system and its expanded network to increase efficiency and emissions reductions.
click to enlarge
The
study assesses 9 mechanisms of electricity generation and transmission
through which the smart grid could make energy consumption more
efficient and cut GhGs.
The 9 mechanisms that together can
produce a total direct reduction in GhGs by 2030 of 12% and a total
indirect reduction of another 6%:
(1) Conservation Effect of Consumer Information and Feedback Systems (Direct reductions of 3%)
(2) Joint Marketing of Energy Efficiency and Demand Response Programs (Indirect reductions of 0%)
(3) Deployment of Diagnostics in Residential and Small/Medium Commercial Buildings (Direct reductions of 3%)
(4)
Measurement & Verification (M&V) for Energy Efficiency Programs
(Direct reductions of 1% and Indirect reductions of 0.5%)
(5) Shifting Load to More Efficient Generation (Direct reductions of <0.1%)
(6) Support Additional Electric Vehicles and Plug-In Hybrid Electric Vehicles (Direct reductions of 3%)
(7) Conservation Voltage Reduction and Advanced Voltage Control (Direct reductions of 2%)
(8)
& (9) Support Penetration of Renewable Wind and Solar Generation
(25% renewable portfolio standard [RPS]) (Direct reductions of <0.1%
and Indirect reductions of 5%)
click to enlarge
Air
and water quality and land use impacts were not considered in the PNNL
study. The use of natural gas by end users was also not considered.
Uncertainty
in the specific estimates is relatively high, in a range of ~50% and in
some cases larger. There is a higher level of confidence in the
accuracy of the total estimate of reductions based on the fact that the
wide variety of mechanisms allows for compensating over and under
estimates.
The estimates assume full deployment (100% penetration) of smart grid technologies.
Several
of the mechanisms may have little or negligible impacts but 5 could
potentially cut emissions more than 1% each. The combined effect is
what is important. The total direct reduction of 12% of GhGs and the
indirect reduction of 6% of GhGs by 2030 means the smart grid is an
important tool for the U.S. in meeting its total emissions cutting
goals.
The effects estimated in goals (8) and (9) pertaining
to the deployment of New Energy also make the smart grid a crucial tool
in the nation’s energy policy.
click to enlarge
The PNNL’s general recommendations for next steps:
(1) All technical mechanisms must be analyzed in more depth, with quantification of and uncertainties for the estimates.
(2)
Customer feedback is needed to better implement and sustain energy
efficiency and demand response management programs. A better
understanding of consumer behavior and response to smart grid
technologies will be necessary.
(3) Customer programs will work
better with better long-term measurement and verification (M&V) and
diagnostics. This necessitates improved analytic methods and software,
especially on the customer side of the meter.
(4) Key research
needs: How smart grid technologies can support (a) integration of New
Energies above 20% through demand response, New Energy sources and
storage technologies, (b) increased levels of battery electric
vehicles, (c) management of voltage control and losses within the
transmission and distribution system, and (d) increased reliability of
electricity delivery.
Key issues:
(1) Acceptance by federal
and state regulatory bodies. A major driver will be how cost-efffective
smart grid technology proves to be, while providing equal or improved
levels of power delivery and reliability. A quantitative method to
define and monetize improvements will be needed. Involving stakeholders
in moving from a centralized to a decentralized system will also
improve acceptance.
(2) The smart grid must deliver offsetting
increases in consumption from servers located in every distribution
substation and from demand response/GFA devices installed in the stock
of appliances. The combined effect may increase emission reductions by
a small but significant ~0.1-to-0.4%.
click to enlarge
Among
the most salient features of the PNNL study were discussions of (1) the
business case for the smart grid, (2) how the smart grid can support
the transition to plug-in vehicles, and (3) how the smart grid can
support the transition to New Energy.
(1) The business case for
the smart grid compares the capital investments in its parts to the
many value streams from the multivarious applications they support. The
business case is successful when the sum of the value streams is
greater than their total cost.
Each of the many parts of the
smart grid support a number of functions. Any of the many functions can
be supported by a variety of components. The result is that the
component assets support and compete against each other. Therefore, a
primary asset and its enabling assets must be more cost effective than
its competitors.
One of the earliest indications of the smart grid’s viability was Xcel Energy’s SmartGridCity
in Boulder, Colorado. Subsequently, various utilities and states have
done successful work with advanced metering infrastructure (AMI) and
demand response (DR). DOE has also invested much in pilot projects.
The
PNNL study does not include a monetization of the smart grid concept
but catalogues a list of evidence of its cost effectiveness and
predicts only that smart grid deployment will be justified once it is
instituted and the nation will additionally reap enormous benefits from
energy and emissions savings. Associated marginal costs for software
applications and control algorithms will be low.
The study's
author stress, however, that the business case for a smart grid cannot
be made without including the additional energy and emissions benefits.
click to enlarge
(2)
The smart grid can support the transition to plug-in vehicles through
its advanced load management technologies in conjunction with plug-in
vehicles’ smart charging capabilities. The result will be a significant
gain in energy efficiency and a big reduction in GhGs.
Because
battery electric vehicles (BEVs) have electric drive engines that are
far more efficient than the internal combustion engines (ICEs) that
burn gasoline for fuel, even plug-in light duty vehicles (LDVs) (cars,
vans, SUVs, and light trucks) that draw from a grid powered by dirty
coal will generate fewer GhGs. It would, of course, also move the
nation away from dependence on imports of foreign oil. As more New
Energy sources supply the grid, BEVs will allow for greater and greater
emissions-free driving.
BEVs are estimated to require 30% less
energy and to cut GhGs 27% while reducing by 52% dependence on foreign
oil. Plug-in hybrid electric vehicles (PHEVs) are expected to be the
transitional phase in a process that will eventually lead to all
electric vehicles (EVs).
Reliable estimates show that the
present U.S. transmission system could supply over 70% of today’s LDV
fleet if it were electric and if the bulk of the charging was
effectively managed, through time-of-use pricing and smart charging.
click to enlarge
Managing
the charging is the crucial enabling characteristic of smart
technologies. The big cost is in the vehicle, not the smart grid, but
the combination could represent big savings in energy and emissions. By
facilitating the energy savings and the concomitant cost savings, the
smart grid becomes a means to spur the penetration of electric
transportation and the emissions savings that will come with it.
In
the PNNL study, driving data was used to estimate when vehicles arrive
at home and it was assumed battery-charging at 120 volts would begin
immediately. Absent smart charging, this could detrimentally add to the
last part of the peak demand period. With smart charging and a smart
grid, the grid could support 18 million more BEVs. This significantly
increases the benefits from BEVs and the convenience of having one.
There
is some question as to whether 120-volt charging will be the norm.
Large vehicles (like SUVs) can take 12 hours to charge for a 30-mile
range at 120 volts. 240-volt charging may become necessary. Charging at
240 volts doubles the peak load impact of unmanaged charging and
further impedes by as much as 32% the benefits from BEVs and therefore
increases the need for, and enhances the value of, the smart grid.
An
indirect benefit of the smart grid would be that by facilitating the
penetration of BEVs it furthers the use of intermittent New Energies.
If there are enough vehicles to use V2G technology to charge and
discharge New Energy sources on demand, more resources can be
developed, though the impacts on the vehicles and their batteries is
not yet established.
click to enlarge
(3)
The smart grid can support the transition to New Energy through V2G
technology but it can also do so in a much more important way
independently of the BEV revolution.
A smart grid can facilitate
the integration of New Energies through the implementation of
price-scheduling and/or incentives that engage demand response and
distributed storage (DS, including but not limited to storage in BEVs).
With
DS and V2G technology, storage sources and BEVs can relieve the burden
on power plants to absorb the supply fluctuations inherent with
intermittent New Energies by allowing grid operators to dispatch the
stored power and charge and discharge available BEVs as needed.
This
type of power plant regulation is standard operating procedure by grid
operators already but can become a standard ancillary service provided
by a smart grid to integrate higher proportions of New Energy into the
power supply.
In February 2008, Texas’ wind production dropped
1700 megawatts unexpectedly early in the evening. Auxilliary supplies
were inadequate in the time frame. But grid operators were able to
prevent a blackout by exercising pre-existing emergency curtailment
contracts with large industrial customers.
The amount of such
services needed, now rare, will accelerate as more New Energy is in the
power mix. With demand response and distributed generation and storage
assets, a smart grid will allow widespread automatic and instantaneous
regulation of the grid’s power supply to whatever New Energy
intermittencies might occur without causing service disruptions.
click to enlarge
By
doing so, the smart grid will reduce the need for new backup power
plants, further streamlining the nation’s energy consumption and
reducing emissions generation.
The smart grid will also increase
New Energy’s role in the power mix by removing barriers to a larger
presence in the transmission system. Examples of this include (1)
making larger areas of wind resources available to local grid operators
and (2) increasing the amount of rooftop solar PV a given circumscribed
locality can flow to and from the central grid.
The ultimate
barrier is the limit to New Energy’s role in power generation created
because of the need to have replacement sources. A smart grid’s
capability to draw on stored New Energies and backup distributed
generation would reduce the amount of replacement sources needed
without increasing the cost of the New Energies, making the economics
of a larger share of New Energies equitable.
When the amount of
energy used by power plants for New Energy backup supplies is the only
non-New Energy in the system, there can theoretically be no more New
Energy in the mix. Aggressive management of all sources by a smart
grid, including the use of V2G and a fleet of BEVs, can reduce the need
for backup and therefore expand the absolute limit of the use of New
Energy. (This limit is not enumerated in the PNNL report and has not
yet been estimated.)
Wide-area control (the use of
high-precision data and high-performance computing techniques to
analyze and reconfigure power on the lines), a future capability of the
smart grid, was not analyzed in the PNNL study.
Dynamic thermal
rating schemes for transmission systems (the use of weather sensors in
computing the thermal capacity limits on the lines), presently
available, was also not analyzed in the PNNL study.
Unknowns
exist for both but both are expected to eventually make transmission
more efficient, eliminate losses along the wires and further decrease
energy consumption and increase emissions savings.
click to enlarge
QUOTES
-
Rob Pratt, research scientist and report co-author, PNNL: "By making
the grid smart, we make it more efficient and more accommodating of
renewables, and we're able to cut down on the amount of carbon we emit
to generate the electricity we need…This report suggests that we could
substantially reduce emissions by deploying a smart grid…We wanted to
show the additional benefits inherent in the smart grid's potential
contribution to the nation's goal of mitigating climate change by
reducing the carbon footprint of the electric power system…"
click to enlarge
-
Mike Davis, associate laboratory director/Energy and Environment, PNNL:
"This report has significant implications for public and private sector
interests engaging in future research, financial and policy decisions
in this area…Reducing our dependence on foreign oil and reducing our
carbon footprint can go hand-in-hand and be profitable."
- From
the report: “The economics of the smart grid are difficult to analyze,
but the business case is gradually becoming clearer and the smart grid
vision is becoming a reality.”
click to enlarge
-
From the report: “Regulation is one form of ancillary services needed
to stabilize the grid during normal operations…to manage high
penetrations of renewables. An illustrative example of this occurred in
February 2008, when the Electric Reliability Council of Texas (ERCOT)
had to curtail power to many interruptible customers because wind
production suddenly fell 1700 megawatts. The drop in output had been
forecast, but occurred several hours earlier than expected…[T]his event
exceeded the capacity of the spinning reserves and fast-acting
non-spinning reserves to pick up the deficit in output. In addition,
February is in the off- peak-load season in Texas when many power
plants were down for scheduled maintenance. As a result of this
deficit, grid frequency dropped quickly, and emergency curtailment
contracts, mostly with large industrial customers, were called upon to
drop load to prevent a potential blackout until additional power plants
could be brought online…”
posted by Herman K. Trabish
Smart grid could reduce emissions by 12 percent
January 29, 2010 (PhysOrg)
