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Panel 4: Strategies to Improve the Efficiency
and Reliability with Which Primary Input
Energy is Converted to Useful End-use Services
Smart Grid Development in China and the United States: Status,
Prospects and Opportunities for Bilateral Cooperation
Panel 4: Strategies to Improve the Efficiency
and Reliability with Which Primary Input
Energy is Converted to Useful End-use Services
Remarks by:
M. Granger Morgan
Head, Department of Engineering
and Public Policy
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-2672
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Energy use in the U.S.
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Note that... in 2010, just over 2/3 of the primary energy
that went in to
the U.S.
electric power
system ended
up being
rejected as
waste heat.
Of course, this is not because engineers are doing a bad job. Rather, it results from the basic laws of thermodynamics and the fact that most U.S. power stations are remote from places where the waste heat might be used.
Strategies to increase the ratio (useful service out)/(primary energy in)
• Develop the ability to operate plants at higher temperature so as to increase their thermodynamic efficiency.
• Add thermodynamic "bottoming cycles."
• Co-locate industrial facilities that can use capture waste heat.
• Move central station plants closer to population centers so that "district heating" becomes feasible.
• Promote greater use of smaller distributed generation (DG) with combine heating and cooling (CHC).
Ultrasupercritical coal plants
600 Mw; Cost $1.8 billion
Steam: 3675 psi @ 607 °C
(vs 2400psi @ 540 °C)
Heat rate: 8,950 BTU/KWh
(vs ~10,400)
Image sources: AEP; www.hopeprescott.com
Bottoming cycles & waste heat recovery
It is, of course, common to add a steam cycle to gas turbine systems (combined cycle plants). "Bottoming cycles" can also be run with coal plants.
While waste heat recovery
has been slow to take off
in the US, some like Tom
Caston (CEO of Recycled
Energy Development, Inc.)
have continued to push
the idea and have built a
number of facilities that
are now operating.
Images from Nature and www.recycled-energy.com
District heating In much of the world, including some parts of China, the heat from a power plant is used for district heating. In the U.S. a number of central cities have district heat (e.g., Denver since 1880; New York since 1882). However, in the U.S. very few large power plants also provide district heating because most are located far from urban areas.
This district heating plant in
Cologne, Germany that
generates 400 MWe as well as
heat to ~45,000 households.
Photo and data from www.lahmeyer.de
Source: Nature, 2009 Mar 12
Distributed generation (DG) with combined heat and cooling
This technology holds the potential to roughly double
the efficiency with which input energy (typically gas)
is converted into useful services.
As my recent PhD student Kyle Siler-Evans
demonstrated, present DG technology has
significant economies of scale.
Thus, one would probably not like to run DG in
individual homes but rather in micro-grids, down
below the distribution system.
DG Economies of Scale
Economies of scale for cogeneration applied to a hospital complex. Net present values are based on the average of the four pricing assumption with the full range shown as vertical bars. Results are given as function of generator size (log scale). Generators of more than several megawatts are too large for a single hospital but may be appropriate for a micro-grid, which would serve a small aggregate of end users.
There are regulatory obstacles to building micro-grids in the U.S.
to legacy utilities. This means the operator of a DG or micro-grid system is not allowed to sell power to anyone (except to the legacy utility).
King and Morgan, Journal of Energy Engineering, ASCE,
pp. 150-164, 2007.
Most U.S. states have laws that grant "exclusive service territories"
Of course there are also technical issues of stability and protection… …but these can be solved without too much difficulty.
Marija Ilic (and I) have worked with two students (Masoud
Nazari and Siripha Junlakarn) who have addressed these
issues. Work by Masoud Nazari
Note that these issues limit free market "plug and play"
strategies, but could be handled with appropriate policy
frameworks.
Beyond the energy efficiency benefits … … wide adoption of DG, together with distribution automation and smart meters, holds the potential to make it possible to secure critical social services when the bulk power system goes down.
In 2003, a group of us at
Carnegie Mellon began to
argue that, while we should do
everything within reason to
secure the reliability of the
power system, some blackouts
are inevitable and we should
be devoting greater attention
to moderating their impact
when they occur. Figure from Hines, Apt and Talukdar,
Energy Policy, 37,5249–5259, 2009. Data
for U.S. from 1984-2006.
Some examples of "critical social services"
Emergency Services
911, emergency operations
centers, and other dispatch
Police services
Fire protection services
EMS
Medical Services
Transport ambulance services
Life-critical in-hospital care
(life support systems,
operating rooms, etc.)
Non-critical in-hospital care
(refrigeration, heating and
cooling, sanitation, etc.
Clinics and refrigerated
pharmacies
Nursing homes and other
non-hospital care
Non-electric Public Utilities
Water
Sewer
Natural gas
Lighting
Building evacuation and
stairwell lighting
Domestic lighting
Lighting in commercial
establishments
Security lighting
Street lighting
Food
Cash registers
Lighting
Refrigeration
Restock operations
Financial
Cash machines
Banking services
Credit card systems
Fuel Infrastructure
Pump operations
Pipeline systems
Local fuel storage capacity
Transport and distribution
capac ity and operations
(including river locks)
Whole sale and retail operations
Communication and cyber services
Radio transmission and recep tion
Television transmission and
recep tion
Wire-line telephone
Cable systems
Wireless telephone
Wired data services
Wireless data services
Computer services on customer's
premises
Computer services off customer's
premises
Non-emergency government
services
Government information and
service offi ces
Prisons
Transportation and mobility
Building elevators
Traffi c signals
Tunnels
Light rail systems and subways
Conventional rail systems
including railroad crossings
Air traffi c control
Airport operations including
landing and related lighting
River lock and dam operations
Drawbridge operations
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Several studies have … …looked at options to build on DG smart meters, and distribution automation to create islanded systems that could sustain critical social services.
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Work by Siripha Junlakarn
Narayanan and Morgan, "Sustaining Critical
Social Services During Extended Regional
Power Blackouts," Risk Analysis, 32, 1183-
1193, 2012. NRC, 2012
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Sustaining critical social services
Figure source: Narayanan and Morgan, "Sustaining Critical Social Services During
Extended Regional Power Blackouts," Risk Analysis, 32, 1183-1193, 2012.
Modest incremental cost Our analysis suggests that the incremental cost, above the cost of the upgrades that many power companies and customers are making, are modest.
However, no profit-maximizing utility can be expected to make such an investment on its own.
DoE or DHS should fund a few demonstrations. That could give PUCs or local governments the confidence to move forward in more vulnerable regions.
Not all critical services should be
addressed this way. Hospitals, water and
sewer systems, etc. should have their
own back up. Traffic lights should use
LEDs with PV trickle charge back up, etc.
Image sources: www.kaybeeelectric.com; www.indiamart.com 17
End
In developing the ideas discussed in this talk, I have been fortunate to have generous support from the
National Science Foundation (SES-9209783, BCS-9218045; SES-034578; SES-0949710 and others),
the Department of Energy (DE-FG02-93ER61712, DE FG02-93ER61711, DE-FG02-94ER61916), the
Electric Power Research Institute, Alfred P. Sloan Foundation, the Gordon and Betty Moore Foundation,
the Scaife Family Fund, the Doris Duke Charitable Foundation, the MacArthur Foundation, the IRGC,
DHS via the NRC, Carnegie Mellon University and a number of others. Thanks also to my many
colleagues and students including Jay Apt, Marija Ilic, Lester Lave, Anu Narayanan, Sarosh Talukdar
and members of the NRC study panel on Terrorism and the Electric Power Delivery System.
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