Transcript Wind and Solar Renewable Energy Sept , 2011 David Wright Duke Energy What We Will Cover  Basics of Utility Electricity  History of Wind.

Wind and Solar Renewable Energy
Sept , 2011
David Wright
Duke Energy
What We Will Cover
 Basics of Utility Electricity
 History of Wind Energy
 Science of Wind Energy
 Types of Wind Turbines
 Wind Farm Construction
 Renewable Wind Operations
 Other Types of Renewable Energy
oSolar, Biomass, Hydroelectric & Geothermal
 Renewable Energy - Property Valuation Issues
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The ‘Drivers’ of an AC Generator
Steam
 Water
 Hot Gas
Wind
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The Grid
 Two Types, Transmission and Distribution
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Transmission System
Operates at ‘higher’ voltages
Covers larger geographic areas
Crosses state lines
Owned and operated by various entities, Utilities, Federal Government, etc.
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Distribution System
Operates at ‘lower’ voltages
Covers smaller geographic areas
Brings power ‘to the people’
Owned and operated by your local utility, CLF&P
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The Grid
http://www.oncor.com/images/content/grid.jpg
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History of Wind Energy, NASA
 NASA’s wind turbine program was a partnership between NASA, DOE, and
NSF
 Began in 1973 and continued on until around 1988
 Worked with the Bureau of Reclamation on the WTS-4 at Medicine Bow, WY
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NASA Turbine Program
Mod 2
Mod 0a
Mod 5b
Mod 1
WTS-4 4MW Hamilton Standard
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History of Wind Energy, California Wind Rush
 California tax incentives and improvements in technology led to a boom in
construction starting in the early 1980’s
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History of Wind Energy, Modern Wind Turbines
 3 blade, upwind, HAWT, of massive proportions. Multi MW capacity
 Constructed both on land, and offshore
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Science - Wind Shear
The change in the wind’s speed, or direction, due to the
effects of the earth’s surface
Speed shear (left) and directional shear (right).
From the National Weather Service at http://www.srh.weather.gov/srh/jetstream/mesoscale/windshear.htm
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Science - Roughness Classes
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0.0 = Water Surface
0.5 = Smooth surface, concrete runway, mowed grass
1.0 = Open agricultural areas, very scattered buildings, softly rounded hills
1.5 = Agricultural land with some houses, some sheltering hedgerows, dist 1250 meters
2.0 = Agricultural land with some houses, more sheltering hedgerows, dist 500 meters
2.5 = Agricultural land with many houses, many sheltering hedgerows, dist 250 meters
3.0 = Villages, small towns, many hedgerows, forests, and rough or uneven terrain
3.5 = Large cities with tall buildings
4.0 = Very large cities with tall buildings and skyscrapers
Disruption of wind flow by upstream objects. From (Nelson 2004), his Figure 9.2
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Science – Continued Growth
 The rotor swept area and height of
tower continues to increase
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Science – Continued Growth
 Increase in swept area and height of tower
improve production
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Science - Wind Density
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Types of Wind Turbines
 Many variations exist in the evolution of wind turbines for
producing electricity
 Number of blades, 1, 2, 3, 4 etc.
 Upwind vs. Downwind
 Vertical axis, (VAWT) vs. Horizontal axis, (HAWT)
 Synchronous vs. Asynchronous generators
 Tower height and materials
 Terrestrial and Off-shore
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1 Bladed Turbines
 Not very common
 Required a counterweight to operate
 Higher rotational speed
 Noise and visual intrusion
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2 Bladed Turbines
 Saves the cost and weight of one rotor blade
 Require higher rotational speed than 3 bladed
 The hub and rotor need to be hinged
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3 Bladed Turbines
 The most common design based on years of testing and research
 Gives good ‘balance’ between cost and energy output
 Upwind turbine design on tubular towers most prevalent
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Vertical Axis Wind Turbines
 Several designs; most commonly referred to as the Darrieus, Savonius,
and Giromill type
 The only commercially manufactured VAWT, was of the Darrieus
design, by a company called Flo Wind
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Wind Farm Construction
 12 sites constructed to date
 Standard design template
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How a Wind Turbine Works
 Most large modern wind turbines work in the same way
 They are 3 blade, upwind, HAWT, with an asynchronous generator
 The slow moving rotor is connected to a shaft, which is connected to the
gearbox, and then another shaft is connected to the generator
 The nacelle is rotated into the wind by an automatic yaw control
 The rotor speed is governed by ‘pitching’ the blades
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How a Wind Farm Works
Multiple wind turbines are connected electrically to the grid
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Wind Farm Construction
 Environmental Concerns
 Integration with wildlife
 Integration with livestock
 Effect on water and erosion
 Effect on grass and trees
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Leading Causes to Total Avian Deaths
500
450
Estimated Avian Deaths (millions)
400
350
300
250
200
150
100
50
0
Building Collisions
Cats
Power Lines
Pesticides
*Based on a review of literature and known mortality data conducted
in December 2010 (January 2011-Tetra Tech, Inc.)
Vehicles
Communication
Towers
Oil & Wastewater
Pits
Wind Turbines
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Renewable Wind Operations
 Remote Operations
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“Eye in the sky”
24/7 coverage
2 employee / shift
Approx. 600 turbines / employee
6 states, 12 sites
Third party contracts
Wind and solar ops
New expanded center
 Asset Management
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Land lease payment
NERC compliance
PPA contract management
Parts management
Financing activities
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Renewable Wind Operations
 Condition-based monitoring
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Industry leader in this area
Allows for small uptower repairs
One “find” pays for the system
Estimated 2010 O&M expense reduction $1.4MM
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Other Forms of Renewable Energy
 Renewable Energy is defined as “Energy which comes from natural
resources such as wind, sunlight, rain, tides, and geothermal heat, which
are naturally replenished”.
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Other Forms of Renewable Energy
 Solar Energy
 Solar Photovoltaic
 Solar Thermal
 Biomass Energy
 Direct Combustion
 Anaerobic Digestion
 Biofuels
 Hydroelectric Energy
 Run of River
 Tidal
 Wave
 Geothermal Energy
 Direct-use geothermal
 Hydrothermal geo-energy
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Growth Moving Forward
 In 2010, Duke Energy started with 3 solar energy plants.
 By the end of 2012 Duke will own approximately 20 sites Nation Wide.
 As time goes on, Duke Energy plans to continue to grow and expand
their solar business investing more interest in clean renewable energy
sources.
1,900 MW
2012
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Solar Energy
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Solar Photovoltaic
 Photovoltaic Panels
 Ground Mount Fixed
 Ground Mount with Tilt Drivers
 Roof Top Panels
Solar Photovoltaic
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Solar Photovoltaic
 Solar cell – A semiconductor device which generates direct current (DC)
electricity when exposed to sunlight. Also known as a photovoltaic cell.
Each cell generates approximately 0.5 volt. Solar cells can be wired in
series or in parallel to produce higher voltage and current. Made from
crystalline silicon or thin film amorphous silicon
 Solar Panel – A collection of solar cells, wired in series and/or in parallel,
and enclosed in a protective housing.
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Solar Photovoltaic
 Power inverters
 These panels will create DC
current that will be sent to
a power inverter to make it
useable, AC current.
 Standardizing
 Panels continue to get smaller
while improving power output
 Duke Plans to wait for technology
to settle into it’s most efficient product
before standardizing.
Solar Photovoltaic
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Solar Thermal
 2 Basic Designs
 Direct heating of air, water,
solids,
 Heat transfer for power generation
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Biomass Energy
 Biomass – A renewable energy source from organic matter such as
plants, animal wastes, and algae
 Biomass gives off energy in one of several ways
 Thermal Conversion – Combustion
 Chemical Conversion – ‘Black Liquor’
 Biochemical Conversion – Fermentation and Anaerobic Digestion.
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Anaerobic Digestion
 Anaerobic digestion – A series of processes in which microorganisms
break down biodegradable material in the absence of oxygen, used for
industrial or domestic purposes to manage waste and/or to release
energy.
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Hydroelectric
 Run of River Hydroelectric
 Wave Energy
 Tidal Energy
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Geothermal Energy
 2 Main uses of geothermal energy
 Direct-use geothermal – Primarily heat pumps, storage. For space heating.
 Hydrothermal geo-energy – Use of stored heat in magma to heat water/steam to
produce electricity.
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Valuation Issues - Government Incentives
• Production Tax Credits
• This is a per KW production tax credit.
• How should production tax credits be treated for property
tax valuation purposes?
• Credits are available for 10 years and do have value to a
qualifying buyer, but the benefit is diminishes each year
the facility is in service.
• Does this diminishing value warrant an economic
obsolescence adjustment during the first ten years, or an
accelerated depreciation?
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Valuation Issues - Government Incentives
• Cash Grants
• The grant is a one time receipt of cash and has no value
to a potential buyer other than a reduction in the cost of
assets to arrive at FMV.
• The grant is recorded as a reduction in PP&E.
• For property tax purposes this reduction in capital cost
has raised some questions.
• WY & TX have agreed to the concept of reductions in
capital cost.
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Valuation issues - Utilization Factors
• The utilization of a Wind or Solar facility is limited, and
therefore we must take into account “Utilization Factors”
when valuing these assets.
• Typically studies are performed prior to building a facility
that will give expected utilization factors. We can then
compare these to actual utilization in order to determine if an
adjustment is warranted for any given year.
• Also, industry averages of utilization can be used to set a
standard for comparison to actuals.
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Summary of Valuation Adjustments
• Renewable Energy and Property Tax Valuation
• With new forms of renewable energy and government
incentives we have to realized the importance of potential
valuation adjustments.
• Renewable energy is not always economically viable, but
necessary to meet carbon reduction requirements.
• It’s important to look at cost and income approaches,
taking into account government incentives, in order to
determine if there’s a case for economic obsolescence
adjustments.
• And finally taking into account utilization factors.
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Thank You For Your Time
If you have any questions or concerns feel free to
contact me. David Wright – 704-382-6125
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