WIND ENERGY WEEKLY
Vol. 15, #680, 15 January 1996, published by the American Wind
The full text of the WEEKLY is available
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It's official: 1995 warmest year on record
Wind integration not major problem for utilities
Ontario Hydro awaits final bids on renewables RFP
Wind-diesel workshop headed for Halifax in June
1995 HOTTEST YEAR ON
RECORD: U.K. SCIENTISTS
A preliminary assessment of weather data from around the
world indicates, according to the British Meteorological Office
and the University of East Anglia, that 1995 was the warmest year
since recordkeeping began in 1856.
The earth's average surface temperature for the entire year
was 58.72 degrees Fahrenheit, the groups said January 3, or 0.07
degrees warmer than 1990, the previous record-holder.
In addition, they said, the five-year period from 1991
through 1995 was the warmest on record, even though the earth was
cooled for nearly two years by haze from the eruption of the
Philippine volcano Mt. Pinatubo in 1991.
The new finding can be expected to lend additional credence
to the theory that the earth is being warmed by human activities,
in particular the emission of greenhouse gases from the burning
of fossil fuels. An international panel of climate experts said
in a recent report that scientific evidence to date "suggests a
discernible human influence on climate."
Dr. James E. Hansen, director of the National Aeronautics
and Space Administration's Goddard Institute for Space Studies in
New York City, noted that the 1995 record was established despite
the fact that two natural contributors to warming, solar energy
and the El Nino current in the Pacific Ocean, were neutralized.
Hansen, who said in 1988 that it appeared that the global climate
had begun to change, told the NEW YORK TIMES that he expects at
least "a couple more" recordbreaking years before the year 2000.
The British groups' finding is based on analysis of
temperature readings from meteorological stations on land and at
sea around the world. The Goddard Institute, which maintains a
separate set of long-term data, also found 1995 to be the warmest
year ever, but said the difference between it and 1990 was within
the margin of sampling error and is therefore statistically
A third set of measurements, the Spencer-Christy series of
satellite readings begun in 1982, showed 1995 to be only about
average for the period from 1982 to 1991, according to Dr. John
R. Christy of the University of Alabama. Christy noted, however,
that the 1982-1991 period was a warm one in the first place, and
said the rate of warming measured by satellites is beginning to
move into the range expected to result from human-caused warming.
Although the satellite measurements are considered to be
more accurate than other data, they measure temperature only in
the lower atmosphere, rather than at the earth's surface.
UTILITY WIND INTEGRATION ISSUES NOT
SERIOUS, SAYS ELECTROTEK'S PUTNAM
Integration of wind power plants into utility operating
systems "has not been a problem," according to a new paper by
Robert Putnam of the consulting firm Electrotek Concepts, "and
any issues that have developed, such as intermittency and voltage
regulation, can be addressed by accepted power system procedures
Putnam's paper, which has been submitted to the annual
conference of the Institute of Electrical and Electronic
Engineers (IEEE), was funded by the U.S. Department of Energy and
is based on interviews with system operators and dispatchers from
Pacific Gas & Electric Co. (PG&E) and Southern California Edison
Co. (SCE). Both utilities have had extensive experience with the
integration of wind energy on their systems since the early
Putnam divides integration issues that have arisen with wind
into "interface (or engineering) issues, operational issues,
[and] planning issues." He describes how the interface and
operational issues which were the focus of his investigation have
been handled as follows:
Interface issues include harmonics, reactive power supply,
voltage regulation, and frequency control.
Harmonics: "Harmonics are undesirable distortions of the
utility AC sinusoidal voltage and current waveforms. . . .
Harmonics are of concern due to potential damage to both utility
distribution and customer load equipment. Some first-generation
wind power plants installed in the early 1980s employed older,
alternative conversion systems such as those using 6-pulse
thyristor bridge configurations without external harmonic
correction or filtering, resulting in the production of lower
order harmonics . . . Advanced converter systems available today
produce output with very little harmonic distortion, well below
that specified in the IEEE Recommended Practice for Monitoring
Power Quality. With the addition of harmonic correction devices
and the current trend towards the use of advanced power
electronics in variable-speed wind turbines, harmonics are no
longer a significant utility concern."
Reactive Power Supply: "Early wind plants using induction
generators were installed with inadequate hardware for reactive
power compensation. As a result, utilities experienced increased
line losses and difficulty controlling system voltage. . . . Wind
plant operators were economically incented to improve the quality
of power injected into the PG&E system when PG&E began to charge
for excessive VAR [reactive power] support. SCE and PG&E now
require small power producers using induction generators to
provide near unity power factor at the point of interconnection.
Power electronics technology used with modern, variable-speed
wind turbines have demonstrated a full range of power factor
control under all operating conditions, even with the wind
turbine shut down."
Voltage Regulation: "Difficulty in controlling voltage
regulation is accentuated when the wind plant is located in a
remote area and connected to the utility through transmission
lines originally designed to service only the load in the area.
SCE experiences periodic voltage limitations on its 66 kV system
in Tehachapi due to the weak system interconnection. Solutions
considered by SCE include new transmission lines, alternative
line arrangements, the addition of static or adaptive VAR
controllers, and wind plant curtailment. Based on an economic
analysis of each of these alternatives, SCE has determined that
the least cost option is to curtail wind plant production and to
compensate wind plant operators accordingly . . . "
Frequency Control: "Utilities operating wind power plants
connected to weak, isolated grids can have difficulty maintaining
normal system frequency. System frequency varies when gusting
winds cause the power output of wind plants to change rapidly.
While maintaining normal system frequency has not been a problem
in the windfarm areas of California, it has been well documented
on the Hawaii Electric Light Company (HELCO) system. [An] EPRI
[Electric Power Research Institute] study showed that a reduction
in capacity or an increase in demand of 10 MW per minute, caused
by a combination of wind power output changes and/or unscheduled
load changes, would cause HELCO's load-following generation
plant, Hill 6, to trip, resulting in a loss of ability to
regulate system frequency within acceptable limits. The report
concludes that in order to accommodate more wind energy, the
HELCO system would require
(1) the use of modern, variable-speed wind turbines with
power electronic control and interface to the grid (the
power electronic system can be controlled to limit wind
turbine output during gusty or strong wind periods) and/or
(2) automatic generation control with additional spinning
In the case of SCE and PG&E, the short-term variations in wind
plant output are small relative to normal load fluctuations and
therefore to not significantly impact the ramping and cycling
duties of available system regulating capacity."
Operational issues include operating reserve, unit
commitment and economic dispatch, system stability, and
transmission and distribution system impacts.
Operating Reserve: "Utilities carry operating reserve to
assure adequate system performance and to guard against sudden
loss of generation, off-system purchases, unexpected load
fluctuations, and/or unexpected transmission line outages.
Operating reserve is further defined to be spinning or non-
spinning reserve. Typically, one-half of system operating
reserves are spinning, so that a sudden loss of generation will
not result in a loss of load, with the balance available to serve
load within 10 minutes. Any probable load or generation
variations that cannot be forecast have to be considered when
determining the amount of operating reserve to carry. . . . At
current wind plant penetration levels in California, the
variability of wind plant output has not required any change in
operating reserve requirements. The exact point at which the
integration of intermittent generation such as wind begins to
degrade system economics is unclear, but the technical literature
suggests that it is at penetration levels in excess of five
percent. Intermittency is becoming an increasing concern to
utility operators in California, particularly during low demand
periods, since wind plant penetration is beginning to reach this
level. . . . As markets for electricity become more competitive,
the ability to forecast and control the wind resource will
increase the value of wind energy to utilities.
Unit Commitment and Economic Dispatch: Unit commitment is
the scheduling of specific power plants on the utility system to
meet expected demand. Units are committed to the schedule based
on "generation maintenance schedules, generator startup and
shutdown costs, minimum fuel burn requirements, and seasonal
availability of intermittent resources such as hydro and wind.
This schedule is usually made at least 24 hours in advance. . . .
The most conservative approach to unit commitment and economic
dispatch, and the one adopted by PG&E and SCE, is to discount any
contribution from interconnected wind resources . . . In fact,
wind plant output may be fairly predictable as in the case of the
Altamont Pass region of California, due to seasonal and diurnal
wind resource characteristics observed over many years of wind
farm operation or as a result of wind resource monitoring
programs. Further research is needed to develop the capability
to accurately forecast wind plant output on an hourly basis over
time periods ranging from one day ahead to one week . . . "
System Stability: " . . . Large wind turbines typically
have low-speed, large-diameter blades coupled to an electric
generator by a high-ratio gear box. This feature results in a
large turbine inertia and low mechanical stiffness between
turbine and generator [which] gives large wind turbines excellent
transient stability properties. Operating experience with wind
power plants in California confirms that wind turbine transients
due to speed fluctuations or network disturbances have not
resulted in system stability problems."
Transmission and Distribution System Impacts: Wind systems
can affect transmission and distribution systems by "[altering]
the design power flow or [causing] large voltage fluctuations . .
. " Also, "islanding," in which a wind plant might energize a
line that otherwise would be dead, has been a concern.
"Operating experience with wind power plants in California has
not shown system protection or safety to be an issue.
Circumstances that may have led to islanding in the past have
been identified, and hardware and detection schemes have been
tested and approved. In PG&E's case, for example, the
installation of direct transfer trip equipment is designed to
trip the wind farms to prevent them from islanding."
Concludes Putnam, "The positive integration experience with
wind energy in California . . . can provide valuable insights to
utilities planning new projects and needs to become more widely
ONTARIO HYDRO AWAITS FINAL
BIDS FROM SHORT LIST
Ontario Hydro has selected a short list of bidders from
those replying to its 60-MW request for proposals (RFP) for
renewable energy projects (see WIND ENERGY WEEKLY #661, August
28, 1995), and is awaiting final bids.
Bunli Yang, the Canadian utility's renewable energy
strategist, said final bids are due by the end of this month on
the 24 proposals on the short list. Thirty-six proposals were
There were three wind energy categories in the RFP, which
asked for bids in six technology classes. The wind groupings
After the RFP was issued, the deadline for bids in the
medium wind farm category was postponed for 42 weeks to allow
developers time to conduct wind resource assessments.
- Individual wind turbines, "Canadianized" (specially
outfitted for cold weather conditions and/or partially
fabricated in Canada: size no minimum to 1 MW.
- Small wind farms: 2 MW-5 MW.
- Medium wind farms: 10 MW-22 MW.
In the individual category, bidders on the 11 shortlisted
projects are: Fuller Electric, J. Weilandt, J. Liovas (2
proposals), Bidsmore, Controltech (3 proposals), Windtechnik,
WenvorTechnologies, and Great Lakes Power. In the small wind
farm category, four proposals, from Tacke Windpower, New World
Power, Wolfe Island Power, and York Research, were shortlisted.
Ontario Hydro's plans for a Round 2 renewables RFP for 65 MW
of capacity have been delayed, Yang said, due to a decision by
the Ontario provincial government to charter a citizens' advisory
group, the McDonald Advisory Committee, on competition in the
electric power industry. The committee is scheduled to report on
its findings in April. "The key issue [in Round 2] is how to
encourage participation of our own business units," Yang said.
"We are still having internal discussions on that, but I don't
anticipate that we will be able to confer with stakeholders until
well after the McDonald Committee finishes work."
WIND-DIESEL WORKSHOP SLATED
FOR NOVA SCOTIA IN JUNE
Halifax, Nova Scotia, will be the site of the 10th
International Wind-Diesel Workshop, sponsored by AWEA and the
Canadian Wind Energy Association (CanWEA) and scheduled for June
The workshop will be held at the Technical University of
Nova Scotia and will include sessions on: technology review;
remote community priorities, needs and requirements; diesel
industry and plant operator requirements; financing, joint
venture and implementation schemes; and penetration, storage,
control and reliability issues, among others. Deadline for
submission of papers or presentations is March 31.
The fee for the meeting will be Cdn $150. For further
information, contact Malcolm Lodge, Island Technologies, Inc., PO
Box 832, 49 Pownal Street, Charlottetown, PEI, C1A 7L9, phone
(902) 368-7171, fax (902) 368-7139.
AMERICAN WIND ENERGY ASSOCIATION
FOR IMMEDIATE RELEASE: April 12, 1996
Contact: Jessica Maier, (202) 383-2500
WORLDWIDE WIND CAPACITY SURPASSES 5,000 MW
MARK--AND CONTINUED GROWTH IS EXPECTED
New Installations Expected to Total 18,500 MW by 2005
Worldwide installed wind power capacity surged to over
5,000 MW during the first quarter of 1996, and this strong growth
in international wind energy markets is expected to continue,
according to official projections released today by the American
Wind Energy Association, which referred to wind power as "the
world's fastest growing electric power technology."
Total installed wind power capacity will reach over 18,500
MW by 2005, according to the projections, representing a market
of over $18 billion. Over 1,300 MW of new wind energy capacity
was installed around the world in 1995 alone, a 35% percent
increase in capacity over 1994. However, an imbalance in the
world market exists: while many markets flourished in 1995, some
slowed drastically--particularly the U.S.
Germany and India accounted for almost two-thirds of all
new installations last year-- nearly 900 MW. The U.S., on the
other hand, lagged behind, adding only 41 MW of new wind
capacity. In the last ten years, the U.S. share of total world
wind energy capacity has dropped from about 90 percent to 30
percent. "The rest of the world is forging ahead with wind
energy development and leaving the U.S. in the dust," said AWEA's
executive director Randall Swisher. "The current and future
competitiveness of the U.S. in global energy markets is at risk."
Stagnation in the U.S. market can be attributed to the
pending restructuring of the electric utility industry, which has
made utility power planners gun-shy of planning any new capacity
additions. The outlook for U.S. growth is hopeful, though, if
the industry is restructured in a way that is friendly to
renewables. AWEA's projections predict that U.S. wind capacity
additions will grow slowly until about 2000, and then increase
over the next several years, totalling about 2,700 MW of new
capacity by 2005.
"Utility restructuring has caused a short-term mentality
among many power planners, making them hesitant of any new
capacity additions," said Swisher. "This short-sighted outlook
could unfairly disadvantage renewables when the industry is
restructured. If the U.S. wants to retain its leadership role in
world energy markets, strong policy encouraging renewables must
exist." Some of the policies AWEA proposes to ensure U.S.
AWEA's projections are based on publicly and privately
held information on existing installations and planned capacity
additions worldwide. The projections assume no significant
political shifts that would cause an increase or decrease in
national support for wind energy. They also assume only a
moderate shift in fossil fuel prices and efficiency gains from
combustion technologies, as well as moderate improvements in the
cost of wind-generated power.
- As part of restructuring, implementation of a renewables
portfolio standard, which would rely on market mechanisms to
ensure that a minimum level of renewables is developed.
- Sufficient federal research and development funding to
ensure that wind technology continues on the course that
has reduced its costs over 80% in the last 15 years.
- Continuation of current production tax credits to help wind
achieve tax equity with conventional fuel sources.
- Federal international aid and trade programs to support U.S.
industry in the development of renewable energy projects
Growth of Installed Wind Capacity in Selected Countries, 1995
Country New capacity Total installed % growth,
installed, 1995 capacity, 1995 1995
India 383 MW 565 MW 210%
Spain 73 MW 145 MW 100
Germany 498 MW 1136 MW 77
Holland 106 MW 259 MW 69
United Kingdom 46 MW 193 MW 31
China 7 MW 36 MW 23
Denmark 75 MW 614 MW 14
United States 41 MW 1770 MW 2.4
TOP FIVE GROWTH MARKETS FOR WIND ENERGY
Projected Additions Through 2005
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Total
U.S. 30 150 200 150 200 300 300 400 500 500 2730
India 400 300 300 250 250 200 200 200 200 200 2500
China 50 50 50 100 150 150 150 200 200 200 1300
Germany 300 200 100 100 100 100 100 100 100 100 1300
Spain 100 125 150 150 200 150 100 100 100 100 1275
AWEA, formed in 1974, is the national trade association of the
U.S. wind energy industry. AWEA's membership of over 800 includes
turbine and component manufacturers, project developers,
utilities, academicians, and interested individuals from 49
Renewables Portfolio Standard A Detailed description is available from AWEA on
the World Wide Web