Wind Power Spins Into Contention
1999 was a banner year for the wind energy
industry, and 2000 promises to be just as good
if not better since the renewal of the wind
energy tax credit near the end of 1999.
Preliminary industry estimates show more than
3,600 MW of wind generating capacity was
installed last year, bringing total worldwide
installed wind capacity to 13,400 MW. This total
represents an increase of more than 36 percent
over the 1998 total installed capacity of 9,751
MW and the largest worldwide addition to wind
capacity in a single year, according to American
Wind Energy Association records.
Between 1995 and 1998, 4,893 MW of wind
capacity was installed worldwide for an average
annual growth rate of 27.75 percent. Wind
capacity has surged from less than 2,000 MW in
1990 to 13,400 MW at the close of 1999.
These statistics seem to support European
Wind Energy Association claims that wind power
can produce 10 percent of worldwide energy
supply by 2020, even if electricity consumption
increases substantially. Denmark and Germany's
Schleswig-Holstein region are already
approaching this 10 percent figure.
"The 1990s have seen Europe emerge as a
world leader in wind energy development, and
we expect this strong performance to continue,"
said Christophe Bourillon, EWEA executive
director. "Our association has set targets for
Europe alone of 40,000 MW of wind capacity by
the year 2010 and 100,000 MW by the year
Bourillon attributes the surge in wind power's
popularity to concern about climate change,
worries about fossil fuel supplies, and the need
to sustain an ever-increasing population. "Wind
energy can reduce the amount of greenhouse
gases released into the atmosphere, preserve
valuable fossil fuel reserves for specialized uses
and help poorer rural countries develop without
resorting to polluting technology," Bourillon
said. "Although there are uncertainties because
of the changeable policy environment, we are
projecting more than 5,000 MW of new growth
in the United States over the next decade," said
Randall Swisher, AWEA executive director.
"Overall global investment in wind turbines
should surpass $200 billion by 2010. The growth
this past year is just the beginning of a rapid
investment into renewable energy sources
worldwide," said Michael Kujawa, senior Allied
Business Intelligence Inc. analyst.
The top three countries added 2,582 MW of new capacity and account for
percent of total capacity additions in 1999. (See table.)
According to the AWEA's recently released
"1999 Global Wind Energy Market Report," some
732 MW of new wind capacity and an additional
173 MW of repowering projects using new
turbines to replace less efficient older machines
were installed in the United States, bringing the
nation's total capacity to approximately 2,400
MW. 1999 saw wind capacity jump 40.8 percent
over the previous year.
An important catalyst to this unprecedented
growth was the expiration of the wind energy
production tax credit in June 1999. Developers
raced to complete projects before the expiration
deadline. The tax credit has since been
retroactively reinstated and will run through
Dec. 31, 2001. Wind energy producers can
continue to receive inflation-adjusted 1.5
cents/kWh tax credits for utility-scale projects.
AWEA expects the continuing tax credit to spur
more growth in the wind energy market.
Other driving forces included progressive state
policies, especially in Minnesota and Iowa, and
the movement toward customer choice and
green power programs in several states. Wind
energy's relatively low cost has led more than
80 utilities to offer a wind energy-based product
"After struggling for most of the '90s, it (wind
energy) has come of age at the very end of the
millennium," states the AWEA report. "One
reason for the limited activity in the mid-'90s
was the uncertainty caused by deregulation of
the electric sector, which caused many utilities
to re-evaluate their priorities, and freeze any
new investment in new capacity. In the
meantime, wind technology has continued to
mature, gradually convincing the electric
industry that it is ready for broad deployment."
The highest levels of development activity in
the next few years are expected to be
concentrated in the plains states and in Texas,
which has mandated 2 GW of new renewable
capacity in the coming decade. In the
Northeastern region, restructuring legislation is
opening the market to green power producers.
Enron Wind Corp. recently dedicated its Green
Power I wind power facility near Palm Springs,
Calif. The 22-turbine, 16.5 MW project was built
solely to supply emerging green power markets
and is the first major renewable power plant to
enter California's market since it opened to
competition in 1998.
Green Power I began producing power in June 1999. Traditionally, wind power
has been sold only under long-term contract to utilities, however, the Green Power I
facility was built without contract and its power is being sold through retail marketers.
The facility was developed, constructed and is
operated by Enron Wind Corp. The project uses
advanced Zond Z-750kW Series wind turbines.
With 158 and 164 foot rotor diameters,
approximately the size of the wingspan of a
MD-11 jumbo jet, the Z-750kW wind turbines
are the largest manufactured in the United
The U.S. Department of Energy has been
working with the nation's wind turbine industry
to improve technology and lower costs since
1992. The first turbines created under these
partnerships are already on the market, and a
whole new generation of turbines is expected to
arrive in 2002.
Two new turbines are under development. In
1994, DOE announced a $40 million program to
develop a new generation of innovative utility
wind turbines. The cost-effective turbines are
expected to expand markets for U.S. companies
in both the United States and in Europe, where
competition for new wind projects is driving
Eight industry teams created concepts for new
utility wind turbines rated up to 1 MW. In 1996,
the National Renewable Energy Laboratory
selected two firms, Zond Energy Systems Inc.
and The Wind Turbine Co., to move forward
with their concepts.
Zond, a subsidiary of Enron Wind Corp., is
developing the A-56, which will probably be a 1
MW machine. Its architecture has not yet been
determined, but it may use a direct-drive
generator alone or in combination with a
conventional gearbox. Significant departures
from conventional design are expected,
including purpose-designed airfoils and
low-solidity, flexible blades with individual pitch
control. Taller, low-stiffness towers are
expected, as are advanced control strategies to
optimize energy capture and reduce loads.
The Wind Turbine Co. is designing the WTC
1000, a lightweight, two-bladed, downwind
machine. The megawatt-scale turbine will
include purpose-designed blades with individual
pitch control, a variable coning rotor, highly
integrated structure and drivetrain,
load-mitigating control strategies, simplified
fluid systems, and an extremely tall guyed
tower. The WTC is targeted for applications in
the Midwestern states.
DOE is also working with three small turbine
manufacturers, selected through competitive
solicitation, to improve their turbines. The goal
is to develop tested systems up to 40 kW in
size that achieve a cost/performance ratio of 60
cents/kWh at sites with annual average wind
speeds of at least 12 miles per hour.
Cost/performance ratio is defined as the initial
capital cost of the turbine divided by its annual
Bergey Windpower Co. is working to improve
cost/performance ratio for its BWC Excel 40 by
designing a turbine with minimal maintenance
requirements. The BWC Excel 40 is a 40 kW
turbine targeted for battery charging in the
village power market. It is a three-bladed,
upwind, variable-speed machine with a
direct-drive permanent-magnet alternator. Rotor
blades will be pultruded fiberglass in three
lengths for use in different wind regimes. The
guyed lattice towers will be available in three
heights. Projected cost/performance ratio is 38
cents/kWh. DOE is funding $1.21 million of the
WindLite Corp. is developing an 8 kW,
variable-speed, direct-drive machine with a
rotor diameter of 23 feet. The turbine uses a
wound-rotor generator and proprietary controller
that significantly increases its battery-charging
efficiency compared to permanent-magnet
generators. The projected cost/performance
ratio for the WLC 7.5 is 46 cents/kWh. DOE is
providing $1.43 million in funding.
World Power Technology makes six small
turbine models. Its Windfarmer, a 7 kW
battery-charging wind turbine, is a
three-bladed, upwind, variable-speed machine
using a direct-drive, permanent-magnet
generator. Fiberglass blades will be used on a
16-foot diameter rotor. The machines will use a
unique, patented angle-furling governor for
protection in high winds. World Power is also
developing a counter-weighted, tilt-down
90-foot tower. Projected cost/performance ratio
is 59 cents/kWh. DOE is providing $1.25 million
Big Spring Keeps on Turning
As early as 1993, TXU Electric and Gas
investigated the level of demand for renewable
energy in Texas. Encouraged by the enthusiasm
of its customers toward green energy, TXU
unveiled plans for the $40 million Big Spring
wind power project near Midland in December
1998. Developed by York Research, the project
has 46 turbines with a total capacity of 34 MW.
The final phase, completed in April 1999, saw
the commissioning of the largest commercial
wind turbines in the world-four Vestas V66
turbines standing approximately 260 feet tall
above the elevated plateau of west Texas ranch
TXU believes that the project is testament to
the fact that as power technologies advance,
electricity generated by renewable resources
will become more common and economic.
The Big Spring project is built on mesas, rising
195 to 295 feet above the surrounding areas.
The winds accelerate as the move up over these
mesas. Annual average hub-height wind speeds
range from 18.4 to 22.2 mph over the site.
There are three phases to the site. Phase I has
16 Vestas V47 660 kW turbines, Phase II has
26 Vestas V47s, and Phase III has the four
Vestas V66 1,650 kW turbines.
Projected annual electricity generation for Big
Spring is 117 million kWh.
Both turbine models use three rotor blades of epoxy and fiberglass composite.
Crosswind separation of the machines is nominally 3.5 rotor diameters. Row-to-row
spacing of the machines exceeds 10 rotor diameters to minimize the impact of
turbulence from adjacent rotors.
The turbine control system monitors turbine
starts and stops under normal operating
conditions and also protects the turbines under
extreme emergency conditions such as faults
caused by a loss of grid load while under power
or a component failure. In addition, the system
manages the power output of each turbine by
pitching the blades and changing the generator
slip to maximize energy production while
minimizing loads at wind speeds greater than
The control system is operated by a digital
computer using Vestas-developed programs.
Portions of the system are located in the base
of the tower and in the nacelle of the wind
turbine. These are linked by fiber optic lines to
minimize interference and damage from
A key feature of the control system is OptiSlip,
which controls loads and spikes from the
turbines under high wind speeds. OptiSlip
allows the turbine to operate in a similar way to
a variable speed machine, preventing the drive
line of the machine from experiencing torque