The utilization of wind energy is technically feasible as evidenced by the many past demonstrations of wind generators. The cost of energy from the wind has been high compared to fossil fuel systems; a sustained development effort is needed to obtain economical systems. The variability of the wind makes it an unreliable source on a short term basis. However, the effects of this variability can be reduced by storage systems or connecting wind generators to: (1) fossil fuel systems; (2) hydroelectric systems; or (3) dispersing them throughout a large grid network. Wind energy appears to have the potential to meet a significant amount of our energy needs

Savino, J. M.

Thomas, R. L.

English

NASA Technical Reports Server

NASA TECHNICAL NASA TM X-71523
MEMORANDUM
(NASA-TM-X-71523) STATUS OF WIND-ENERGY N74-19
CONVERSION (NASA) 9 p HC $4.00 CSCL 10A
Unclas
G3/03 34365
STATUS OF WIND-ENERGY CONVERSION
by Ronald L. Thomas and Joseph Ivi. Savino
Lewis Research Center
Cleveland, Ohio 44135
TECHNICAL PAPER presented at RANN Symposium
sponsored by the National Science Foundation
Washington, D.C., November 18-20, 1973
REPRODUCED BY
NATIONAL TECHNICAL
INFORMATION SERVICE
U. S. DEPARTMENT OF COMMERCE
SPRINGFIELD, VA. 22161
https://ntrs.nasa.gov/search.jsp?R=19740011592 2020-03-23T11:46:42+00:00Z
STATUS OF WIND-ENERGY CONVERSION
by Ronald L. Thomas and Joseph M. Savino
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio
INTRODUCTION
Can the energy in the winds be utilized to help meet our nation's
energy needs? That is the primary question to be answered concerning a
very old but presently little-used source of energy.
Wind energy has several advantages that make it worthy of a re-
evaluation as a potential energy source. These advantages include:
1. Wind energy is a free, clean, nondepletable energy source. Wind
is a form of solar energy that nature concentrates in certain areas and
allows us to capture it without using a large amount of land area.
CN 2. Preliminary estimates indicate that wind could supply a signifi-
cant amount of our electrical requirements.(1 )
F-.
3. Utilizing energy from the wind is technically feasible; this is
discussed more in detail below.
The disadvantages of wind energy include its variability and the
high systems costs of past efforts. On an hourly or daily basis, the
winds are not dependable, but on a monthly and yearly average the winds
are a rather firm energy source. Past experience has shown that wind
energy systems have usually cost about two to five times as much as
fossil fuel systems on a cost per kilowatt-hour basis.(2 ) However, now
that fuels are becoming expensive, it is important to re-examine wind
energy systems to determine if such systems can be made compatible with
the variability of the wind and if the high costs of such systems can be
reduced.
Obviously there is no doubt that wind generators are technically
feasible. The question can then be asked: Why haven't they been more
fully utilized? There appears to be several reasons:
1. The costs of wind-generator systems have been high compared to
fossil-fuel systems.
"
1 )NSF/NASA Solar Energy Report: Solar Energy as a National Energy
Resource, Dec. 1972.
(2)E. W. Golding, "Electrical Energy from the Wind," The Engineering
Journal (England), June 1957.
22. The wind is variable and the wind generator by itself cannot
always produce power on demand.
3. There have been no recent sustained development efforts, pri-
marily because of reasons 1 and 2.
EXPERIENCE WITH WIND GENERATORS
Wind generators are technically feasible. Many moderate sized
machines have been built and tested, for example:
1. The Dutch have used wind generators for years to provide power
for pumping water and grinding grain. Figure 1 shows a typical Dutch
windmill.
2. An experimental 100 kilowatt wind generator was built by the
Russians at Balaclava in 1931. This wind generator, shown in figure 2,
had a 100-foot-diameter rotor on a 100-foot tower and delivered 100 kilo-
watts at a wind speed of 24 miles per hour. In addition to this machine,
many smaller machines have been installed in Russia to supply power to
agricultural communities.
3. The Danes used wind as a major source of power for many years.
They built the Gedser Mill System, shown in figure 3, in 1957 and oper-
ated it through 1968. This wind generator produced 200 kilowatts in a
wind of 33 miles per hour with a rotor diameter of 79 feet and a tower
height of 85 feet.
4. The English built several large wind generators. One machine was
the Enfield-Andreau shown in figure 4. This machine was built in the
early 1950's and had a maximum output of 100 kilowatts. The rotor was
79 feet in diameter mounted on a 100-foot tall tower.
5. The Smith-Putnam machine, shown in figure 5, was built in Vermont
in 1941 and supplied power into the hydroelectric grid. This wind gen-
erator was the largest ever built with a rating of 1.25 megawatts in a
30 miles per hour wind from a 175 foot diameter rotor on a 110 foot tower.
6. The Germans did some fine work in the 1950's and 1960's under the
direction of Dr. U. Hutter. Machines of 10 kilowatts and a 100 kilowatt
were built and tested over this period. The machines used light Fiberglas
blades with a simple hollow pipe tower with guy wires as shown in fig-
ure 6. An interesting point of this design is that it delivered its
rated output of 100 kilowatts at 18 miles per hour. At 18 miles per hour
most of the other machines were just beginning to produce power. The
German effort represents the most modern work to date for machines of
this size.
No large machines are presently in operation. However, several
firms around the world are supplying wind generators in the range of
35 kilowatts or less.
DISCUSSION
As mentioned above, the wind is not dependable on a short-term basis
but on a monthly and yearly basis, the winds are fairly reliable. Sev-
eral options are available for reducing or accommodating the effects of
wind variability; these are:
(1) Storage systems, such as those shown in figure 7, including bat-
teries, flywheels, pumped hydro-storage, compressed air, and
electrolysis of water to hydrogen
(2) Connecting wind generators to small diesel-electric systems as
shown in figure 8. Such systems would save fuel and provide
supplemental power.
(3) Large wind systems may be connected to hydroelectric systems
(fig. 9) to provide base-load power. In such an arrangement
the wind generators could supply power whenever the wind is
blowing allowing water to be saved to be used as the wind drops
off. Our hydroelectric systems are water limited and wind gen-
erators could increase the base load of the systems.
(4) Wind generators connected in a large grid (fig. 10) may prove
practical for generating base-load power. Over a large area
the wind may be always operating some percentage of the wind
generators.
PLANNED PROGRAM
Studies sponsored by NASA and the NSF are planned to assess these
applications and to determine the cost goals for the wind-generator sys-
tems. Several research areas will be included in the program for the
development of wind as a practical energy source; these include:
(1) Cost reduction of subsystems, components and total systems
(2) Wind characteristics to determine practical potential in the U.S.,
the wind regions, and preferred sites
(3) The user requirements including verification of site character-
istics
(4) The legal, environmental, institutional, and aesthetic issues
(5) The testing of larger and improved systems
Some of the first steps in this program are:
(1) Design, build, and test modern machines for actual applications.
This will provide baseline information for assessing the potential of
wind energy as an electric power source.
(2) Operation of wind generators in selected applications for deter-
mination of actual power costs
(3) Identification of subsystems and components that may be further
reduced in cost.
The practical conversion of wind energy is a major part of the NSF
$12 million FY 1974 Solar Energy Program. The NASA-Lewis Research Center
has also been working in the area of wind conversion for about two
years. Lewis, at the request of the Puerto Rican government, has
agreed to perform a conceptual design of a wind generator for Puerto Rico.
Puerto Rico has favorable winds and a rapidly increasing demand for elec-
tric power. Possibly, wind power may prove to be a valuable source of
energy for Puerto Rico. The NASA will be contributing to the overall NSF
Wind Program, particularly in the 100 kilowatt and megawatt size conver-
sion systems. From the 100 kilowatt and megawatt systems tests, it will
be possible to make a realistic assessment of wind energy conversion sys-
tems costs, operating characteristics, and the potential for significant
power production.
As its part of the program, NASA will design the 100 kilowatt system
for test in 1975. This machine will be similar to the German design
shown in figure 6. The NASA design calls for a rotor of 125 feet in diam-
eter mounted on a 125-foot tower. The machine is designed to provide a
net output of 100 kilowatts in a wind velocity of 18 miles per hour. The
controls will be located in a remote control room at the base of the
tower. The pitch of the rotor blades will be varied to maintain syn-
chronous speed for the generator.
The NASA-designed 100-kilowatt system will provide operation and
performance data and an indication of the costs of wind energy. By 1976
additional 100 kilowatt field tests are planned in several locations of
the country. In parallel with the 100 kilowatt projects, megawatt de-
signs will also begin this year. The results of the 100 kilowatt tests
and the Phase 0 applications and wind studies will help directly in the
megawatt systems design. If these results are satisfactory, testing of a
megawatt system is planned for 1976-77, with larger systems following.
CONCLUDING REMARKS
In conclusion, the following comments are relevant to the utiliza-
tion of wind energy as a source to help meet our energy needs.
1. The utilization of wind energy is technically feasible as evi-
denced by the many past demonstrations of wind generators.
52. The cost of energy from the wind has been high compared to
fossil-fuel systems; a sustained development effort is needed to obtain
economical systems. Also, wind-energy systems will become more econom-
ically competitive if present fossil fuels continue to rise in price.
3. The variability of the wind makes it an unreliable source on a
short-term basis. However, the effects of this variability can be re-
duced by storage systems or connecting wind generators to (1) fossil fuel
systems, (2) hydroelectric systems, or (3) dispersing them throughout a
large grid network.
4. Wind energy appears to have the potential to meet a significant
amount of our energy needs. It will not meet all our needs, as will no
other one source.
Wind energy is one of the clean, nondepleting energy sources that
should be seriously investigated as a source to help meet our nation's
energy needs.
Figure 2. - 100 kW (24.6 mph wind) Russian wind
generator.
Figure 1. - Typical Dutch windmill.
Figure 3. - Danish Gedser mill wind-tur-
bine200 kW (33.6 mph wind). Figure 4. - English Enfield-Andreau wind-turbine
100 kW. (30 mph wind.)
7 "
Figure 5. - American Smith-Putnam wind
generator 1.25 mW (30 mph wind).
Figure 6. - German (Hutter designed) wind generator 100 kW (18 mph
wind).
BAT
T
ERY
FLYWHEEL
MOTORIGENERATOR
TANK
COMPRESSED AIR ) csm--om
Figure 7. - Storage systems for wind eneratorsCS-68733Figure 7. - Storage systems for wind generators.
E-7912
OIL
CS-68734
GENERATOR c
CS-68735
Figure 8. - Wind generators with existing Diesel-Electric Systems. Figure 9. - Wind generators integrated with 
Hydro-Electric Systems.
-CD-Il59-03
FeCS-6873Z
Figure 10. -Wind generators integrated on a large grid.


Status of wind-energy conversion

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server