WIND ENERGY SYSTEMS - Cd3wd

Chapter 7—Asynchronous Loads 7–39
(3.23 to 3.52 MJ/MJ). There are new types of fossil fueled generating plants being developed
which use systems like magnetohydrodynamics and combined cycles to get the heat rate down
to 8000 Btu/kWh (2.35 MJ/MJ) or less.
The cost of fuel per kWh can be defined as
C fuel = C MB (heat rate) (23)
where CMB is in dollars per million Btu and the heat rate is in million Btu per kWh generated.
Example
The cost of coal delivered to a plant in Kansas is $0.71/106 Btu in 1981 dollars. The heat rate is
9800 Btu/kWh. What is the fuel cost per kWh?
C fuel =($0.71/10 6 Btu)(0.0098 × 10 6 Btu/kWh) = $0.0070/kWh
Example
The cost of residual low sulfur fuel oil delivered to a municipal generating plant in 1981 is $8.26/106
Btu. The heat rate is 11,000 Btu/kWh. What is the fuel cost?
C fuel =($8.26/10 6
Btu)(0.011 × 10 6 Btu/kWh) = $0.0909/kWh
Numbers such as shown in these examples are obsolete as soon as they are written, but
they do illustrate the fact that oil fired electricity costs considerably more than coal fired
electricity. This means that wind machines will probably be used to save oil before they can
be justified to replace new coal generation.
We should mention that relatively large amounts of oil and natural gas are used as boiler
fuels by the utilities. In 1977, 90.3 × 10 9 m 3 of natural gas and 574.9 million barrels of oil
were burned as boiler fuels[16]. Fossil fuels were used to generate 1, 648.7 × 10 9 kWh, with
coal contributing 60 percent of the total, gas 19 percent, and oil 21 percent. The average
power from the oil and gas fired units was 75,000 MW.
It is national policy to replace this oil and gas fired electricity with electricity generated
from coal and nuclear plants. However, political, environmental, and economic problems are
delaying this transition. It appears that significant quantities of oil and gas will be used for
boiler fuel for some time.
It seems logical that wind generated electricity would be used first as a fuel saver, so
that less oil and gas would be burned when the wind is blowing. This eliminates the extra
expenses for storage equipment and results in minimum cost to the electricity customer. The
major technical limitation is the capacity of existing transmission lines. That is, a region of the
country with 10,000 MW of oil and gas generation may only have 1000 MW of transmission line
capacity which could be used to move wind generated electricity into the region. Additional
Wind Energy Systems by Dr. Gary L. Johnson November 21, 2001