a price of $59/ton. In this scenario, the
purchase of nearly 2,000 k Wh of wind is
required to reduce carbon emissions by
1 ton.
When purchasing varying amounts of
energy in a way that maximizes efficiency,
the model predicts 2,390,000 k Wh of wind
energy purchased at a cost of $495,000
($0.207/k Wh). The natural gas bill was
reduced by $202,320 for the 25,290 MMBtu
reduction, putting the added cost of
utilizing wind energy at $292,000 to
reduce carbon emissions by 1,463 tons –
a cost of $200 per ton. The greater efficiency achieved in this scenario results in
1,600 k Wh of wind energy required to
offset 1 ton of carbon.
A tradeoff exists between these two
scenarios: The constant 5 MW results in a
lower price for 1 ton of carbon reduction,
but requires purchasing more wind energy
to achieve that reduction. The variable
energy purchasing has a higher cost per
ton, but sees greater carbon reductions
for the wind energy purchased ( 1,600
k Wh/ton versus 2,000 k Wh/ton).
With the goal of reducing carbon
emissions, the constant 5 MW is more
economically viable. However, as a comparison, current post-combustion CO2-
capturing methods have an operating
cost of $57/ton of CO2 removed, as
determined through the International
Energy Agency Greenhouse Gas R&D
Programme ( www.ieagreen.org.uk/
glossies/co2capture.pdf). The Chicago
Climate Exchange currently trades at
$3.65/ton of CO2. When compared to the
efficiency gains and CO2 reductions of
installing an updated gas turbine, pur-
chasing wind power is a much less cost-effective alternative.
Future Efficiency Gains
Gas turbine No. Eight came online in
1986 and has been the primary unit ever
since. Current plans are to install a new
primary gas turbine, using gas turbine
No. Eight for peak loads as necessary.
This new turbine could come online as
soon as 2010.
The increased operating efficiency of
this new unit will greatly reduce the
power plant’s fuel requirements. Model
predictions show that for fiscal year
2006, during which 4,401,000 MMBtu of
fuel was purchased, operating the new
turbine could have reduced total fuel consumption to 4,155,000 MMBtu – a $2 million savings in fuel costs and a 5. 6 percent reduction in carbon emissions.
Modeling the effects of bringing in the
constant 5 MW of wind power, the carbon
emissions would have been reduced by
11. 6 percent; however the sum of the fuel
and imported electricity costs would have
actually risen by $331,000.
While purchased wind power may
reduce carbon emissions by a greater
amount, the new turbine allows for both
a reduction in CO2 and significant reductions in operating costs. These savings
result in money that will be available for
continued improvements in CHP efficiency and to allow UT to fund academics and
research instead of the fuel bill. The new
turbine will also provide capacity to handle
future campus growth (fig. 3).
Although UT remains interested in
the promising wind energy industry,
detailed analyses of the costs and impacts
of integrating wind energy purchases with
current plant operations show that
adopting the technology would have a
negative effect on UT plant efficiencies
and an increase in operating costs.
Because the department provides
100 percent of the campus energy with
an optimized baseloaded system, importing wind power would cost the plant more
than just the premium rate of wind energy
overall. Through the new gas turbine and
other planned projects, plant efficiency
will continue to increase as the campus
continues to grow – maintaining UT’s tradition of low-cost, reliable energy generation. Meanwhile, the University of Texas
will continue to look for ways to integrate
renewable energy resources for the main
campus in ways that take the greatest
advantage of what they offer, while doing
what is best for future campus growth.
Renewable resources will also be considered for noncontiguous portions of the
campus not served by the university
CHP system.
Figure 3. University of Texas at Austin: Campus Size, Electricity Demand and Fuel Usage,
1996-2010.
Ryan Reid serves as assistant
manager, plant engineering, in
the University of Texas at Austin’s
Utilities and Energy Management
Department. He assists in a variety
of plant projects aimed to improve
the reliability, performance and efficiency of
existing and planned systems. Reid is a recent
graduate from the University of Texas at Austin
with a bachelor’s degree in mechanical engineering. During his undergraduate study, he
served as an intern for the power plant and
generated environmental and efficiency modeling
tools. He can be reached at reidrb@austin.
utexas.edu.
Fuel Use (MMBtu)
Campus Size Increase
Electrixity Use Increase
Fuel Use (MMBtu)
Source: “Study in the Benefits of Efficiency Improvements to Emissions
and Fuel Costs,” Ryan Reid, et al.
Ryan Thompson began working
at the University of Texas at Austin’s
Utilities and Energy Management
Department 10 years ago. As project
manager, he currently is responsible
for planning, design and oversight
of projects that improve operability and efficiency
of equipment within the combined heat and
power plant. He teaches a course in wind power
delivery systems at Austin Community College.
Thompson was formerly in the U.S. Naval Nuclear
Propulsion program for six years. He holds a
master’s degree in mechanical engineering from
the University of Texas at Austin. His email address
is Ryan. Thompson@austin.utexas.edu.
