UI Steam Turbines

Summary
The goal of this project is to draft a plan for integrating one to three Microsteam(TM) turbines into the University of Idaho steam plant for the purposes of reclaiming energy from backpressure steam produced by the boilers. These turbines will convert waste steam back into electric power which can be used to offset electricity costs to the University, saving money.

Goals
Tasks for this project are divided into two phases. In Phase One, multiple turbine packages will be analyzed from an economic standpoint. The two best options will be presented to Facilities. This will be done over the course of the spring semester. Phase Two will begin over the summer and through the fall semester. A more in-depth economic analysis and study of implementation options will be developed during this phase.

Phase One consists of an analysis of the economics of one, two, three, or four turbines installed at the University of Idaho steam plant. The two most optimal turbine packages will be presented to Facilities. An analysis based on historical steam production trends and research of similar projects will be included in this phase. Additionally, preliminary research into grid connection options will be performed towards the end of the semester. At the end of this phase, a presentation of the developed economic analysis and the preliminary electric grid integration options will be given to Facilities.

Phase Two follows University of Idaho Facilities's decision on what turbine package to pursue. It begins with research into integration options for the turbines in the University of Idaho electric grid. Electric consumption of campus buildings and control system options will be considered in the beginning portion of Phase Two. A much more in-depth economic analysis of the chosen turbine package and its implementation options will be performed. By the end of the semester, a well-modeled grid implementation option, in-depth economic analysis of the turbine package, and confirmation of Avista Utilities rebates will be presented to Facilities.

Background
The University of Idaho Steam Plant currently regulates steam pressure through the use of pressure regulation valves (PRVs). The energy in the steam vented through these valves is effectively wasted. To recapture this energy, turbines can be installed in parallel with the PRVs to produce electricity from the vented steam. This power can then be used to help power campus, reducing the university's electric bill and conserving energy.

To find the most viable number of turbines, an economic analysis of the different turbine options offered by NLine must be performed. This takes into account historical steam production, expected future steam production, steam turbine power output and efficiency degradation, turbine cost, installation and maintenance costs, and potential rebates from Avista. Once University of Idaho Facilities makes a decision on the desired turbine package based on the information provided by the economic analysis and other research, work can be started on the second phase of the project.

The second phase consists of a more in-depth economic analysis of the chosen turbine package and development of an integration plan for the turbines into the electrical grid. These parts will require selection of power modeling software, comprehensive electrical usage data from the entire campus, and research in how to tie the turbines into the grid. All mechanical work will be done by NLine.

Specifications
To be considered a success, the final project needs to receive University of Idaho Facilities' approval and either initiate or influence installation of turbines on campus. To achieve this approval, the top two turbine installation packages will be presented to Facilities at the end of the first semester; work over the summer and second semester will be a more in-depth analysis of the economics and actual implementation of their chosen package.

In addition to the primary goal of satisfying Facilities on an economic scale, the proposed implementation should also be compatible with a future microgrid project and be able to accommodate future steam production loads out to 20 years.

Turbine Package Options
NLine offers turbine packages consisting of one, two, or three Microsteam turbines. The economic analysis looked at the net gain and buyback periods of each of these options. Two turbines were found to be strictly superior to one turbine in every area except initial cost, having a shorter buyback period and nearly twice as much net gain over 20 years. Three turbines greatly boost output and net savings but extend the buyback period. Anything past three turbines gives a very marginal return at today's steam levels.

With two and three turbines as the most logical options, a closer look at the respective packages' power output and energy savings was made.



This chart illustrates the power output of the two and three turbine options. The extra capacity of the three turbine option gives better power output during peak steam production periods than the two turbine option. This results in better total power output as early as the first year for the three turbine option. At the end of the 20 year period, the two turbine option is expected to reach full annual utilization. The three turbine option will be around 90%, similar to the two turbine option at the start of the 20 year period.





While the three turbine option produces more power and returns more money over the 20 year period, the two turbine option has a much lower initial cost, and as a result a lower buyback period. Nonetheless, the three turbine option's buyback period is still relatively short at 5.57 years.

Documents
[Steam Team Contract]

[Preliminary Economic Analysis]

Presentation Slides
[Snapshot Presentation]

[Design Review/Facilities Presentation]

[Facilities Presentation Handout (Scope Inside)]

External Information
[University of Montana Case Study]

Minutes
[20 Feb 2018]

[27 Feb 2018]

[8 March 2018]

[20 March 2018]

[27 March 2018]

[3 April 2018]

[17 April 2018]