Abstract
Myles Danforth, Shannon Townsend, Paul Danenberg, John Mitscha, Phil Lucas, performed an analysis on the photovoltaic system at Campus Center for Appropriate Technology at Humboldt State. Parameters analyzed include embedded energy, life cycle cost, system performance, and a building energy audit.
==Background== (myles) This section is the background of the project. Describe the reason (e.g. client or class assignment), coauthors, and why it is important.
The Campus Center for Appropriate Technology a student run organization focusing on renewable, environmental and self sustainable technology through a live-in demonstrational house and educational center on HSU campus. Recently the photovoltaic system at CCAT was attached to the grid.
Problem statement
The problem statement should state:
- clearly what your spreadsheet will be answering, with a little bit about why.
- explicitly what metrics you will be using for comparison.
Problem Definition: Our team is responsible for analyzing the CCAT house’s PV Solar System. CCAT is a demonstration house for appropriate technologies, it is part of their mission statement to record and document the technologies they implement to obtain pertinant data for everyone to view. We will be answering questions about the energy input (embedded), energy output, efficiency, costs, and buyback time. We will be creating a spreadsheet that will contain initial costs, effieciency, energy production, energy usage, and energy fed into the grid from the system. One question we plan to answer is to find the date in which the system buys it self back entirely so that CCAT can celebrate by throwing an educational party for solar technologies.
The goal of this project was to assess the new grid tie system by addressing issues such as embedded energy, life cycle costs including buyback time, and system performance including energy load, system specifications, and energy production values.
Instructions
If your excel sheet has thorough instructions, the instructions in the writeup can be brief and refer to the excel (and use a screenshot or two), otherwise, be very specific (and use screenshots). Make sure to link to your spreadsheet here.
Justification of assumptions
This section is a reference, thorough justification of your assumptions and values. Use references you gained during your literature review to back these up. Using automatic references [1] in this section is best.
Results
Describe overall concrete results based upon assumptions. Use graphs throughout the results section.
A subsection/title for each metric
Describe the results for each metric based on specific assumptions. Use graphs throughout the metric result subsections.
Discussion
The solar radiation at the installation site of the PV could affect our results. We noted that 2009 was a particularly sunny year. Only one of the two inverters was working so the solar PV system was therefore working at half-capacity.
We assumed $0.14/kwh instead of the regular $0.15 because CCAT uses significant amount of energy less than the typical household, making them in a tier 1 rate system. The higher the energy cost the less time it would take to pay back.
We did not account for rate inflation or maintenance costs which would affect the pay-back year - making it slightly higher than 43 years. We also did not account for the replacement of the inverters because the pay back time is sooner than the time it would take for the inverter to need to be replaced.
We assumed all of the embedded energy in the components of the solar PV system was based on the national grid mix making it more ‘dirty’ with a higher carbon output. The offset carbon was based on the PGE grid mix because we are using the solar PV system here in northern california.
We should note here that CCAT costs are extremely low because most of everything was donated. We may have over or underestimated the components of the solar PV system when calculating the embedded energy because we used weights to calculate the percentage of components (eg. copper, steel, plastic, etc.) but this should not change the results significantly.
We were surprised by how fast the carbon buy-back was at 9.2 years with already 24 % being paid back.
Next steps
Describe things to change and ways to expand the model. There are several next steps that would be helpful to this project. One would be to continually update the assumptions and running system data on the system as this would make the payback times as accurate as possible. The accuracy of the running percents on the first page of the work book is dependent on continual updates of the running system data and change in grid mix over the next 10 to 30 years. Another step to be taken is to take the shell of this workbook and stipulate it to run an energy analysis on the recently installed Solar Thermal System at CCAT. A monitoring system was also recenlty installed which can provide concrete numbers on energy generation and exchange.