The Solar Development Process
The Spartan Superway Solar Team is encouraged to consider the following design steps:
- Develop Preliminary Designs
- Identify Suppliers and System Components
- Detailed Design
- Acquire Components
Identifying Appropriate ProductsIdentifying appropriate products for transportation applications is complex. Following are numerous product categories and examples of innovative solutions that may be useful in the Spartan Superway development process.
- Miasolé (sponsor, offers lighweight thin-film modules that can be curved)
- Alta Devices (super-lightweight cells)
- Stion (sponsor)
Here are products from a few companies that help with cable management.
- Standard solar connectors
- Anderson Connectors for prototyping
The Regulatory Environment
- Smart Inverters: Read CPUC Electric Tariff Rule 21 for Smart Inverters
- Solar Access: Read these papers about California's Solar Rights Act and California's Solar Access Laws.
- Sole Source Procurement: California Statutes have provisions for sole source procurement.
- "... [A] public agency may enter into an energy service contract ... on terms that ... are in the best interests of the public agency..." Section 4217.10-4217.18.
- Schools and Community Colleges Banned from Using Sole Source Procurement for Prop. 39 Funded Projects
Prior to Prop. 39, many districts performed energy efficiency improvements or clean energy generation projects under Government Code section 4217.10 et seq. (Section 4217) procedure. Section 4217 provides local agencies great flexibility to use the contracting method that the governing body determines to be in the best interest of the agency, including sole source procurement.
Energy StorageWhenever the concept of solar powered transportation is presented in a public event, inevitably someone in the audience asks, "What are you going to do at night?"
To that question I reply, "I just tell everyone to stay home!"
Mind you, that's what most people did 100 years ago. Travel was largely a daytime activity and still is – most travel occurs when the sun is shining. The challenge is not as daunting as it might seem.
... with evening extension
Here are some examples of advanced storage technologies for consideration.
- Hot Rocks (not to be confused with Pet Rocks)
- Compressed Air
- Gravity Power: pumped hydro, even if there are no mountains nearby
- Rail Energy Storage: if there are mountains nearby (but no water)
- Batteries (onboard storage for regular operation and short distances when grids fail)
MicrogridsOnce storage options have been resolved, it is a simple step to establish a microgrid in which the solar system is directly coupled to the load, even when external grid support is lost. Here are a couple of examples — for single phase and three-phase power systems.
|Single Phase multi-source Sunny Island Microgrid|
|Three Phase Sunny Island Microgrid|
Art in Solar DevelopmentCheck this out!
Modeling and AnalysisThere are many good websites and software tools for analyzing solar PV systems that available in the public domain:
- System Advisor Model (SAM): https://sam.nrel.gov/
- Calculating insolation as a function of date and latitude: http://dosbat.blogspot.com/2014/12/calculating-insolation-as-function-of.html
- Calculating solar position and intensity: http://rredc.nrel.gov/solar/codesandalgorithms/solpos/
- PVWatts calculator: http://pvwatts.nrel.gov/
- PV Education.org: http://www.pveducation.org/pvcdrom/properties-of-sunlight/calculation-of-solar-insolation
- Azimuth-Elevation calculator: http://www.renewable-energy-concepts.com/solarenergy/solar-basics/orientation-azimuth-angle.html
- Annual insolation as a function of panel orientation: http://www.solmetric.com/annualinsolation-us.html
- University of Oregon Solar Radiation Monitoring Laboratory: http://solardat.uoregon.edu/index.html
- Florida State University Energy and Sustainability Center: https://esc.fsu.edu/courses.html
- A straightforward explanation of Net Energy—related to Energy Payback Time (EPBT) and Energy Return on Energy Invested (EROI)—can be found here: http://rameznaam.com/2015/06/04/whats-the-eroi-of-solar/.