The Solar Development ProcessThe Spartan Superway Solar Team is encouraged to consider the following design steps:
- Develop Preliminary Designs
- Identify Suppliers and System Components
- Detailed Design
- Acquire Components
Solar OverviewOn the ABB website, there is a fairly comprehensive overview of commercial solar energy systems, showing the various elements which constitute a solar system. Descriptions of these elements may be found by drilling down into the Products section, for example.
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)
Imagine an off-grid system with just 2 consistently low deep cycle batteries in a 48 volt battery pack. Consequently all batteries will have to be replaced even though only 2 are bad. This is where a Battery Management System (BMS) comes into play.
- Battery Management System [Wikipedia, general explanation]
- What is a Battery Management System / BMS? [20+ minute video, very understandable]
- ElectroDacus [Canadian Kickstarter who makes a BMS for solar house scale.]
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.
- Orange Button Data Taxonomy: This Data Taxonomy was developed under the US DOE's SunShot Initiative to make it easier to access and share solar data, facilitating more efficient and cost-effective financing of distributed energy projects.
- "The SunSpec Alliance team will establish an open, easy-to-adopt solar data architecture and standards —comprised of uniform data taxonomy, information models, data schemas, data exchange protocols, functional specifications for interoperability, compliance test suite and reference software—that will enable the free flow of data between existing software products that address critical aspects of the solar asset life cycle."
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)
- SuperCapacitors (a.k.a. UltraCapacitors)
- Kilowatt Labs: Supercapacitors are connected in series and parallel and balanced through a set of algorithm based microcontrollers that monitor, balance and control the entire process.
- Hybrid Batteries+Ultracapacitors (combining the 20,000+ cycle life and high power density of supercapacitors/ultracapacitors with lower cost conventional batteries)
- Flywheels (many online sources can be searched)
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/.