Solar

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
  • Install
  • Test
Critical to success in R&D is to quickly obtain small samples of products that are to be integrated into overall system design, and then to iterate with innovations as new requirements become evident or new products come onto the market.

Solar Overview

On 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 Products

Identifying 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.

Solar Modules 
  • MiasolĂ© (sponsor, offers lighweight thin-film modules that can be curved)
  • Alta Devices (super-lightweight cells)
  • Stion (sponsor)
Module Level Power Electronics (MLPE)
  • DC-DC (Optimizers)
  • DC-AC (Micro-Inverters)
Inverters
Charge Controllers and Load Controllers
Battery Management Systems

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. 

 Racking
Robotic installation technologies
Cable Management

Here are products from a few companies that help with cable management.
Connectors and Conductors
  • Standard solar connectors
  • Anderson Connectors for prototyping
Module Cleaning

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 Storage

Whenever 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.

Trip patterns closely match the pattern of sunshine...

... with evening extension
When the audience takes that in, I point out that none of us would be here today if our ancestors hadn't figured out how to manage half their lives without sunshine, and I suggest further that humans aren't dumber than trees which have managed for eons through nights – and winters for that matter. We can solve this problem... and build a better transportation system than we have now.

Here are some examples of advanced storage technologies for consideration.
Here is a summary article about supposedly "disruptive" energy storage systems which are generally ordinary compared to the technologies listed above, though interesting to consider as a benchmark:

Microgrids

Once 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
An extensive Sunny Island tutorial is available here. An overview video is available here.
 

Art in Solar Development

Check this out!

Modeling and Analysis

There are many good websites and software tools for analyzing solar PV systems that available in the public domain:
Net Energy

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