Technical Review by Bill Rever

Technical Review by Bill Rever

Screen Shot 2013-01-21 at 10.14.06 AMBio on Bill Rever:
Bill Rever began his career in Solar energy in 1982 with industry pioneer Solarex (inventor of the first poly-chrystalline cells), which eventually merged with and became part of BP Solar in 1999.  Bill held a variety of roles within that company including applications engineering, project management, product management, marketing, business development and strategy.  In his tenure with BP Solar and Solarex, Bill was involved in the production, marketing, and deployment of over 1 GW of PV in over 150 countries including many seminal applications, product innovations and projects. With 30 years of experience in PV he is frequently called on as an industry expert and has spoken at numerous conferences and events.

Bill has a B.A. in Physics from the Johns Hopkins University, an M.S.E. in Energy Engineering from the University of Pennsylvania, and an M.B.A. from the Wharton School of the University of Pennsylvania.  He is a member of the Sigma Pi Sigma Physics Honor Society and the Solar Energy Industries Association (SEIA).  He is a board member and past President of the Maryland/DC/Virginia chapter of the Solar Energy Industries Association and a board member and former Co-Chairman of the PV Advisory Group of the North American Semiconductor Industry Association (SEMI).

Report and Evaluation of V3 Solar Technology

Bill Rever, Independent Consultant

December 18, 2012


Introduction & Background

I had been introduced to V3 Solar earlier this year by Jigar Shah and made a visit on November 29th and 30th to Long Beach, California to meet with the firm’s Chief Marketing Officer Robert Styler, CEO Michael Neistat, and an independent design firm Nectar Design who has been hired by V3 Solar to do initial third party testing of the concept and preliminary design work.  We also conducted a conference call with the inventor Chris LaDue.  This report is the result of that visit and documentation provided by V3 prior to and subsequent to the visit.

V3 Solar has invented a unique solar photovoltaic system that uses spinning arrangements of standard solar cells under concentration to provide a number of potential advantages and differentiated features in comparison to standard photovoltaic systems.  In this report I will review the system, these features, and the company’s approach to development.

V3 Solar Technology Synopsis

The V3 Solar system is fundamentally a rotating assembly of photovoltaic cells under a structure of lenses that concentrate light onto the moving cells.  The nominal shape of both the lens arrangement and the assembly of cells is conical, although this shape could be different if more optimal forms emerge in the design process.  The design is referred to as the “Spin Cell”.  The essential characteristics of the design are:

  1. Captures light from the full hemisphere of the sky to maximize the use of available insolation
  2. Motion of the cell assembly provides cooling solving a fundamental problem of systems using concentration
  3. The moving cell assembly can be used to produce an alternating current (ac) output directly without a traditional inverter
  4. The cooling effect is sufficient to allow for the use of mass produced one sun cells available from hundreds of manufacturers globally
  5. Enhanced efficiency is hypothesized via a “cascade effect” whereby cells retain and build some energy as they pass by the sequence of lenses
  6. The system is self-contained and doesn’t require additional racking and mounting – it can be mounted directly to earth screws, poles or other low cost foundations.

In the remainder of the report, I will address each of these aspects as well as assessing the current state of development and path forward and a preliminary view on potential markets for the V3 Solar technology.

State of Development

V3 Solar is currently developing a complete working prototype, but has wisely chosen to first investigate the specific aspects of the design in order to know how best to configure the system.  Nectar Design of Long Beach, California has been hired to conduct tests on specific design aspects before moving to a fully working model.  The tests referred to in this report are those done by V3 Solar and by Nectar Design.  As an aside, I was impressed first by the fact that V3 Solar has chosen to “do the homework” rather than simply building something without really understanding it (which would provide little direction for improvement), and second by their hiring of a firm of experienced design engineers who have many years of experience and a positive but no-nonsense attitude about investigating the Spin Cell concept.

V3 Solar Technology Evaluation

While there are many design concepts contained in the Spin Cell, the most fundamental innovation is the ability to use one sun cells in a concentrating system operating at 20X concentration or above.  The main issue to resolve is temperature which at 20X concentration can quickly rise to destructive levels unless heat transfer out of the cell is enhanced.  Tests conducted by V3 illustrated in the charts below show that the spin cell concept can solve this problem.

Screen Shot 2013-01-23 at 5.16.36 PM

While the final design has not been determined as yet, the ability of the Spin Cell to use standard cells under concentrated light provides a number of advantages.

The concentration of the sunlight improves both the production of the PV cells and the efficiency of the cells.  Although normally one sun cells are not fully optimal for higher concentrations, current test data on the V3Solar Spin Cell shows 20X greater current production and an additional 20% higher voltage under 20X concentration during the dynamic spin.  Using concentration also implies using substantially fewer PV cells per Watt of rated power or per kWh of output.  This should reduce the cost of the finished units vis-à-vis conventional flat plate PV, provided the balance of the costs per watt are comparable.

Using conventional cells also allows for a large selection of potential vendors and low prices for “commodity” PV cells which are currently experiencing a substantial oversupply that is expected to continue for the foreseeable future.

The spinning nature of the device makes it possible to generate alternating current directly in a manner similar to induction machines without the use of conventional inverters.  Whether this will be the most cost effective design (vs. solid-state inversion) has not yet been determined as it depends on the costs of the different approaches, but it is an option available for consideration with the V3 Technology that is not available in conventional PV.

The Spin Cell is a self-contained unit that can be mounted very simply using poles or earth screws.  Thus the spin cell does not need separate racking that is needed for flat plate PV which should provide a cost savings.

The proposed design of the Spin Cell also allows for the reception of light from the entire hemisphere of the sky.  This allows the use of both diffuse and direct insolation whereas traditional concentrator designs use primarily the direct component only.  This will add to the amount of energy produced and also allow application in a broader range of climates, specifically those where higher humidity results in more of the insolation coming from the diffuse component (e.g. tropical or temperate zones).

Finally, a hypothesis currently being tested is that a “cascade effect” can occur as cells are cycled through the sequence of illuminations by different lenses in the spin cell.  This effect has been shown to occur to an approximate value of 20% when looking at the short circuit current of a cell receiving a sequence of pulses of light.  The effect on the output power (driving current into a load) and energy (power x time) in each pulse are now being measured.  The extent of this effect and need to optimize it will be taken into consideration in the design of the next stage working prototype.  A sample of recent test data from Nectar Design showing this effect is below:

Market Assessment and Commercial Evaluation

The global PV market is expected to be approximately 30 GW of new installations worth about $100 B at the point of use in 2012.  It has experienced remarkable growth (approximately 50% CAGR) in the last decade primarily due to substantial incentives put in place in Germany, Italy, Spain, and other EU countries and to a lesser extent the U.S. and China in more recent years.  The attractive markets created by the incentives have created an even greater response of PV manufacturing capacity which is now estimated to be approximately 60 GW p.a. globally.  The excess capacity has driven prices down to the production costs of the marginal producers.  Markets globally are only now reacting to this changed landscape for PV economics.  While there are certainly some downsides to the commercialization of any new PV technology in this market environment, there are some large upsides as well for the Spin Cell.  First, the low prices of PV systems are now causing an explosion of new markets.  The awakening of many countries of the world to the potential of PV creates an environment where much of the “heavy lifting” of creating awareness and interest in the PV technology has already been done and nations, corporations, and individuals are ready to purchase – provided the economic value proposition is solid.  The blossoming of markets also means that applications are broadening and opportunities for differentiated products (like the Spin Cell) are expanding.

Additionally, the availability of low-cost PV cells from many suppliers makes V3 Solar a potentially valuable customer for the main part of the PV supply chain.  This should help keep V3 Solar’s costs low on this key component.  Although the precise numbers won’t be known until the design has been finalized, the use of concentration should also allow V3 Solar to use a fraction of the amount of PV cells needed by traditional flat plate designs to produce similar amounts of energy.

In looking at the market, if V3 Solar were to only garner 0.1% of today’s global PV market this would represent approximately $100 m per year in revenue, and a 1% share would represent roughly $1b in sales.  If V3 Solar can achieve its goals for cost, performance, and reliability a significant penetration seems likely.

While competing economically with other PV approaches and ultimately other renewable and fossil sources of energy is important for long term success, the unique appearance and other attributes of the spin cell can be exploited to carve out market niches where those aspects provide value above that of electricity alone.  In the former case, architects and designers often express their disappointment at the pedestrian appearance and lack of dynamism of traditional flat plate PV arrays.  The spin cell by virtue of its shape and motion should excite the imaginations of those in these communities looking to have solar energy with an active visible component in their projects.  On a more technical front, the rotational inertia and stored energy of the spin cell may provide additional value in ancillary services on the grid such as voltage and frequency support.  It should also mitigate one of the problems of traditional PV, the rapid ramp up and ramp down of PV power on the grid as clouds pass over PV arrays.

The fact that the Spin Cell system has a lower fraction of its costs in PV cells in comparison with conventional PV means that there is also more potential for local value added where countries are looking to develop local PV manufacturing and local employment.  This should also provide an advantage to V3 Solar in developing business in emerging markets where the opportunity to develop the local solar energy economy is important to local and national governments.

The Spin Cell concept has substantial IP protection covering all aspects of dynamic spin in PV and this IP should be highly valuable when the Spin Cell has been reduced to practice.  Since the concept is highly visible any imitation would be difficult to accomplish without a presenting a public violation of the IP.

In looking at the costs of the Spin Cell, it makes sense to outline the savings possible in comparison to flat plate PV using the following “round numbers” example.  PV costs approximately $100 per square meter.  The lensing material for the outer cone of the Spin Cell costs approximately $10 per square meter.  The cost per watt of the Spin Cell can be reduced by increasing the ratio of the lensing material to the PV.  If one square meter of PV costs $100 and produces 200 watts, and one square meter of the lensing material that concentrates the sunlight in the Spin Cell 20 times would only cost $10, then 1/20th of the PV would be required to produce 200 watts, at a cost of $5 for the PV.  In this case, the Bill of Material (BOM) costs would be $15 instead of $100 for the flat panel.  The Spin Cell has other BOM costs, but these are balanced by the increased production due to the built in tracking of its shape which allow it to produce more energy for longer periods during the day when compared to currently available flat panel products.  While the exact costs will not be determined until the design is complete, the initial estimates are competitive with or lower than today’s standard PV systems and it is expected that these costs will decline substantially due to scale and experience curve effects once production ramps up.

Overall, V3 Solar appears to have a concept that can carve out a solid place in the solar and overall electricity market and is pursuing a sound strategy in examining and understanding the details of the technology to provide the best possible initial design.

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