Green Patent Blog®

eSolar is a Pasadena, California solar thermal startup that makes solar power plants using flat mirrors, or heliostats, to concentrate sunlight onto a centrally located water tank suspended on a tower.  This type of structure is known as “power tower” architecture.

Founded in 2007, eSolar has seen very rapid success in business deals to implement and deploy its technology.  The latest, which is the biggest solar thermal deal ever, is a master licensing agreement with Chinese electrical power equipment manufacturer Penglai Electric (Penglai).

Penglai will develop at least 2 gigawatts of solar thermal power plants in China over the next 10 years using eSolar’s technology.

eSolar owns at least four published U.S. patent applications and at least half a dozen international applications relating to its solar thermal technology.  U.S. Patent Applications Pub. Nos. 2009/0241938 and 2009/0241939 are directed to solar receivers and U.S. Patent Application Pub. No. 2009/0107485 is directed to calibration and tracking control systems for heliostats. 

According to the technology description on eSolar’s web site, its cost-effective utility scale power plant is “based on mass-manufactured components and designed for rapid construction, uniform modularity, and unlimited scalability.”  The company’s heliostat is the “building block” of its power plants and is designed for deployment in pre-fabricated “heliostat sticks” for easy installation.

One factor that affects the efficiency of power tower plants is the positioning of the heliostats relative to the tower and to each other.  eSolar’s “modular field” of concentrating mirrors consists of thousands of systematically spaced heliostats arranged to optimize the layout and maximize efficiency. 

U.S. Patent Application Pub. No. 2009/0133685 (’685 Application) is directed to eSolar’s heliostat array layouts.  Some embodiments of the ‘685 Application comprise three segments (128) with each segment divided into two variably spaced heliostat zones (128a, 128b).

Heliostats (328a) in the first zone (128a) are spaced closer together than heliostats (328b) in the second zone (128b).  The heliostat locations are also staggered with respect to heliostat locations in adjacent rows.  A thermal receiver (228) is mounted on a central power tower.

Last year, eSolar entered into a similar deal with an Indian partner, ACME Group (ACME), to build solar thermal plants generating up to 1 gigawatt of power in India.  ACME is the exclusive licensee of eSolar’s technology in India.

eSolar’s success in deploying its solar thermal technology in emerging markets such as India and China belies claims by those countries and other developing nations that IP rights are acting as a barrier to transfer of clean technologies (see China View article here and my previous post here). 

Various proposals to weaken or eliminate IP rights, including compulsory licensing and even excluding green technologies from patent protection, have been put forth by India, China and other emerging market and developing countries and were contained in the official UNFCCC negotiating text for the Copenhagen meetings in December.

However, eSolar’s success in finding willing partners in India and China may actually be driven, at least in part, by intellectual property protection:  it’s hard to imagine Penglai or ACME investing in such large scale projects without the exclusivity in their home markets guaranteed by the master license agreements.

eSolar’s China deal was announced in early January.  It’s interesting that while climate change treaty negotiators were discussing IP as a barrier to international clean tech transfer eSolar and Penglai were probably finalizing the terms of the master license agreement that would be part of the largest ever transfer and deployment of solar thermal technology to China.

Applied Energy Technologies, Inc. (AET) is a Michigan startup that makes racking systems for solar panels. 

In May of 2009, AET sued Solar Liberty Energy Systems, Inc. (Solar Liberty), a Buffalo, New York solar panel distributor and installer, seeking a declaratory judgment that AET had not breached a non-disclosure agreement (NDA) the parties had entered into.  The suit was filed in U.S. District Court for the Eastern District of Michigan.

According to the complaint (applied_energy_complaint.pdf), an AET predecessor-in-interest called Latitude Energy Structures, LLC (LES) agreed to design certain ballasted solar panel racking systems for Solar Liberty, and the two parties signed the NDA (applied_energy_complaint_Ex A.pdf) in connection with the agreement.

The complaint alleges that LES presented several new design concepts to Solar Liberty in late 2008 and a prototype of a design in early 2009.  Subsequently, LES assigned all its rights to AET, and Solar Liberty told AET that it had decided to use a racking system from a another supplier.

According to the complaint, while both parties were at the American Solar Energy Society’s National Solar Conference the President of LES told some prospective AET customers that AET stole LES’s proprietary racking system design. 

A subsequent letter from LES’s attorney accused AET of violating the NDA by misappropriating and publicly disclosing LES’s proprietary designs in AET’s racking system.  AET filed the suit shortly thereafter.

LES moved to dismiss or transfer venue to the Western District of New York.  In August, the court granted the motion (applied_energy_order_transfer.pdf) because the NDA provided that any action would be brought “in the home jurisdiction of the other party.”

AET moved for reconsideration of the decision, and last month the court denied the motion (applied_energy_order_reconsideration.pdf), finding no “palpable defect” in its August ruling.  So the case will move to LES’s home court in western New York.

Pyron Solar Inc. (Pyron) is a San Diego company that develops and makes solar concentrators.

Pyron and San Diego Gas & Electric (SDG&E) recently announced that SDG&E is building a demonstration project to test Pyron’s patented concentrated solar power system.  The system uses shallow pools of water as a passive cooling system for high efficiency solar cells.

Pyron’s U.S. Patent No. 7,299,632 (’632 Patent) is entitled “Solar electricity generator” and is directed to a solar electrical generator comprising a concentrator, a homogenizer and a photovoltaic (PV) cell.  The concentrator concentrates solar rays onto an entrance surface of the homogenizer, which is in turn attached to a PV cell.

The concentrators are positioned in troughs (1) that sit in bodies of water (5).  The water (5) acts as a passive coolant to disperse the heat generated by the PV cells.   

In addition, buoyancy torque created by pumping the water (5) between ballast compartment (8) and ballast compartment (9) and pressure differentials between the compartments pivots the troughs (1) to keep the lenses (2) aimed directly at the sun.

The lenses (2) concentrate solar rays (3) at focal spot (4).  According to the ‘632 Patent, the highly concentrated “pencil” of solar rays (3) then enter homogenizer (43) and are evenly distributed onto PV cell (4′) by loss-free total internal reflection.

According to the ‘632 Patent, this system makes better use of solar farm real estate by covering 87% of the set-aside land.  Pyron’s product description also touts the greater power production and reliability of its passive coolant design, noting that it protects the equipment from exposure to extreme wind. 

Pyron plans to stock the pools of water with fish to prevent mosquito infestation, leading Matter Network to speculate that “perhaps the fish farms of the future will double as solar energy collectors.”

Akeena Solar is a Los Gatos, California solar installer and the owner of U.S. Patent No. 7,406,800 (’800 Patent”), entitled “Mounting system for a solar panel” and directed to an integrated module frame and racking system for solar panels.

The ‘800 Patent describes a mounting system for a solar panel (100).  FIG. 2 shows three modules (102A-102C) coupled together to form an integrated system.  A splice (104e) mechanically connects one module to another and provides the electrical grounding connection between the solar modules.

In the example shown in FIG. 2B, an east-west splice (104) connects modules (102A and 102B).  The splice (104) is a tapered conductive metal to provide the grounding between modules and is grooved for easy screw insertion.  The splice (104) precisely aligns the modules and allows for compression of connector sockets to complete the electrical connection between adjacent modules.

According to the ‘800 Patent, the splice (104) provides several useful features, including mechanical rigidity between modules, an alignment method between modules and a grounding path that eliminates the need to run a grounding wire between the modules.

Last month, Akeena sued Zep Solar, Inc. (Zep), groSolar and High Sun Technology, Inc. (HST) in the Northern District of California. 

The complaint (akeena_complaint.pdf) contains two counts.  The first is against groSolar and HST for infringement of the ‘800 Patent.  According to the complaint, Zep’s solar panel mounting system infringes the ‘800 Patent, and groSolar has teamed up with Zep to distribute and install Zep systems.

The second claim is against Zep and HST for a declaratory judgment that Akeena does not infringe Zep’s U.S. Patent No. 7,592,537 (’537 Patent), entitled “Method and apparatus for mounting photovoltaic modules.” 

The complaint bases DJ jurisdiction on a couple of e-mails between the parties.  Specifically, the complaint alleges that Zep sent an e-mail to Akeena’s counsel to bring the ‘537 Patent to its attention, and Zep’s CEO sent an e-mail to Akeena’s president regarding the ‘537 Patent and stating that “Zep’s legal team is ready for a fight if that is what is needed.”

Though solar installers don’t invest as heavily in IP as other players in the solar sector, it is an increasingly crowded field that may see more patent suits like this one in the future.

Nansolar, a San Jose, California thin-film solar company, has made a lot of press announcements lately for various news items, including opening a solar panel assembly facility in Germany, boosting its CIGS cells’ efficiency and unveiling new Utility Panel technology. (read the Greentech Media story here)

According to Nanosolar, its Utility Panel is the first solar electricity panel specifically designed for utility-scale systems. 

The company’s white paper says the new solar panel provides electrical benefits (increased power per panel), reliability benefits (better sealing and encapsulation to prevent moisture damage) and mechanical benefits (superior strength due to tempered glass panes on both the back and front of the panel).

Nansolar has several pending patent applications relating to its encapsulation technology and large-scale solar modules.  U.S. Application Pub. Nos. 2007/0295385 (’385 Application), 2007/0295386, 2007/0295387, 2007/0295388, 2007/0295389 and 2007/0295390 comprise a family of applications directed to encapulated solar cells.

The ‘385 Application describes a solar cell (10) having a protective layer (20) mounted in packaging that includes pottant layers (30, 32).  The packaging has at least one outer barrier layer (40), which may be made of tempered glass.

The packaging may also have a backside support layer (50).  Edge sealing material (54) prevents moisture penetration and may be made of butyl rubber tape or epoxy.

U.S. Application Pub. No. 2008/0041434 is directed to a photovoltaic module designed to be used without a junction box. 

The module (10) includes a rigid transparent upper layer (12), a pottant layer (14) and a plurality of solar cells (16).  The transparent upper layer (12) is made of glass and provides structural support and acts as a protective barrier.

A protective backsheet (20) has an electrically insulating layer (22), a support layer (24) and another electrically insulating layer (26).  In one embodiment, the electrically insulating layers are made of black alumina to maximize emission of heat, and the support layer is made of aluminum.

Openings (30) in the backsheet (20) allow wire (40) or wire ribbon (42) to extend outward from the module (10) and be connected to another module to create an electrical interconnection between modules, eliminating the need for a junction box.

According to the ‘434 Application, this solar module design reduces manufacturing costs and redundant parts in each module.