eSolar and Penglai Electric Co. Enter Master Licensing Agreement for Solar Thermal Power in China


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 , 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.


Eric Lane Avatar

Eric Lane

Eric Lane, the founder and principal of Green Patent Law, is an intellectual property lawyer and registered U.S. patent attorney in New York and is a member of the bar in New York and California. Eric has more than two decades of experience working with wind, solar PV, CSP, biofuels, and geothermal, energy storage technologies, carbon capture and sequestration, medical devices, data communications, mechanical, chemical, internet and software.