Len Conapinski


Len Conapinski is a founding partner at DuFour Conapinski LLP.  His areas of practice include infrastructure project negotiations, equipment supply contracts, commercial and legal process management, and intellectual property.  With an MBA, a JD, and an engineering degree, and extensive experience, Len brings an ideal blend of business, technical, legal intelligence to guide renewable energy and tech clients. 

Prior to founding DuFour Conapinski LLP, Len served as Vice President and General Counsel for Yingli Green Energy Americas Inc., the Americas region subsidiary of China-based Yingli Green Energy Holding Co. Ltd.  Len oversaw corporate expansion and operations in the US, Latin America, and South America, and helped establish the company’s internal processes and controls for a variety of business-critical systems, including sales contract negotiations, security instruments for credit protection, and legal compliance matters.

During Len’s tenure, Yingli grew to be the world’s largest manufacturer of solar panels.  Len oversaw all aspects of legal in North and South America, including legal issues for the company’s half-billion dollar US sales organization.  At Yingli, Len managed the negotiation and contract process for hundreds of megawatts of utility-scale solar projects as well as sophisticated multi-year solar panel supply agreements. Len also coordinated Yingli’s response to one of the largest and highest-profile anti-dumping and countervailing duty petitions in US history.  

Previously, Len served as in-house counsel for Caterpillar, focusing on intellectual property and commercial matters across a range of Caterpillar business and research units.  Len managed Caterpillar’s general software patent portfolio, as well as inventions relating to sustainable energy (batteries, inverters, wind/solar system integration), machine control systems, predictive analytics, and data aggregation.  During this time, Len helped to design and program a custom patent portfolio analysis tool that integrated with Caterpillar’s internal patent database and docketing system.

Before going in-house, Len was a patent litigation attorney in a private practice in Chicago, where he worked on high profile litigation and federal appeals.  Len also served as a law clerk to the Honorable Alvin A. Schall of the United States Court of Appeals for the Federal Circuit.



E: len@dufour-law.com

T: (510) 859-8373



University of California, Berkeley (M.B.A.)

Northwestern University       (J.D., magna cum laude)

University of Notre Dame     (B.S. & B.A., cum laude)


McDermott, Will & Emery LLP

McAndrews, Held & Malloy


Yingli Solar

Caterpillar Inc.



US Court of Appeals for the Federal Circuit (law clerk)

US District Court for Northern District of Illinois (extern)