Growth Equity to Accelerate the Energy Transition

Lime Rock New Energy partners with companies and entrepreneurs building differentiated, innovative businesses that are driving the clean energy transition.


We bring our dedicated energy transition focus, deep industry and operating expertise, and true value-added partnership to help leaders in the new energy economy grow profits, operations, and market share.

Our senior investment team averages more than 20 years each of experience in energy and investing, operations, and energy transition technologies and innovation. The investment team is supported by an engaged and active Advisory Board that includes global leaders in energy technology, policy, and executive leadership in the transition to a low-carbon energy economy.

We seek to accelerate the transition to a clean energy economy by bringing to leading entrepreneurs equity capital to accelerate growth, strategic execution and process expertise, and Lime Rock New Energy’s deep network of relationships across all facets of the new energy economy.


We are exclusively focused on companies that help their customers produce, consume, or decarbonize energy with a measurable, positive environmental impact. We are particularly focused on companies that provide products and services for:

Renewable generation and power grids
Energy efficiency for industry and the built environment
Decarbonization of transportation

Our focus is on North American companies and global companies with a commitment to the North American market.

We are focused on providing true growth capital to new energy companies—not venture capital or project finance. We seek to partner with companies that have a demonstrated track record of commercial success by profitably delivering products and/or services to their customers and have a clear strategy to grow revenue, profitability, and market share.

We seek to bring our experience to help our portfolio companies grow faster. We want to partner with leaders that believe their business can gain a competitive edge with a value-adding investment partner.  Fundamentally we invest in people and look to partner with exceptional business leaders and teams.


We are investors, energy executives, policy leaders, and scientists with experience across the energy and energy transition economies.


We came together to help growing companies achieve their potential and to be a catalyst for a rapid—and profitable—transition to a new, lower-carbon economy in the United States and globally.

We bring more than 20 years of experience partnering with growing, innovative energy companies at Lime Rock Partners, where we have been providing growth capital to the energy industry since 1998.

Lime Rock New Energy’s Advisory Board includes some of the world’s preeminent energy and sustainability experts who are engaged and active with all aspects of our investment process from initial evaluation through to ongoing portfolio company support.



Aperia Technologies Burlingame, CA
Electric Power Engineers Austin, TX
Smart Wires Raleigh-Durham, NC


Qmerit Irvine, CA

Mark Lewis Joins a Panel of Energy Experts to Discuss Key Trends in the Energy Sector in 2023 and Beyond

Mark Lewis Discusses Lime Rock New Energy’s Unique Investment Approach on the “Entrepreneurs for Impact” Podcast

Mark Lewis and Mark McCall Discuss Lime Rock New Energy and How Innovative and Entrepreneurial Businesses Are Driving the Energy Transition on the Impact Capital Managers "Better Money Better World" Podcast

Mark McCall Discusses Renewable Energy Investment on FEG’s Insight Bridge Podcast

Conversation with Former Secretary of Energy Dr. Ernest Moniz on Energy Policy in the Biden Administration

Reach Out to Us

274 Riverside Avenue, Suite 3
Westport, CT 06880

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