About Us

Clean Power Research was originally founded by Thomas Hoff, Ph.D. as a consultancy focused on the economics of renewable energy and has since evolved into a world-class software company serving 10 of the top 10 Fortune 500 utilities and many of the world’s largest renewable energy companies.

Today we’re focused on expanding our impact with new software technologies that help solve the energy industry’s most challenging problems.


For more than 20 years, leading utility and energy enterprises have relied on Clean Power Research to successfully navigate the energy transformation. Our innovative solutions inform, streamline and quantify energy-related decisions and processes. We are best known for building and operating adaptable and efficient cloud software.


PowerClerk logo

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Energy program digitization and automation

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Customer engagement, education & enrollment

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Utility DER adoption modeling

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Bankable solar irradiance data

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Solar benchmarking & performance evaluation

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Solar planning & forecasting

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Our vision is a clean-powered planet

Our mission is to power the energy transformation with trusted,adaptable and efficient solutions

We believe…

…in the advantages of software-as-a-service to affordably bring powerful tools to the broadest audience.

…that new techniques and algorithms must be applied to be real; they can’t languish in a paper or textbook.

…in creating innovative and elegant analytical approaches to simplify the complex.


Clean Power Research is a trusted partner of leading utility and energy enterprises. We are a team of talented, innovative, dedicated people passionate about clean energy and committed to transforming the global energy landscape.


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We strive for honesty and integrity in everything we do

balanced scales - objectivity


We approach problems and evaluate solutions with objectivity

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We demand excellence and are always striving for improvement

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We value team members’ ingenuity and commitment to innovation

Jeff Ressler, CEO - Image of smiling man in a blue shirt on a green leafy backgroundJeff Ressler
Chief Executive Officer

Tom Hoff, Founder and Chief Research Officer - Image of smiling man in a blue shirt on a green leafy backgroundTom Hoff
Founder and Chief Research Officer

Carlos Brito, VP of Engineering - Dark haired man in a black jacket on a green leafy backgroundCarlos Brito
VP, Engineering

Alan Saunders, VP Sales & Business Development - Grey haired man in a blue sweater on a green leafy backgroundAlan Saunders
VP, Sales & Business Development


1997 in a gray arrow

Founding the Company

Thomas Hoff, Ph.D., a Stanford graduate with a passion for renewable energy and photovoltaic (PV) economics, founds Clean Power Research as a research consultancy.

1998 in a yellow arrow

From Research to Software

A neighbor asks Tom, “What is the value of solar to me?” To answer, Tom develops Clean Power Estimator® (now PowerBill® API), an online PV calculation tool that is rapidly adopted by utilities and PV manufacturers.

2000 in a yellow arrow

PowerClerk Launches

To alleviate the challenges of paper-based incentive application processes in the face of rapidly growing volumes, Clean Power Research launches PowerClerk®. Designed specifically for utilities, PowerClerk automates and optimizes application workflows, reducing costs and processing time.

2007 in a gray arrowSoftware Services Group Is Formed

PowerClerk’s success leads to the creation of the company’s Software Services Group and marks a new focus on delivering adaptable, scalable and secure cloud software solutions to the energy industry. Jeff Ressler, a 10-plus year veteran of Microsoft, joins the company to run the new team, and the Kirkland, Wash., office opens.

2008 in a yellow triangleSolarAnywhere Launches

A partnership with the University at Albany (SUNY) and Dr. Richard Perez leads to the development of SolarAnywhere® Data, bankable irradiance data that is at the core of the current suite of solar data and intelligence offerings.

2010 in a blue triangle

New PV Variability Method

In a paper published in the ISES journal Solar Energy, Clean Power Research shows that the relative power output variability of distributed PV fleets can be quantified. This insight helps in the management of existing PV fleets or designing new ones.

2012 in a gray triangle

SolarAnywhere FleetView Launches

SolarAnywhere® FleetView® launches to address the need for utilities and ISOs to cost-effectively and reliably integrate distributed PV into the grid. This allows for higher PV penetration and reduces costs for utilities, ratepayers and PV system owners.

2014 in a yellow trianglePowerClerk Interconnect Launches

Funded by a U.S. Department of Energy SunShot Initiative Incubator award, PowerClerk® Interconnect launches to help reduce solar soft costs by taking formerly paper-intensive interconnection processes online. The new PowerClerk platform provides utilities more control over their interconnection and DER program workflows to streamline processes for everyone involved.

2015 in a blue triangle

WattPlan Advisor Released

WattPlan® Advisor is developed to enable utilities to cost-effectively engage customers with highly-personalized answers to energy questions such as: “Is solar right for me?” Advisor incorporates newly available information such as interval data from smart meters and innovations like rate optimization to set a new standard for user-facing energy modeling tools.

2017 in a gray triangle

20th Anniversary

Clean Power Research celebrates 20 years providing innovative, efficient and adaptable software solutions that are helping to solve the energy industry’s most challenging problems.

2018 in a yellow triangle

WattPlan Grid Launches

Clean Power Research and the Sacramento Municipal Utility District (SMUD) form a unique partnership to solve the critical challenge of utility DER planning. WattPlan® Grid is launched, a SaaS solution that addresses a range of challenges including load analysis, rate scenario testing and customer adoption propensity modeling.

2019 in a blue triangleData Visualization in PowerClerk

A new Dashboards feature for PowerClerk launches that enables program administrators to support program transparency with built-in reporting and data visualization capabilities—no export, programming or third-party tools required.

2020 in a gray triangleevAPP Launches

The Electric Vehicle Analytics & Program Platform (evAPP™) is launched, giving utilities a new solution to manage EV programs end to end, including: engagement and enrollment, administration and automation, and EV adoption detection and modeling.