Resources for Sustainability: 10 Ready-for-100 Case Studies

Resources for Sustainability: 10 Ready-for-100 Case Studies

An increasing number of case studies support a transition to 100% renewables, with political, economic, environmental, and other factors contributing to successful models.

Team Gemini develops projects based on the understanding that a variety of technologies are ultimately needed to provide a fully closed-loop, sustainable model for industries and communities. No single renewable energy technology can meet all sustainability demands, with a combination of technologies providing the best benefits based on different synergies (like AD and CHP units providing combined benefits of electricity and thermal energy, energy storage, and waste remediation).

In an effort to showcase and support successful cities and regions pursuing increased sustainability, the Sierra Club launched the Ready for 100 Campaign. “The Ready For 100 campaign is challenging 100 cities across the United States to set a target of 100% clean energy.”

It’s important to note that these examples focus primarily on electricity generation, whereas full-fledged sustainability also incorporates many features, technologies, and methods dealing with water conservation and wastewater treatment, bio-products conversion and processing, waste remediation, sustainable agriculture, and much more.

Cities have long been the hotbed of innovation, the drivers of change, the incubators of solutions to the world’s biggest challenges. Clean energy is the latest example of how leadership at the local level is pushing the envelope at a critical juncture.

This report showcases 10 U.S. cities that have made ambitious commitments to be powered by 100% renewable energy.

For a variety of reasons and in diverse circumstances, public officials and community leaders see the transition from dirty fossil fuels to clean energy not as an obligation but as an opportunity. Cities powered by 100% clean energy save taxpayer dollars, help their residents save money, create good jobs, and foster a better quality of life. They are catalysts for a new economy and clean energy future.

CLEAN ENERGY: While there are many definitions for the term “clean energy,” in this report we specifically mean carbon- and pollution-free energy collected from renewable, sustainably harvested sources, such as wind, solar, hydro, tidal, and geothermal, as well as energy efficiency. Our definition does not include natural gas, nuclear, or any carbon-based energy source.




Report Case Studies Summary

City/Location Overall Goal/Progress Renewables Highlights
Aspen, CO 100% Renewable Electricity (Achieved 2015)
  • Population 6,658 (permanent residents)
  • Legislative commitment, part of Canary Action Plan in 2007
  • Colorado: Renewable Portfolio Standard (RPS) 10-20% by 2020 for municipal utilities; allows Community Choice Aggregation, Power Purchase Agreements, community solar
  • Utility: City of Aspen Utilities (municipal)
  • Key Entities Involved: Mayor, City Council, Utilities Department, Environmental Health Department, City’s Canary Initiative
  • Best known as a glamorous ski town in the Rocky Mountains
  • Third city in the country to reach the 100% threshold
Burlington, VT 100% Renewable Electricity (Achieved 2014)
  • Population 42,282
  • Vermont: RPS 75% by 2032; Allows Power Purchase
  • Agreements, community solar
  • Utility: Burlington Electric (municipal)
  • Vermont’s largest city
  • First city in the country to cross 100% threshold
East Hampton, NY 100% Renewable Electricity By 2020; Heating/Cooling And Transportation By 2030
  • Population 21,500
  • Legislative commitment adopted in 2014
  • New York: RPS 50% by 2030 (policy under development, directive of governor); Allows Power Purchase Agreements, community solar
  • Utilities: Long Island Power Authority (LIPA), the second-largest municipal utility in the country, and PSEG Long Island (municipal)
  • Key Entities Involved: Town Board, Energy Sustainability Committee, nonprofit Renewable Energy Long Island
  • Second homes comprise half of the housing stock, driving up peak summer demand for electricity
  • Located on a peninsula among the Atlantic ocean and several sounds and bays, leaving it vulnerable to sea level rise and storms
Georgetown, TX 100% Renewable Electricity By 2017
  • Population: 54,898
  • Texas: RPS 10,000MW by 2025; Allows Power Purchase Agreements, community solar
  • Utility: Georgetown Utility Systems (municipal)
  • Key Entities Involved: Mayor, City Council, Utility Board, Electric Department staff, private sector partners
  • Located in one of the fastest growing regions in the country, 25 miles north of Austin
Grand Rapids, MI 100% Renewable Electricity By 2020 (Status: 25% In 2013)
  • Population: 192,000 (2013); More than 1.3 million in metropolitan area
  • Legislative commitment, part of Sustainability Plan
  • Michigan: RPS 10% by 2015 (met); Allows Power Purchase Agreements, community solar
  • Utility: Consumers Energy (investor owned)
  • Key Entities Involved: Mayor, Office of Energy and Sustainability, Renewable Energy Team
  • Second largest city in Michigan
  • Located on the Grand River east of Lake Michigan
Greensburg, KS 100% Renewable Electricity (Achieved 2013)
  • Population 785 (down from 1,400 pre-tornado)
  • Legislative commitment, as part of Sustainable Comprehensive Plan
  • Kansas: RPS 20% by 2020 (voluntary); allows community solar
  • Utility: Greensburg Utilities (municipal)
  • Massive tornado in 2007 damaged or destroyed 95% this town in south central Kansas
  • Adopted the motto “Rebuilding…Stronger. Better. Greener.” With sustainability at the core of the town’s economy and identity
Rochester, MN 100% Renewable Electricity By 2031
  • Population 100,000
  • Administrative commitment
  • Minnesota: RPS 25% by 2025 (municipal utilities); allows community solar
  • Utility: Rochester Public Utilities (largest municipal utility in the state)
  • Key Entities Involved: Mayor, City Council, Energy Commission, Destination Medical Center representatives
  • Hub for the healthcare industry, with a massive new Destination Medical Center under development
San Jose, CA 100% Renewable Electricity By 2022 (Status: 24% 2013)
  • Population: 960,000
  • Legislative commitment, adopted as part of Green Vision in 2007
  • Utility: Pacific Gas & Electric
  • Key Entities Involved: Mayor, City Council, Environmental Services Department, Transportation and Environment Committee, nonprofit San Jose Community Energy
  • First large city in the U.S. to push 100% goal
San Diego, CA 100% Renewable Electricity By 2035 (Status: 33% In 2014)
  • Population: 1.37 million
  • Legislative commitment, part of Climate Action Plan introduced in 2015
  • California: RPS 50% by 2030 (33% by 2020 for utilities procurement); allows Community Choice Aggregation, Power Purchase Agreements, and community solar
  • Utility: San Diego Gas & Electric (investor owned)
  • Key Entities Involved: Mayor, City Council, Economic Development Department, Environmental Services Department, Climate Action Plan Implementation Working Group, sustainable Energy Advisory Board
  • Eighth largest city in the U.S. and second-largest in California
  • First large city in U.S. to commit to legally binding 100% renewables goal
San Francisco, CA 100% Renewable Electricity By 2030
  • Population 864,000
  • Administrative commitment
  • California: RPS 50% by 2030 (33% by 2020 for utilities procurement); allows Community Choice Aggregation, Power Purchase Agreements, and community solar
  • Utility: Pacific Gas & Electric (investor owned), SF Public Utilities Commission (CCA administrator, municipal power)
  • Key Entities Involved: Mayor, Board of Supervisors, Mayoral Task Force, Department of the Environment, SF Public Utilities Commission
  • Second most densely populated city in the country with 18,400 people per square mile
  • Community Choice Aggregation program brings renewable energy options to homes and businesses

Supporting and developing a closed-loop, 100%-sustainable infrastructure is among Team Gemini’s primary endeavors. Many technologies ultimately contribute to this goal, including the appropriation of waste as a source for (electric and thermal) energy production, in addition to valuable commodities like biofuels, fertilizer, compost and more. Additionally, Team Gemini closely examines and implements methods of minimizing or even eliminating any pollution and environmental impacts, including protecting and treating valuable water resources and implementing sustainable agriculture.

Feel free to explore more topics on our Resources page, or contact us if you’d like to recommend others.

For a full listing of Team Gemini sustainability tools and resources, please visit our resources page at