Cities of the Future: Rob Thornton of the International District Energy Association On How to Create Cities That Are More Productive, Efficient and Sustainable
An Interview With Dina Aletras
Waste to Energy — Around the world, and especially in Scandinavia and northern Europe, waste to energy facilities reduce or eliminate landfills and convert solid waste streams into valuable heat and power via combined heat & power for large district heating systems, strengthening the local economy and improving trade balance while reducing outflow for fossil fuels.
As urbanization continues to accelerate, the need for cities to become more productive, efficient, and sustainable has never been greater. Innovative approaches and technologies are essential to address challenges such as resource management, transportation, and quality of life. How can we design and implement strategies to build the cities of the future? As a part of this series, I had the distinct pleasure of interviewing Rob Thornton.
Rob Thornton is President & CEO of the International District Energy Association (IDEA), representing the interests of nearly 3,000 members from 28 countries in energy and environmental policy advocacy for the district energy industry. He is a recognized global expert in district cooling systems and serves as US representative to the International Energy Agency Executive Committee for District Heating & Cooling and is a founding partner to the United Nations Environment District Energy in Cities Initiative. Rob has moderated discussions on sustainable cities at the United Nations Climate Change Conference, multiple Conference of the Parties (COP) sessions, and provided briefings to the U.S President, Cabinet members and members of Congress as well as executive leadership at the US EPA, Department of Energy, Department of Commerce and a range of international governments in Europe, Asia and the Middle East.
Thank you for joining us! To start, can you share a bit about your early background and how it influenced who you are today?
I grew up in a small town in Rhode Island where we played outside all day until the streetlights came on. We had a great crew of kids, riding our bikes everywhere, playing street hockey, touch football, kickball and we refereed our own foul balls, outs and safes. Looking back, fairness mattered, but it also shaped my instincts to advocate for a desired outcome.
My father worked for General Electric in Providence, RI where he was a plant facilities engineer, responsible for operations and maintenance of a small physical plant that manufactured light bulbs (he called them lamps…) I remember joining him on Saturday mornings to inspect projects and check up on systems. Even today, the smell of machine oil brings back memories of walking the plant floor, inspecting metal shavings on the ground, and informal chats with the shop foreman. My dad worked for GE for 42 years and was early to work every day of his life. He and my mom worked hard to put me and my three older sisters through college. My dad always treated everyone he met with respect and kindness. I like to think I learned the same from him.
What inspired you to pursue a career in this field, and can you share the story behind your decision?
Between my freshman and sophomore years at Tufts University, I wanted to stay in Boston for the summer, so I went to Tufts Financial Aid Office to inquire about internships. They sent me into Beacon Hill to the Energy Policy Information Institute, a small NGO funded by the Ford Foundation. I was assigned to research “The Greenhouse Effect.” The year was 1978. Jimmy Carter was in the White House where he declared the second oil embargo to be “the moral equivalent of war.”
My research uncovered troves of information on global burning of fossil fuels, growing CO2 levels in the atmosphere, deforestation of the Amazon, and alarming findings from early atmospheric models indicating outcomes like melting polar ice caps, sea level rise, more frequent and intense storms, shifting agricultural zones and population displacement. I had an epiphany that the Greenhouse Effect/Global Warming/Climate Change was a serious issue that needed more attention and action. And as I learned more about US energy and regulatory policy and the lagging impacts of poor energy efficiency, I felt that I could make a difference and maybe make a living in the field of energy efficiency.
I continued with internships at the US Department of Energy Region One office in Boston, in Appropriate Technologies (small grants to entrepreneurs) and Office of Consumer Affairs (national policy issues). I was accepted for a full-time job at US DOE in California after graduation, but that position was eliminated by the new administration before I even started, which may have been a blessing in disguise. I went off to work in Vermont for the winter where I got to know Jake Burton Carpenter and started snowboarding, long before it was allowed on ski areas. But that’s another story for another day.
I declined an opportunity to join the Burton Snowboard company (would have been employee #5) and returned to a private sector position in solar thermal, followed by a manufacturer/installer of innovative earth-coupled heat pumps. I joined the Hartford Steam Company in 1987 to drive development of the non-regulated district energy systems serving downtown and the Capitol Area. We doubled the size of that business in the five years I was there, ultimately producing 23% of the earnings per share for the parent utility, with only 10% of the revenue. I followed that with an opportunity to launch a new downtown district cooling system in Cleveland in 1992 and then returned home to Boston in 1996 to help launch/grow a new district cooling joint venture between two large electric utilities, before agreeing to serve as President of IDEA in 2000.
What’s the most intriguing or memorable experience you’ve had since starting your career?
In April 2001, I took a call from the White House asking for suggestions where newly inaugurated President George W. Bush might hold an event to announce his new National Energy Plan. I suggested 5 or 6 locations with innovative district energy systems as potential sites. A week later, I got a call back indicating they would like to tour District Energy St. Paul and its new biomass combined heat & power facility. President Bush, EPA Administrator Christie Todd Whitman and Energy Secretary Spencer Abraham came on the tour along with a full entourage of White House staff, US media and Secret Service. Anders Rydaker and Mike Burns of District Energy St Paul toured the group. I provided a short briefing on district energy with 1:1 conversation with President Bush. When I mentioned that district energy systems were operating at the respective alma maters of himself and his Cabinet members (Yale, Wheaton College and University of Michigan), President Bush remarked, “This man is well-briefed.”
The tour was followed by a major policy address at the St. Paul Convention Center. It was powerful to hear the President of the United States include in his address the very topics and key points I had highlighted to White House staff. President Bush said “This morning I toured a plant that makes the most of new technologies to capture and use waste heat to heat 140 major office buildings. Not a bit of energy is wasted. Not even the waste.” As this was his first major policy address since inauguration, the tour was covered by national TV news and featured above the fold on the cover of New York Times, Washington Post and LA Times. It was an important win for our industry to be recognized and featured as a scalable solution.
A close second was attending the UN Secretary General’s Climate Summit in New York City in 2014 to launch the UN Environment District Energy in Cities Initiative. We had UN security credentials for access to our event, but decided we would also like to attend the General Session of the Parties to hear heads of state speak on climate change. So we just sort of made our way and kept opening doors until we emerged into the main UN hall. 34 heads of state took to the UN podium including David Cameron (UK); Hugo Chavez (Venezuela); and last in the lineup, President Barack Obama. A lifetime moment occurred when Kathy Jetnil-Kijiner from the Marshall Islands, who was chosen among over 500 applicants to represent civil society, offered “A Poem to My Daughter”, accompanied by a stirring, emotional video. It was a powerful plea for action as her home island nation is being over-run by rising seas, threatening to eradicate her village and extinguish a way of life for generations. It was met by a standing ovation, thunderous applause from 196 attending nations and not a dry eye in the house. For me, it clarified and humanized the urgency of climate change.
As a successful leader in the industry, which three character traits have been key to your success? Can you provide a story or example for each?
First, be a lifelong learner and look beyond the tips of your skis. The energy industry is changing rapidly and it’s important to look ahead down the mountain and assess where opportunities and threats might emerge. There will be bumps in the terrain and new technologies. Looking back at the naïve college student I was in 1978, I have been fortunate to find a field that remains very interesting and challenging, where I’m able to work globally with very smart people, and has afforded me opportunities to contribute and make a difference.
Treat people with respect. Honesty matters. Stay to the high road. Sometimes, we look at energy as a zero-sum game. If you win, I lose. In my career launching new downtown district energy systems in three different cities, it was a highly competitive endeavor. Every building was critical to gaining scale, and winning the confidence of the market was a multi-headed hydra. Developing a new downtown district energy business is a task of Sisyphus, constantly pushing the boulder back up the hill. You only have one reputation, so never trade your ethics for a short-term win.
Persistence pays. Early in my career, I was responsible for selling district energy services to building owners, often interacting with architects and consulting engineers during the early stages of design development. The sales cycle can involve years as new buildings go through design, permitting and construction. Many points of view can intercede during the gestation period, so be mindful of the process. It is critical to understand how people perceive an issue and what information they may need to make a fully informed decision.
Find your peer group and get involved in your industry association. Raise your hand and say yes to opportunities, especially when asked to volunteer as a presenter or panelist. But as important, follow through on your commitments. Working collectively and collaborating can enhance your likelihood of success. If someone asks for your help. Provide it. As Margaret Mead once said, “Never doubt that a small group of thoughtful committed citizens can change the world. Indeed, it’s the only thing that ever has.”
Be the person your dog thinks you are. My dog Huckleberry looks at me and talks with his eyes. He frequently tosses me the “tummy tax” so I take a minute to scratch and rub. Those moments of connection help me to slow down and live in the moment, understand how we connect with each other, and how we rely on each other.
Finally, a life lesson — kindness does not really cost anything. It is just as easy to treat people with a kind word and listen.
What innovative technologies and practices do you believe will be most critical in enhancing the sustainability and efficiency of future cities?
In 1800, the global population was one billion souls and there was only one city on the planet with a population greater than one million — London. It took 120 years for the global population to reach 2 billion. Today, we have 8.1 billion people sharing the planet and we add one billion souls every 12.5 years. In 2024, there are over 512 cities with a population over 1 million and 35 “mega-cities” with populations over 30 million. By 2030, projections call for 610 cities over 1 million people.
District cooling systems will be critical for dense cities, particularly as urban populations continue to grow, and outdoor temperatures continue to climb. As extreme temperatures rise along with urban heat islands and longer duration heat domes, even cities in northern climates, like London, Berlin, and Seattle will need air conditioning, not just for comfort but for productivity and life safety reasons.
District cooling systems can cut peak electric demand in half and shift loads from daytime to nighttime with thermal storage. By aggregating the cooling loads of dozens or even hundreds of buildings, district cooling systems create economies of scale to enable investment in long-life renewable assets like deep lake water cooling in Toronto or Cornell University. There are a range of converging technologies like waste to energy and wastewater thermal recovery that integrate energy and environmental solutions at city scale. It is very important to consider holistic solutions that solve multiple challenges.
How can urban planners and architects design cities that effectively balance economic productivity with environmental sustainability?
Energy is not just electricity. Heating and cooling of buildings frequently consumes more than 50% of primary energy in the local economy. It’s important to understand how to leverage local thermal resources like surplus heat from industry or renewable cooling from nearby lakes or rivers can be integrated into district thermal networks for heating and cooling of buildings. For instance, at the National Western Center in Denver, CenTrio Energy built a sewer-water thermal energy recovery system that harvests the heat from a large sewer main with industrial heat pumps to provide zero-carbon heating and cooling for the community. The system cuts carbon emissions while strengthening the local economy, keeping energy dollars recirculating locally. With over 900 district energy systems across North America, architects and planners can start by discovering if there is a district energy network in operation or nearby to their development site.
To help local communities explore deployment of new district energy systems, some years ago IDEA produced the Community Energy Development Guide to assist city planners and agencies in the process of mapping, assessing, options testing and governance models.
In what ways can transportation systems be reimagined to improve mobility and reduce the environmental impact in future urban areas?
Integrating district energy with transit-oriented development can enable urban density around live/work/play hubs. In aggregating the thermal energy needs of dozens of buildings, district energy systems achieve economies of scale that enable investment in highly efficient, lower-carbon solutions. Cities would do well to strengthen public transport to rely less on automobiles. That would alleviate road congestion, improve air quality, reduce transit times, and parking lots can be reclaimed for other uses. Once a person is in the city, personal mobility like e-bikes or scooters can provide last mile services.
There are other areas of convergence between energy and transport in cities. For instance, in San Francisco, IDEA member Cordia operates a district energy system that recovers more than 30 million gallons of water per year. The water — which the system cleans and converts for use in the district energy plant — is surface water and runoff that frequently flooded subway stations in San Francisco that are part of the Bay Area Rapid Transit (BART) network. Thus, this district energy system not only saves millions of gallons of water per year, but also solves an environmental and transportation issue for commuters in one of the country’s largest cities.
What role do you see public policies playing in the development of smarter, greener cities, and how can governments incentivize sustainable practices?
Today in Germany, a new national law requires cities with populations greater than 20,000 citizens to conduct district energy heat mapping to identify opportunities for development of thermal networks. By identifying sources and uses of thermal energy — surplus heat from data centers or industry; renewable cooling opportunities from rivers, lakes or bays; recovery of industrial heat — all can serve as anchors for district energy deployment.
It’s important that building codes and zoning look beyond just the skin of individual buildings. From time to time, we see restrictive policies that not only overlook opportunities to aggregate, innovate and optimize through thermal networks but frustrate or hinder community -scale solutions because the policy dictates are based on individual buildings. As President Eisenhower once said, “If you can’t solve a problem, make it bigger.” By looking beyond the immediate to draw a radius to integrate more participants, you will find that lower-carbon solutions emerge.
I bristle when I hear the simplistic term “electrify everything.” If you have ever viewed an urban excavation up close, you will see the dense infrastructure underground in cities. It’s often a jangle of wires and pipes with little or no space for additional infrastructure. Adding loads to the electric grid for heating and cooling buildings will require substantial additions of transformer capacity, underground vaults and capital-intensive equipment. In some cases, space is prohibitive. What makes matters worse is that by adopting electric-only reliance, building owners will be fully exposed to volatile power markets where pricing can fluctuate wildly depending on grid constraints, weather gradients and supply issues. The price of power on a July afternoon can dramatically increase while winter reliability concerns grow with increasing reliance on long distance transmission resources to meet demand.
Fundamentally, there are no silver bullets and the climate challenge will require a quiver of solutions, often best determined by local conditions. Biomass in Vermont has advantages of proximity and plentiful supply. Wastewater thermal has widespread potential along with geo-exchange. The Inflation Reduction Act (IRA) offers a range of funding streams to assist local governments and investors to implement larger capital intensive solutions. Policies can impact uptake and scale.
How can future cities ensure a high quality of life for all residents while managing rapid urban growth and resource constraints?
It’s pretty clear that cities are on the front lines of climate change, both as sources of emissions and where populations need robust, resilient infrastructure to defend populations from extreme weather events and urban heat islands. District energy microgrids, anchored by combined heat & power, can deliver reliability and resilience, especially to support mission-critical users like healthcare, first responders and community centers. During Superstorm Sandy in 2012, district energy systems at Princeton University and Co-op City in the Bronx maintained heating, cooling and power supply for their respective campuses, protecting valuable research and vulnerable residents. Relying on the power grid alone, with large remote generating stations linked by long transmission lines is not a recipe for resilience. District energy microgrids have proven their value during extreme weather events.
In 2024, about 4.5 billion people live in urban areas; 56% of the world’s 8.1 billion population. By 2030, urban area population will increase to 4.9 billion; global population will reach 8.56 billion. By 2050, with urbanization and population growth, cities are expected to surpass 6.0 billion people with global population at 9.8 billion.
Cities account for over 70% of global energy use and nearly 50% of greenhouse gas emissions worldwide. In several regions, heating and cooling of buildings accounts for over 50% of local energy consumption. In warmer climates and emerging economies, over 70% of electricity production may be used for air conditioning and cooling. District cooling systems typically consume 50% less energy than traditional air conditioning units. It’s pretty clear that cities should be a primary focus to combat climate change.
Thank you for all that insight. Now, let’s dive into the core of our interview: What are the “Top 5 Things Cities Need to Make Them More Productive, Efficient and Sustainable”?
Encourage investment in district energy — Invest or support investment in district energy systems to scale up and aggregate for more efficient, lower-carbon solutions. In Toronto, in 2004, the district energy company, Enwave and the city invested in a deep lake water cooling system, which today serves over 120 buildings in the downtown core, using cold water from Lake Ontario as a renewable source of air conditioning, cutting peak power demand, reducing emissions and creating huge value for connected customer buildings.
Hybrid/Adaptive Heat Sources — In larger cities with an existing legacy district steam system, transform the heating source at the central plant to integrate renewable electricity through electric boilers, heat pumps and thermal storage. Vicinity Energy in Boston/Cambridge is solving the need for connected customers to cut building emissions without incurring the risk or disruption to change in-building HVAC equipment. Again, the scale and adaptability of district energy systems enable conversion of one source to benefit hundreds of customer buildings.
Enlightened building codes — Curate building codes to recognize and enable thermal energy-sharing across public streets and rights of way so that surplus heat in one building can be re-used in adjacent or contiguous buildings. Amazon Headquarters in downtown Seattle harvests enough heat from a nearby data center to provide heating for four connected buildings nearby. This is zero-carbon policy at work.
Wastewater thermal energy systems — Tapping huge volumes of low-grade heat from municipal waste-water systems for boosting with industrial heat pumps to provide district heating for a community. In locations like The National Western Center in Denver and Markham District Energy in Ontario, the district energy provider can harvest low-carbon heat that also improves the efficiency of the waste streams. Again, another win/win solution.
Waste to Energy — Around the world, and especially in Scandinavia and northern Europe, waste to energy facilities reduce or eliminate landfills and convert solid waste streams into valuable heat and power via combined heat & power for large district heating systems, strengthening the local economy and improving trade balance while reducing outflow for fossil fuels. In Copenhagen, the Copenhill facility not only avoids landfill but also provides a ski hill for community benefit. Sector-coupling makes absolute sense but may require community engagement and support.
Do you have a favorite quote that has influenced your life? Can you share a story that illustrates its relevance to you?
When he was asked how he managed to score over 200 points in a single season, eclipsing all previous records, Wayne Gretzky replied, “I skate to where the puck is going to be.” The energy industry is in a moment of significant transition from central station fossil power to more distributed cleaner solutions. Customers want resilience, reliability and predictable costs, all with a lower-carbon footprint. In my role, it’s important to stay informed and look ahead on multiple layers — technologies, policies, markets, and government. At the same time, district thermal networks are finally being recognized for their adaptability and critical supply, especially in cities. Our industry is experiencing significant growth and investment globally, with innovative technologies being plugged in to enable faster adoption of low-carbon solutions. It is a brilliant time to be in the district energy space and I am grateful for the platform we have built at IDEA.
With your considerable influence, if you could start a movement to make a significant positive impact, what would it be?
During a career in district energy that started in 1987, I like to believe I have already helped to launch a movement. I would urge people to read the UN Environment Program Report — District Energy in Cities Initiative. There are 40+ case studies of district energy systems using a range of technologies — deep lake water cooling, waste to energy, combined heat & power, energy-sharing. It is a very valuable compendium that shares a range of technology applications while explaining the development pathways for cities and communities. The International District Energy Association (IDEA) is a founding partner.
IDEA has recently released a similar research report on Best Practices for District Energy/CHP in the United States, as part of a cooperative agreement with the US Department of Energy. There are 40+ case studies along with highly instructive guidance from owners/operators of district energy systems on campuses and in cities. Fundamentally, this report focuses on “the how” of district energy, rather than “the why” but the reports uncover issues like master planning, financial strategies, and talent management. IDEA appreciates the support of the US DOE in this 3-year effort.
IDEA’s 25 years of involvement in the deployment of district cooling in the Middle East has contributed to massive investment in locations like Dubai and Abu Dhabi. We authored the District Cooling Best Practice Guide to help emerging economies better navigate the complexities of launching a district cooling industry. Clearly, we are not taking credit for the investment and scale by leaders in the region like Empower, Tabreed, Emicool and others, but IDEA has been an active partner and supporter of our members across the GCC region. As part of COP28 in December 2023, IDEA helped organize the Global District Cooling Summit to showcase the important contributions to sustainable development. District cooling has delivered dramatic reductions in carbon emissions, conserved billions of gallons of fresh water, and enabled brilliant development of world-class clusters of highly valuable real estate. District cooling has become the standard in a region where extreme temperatures are the norm and reliable cooling is a matter of life safety.
On a more granular level, I serve as the US Representative on the Executive Committee for the International Energy Agency Technical Collaboration Program for research on district heating and cooling. The IEA DHC TCP now includes 16 full member countries and IDEA is the US sponsor delegate — Austria, Belgium, Canada, China, Denmark, Germany, Estonia, Finland, France, Italy, Ireland, Korea, Norway, Sweden, the Netherlands and the United Kingdom. Every three years, member country delegates evaluate and select for funding a series of research projects to advance innovation and progress in the district energy industry, including tools like business modeling, assessing carbon abatement, integrating renewables, and optimization strategies. The IEA committee demonstrates the value of global collaboration and shared commitment with over 40+ years of research projects.
How can our readers stay updated with your work online?
Please visit the IDEA website — www.districtenergy.org and subscribe to our free weekly newsletter, and the digital version of our quarterly magazine — District Energy. We have a blog entitled “I Am District Energy” to feature IDEA colleagues doing great things and we provide a valuable weekly newsletter for IDEA members. We just held our 115th Annual Conference in June 2024 and are actively organizing our 38th Annual Campus Energy Conference in Boston for February 2025. And, of course, I welcome followers on LinkedIn.
Thank you for sharing these fantastic insights. We appreciate your time and wish you continued success.
About the Interviewer: Dina Aletras boasts over 20 years of expertise in the corporate media industry. She possesses an in-depth understanding of growth, strategy, and leadership, having held significant roles at some of the UK’s largest media organizations. At Reach PLC, the UK’s largest tabloid publisher, she served in various director capacities. Additionally, she held leadership roles at The Independent Magazine Group and DMGT. Her extensive knowledge spans editorial, digital, revenue, sales, and advertising.
Upon relocating to Switzerland, Dina took on the responsibility of managing and promoting the international section of Corriere del Ticino — CdT.ch pioneering the English page “onthespot.” She also was the Co-Editor of Southern Switzerland’s first official Italian and English bilingual magazine.
Cities of the Future: Rob Thornton of the International District Energy Association On How to… was originally published in Authority Magazine on Medium, where people are continuing the conversation by highlighting and responding to this story.