Net Zero | Sustainability | Renewable Energy

GCT Featured Articles

Austin, Texas: a sustainable city
By Daniel 2020/02
Europe’s greenest city district
By Daniel 2020/01
Oslo, Norway – Europe’s Eco-capital
By Daniel 2020/01
Profiles in Sustainable Cities – San Diego, California
By Daniel 2019/11
The fight against climate change: NDCs
By Daniel 2019/11

What makes a city a leader in sustainability, and among the greenest cities in the world?

All of the cities on the Green City Times' 10 GREENEST CITIES list below exemplify successful high use of a couple or more renewable energy sources in their energy mix. All have robust low emission and clean sustainable public transit systems. All prioritize green urban spaces and several also maintain vibrant urban forestry.

The cities in the below list have unique solutions for incorporating energy efficiency in buildings, new construction, mass transit, and across other energy intensive sectors of the city's economy. These cities pursue decarbonization and environmental conservation on a local level with legislated climate action measures; as well as by utilizing, harnessing, and/ or conserving, local sustainable resources to significantly lower the city's carbon footprint.

Each of the cities on the below list have implemented their own unique set of clean energy technological solutions based on the sustainable resources available locally. Each of these technological solutions represents a unique pathway to achieve carbon-neutrality in the city. The most efficient, widely available sustainable technological solutions today globally are solar + batteries, and wind + batteries (or some other form of energy storage besides batteries); as well as electric vehicles.

Electrification and optimal energy efficiency technologies for transportation and buildings; using renewable energy generated from the most sustainable energy sources, are also ideal solutions. However, in practical measures, most cities in the world can not and/ or do not implement only these ideal sustainable solutions.

In order to get to net zero GHGs globally, public policy worldwide must prioritize solutions which every city worldwide can invest in: carbon net neutral and low carbon energy generation sources (biomass, hydro, natural gas - combined cycle gas turbines {CCGT} - ideally with CCS, along with other renewables); low carbon transportation fuels (biofuels, synthetic or compressed natural gas {SNG or CNG}, other hybrid transit options such as  biofuel + electricity). The most efficient path for a city to develop sustainable mass transit is with electric vehicles as the bulk of their public mass transit fleet. Many of the cities on the below list have invested substantially in sustainable public mass transit.

When a city can't (or doesn't) electrify transportation completely, it becomes necessary to invest in these fuel types - biofuel blends, LNG, CNG, and/ or SNG made from biogas and/ or natural gas. Serious climate policy for some cities must also consider investment in zero carbon emission or low carbon energy generation such as nuclear power and CCGT, to augment renewable energy; when clean and renewable energy sources aren't able to provide constant energy generation. Thus, clean energy and sustainable pathways for cities potentially involve a variety of solutions. Where expedient and feasible, the cities on the below list have made progress on some or most of these sustainable energy pathways.  

The cities listed below exemplify sustainable urban planning; and have invested in developing innovative, extensive renewable energy and energy efficiency technologies, green building, green public spaces, and sustainable public transit. Additionally, these cities are implementing bold greenhouse gas emission reduction and climate mitigation strategies, public policies, and legislated mandates. The green cities listed below meet or exceed targets set by their home countries at the Paris Climate Accord - in terms of achieving goals for climate mitigation policies and implementation of those targets with sustainable climate measures.

The TOP 10 greenest cities in the world (as determined by Green City Times):


Freiburg, Germany
Freiburg, Germany
  1. Reykjavik, Iceland  
  2. Vaxjo, Sweden
  3. Freiburg, Germany
  4. Vancouver, Canada 
  5. Copenhagen, Denmark
  6. London, UK
  7. Curitiba, Brazil
  8. Portland, Oregon, US
  9. San Diego, California, US
  10. Oslo, Norway

Honorable mentions for world's greenest city:

Paris, France, Austin, Texas

These cities all incorporate some of the 10+ ways to:

Stabilize Greenhouse Gas Emissions

Please also see:

World Cities’ Initiatives to Fight Climate Change

Creating a sustainable city involves creating environmentally focused measures, such as renewable energy and energy efficiency mandates; and successful implementation of clean energy technologies. Public policies which support expanded investments in environmental conservation, green spaces/ urban forestry, sustainable mass transit, as well as energy efficient infrastructure for clean mass transit and green buildings; are also hallmarks of a sustainable city.

After these sustainable measures have been successfully implemented, the global focus must shift to deep decarbonization of all fossil fuel intensive sectors of the global economy; on the path to global net zero emissions by 2050. After net zero goals have seen substantial progress over the next decade in terms of energy generation, transportation, and buildings; the focus must shift to the hardest to decarbonize sectors. Those are: industry (and manufacturing), agriculture (land-use as well as food & water production), and aviation (& shipping freight).

Net zero by 2050 is needed to keep global warming well under 2° C global by the end of the century. In order to stay below 2° C, there needs to be carbon-neutrality on a worldwide level. That can be accomplished with low and zero carbon emissions technologies for energy generation, transportation, buildings; as well as the hard to decarbonize sectors.. In addition, to make global climate sustainable, here must be substantial investment in carbon sequestration/ carbon removal technologies and measures (stop deforestation, reforestation, sustainable agriculture, carbon farming, reduction of waste/ waste management, using waste to create energy as with biomass and anaerobic digestion). 

More on:

A Canadian city that is striving to be "the greenest city on earth", consistently ranking as one of the most livable cities on the planet...

A European city that averages between 2-5 inches of rainfall each monthhas rain year-round and temperatures between 30-50° F for at least half of the year, however is still considered Europe's "solar city".

An American green city that leads the nation in recycling, and features over 92,000 acres of green spaces...

The city whose metropolitan population is among the largest in the world, yet still maintains almost 40% of its area as either green space or water (a sustainable metropolis).

Please take your time to browse Green City Times' articles on the world's most sustainable cities, our information on types of renewable energy (solar, wind, geothermal, hydroelectricity, and biomass), energy efficiency, energy storage, green urban planning, green building, and other trends in sustainability. 

Try the following links to some of Green City Timesmost read articles:

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