Net Zero Case Study: Cascais, Portugal

Cascais, Portugal

Cascais is a traditional fishing town located on the west coast of Portugal, not far from Lisbon. As such it has become an increasingly popular holiday destination. With a population of just over 200,000 people, the town is known for providing its residents with a high quality of life.

An important part of this quality of life is the development of a roadmap that should allow the town to reach carbon neutrality by 2050. Put in motion in 2015, Cascais was the first municipality in Portugal to adopt such a roadmap[1] setting an example to follow for other towns across Europe, and the world.

Representatives of Cascais have stated, ‘on the path to sustainability and carbon neutrality 2050, every action counts.’ In this case study, we look at a number of these actions, both large and small, in which they have implemented changes to progress towards net zero.


The town of Cascais intends to create ‘local energy communities’ as part of their road map to carbon neutrality. The main purpose of this is to reduce the amount of electricity being drawn from the grid and to reduce both overall energy consumption and carbon emissions.

Cascais has a high ratio of rooftop square metres per inhabitant[2], therefore making it an ideal location to benefit from solar energy. With partial funding from a European Union Grant (European City Facility), Cascais aims for the project to generate 213GWh a year via photovoltaics, which would make up 23% of the town’s electricity consumption requirements.[3] The community aspect means that residents will be able to purchase energy produced by neighbours under the scheme. The project was started in 2022 and continues to progress; it is hoped that communities in Cascais will shortly be self-sufficient for their energy.[4]

You can read more on the many benefits of Solar Energy in our dedicated article or gain expert knowledge of photovoltaics by enrolling on our accredited Solar Energy Consultant Expert Certificate.


As of 2021, Cascais has implemented a bus system that is powered by hydrogen. These buses have hydrogen tanks, batteries and fuel cells located on the roofs, allowing them to achieve the status of zero-emission travel and provide a comfortable experience for passengers.[5]

Hydrogen Bus

A portable hydrogen station is also available within the town for refuelling these buses.[6] The company who designed these, PRF Gas Solutions, hopes to introduce these more widely in Portugal in the future; once again showing how Cascais has acted as a pioneer of sustainability.

It is worth noting that this project encompasses just two buses at this time, based on the needs of the town. Therefore, larger towns and cities may find it more difficult to implement such technology. However, it is nevertheless evidence of significant steps forward in decarbonising travel and, if suitably scalable, could be crucial for the global journey to net zero.

Cascais airport is also taking steps to reduce carbon emissions and leading the way in the decarbonisation of air travel. The airport works with Air bp on an ongoing basis, to offset the emissions of the fuel used.[7] This is achieved by purchasing carbon credits, based on the perceived emissions, which are then used to fund global carbon reduction projects.

You can find out more about the process of offsetting using carbon credits in our accredited Carbon Finance course.


Due to the popularity of Cascais and the quality of life provided, the town’s population has been increasing steadily over the last decade. Through environmental policies and a focus on the ‘7 R’s of Sustainability’ (rethink, refuse, reduce, reuse, repurpose, recycle and recover), Cascais has been able to record a decrease in the amount of waste produced locally since 2019[8], despite the growing population.

Here we can see how the town combines both individual and municipal action to reduce the amount of waste going to landfill with obvious success. As an example, between 2014 and 2022, the amount of plastic being recycled has increased by 152% from 1,485.36 tons to 3,743.60 tons.[9]

The town has robust recycling measures in place for a wide array of everyday waste. Residents can even recycle their used cooking oil in public recycling containers. These containers are then sent away for reuse and the oil is turned into biodiesel, diverting the oil from the water system.

In November 2022 the town also introduced a waste truck powered 100% by electricity; this was part of a pilot project in Portugal to assess the efficiency of such a vehicle, as well as its impact on air and noise pollution.[10] Full details of the pilot’s findings have not yet been made widely available but nevertheless it is another example of promising green technology in use.


While full details of the various projects’ outcomes are yet to be reported, it is clear that Cascais is acting as a pioneer in decarbonisation, and should serve as an example to follow for other towns across the world. It is imperative that research is undertaken on how to scale these technologies so that they can be implemented by towns and cities alike.

From recycling to decarbonising air travel, Cascais has put in significant effort to work towards their roadmap to net zero and is making impressive progress. The Institute hopes to hear even more from Cascais in the future and see other towns across the world emulate the actions taken.


[2] As above

[3] As above






[9] As above