Barcelona Turns Human Waste Into Clean Fuel For Public Transport - 1

Image by Timotheus Wolf, from Unsplash

Barcelona Turns Human Waste Into Clean Fuel For Public Transport

  • Written by Kiara Fabbri Former Tech News Writer
  • Fact-Checked by Sarah Frazier Former Content Manager

For five years, passengers on Barcelona’s V3 bus line unknowingly rode on a vehicle powered by human waste.

In a rush? Here are the quick facts:

  • Biomethane fuel emits 80% less CO2 than natural gas.
  • The Baix Llobregat plant turns 4 cubic meters of sludge into fuel hourly.
  • Passengers praised the idea once they learned the bus ran on waste.

The Nimbus project ran a bus using biomethane produced from sewage sludge as fuel, without foul odors, and generated significantly lower emissions than conventional fuels.

TechSpot reports that the project was developed by a partnership between Veolia, Barcelona’s public water distribution company, TMB, the city’s transport operator, and the Autonomous University of Barcelona.

Using the Baix Llobregat treatment plant, one of Europe’s largest, researchers refined wastewater into biomethane, a renewable fuel that emits 80% less carbon dioxide than natural gas, as reported by TechSpot.

The plant handles 400,000 cubic meters of wastewater daily, generating 250 metric tons of sludge. Biomethane from four cubic meters of sludge processed each hour was enough to keep the V3 line operating 100 kilometers daily.

Biomethane production requires refining biogas until it reaches 90% methane purity. Veolia’s process goes beyond standard practice by combining CO2 with hydrogen from water and renewable sources to convert nearly all biogas into biomethane.

The resulting fuel met Euro VI emission standards while producing small amounts of nitrogen oxides and fine particles.

Passengers who learned of the bus’s unusual fuel source reacted with surprise but approval. “I think it’s a fantastic idea. We already put animal waste to good use, so why not ours?” said Rosa Maria Gay, a 68-year-old retiree, as reported by Le Monde .

“If our excrement is useful for something, all the better!” added Leire Muños, a 32-year-old receptionist, reported Le Monde. “As long as it’s renewable energy and doesn’t smell bad, I think it’s great,” said Alessandra Spano, an 18-year-old computer science student, according to Le Monde.

After its success, Nimbus will now expand into a new project, SEMPRE-BIO, aimed at producing even more biomethane to fuel additional bus lines across Barcelona.

OpenAI Launches Affordable $4.60 Plan In India To Accelerate Market Expansion - 2

Photo by Andrew Neel on Unsplash

OpenAI Launches Affordable $4.60 Plan In India To Accelerate Market Expansion

  • Written by Andrea Miliani Former Tech News Expert
  • Fact-Checked by Sarah Frazier Former Content Manager

OpenAI launched a new subscription plan for customers in India on Tuesday. The affordable plan, called ChatGPT Go, costs 399 rupees—about $4.57—per month and includes expanded access to the latest model, GPT-5.

In a rush? Here are the quick facts:

  • OpenAI launched ChatGPT Go, a subscription plan for India that costs less than $5 a month.
  • The new tier offers extended usage of its models, including GPT-5, longer memory, and access to custom GPTs and projects.
  • The program can expand to more regions and countries in the future.

According to the information shared on OpenAI’s website, the new plan offers all the features of the free version, plus additional benefits such as extended usage, longer memory, more personalized responses, access to projects, and custom GPTs.

We just launched ChatGPT Go in India, a new subscription tier that gives users in India more access to our most popular features: 10x higher message limits, 10x more image generations, 10x more file uploads, and 2x longer memory compared with our free tier. All for Rs. 399. 🇮🇳 — Nick Turley (@nickaturley) August 19, 2025

Nick Turley, Head of Product for ChatGPT, said on the social media platform X that ChatGPT Go in India will provide 10 times higher usage limits, 10 times more image generations, and 10 times more file uploads. OpenAI also noted that the plan could expand to other regions and countries in the future.

The new affordable plan has been designed to provide users more access to popular features at a lower price point. The next tier, ChatGPT Plus, includes more advanced tools such as deep research, the AI video generator Sora, and agent mode.

According to CNBC , OpenAI is using this strategy “to grow in its second-largest market by user base.” The idea was first discussed in February, when Sam Altman—OpenAI CEO—met with Indian IT Minister Ashwini Vaishnaw to explore launching a low-cost AI system tailored for the region, which represents a key market for OpenAI and its competitors.

Other tech companies, including Google and Perplexity, have also introduced affordable offerings for India’s 800 million active internet users.

The new announcement comes just days after the release of GPT-5 and recent adjustments after users backlash and security concerns .