Tracking sources of greenhouse gases with satellites

Climate change is one of the greatest challenges of our time. Its consequences – including extreme weather, drought, forest fires, and rising sea levels – can already be seen worldwide. These threaten the stability of ecosystems, our food supply, and our habitat. TNO is working on several solutions that could help reduce greenhouse gas levels, with innovations such as alternative energy sources or CO2 filtering from the atmosphere. Another solution is to identify emission sources, which TNO is doing by monitoring the Earth from space using satellites.

Insights and ideas for action

Anton Leemhuis is a Business Director at TNO and an expert in Earth observation. He explains why this monitoring is needed: 'Measurements show that many greenhouse gases are emitted worldwide and accumulate in the Earth’s atmosphere, but we still know very little about where exactly these gases come from. This makes it tricky to take action against polluters and check whether the measures taken by companies are working. Through Earth observation, we are giving governments and companies insights and ideas for action.'

Major incidents and emissions sources uncovered

The Netherlands is a global leader in monitoring emission sources from space. For example, TNO developed the technology in the TROPOMI instrument launched on the ESA’s Sentinel5-P satellite in 2017. TNO designed the instruments and developed some of its essential optical systems. The instrument was created by Airbus Defence & Space Netherlands with scientific partners KNMI and SRON. TROPOMI can measure air pollution and the greenhouse gas methane from an altitude of about 800 kilometres.

Leemhuis: 'TROPOMI allows us to map methane super-emitters in a single overpass, and verify them. For example, TNO played a part in finding leaks in oil and gas pipelines, and we saw that coal mines in Australia were emitting many times more than what we thought. TROPOMI also provides insight into how much methane is emitted from large landfills in cities like Madrid and Buenos Aires.'

Compact and affordable twin satellites

These super-emitters, while highly polluting, are unfortunately just the tip of the iceberg. Together, they account for about 5% of total emissions, with the lion’s share coming from smaller sources. In addition, TROPOMI’s spatial resolution is limited to 7x7 kilometres, and the instrument cannot measure CO2. To detect more sources of air pollution, TNO – together with ISISPACE, SRON, and KNMI – form the core team developing TANGO: an ESA satellite mission that will measure global CO2 and methane emissions at the source. Leemhuis: 'We see this form of collaboration and knowledge sharing with industry and science as a blueprint for future Earth observation missions in the Netherlands.'

For this mission, TNO scaled down the TROPOMI technology and divided it across two compact satellites flying in tandem. Both satellites have a magnifying lens that can zoom in up to 300 by 300 metres.

Leemhuis: 'This allows us to detect smaller sources, which together make up about 75% of methane emissions of, for axample, oil and gas fields, coal mines, and landfills. The TANGO satellite can also measure CO2, which is extraordinary because CO2 is difficult to measure. This gas is emitted from sources such as power stations and factories. All data will also be made publicly available, just as it was with TROPOMI. ESA’s TANGO satellites will be an independent set of eyes on the world.'

Another key advantage of TANGO is its compact size, meaning these satellites can be mounted on a standard platform, whereas traditional satellites always require a custom-built one. Leemhuis: 'This makes the satellite a lot more affordable, and soon it will allow us to go into space quicker.'

Emissions atlas

In parallel with developing the satellite, TNO is working on a global emissions atlas using existing data sources, which will soon be supplemented by measurements from the TANGO satellite, for instance. Leemhuis: 'This is how we are creating the first public overview of global greenhouse emissions.'

That is crucial, he says, because companies and governments often look to each other when it comes to climate policy. 'They want to take action, but not if they’re the only ones. They want to be sure that others are also abiding by international agreements. That’s where this map can help. The emissions atlas can also support companies and governments in making international investments by factoring a particular supplier’s emissions into their decision, for example.'

World’s top space agency

Leemhuis: 'The Netherlands has always punched above its weight in optical technology. And at TNO, we have over 40 years of experience in satellite monitoring. We have the whole breadth of knowledge needed to develop and build satellite instruments, from knowledge of emissions, atmospheric chemistry, optics, mechanical engineering, and space system enginering, to designing and building instruments at our workshops and clean rooms in Delft. We are proud to have ESA and NASA as clients. The Netherlands is also a scientific powerhouse, and we have a leading Dutch industry that TNO works closely with. Thanks to our close collaboration with an array of partners, we really are among the world’s best in this field of work.'

'With projects like TROPOMI and TANGO, we are not only working to reduce greenhouse gases, but also strengthening our economic position. This doesn’t just benefit space companies, but also service providers that can get in on the emerging climate data market.'

Real-time monitoring

If all goes well, ESA’s TANGO satellite mission will launch into space in just a few years. Over time, TNO plans to develop more compact satellites for Earth observation. Leemhuis: 'Because these satellites are so compact and affordable, we can deploy them quickly and on a large scale. Soon we will be able to map the sources of greenhouse gases in real time all over the world and see what effect the measures are having. Ultimately, we can help shape an informed and effective climate policy.'

From design to serial production

TROPOMI and TANGO are excellent examples of how technologies are developed, applied, and used to create impact. These projects demonstrate the power of collaboration between knowledge institutions and companies, from SMEs to corporates. However, innovation only has a real impact when it is rolled out on a large scale.