Most regions can be well monitored by satellites, but some challenging regions remain

70% of fossil fuel extraction sites are in regions favourable for satellite observations during most months of the year, while 30% are in areas classified as ‘moderate’ or ‘difficult’ for observation. The number of such facilities varies significantly between countries.

The environmental conditions affecting satellite monitoring around the world are far from homogeneous. Areas we classify as  challenging – where conditions are ‘moderate’ or ‘difficult’ for at least six months per year – are located primarily in tropical regions, mainly driven by persistent cloud cover, and high latitudes, that face the added challenge of low light conditions during winter. Mountainous regions with rough terrain in east Asia, western America, and Europe are also hard to observe, mainly for area-mapping satellites. 

In contrast, relatively arid regions in north Africa, central Asia, Australia, and the southern US appear to have near ideal observation conditions throughout the year. Not surprisingly, many of the initial satellite studies that inform our understanding of methane emissions are focused on these relatively arid regions. 

Based on production data from the GEM’s Global Coal Mine Tracker (GCMT), our analysis shows that 30% of coal production occurs in regions that are challenging to observe. For onshore oil and gas, data from the GEM’s Global Oil and Gas Extraction Tracker suggests that 29% of global production is situated in challenging-to-monitor regions.

An interactive map showing the methane detection category of each fossil fuel asset, as it varies every month, can be explored online.

Country-level differences in the ease of satellite monitoring of coal production

An analysis of the top 10 coal producing countries reveals that conditions for satellite-based methane monitoring are nearly ideal in South Africa, where 99% of production occurs under favourable conditions, and in Australia, where 91% of coal production takes place in favourable regions. In contrast, the majority of coal production in regions with challenging-to-monitor conditions are concentrated in parts of China, Indonesia, India, Russia, and the United States. Challenging-to-monitor is defined as having six months or more with either a ‘difficult’ or a ‘moderate’ category.

China

22% of China’s coal production, amounting to 633 million tonnes annually, is found in challenging-to-monitor regions. Many of the mines are located in southwestern China, where cloud cover and rugged terrain create challenging conditions for methane monitoring, especially for area-monitoring satellites.

Indonesia

Remarkably, Indonesia, the world’s third-largest coal producer, has 84% of coal production located in challenging-to-monitor regions.  This amounts to 496 million tonnes of coal production per year that may go unmonitored.  Most coal mines are clustered on the islands of Sumatra and Kalimantan where challenging conditions are caused by persistent cloudiness and mountainous terrain. 

India 

27% of the coal production in India, which is 251 million tonnes annually, is located in regions that are challenging to monitor for a few months of the year. This is caused by cloudiness during the monsoon season between the months of July-August which might impact satellite monitoring. 

Russia

In Russia 46% of coal production, amounting to 211 million tonnes annually, is in challenge to monitor regions. Methane monitoring by satellite may be challenging due to seasonal low sun elevation and cloudiness.   

United States 

In the United States 22% of the country’s coal production is in challenging-to-monitor regions, which amounts to 104 million tonnes per year. In the Western Interior Basin coal mining region, challenging conditions are caused by the rugged terrain of the Rocky Mountain ranges. In the Appalachian Basin, conditions are challenging due to a mixture of mountainous terrain (Appalachian mountains), intermittent cloud cover and dark surfaces.

Other coal mining regions that are challenging-to-monitor

There are other clusters of regions with coal mines in challenging locations. One such cluster is found in the western Balkans—specifically in Bosnia and Herzegovina, Serbia, and North Macedonia. These mines are located in the Dinaric Alps, where mountainous terrain might make methane monitoring by satellite challenging for area flux mappers.

Country-level differences in the ease of satellite monitoring of oil and gas production

An analysis of the 10 top oil and gas producing countries reveals that conditions for satellite-based methane monitoring are nearly ideal in Saudi Arabia, where 100% of production occurs under favourable conditions, and in Algeria, where 99% of production takes place in favourable regions. 

The majority of oil and gas production in challenging-to-monitor regions are concentrated in parts of Russia, Canada and the United States.

Russia 

In Russia, 62% of the country’s oil and gas production is in challenging-to-monitor regions. The majority of hard-to-monitor oil and gas sites in Russia are clustered in the Western Siberian Basin,  which is Russia’s largest oil and gas-producing region, with substantial hydrocarbon reserves. Monitoring these sites is challenging for several months every year due to low sun elevation in winter, frequent cloud cover, and intermittent dark surfaces. 

United States

In the United States, 22% of total production occurs in regions that are challenging to monitor. These extraction sites are distributed across several areas. The first cluster is located in Alaska, spanning the North Slope and the Gulf of Alaska. These sites are situated at latitudes above 59.7°N and monitoring conditions are greatly impacted by the lack of sunlight. The second cluster is in the Appalachian Basin, where monitoring is complicated by a combination of intermittent cloud cover and dark surfaces, which can interfere with satellite observations. Additionally, there are smaller clusters, such as in the Ventura Basin, north of Los Angeles. In this area, the rugged terrain of the Transverse Ranges may pose challenges for satellites with coarse spatial resolution.

Canada

In Canada, 46% of the oil and gas is produced in challenging-to-monitor regions. These are found along the eastern flank of the Rocky Mountains where rugged terrain makes monitoring challenging, mainly for coarse resolution satellite sensors. To the east of the Rocky mountains, in the Alberta Basin,  conditions are challenging due to a mix of low sun elevation, cloud cover and sporadic periods when the surface is dark. 

Iran and Iraq

Both Iran and Iraq have 19% of oil and gas production in regions that can be challenging-to-monitor. In Iran these production sites are located within the Zagros Fold Belt, a major area for oil and gas production. The rugged terrain of the Zagros Mountains poses significant challenges for satellite monitoring due to its complex topography, while other factors are favourable for methane observation. As a result, satellite sensors with high spatial resolution can effectively monitor these oil and gas sites, while those with a coarse resolution will struggle to monitor methane emissions. 

In parts of Iraq, production is challenging-to-monitor in between June and August due to the Shamal winds, a strong, seasonal northwesterly wind. 

Other oil and gas producing regions that are challenging-to-monitor

Several countries in Latin America have large parts of their oil and gas production located in challenging-to-monitor regions. For example, 70% of Colombia’s production might be hard to monitor with satellites. This production happens in the Putumayo-Orient-Maranon Basinalong the border with Ecuador, where persistent cloud cover hinders monitoring efforts, and the Upper, Middle, and Lower Magdalena Valley Basins, where monitoring is complicated by the surrounding Andes Mountains. Nearly all oil and gas production (98%) in Ecuador is in challenging-to-monitor regions. Ecuador’s extraction sites are clustered in the Orient Basin, part of the Amazon region, located directly at the equator. As with Colombian sites, due to the tropical rainforest climate, satellite retrieval can be inhibited by persistent cloud cover all year around.

Case Studies

The factors that make methane retrieval challenging vary depending on the location of the facility. These case studies are selected to highlight how different combinations of environmental factors impact a satellite’s ability to monitor methane emission from facilities around the world.

Tabang Project Coal Mines, Indonesia 

Tabang Project Coal Mines, located in East Kalimantan, is a collection of coal mines spanning an area of 30km2.  Sub-bituminous coal is mined at the site. It is the 7th largest methane emitting coal mine in Indonesia according to the Global Energy Monitor.  Methane retrieval is persistently challenging all year (11 moderate and 1 difficult month) due to multiple factors.

The site is cloudy for 9 months of the year. The mine is located in a mountainous region and this will limit observations, especially from satellites with coarse spatial resolution that are more strongly affected by terrain roughness. In the limited cases where satellites can find cloud-free conditions to observe the ground, the surface appears dark in the shortwave infrared wavelengths used by the satellite, so it is possible that only strong plumes will  be detected.

Shanxi Qincheng coal mine, China

The Shanxi Qincheng underground coal mine, located in China’s primary coal-producing region of Shanxi Province, extracts anthracite coal primarily for electricity generation. With a depth of 446 m, the mine is methane-intensive due to its deep structure. Methane retrieval can be challenging all year around (12 months with moderate category) mainly due to the terrain roughness of the Taihang Mountains, which may limit the usefulness of area mapping satellites. There is intermittent cloudiness and the surface is dark during August and September.

Campo Indio Oeste gas field, Argentina

Campo Indio Oeste is a gas extraction site located in the southern province of Santa Cruz, Argentina and its observation conditions are typical of the southern part of South America. Methane retrieval may be challenging for half the year (6 months with moderate category).  The site is windy, with monthly average wind speeds exceeding 4 metres per second between October and January, which would disperse methane plumes making them challenging to detect. Methane monitoring is also hindered during the winter months (June-July) when the sun elevation is low. 

Athabasca Oil Sands, Canada

The Athabasca Oil Sands in Alberta in Canada are large deposits of bitumen and are one of the largest sources of unconventional oil in the world. The region may be challenging for methane retrieval for half the year (2 difficult and 4 moderate months). In the winter (November-February) the sun elevation is low in the sky meaning very little light reaches the surface and, consequently, any satellite sensor. The surface is dark during the winter (November – January) due to snow cover which absorbs shortwave radiation. This absorption means little light is reflected back to the sensor.  June is also a cloudy month which may impact methane monitoring by satellite.