۲۰th June 2016

New method of carbon capture turns CO2 into stone underground

A way of pumping CO2 underground and turning it from a gas into solid carbonate minerals has been demonstrated in Iceland – offering a potentially better method of carbon capture and storage.

Credit: Árni Sæberg

Scientists have announced a more efficient way of removing man-made carbon dioxide emissions from the atmosphere – turning it into rock. Their study, published in the journal Science, has shown that carbon dioxide (CO2) can be permanently and rapidly locked away from the atmosphere, by injecting it down into volcanic bedrock. The CO2 reacts with the surrounding rock, forming environmentally benign minerals.

Measures to tackle the problem of increasing greenhouse gas emissions and resultant climate change are numerous. One approach is Carbon Capture and Storage (CCS), where CO2 is physically removed from the atmosphere and trapped underground. Geoengineers have long explored the possibility of sealing CO2 gas in voids underground, such as in abandoned oil and gas reservoirs, but these are susceptible to leakage. So attention has now turned to the mineralisation of carbon to permanently dispose of CO2.

Until now, it was thought that this process would take centuries or millennia, and therefore wasn’t a practical option. But the current study – led by the University of Iceland, Columbia University, University of Toulouse and Reykjavik Energy – has demonstrated it can be done in just two years.

Lead author, Dr Juerg Matter, Associate Professor of Geoengineering at the University of Southampton, says: “Our results show that between 95 and 98 per cent of the injected CO2 was mineralised over the period of less than two years, which is amazingly fast.”

The gas was injected into a deep well in Iceland. As a volcanic island, Iceland is made up of 90 per cent basalt, a rock rich in elements such as calcium, magnesium and iron that are required for carbon mineralisation. The CO2 is dissolved in water and carried down the well. On contact with the target storage rocks, at 400-800 metres underground, the solution quickly reacts with surrounding basaltic rock, forming carbonate minerals. The diagram below shows conventional methods of CCS (left) and the new method (right):

Credit: P Huey/Science/AAAS

“Carbonate minerals do not leak out of the ground – thus, our newly developed method results in permanent and environmentally-friendly storage of CO2 emissions,” says Dr Matter, who also works at Columbia University. “On the other hand, basalt is one of the most common rock types on Earth, potentially providing one of the largest CO2 storage capacities.”

To monitor what was happening underground, the team also injected ‘tracers’, chemical compounds that literally trace the transport path and reactivity of the CO2. There were eight monitoring wells at the study site, where they could test how the chemical composition of the water had changed. The researchers discovered that by the time the groundwater had migrated to the monitoring wells, the concentration of the tracers – and therefore the CO2 – had diminished, indicating that mineralisation had occurred.

“Storing CO2 as carbonate minerals significantly enhances storage security, which should improve public acceptance of Carbon Capture and Storage as a climate change mitigation technology,” says Dr Matter.

However, it will require huge efforts to be scaled up to the level needed to store the gigatons of gases currently being emitted by human activity.

“The overall scale of our study was relatively small. So, the obvious next step for CarbFix is to upscale CO2 storage in basalt. This is currently happening at Reykjavik Energy’s Hellisheidi geothermal power plant, where up to 5,000 tonnes of CO2 per year are captured and stored in a basaltic reservoir.”

The investigation is part of the CarbFix project, a European Commission and U.S. Department of Energy funded programme to develop ways to store anthropogenic CO2 in basaltic rocks through field, laboratory and modelling studies.

۲۳rd June 2016

U.S. drone industry welcomes new regulations

The Federal Aviation Administration (FAA) has finalised the first operational rules for commercial use of drones across the USA.

The FAA has just released the first operational rules for routine commercial use of small unmanned aircraft systems (UAS or “drones”). This greatly relaxes the existing laws, and paves the way towards fully integrating these flying machines into the nation’s airspace. The new regulations are designed to harness technological innovations safely, to spur job growth, to advance critical scientific research and to save lives.

“We are part of a new era in aviation, and the potential for unmanned aircraft will make it safer and easier to do certain jobs, gather information, and deploy disaster relief,” said U.S. Transportation Secretary Anthony Foxx. “We look forward to working with the aviation community to support innovation, while maintaining our standards as the safest and most complex airspace in the world.”

The guidelines, which take effect in late August, offer safety regulations for unmanned aircraft drones weighing less than 55 pounds that are conducting non-hobbyist operations. The rule’s provisions are designed to minimise risks to other aircraft, as well as people and property on the ground. Pilots will be required to keep an unmanned aircraft within visual line of sight. Operations are allowed during daylight and during twilight if the drone is equipped with anti-collision lights. Drones will be limited to a maximum speed of 100 mph (160 km/h) and maximum altitude of 400 feet above ground level (AGL) or, if higher, must remain within 400 feet of a structure. The person actually flying a drone must be at least 16 years old.

Drones are still prohibited from carrying packages or other goods across US airspace – a setback for companies like Amazon and Google, which for the last few years have been trying to achieve this. However, the commercial potential for drones remains huge. According to industry estimates, they could generate more than $82 billion for the U.S. economy and create 100,000 new jobs over the next 10 years.

Until now, the FAA laws were highly restrictive, cumbersome and expensive. Commercial operators needed a pilot’s licence for even small drones and were forced to apply on a case-by-case basis. The new system is far simpler and will greatly increase the number of drones appearing in the skies.

“This is just our first step,” said FAA Administrator Michael Huerta. “We’re already working on additional rules that will expand the range of operations.”

DJI, a major manufacturer of drones, called the FAA’s announcement a “milestone” and commented further: “The new rules codify common sense – making it easier for a farmer to fly a drone over his fields, for a contractor to inspect property without climbing a ladder, and for a rescue service to use drones to save lives.”

However, concerns will arise over issues of privacy, security and civil liberties. For example, some of the more advanced drones may feature remote sensing technology and hi-res cameras. They could scan entire cities, at sufficient detail to read a milk carton from 60,000 feet away. Others could intercept mobile texts and phone calls. The new law does not specifically deal with privacy issues in the use of drones, and the FAA does not regulate how drones gather data on people or property. However, the FAA confirms it will be acting to address privacy considerations in this area.

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