Strategian Science

As of May 30, 2018, a supercritical carbon dioxide demonstration power plant began operation in Texas, USA.  Operated by NET Power, LLC, the technology is powered by natural gas and generates electricity using CO2 itself to run the turbine.  The technology–called the “Allam Cycle”–may eliminate “virtually all emissions from natural gas power generation without requiring expensive … carbon capture equipment.”

Traditional natural gas power plants burn gas using air and use water to crank the turbine.  A by-product of the process is CO2 which often is released into the atmosphere or is attempted to be captured using expensive equipment.

The Allam Cycle replaces the water with supercritical carbon dioxide which operates as both a liquid and a gas.   Oxygen, CO2, and natural gas are fed into a combustor; the gas ignites; the by-products “are hot water and a lot of supercritical CO2 which acts as an efficient working fluid for driving the adjacent turbine.”  Using CO2 to run the turbine improves efficiency, avoids energy losses, and eliminates parts of the process needed by steam-electric power plants.

The end result could be the production of “low-cost electricity from natural gas while generating near-zero atmospheric emissions, including full CO2 capture.”

The plant fired on May 30 is a demonstration facility.  If successful, NET Power predicts the building and deployment of commercial-scale power plants starting as soon as 2021.

“If it plays out as advertised, it could be an actual game changer.”

Read the articles–here and here (James Temple, MIT Technology Review, August 30, 2017 and NET Power, PR Newswire, May 30, 2018).

In 2017, Hurricane Harvey moved very slowly across parts of Texas (USA) dropping “more than 30 inches of rain in two days and nearly 50 inches over four days.”  “Harvey’s rainfall exceeded every known flooding event in American history since 1899.”

The reason for the high rainfall totals was the slow movement of the storm–and a 2018 study reports that “between 1949 and 2016, tropical cyclone translation speeds (how quickly a storm moves) declined 10 percent worldwide.”

While a 10% change may not seem significant, the reality of Hurricane Harvey and other recent storms show the effect–“devastating flooding and billions of dollars of damage” as well as death, trauma, stress, widespread and long-lasting environmental damage, and the list goes on.

What is the cause of the slower storm movement?  “Broader evidence suggests that climate change is playing a role.”

The winds that push hurricanes along are influenced by temperature differences between the tropics and the Poles.  That temperature difference is getting smaller.  As a result, the steering winds are weakening, and the hurricanes and other storms are moving more slowly dropping more rain and causing more destruction.

Hurricanes are becoming more dangerous.  Additional scientific analysis indicates that as the winds that push hurricanes weaken, the winds inside hurricanes strengthen.

And, the danger from hurricanes is not just along the coasts.  Inland flooding and mudslides caused by the intense rainfall “poses the highest mortality risk nowadays in certain regions.”

Read the article (Kendra Pierre-Louis, New York Times, June 6, 2018).

Most of the world’s fresh water is found frozen in Antarctica.  And, that ice is melting today–and the melting is happening at an increasing rate.  A new study estimates that the rate of melting “has tripled since 2007.”  At this rate, the melting ice will “contribute 6 inches to sea-level rise by 2100.”

While this may not seem threatening occurring over decades, it will cause substantially increased coastal flooding; many coastal areas globally are highly populated.  For example, “around Brooklyn (New York, USA) you get flooding once a year or so, but if you raise sea level by 15 centimeters (6 inches) then that’s going to happen 20 times a year.”

“Between 1992 and 2017, Antarctica lost 3 trillion tons of ice.”  40% of that occurred since 2012.  And, melting ice is not only happening in Antarctica, “Greenland lost an estimated 1 trillion tons of ice between 2011 and 2014“, and there are many other areas of substantial ice loss as well.  The melting ice and warming sea water have “all been primarily driven by human emissions of greenhouse gases.”  “The rate of sea level rise due to Antarctic ice loss has tripled since 2012.”  The main driver of the Antarctic ice melt is actually the edges of the ice sheets interacting with warming ocean water–“forces that you can’t reverse easily.”

Sea level rise is impacting people living on coasts today–including and especially in the U.S.  The economic costs will be immense.  What can we do to mitigate and adapt?

Read the article (Kendra Pierre-Louis, New York Times, June 13, 2018).

Lack of fresh water for agricultural use and for human consumption is a growing and very serious problem globally–including rich countries.  Read this article (Henry Fountain, New York Times, May 24, 2018) for a look at how climate change is affecting rivers in the western United States.  The Rio Grande and the Colorado, two major western U.S. rivers, are experiencing significantly reduced flows due to warmer temperatures, longer and more frequent droughts, less snow and less winter precipitation overall, and the need to serve more people.  By May, stretches of the Rio Grande had already completely dried up.  “Both of these rivers are poster children for what climate change is doing to the Southwest” U.S.  These events are not a theory or a future projection, it is happening today.  How can we as a society and as individuals mitigate and adapt?

See this source behind this story.