September 21, 2020 § 2 Comments

California is ablaze. So are Oregon and Washington. The tally to date is 5 million acres burned, about halfway through the fire season, and well on its way to record territory. Putting that in perspective, the east coast of Australia, devastated similarly earlier this year in the Southern Hemisphere summer, closed the season with 46 million acres burned.

The statistic of greatest concern is that the intensity and scale of the fires is getting worse. Over the last thirty years, the number of fires annually has no discernible trend; certainly, has not gone up. But the acreage burned has; decisively. Both patterns are evident in the figure below. Five of the ten largest fires ever in California are currently active. The largest of these, the August Complex is already at 839,000 acres and still going. The next largest, ever, was 459,000 acres, the Mendocino Complex in 2018. Labeling any of this chance, or poor forestry management, evokes imagery of the proverbial ostrich, and the placement of its head.

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Courtesy US EPA 2019 (Wildland Fire Research Framework 2019-2022)

The average hectares (a hectare is roughly 2.47 acres) burned has nearly doubled over this three-decade period. Nine of the ten largest fires have occurred since the year 2000. Note that this does not include the ongoing five, which certainly would be in that group, making it 14 of the 15 since 2000. Although a regression line would have uncertainty due to big annual swings, an eyeball estimate indicates a strong upward slope. If this is a predictor of the future, that future is indeed bleak and warrants a study of causes.

The recent EPA report, from which the figure was reproduced, ascribes the pattern of increased fire acreage to higher temperatures, drought, early snow melts and historically high fuel loading (which is the fire prone vegetation, including underbrush). We will examine these separately, although they may not be disconnected. But first, a comment on the pattern of numbers of fires being essentially flat. Ignition events determine numbers of fires. In California, the principal ones are arson, campfires, power lines and equipment. The equipment category comprises items such as power saws, mowers, and other operated machinery. Human behavior, absent intervention, can be expected to be constant. So, the flat profile on numbers of fires is to be expected. Interestingly, the incidences are seasonal, even, counter-intuitively, arson.

Climate change is implicated in many of the causes of increasing severity over the years. While the term has many interpretations, one generally accepted aspect is temperature rise in the atmosphere and in the oceans. The debate is not whether this happens, but how fast it does. Also generally accepted (to the extent any climate change causality is generally accepted) is that oceanic temperature rise causes increased severity in the El Niño phenomenon in the Pacific Ocean, which is responsible for catastrophic droughts. These are accompanied by drenching rains in other parts of the world in the same year. Both disturbances are extreme deviations from the norm, with resultant impact on vegetation and the way of life.

Atmospheric temperature rise can also be expected to change the proportion of rain and snow in precipitation. Lighter snowfall can be a result, as also early snow melts. Both are in the EPA list noted above.

California, being generally arid, gets most of its water supply from melting snow. While less snow in a given year is certainly a drought indicator, the phenomenon most studied is that of the timing of the snow melt. Data from four decades commencing in 1973 conclusively demonstrated that burn acreage was strongly correlated with the earliness of the snow melt (Westerling 2016). Decadal comparisons show that the fire seasons in 2003-2012 averaged 40 more days that the seasons in 1973-1982. Fires in the later decade were more severe. Large fires, defined as covering greater than 400 hectares, burned for 6 days on average in the early decade and for more than 50 days in 2003-2012.

Power lines deserve special mention.  Falling power lines were blamed for several fires in 2017 and 2018. The utility has accepted blame and is in bankruptcy. Trees falling on power lines snapped the poles. The tree roots, finding uncertain purchase due to drought conditions, were no match for the Santa Ana winds or any other storm sourced shoves. Those same drought conditions caused the underbrush to be dry. Power lines are usually not insulated.  Sparking wires on dry underbrush and the rest is incendiary history. A poster child for distributed power.

The wildfire future is indeed bleak. Climate change retardation is necessary. But it may not be sufficient in the shorter term. We need a reincarnation of Smoky to change human behavior to minimize the ignition events.

Westerling, A. L. (2016) ‘Increasing western US forest wildfire activity: sensitivity to changes in the timing of spring’, Philosophical Transactions of the Royal Society B: Biological Sciences, 371: 20150178. http://dx.doi.org/10.1098/rstb.2015.0178

Vikram Rao September 21, 2020


February 18, 2021 § 14 Comments

Texas prides itself on being the energy capital. The capital (as opposed to the Capitol of the infamous January 6 insurrection) is under siege.  Nature is asserting its might. Unpreparedness sure helps. 

Few know that Texas has its own grid.  The country is divided into three grids: The Eastern Interconnection, the Western Interconnection, and drum roll here, Texas.  Conspiracy theorists may connect this to secessionist tendencies.  Certainly, recent utterances attributed to the former governor Rick Perry don’t help.  He is quoted as saying, “Texans would be without electricity for longer than three days to keep the federal government out of their business,”.  He is referring to the fact that because the Texas grid does not conduct interstate commerce, it is not governed by the rules of the Federal Energy Regulatory Commission.  This from a guy who just a month ago held federal office as the US Secretary of Energy.  

In a Fox channel interview Governor Abbott of Texas blamed solar and wind for the problem.  Small problem: solar is just 1 – 3% of the total and wind is around 20%.  Then his own folks at ERCOT, which stands for Electric Reliability Council of Texas (the reliability in the name is ironic) said it was primarily due to natural gas supply drop.  This makes more sense because gas generators comprise 47% of the electricity produced.  Abbott later walked back the claims and said he meant that renewables could not be the dominant source.  Tell that to Germany, which gets 40% from renewables.  Then Congresswoman AOC trolled Abbott by Tweeting that Texas electricity was 80 – 90% from fossil fuel.  That is not accurate either (coal plus gas come in at about 65%, according to ERCOT).  Just when you think the election silly season is over, you have politicians using their favorite political points scoring issue whenever there is a remote opening for it.

By all accounts, every source of electricity was hampered by the extreme cold, even the nuclear plants.  But, according to the ERCOT leadership, the biggest culprit was natural gas.  Delivered natural gas nearly halved at the most severe stages due to frozen lines.  We know that methane (the dominant component of natural gas) does not freeze till a frigid -182 C.  So, why are natural gas pipelines (these are the main supply lines, not the little ones going to your house) freezing?

I was not able to find any explanation, so I am going to hazard a hypothesis based on other oilfield knowledge.  Almost all supplies of natural gas will be water wet to some degree.  If films of water form, at pipeline pressures of 800 psi or so, temperatures approaching water freezing can cause hydrate crystals to nucleate on the walls.  Again, with the right conditions, these could grow to plug the line.  This routinely happens in undersea gas pipelines.  Those pipelines have a device known as a “pig” which can be made to traverse the line and mechanically clear out the growing crystals.  The other means is to drizzle in methanol, which lowers the freezing point; basically an antifreeze such as ethylene glycol in your car radiator (which too can be used in this application).

Gas hydrates are large crystals of ice with methane in the interstices.  The overall crystal structure looks like a soccer ball.  Richard Smalley, who co-discovered this structure in carbon (a sixty-atom molecule version), got the Nobel Prize for it, in part because finding a brand-new crystal structure of a common element is rare, and in part because carbon in this form has proven to have compelling value in the form of nano materials.  Gas hydrates in the subsurface were once believed to be the next big thing in natural gas sourcing because they are ubiquitous and, according to the US Geological Survey, the total resource exceeds all other carbonaceous fuels combined.  Some probably still are believers.  In my opinion plentiful shale gas has shot down those dreams.  Gas hydrates are also a neat party trick. Take a block of it in a shallow bowl and the seemingly innocuous ice will light up with a match. 

We can conclude from all that we have seen in Texas that industry, especially a loosely regulated one, operates on probabilities.   ERCOT modeling probably predicted such freezes to be infrequent and more geographically scattered, allowing the management with a minimum of disruption.  Not the way it turned out.  Last year a high proportion of the devastating wildfires in California were known to have been triggered by downed power lines.  A cost-effective solution is yet to be identified.  The Lone Star is not alone after all.

Vikram Rao

February 18, 2021

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