“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Sunday, September 29, 2013

Farewell to The Oil Drum

Graphic credit: TheOilDrum.com
For those interested in a holistic understanding of our energy predicament from an educated and technically savvy point of view, there are a variety of sources of data (BP supplies two of them, the U.S. Energy Information Agency, EIA, is another), there are many blogs devoted almost entirely to energy (some are linked in the blog roll to the right of this post), and many more that touch on the topic.

But occupying a unique place among those who study energy and especially fossil fuels was The Oil Drum. The last post in this amazing resource was made on September 22, 2013, and the site is now an archive of the incredibly deep, varied, and informed discussion that has comprised the site's content since April, 2005. It will be a valuable resource for years to come.

The Oil Drum's demise has been described by its editors as being due to "a dwindling number of contributors" and high costs (both in terms of time and money). Unsurprisingly, those who believe in the fairy tale that the free market can create an infinite supply of a finite resource trumpeted this development as indicative of the capitulation of the "peak oil fanatics" to the technological and financial developments that will always and inevitably overcome resource scarcity.

Without getting into a deep discussion of what "peak oil" really means, suffice it to say that it predicts a plateau and then a decline in the rate (yes, rate) at which oil can be extracted as we exhaust the easiest and cheapest sources first and then the progressively more difficult and expensive sources. All this transpires in the face of increasing world wide demand and massive growth in demand from developing nations. The free market "true believers" (and I lean in this direction but am willing to be flexible in the face of data) believe that price will solve all problems of both source and rate. The chart below indicates otherwise (data from the BP site linked above). While oil prices have multiplied ten-fold since 1976 (albeit in nominal $, but see below), production has risen by a bit under 30% in the face of ever growing demand in the developing nations, especially China.

Update: Dan took me to task in a comment for only showing nominal crude price. I've added an inflation adjusted price using CPI-U data. The inflation adjusted price has risen 116% while production has risen 30%.

Learned discussion by knowledgeable experts at The Oil Drum of the technical, economic, and political aspects of energy availability (not at all limited to crude oil) will be sorely missed. While the thoughts and writings of many of the regular contributors to The Oil Drum can be found elsewhere (and links to many of their blogs and web sites are available at the final post of The Oil Drum) and the articles and comments archived for use, the lively discussions are irreplaceable.

Farewell to the site and to its participants!

Saturday, September 21, 2013

Looking into the CT200H mileage trends

What with work and family, sometimes I don't have as much time as I'd like to devote to authoring posts. And some of them take a significant amount of time. In this case, I've made a couple of posts regarding the the possibility of sequestering CO2 from power plants in carbonate rocks, pavers, bricks, etc. I still owe my audience an analysis of this process in terms of energetics and economics. Those are taking some time.

In the mean time, I want to take a look at some of the data from my records of mileage in the Lexus CT200h that's my daily driver. To the left is a plot of the mileage at each fill-up since my acquisition of the car. It raises some questions.

Of course, the very low and very high numbers are related to the profile of driving done during the applicable tank. The lowest, for example, involved climbing into the mountains above Los Angeles for an outing with my son.

But I noted a trend, beginning at the end of the third quarter of 2012 and extending to the end of the first quarter of 2013, of declining mileage. I took the vehicle in for scheduled service in mid-March and told the service crew about the declining fuel economy. When they returned the car, they said they'd checked all applicable parameters in the fuel delivery system, the engine control unit, etc. and found no anomalies and adjusted nothing. But the mileage increased noticeably and is still appearing to be on that upward trend.

Now, to the best of my ability, I always drive in the same way (much to the frustration of my passengers - those who will still ride with me anyway - and the vehicles that share that road with me). And, to the extent possible, I try to always purchase gasoline from the same station. Assuming that it's not related to my route or driving techniques, what could explain it?

One possibility is "winter blend" vs. "summer blend" gasoline. In summer, particularly in California, refiners must use gasoline blends with lower vapor pressure to minimize vaporization due to warmer temperatures (and more driving). In winter, refiners add butane to blends because it's cheaper (thereby partially explaining winter's lower gas prices) and the higher vapor pressure of butane containing blends isn't as harmful due to the lower temperatures and lesser total vehicle miles driven. And butane has a lower specific energy content, thus possibly explaining my reduced fuel economy.

Is there such an annual "signal" in my fuel economy data? I've got 90 data points, and so ran a Fast Fourier Transform of the data. Such a process is used to transform data from the "time domain" (as in a time series) to the frequency domain (showing periodic components in the data). If the winter/summer blend switch, which happens annually, is a significant part of the fuel economy changes I've noted, my theory is that such periodicity should appear in the frequency domain. If you squint, you can even convince yourself that it's there - lower in winter and higher in summer.

Alas, there's no such peak apparent in the Fourier Transform. It's back to the drawing board. I can't imagine that the dealer fixed  or adjusted something and didn't charge me for it!

Saturday, September 07, 2013

Can we use the carbonate "rocks" from carbon sequestration?

Photo credit: Construction Consulting and Testing
In my previous post, I discussed the launch of a pilot plant by a group of entities with the goal of sequestering COin manufactured carbonates that would subsequently be used in construction. These uses may include bricks, aggregates, pavers, etc. Of course, even were the CO2 not used, it's better to have it in an inert mineral material than contributing to radiative forcing in the atmosphere. I suppose that any unsold inventory could simply be dumped. But what about a market?

The claim I mentioned in the previous post was that 50 plants could sequester a gigatonne of CO2. The veracity of the claim aside, what would this mean? For a start, how much rock is represented by converting a gigatonne of carbon dioxide to calcium carbonate (CO2 + CaO  CaCO3), or possibly magnesium carbonate (CO2 + MgO → MgCO3)?  As an aside, it should be noted that these are EXTREMELY simplistic versions of the actual production reactions. A paper giving technical details is available here. Anyway, the molar weight of COis 44 grams, the molar weight of CaCOis 100 grams. Thus, converting a gigatonne of carbon dioxide would produce (100/44)*1 billion tonnes, or 2.27 gigatonnes. The same calculation for MgCOyields 1.92 gigatonnes. Let's call it 2 gigatonnes. Of course, it wouldn't make a lot of sense to convert this to cement (!) so what's the demand for bricks and aggregate worldwide?

What is typically thought of when "brick" is mentioned is the iconic red clay brick. These are usually formed by an extrusion process of pulverized clay materials mixed with water. The most common result is a brick of length 4", height 2 1/4", and depth of 4" weighing 2.7 kg. A similar volume of calcium carbonate weighs 3.20 kg, and of magnesium carbonate, 3.49 kg.  A gigatonne is 1000 kilograms, so 2 gigatonnes is 2 trillion (~2*10^{12}~) kg. I'll use 3.3 kg to determine that 606 billion bricks could be manufactured. The best information I was able to find says that around "seven to nine billion" bricks per year are used.

OK, can't use it all in brick, what about aggregate? This site estimates that demand for construction aggregate worldwide is on the order of 26 gigatonnes. Clearly, this is where the manufactured carbonates are best used. And, it would seem, there is sufficient demand. In fact, working backward, 26 gigatonnes of calcium carbonate aggregate would absorb 13 gigatonnes of CO2, about 40% of our annual emission. And, one would assume, as emissions rise with a growing developing nations economy, so would aggregate demand. If it works, I like it!

There are two further considerations: energetics and economics. After all, if the energy required to manufacture the carbonates is excessive, particularly if it involves fossil fuel energy, there's a problem. And if the cost is too high, it won't matter about demand because it won't be purchased (unless, of course, carbon is taxed or credited in such a way as to balance the price).

I may or may not be able to get a handle on the economics but I should be able to nail down the energetics. I'll do that in my next post.

Monday, September 02, 2013

A home for CO2?

Photo credit: MIT
A hybrid group comprised of The University of Newcastle (through it's commercial entity, Newcastle Innovation), Orica (a chemical company), and GreenMag Group (appears to be an ecologically oriented innovation facilitator) has launched a pilot plant that converts carbon dioxide into bricks, pavers, aggregate, and other construction products. The idea is to capture CO2 from power plants and other large industrial emitters and turn it into such products. It's seemingly plausible. After all, cement is made, in large part, by cooking the CO2 out of limestone, which is CaCO3, i.e., calcium carbonate, to form CaO, lime. The Mineral Carbonation International facility, in a simplistic view, reverses this.

In the inhabitat.com article that alerted me to this concept, it's stated that "fifty carbon capture plants around the world could potentially sequester over a billion tons of CO2 annually." Now, our species emits on the order of 31.6 gigatonnes (Gt) annually, so this potential, if it's real, represents maybe 3.2% of our emissions (I'm assuming that metric tons or "tonnes" is the unit, if not, then it's 2.9%). I'm assuming that the sequestration plant would be collocated with the carbon dioxide emitter. I wouldn't think compressing and shipping the CO2 would be feasible. There are some 50,000 coal fired power plants worldwide. So, if they all had such capability, we could sequester some 1,000 billion tonnes of CO2, 32 times our actual total annual emissions! Woo hoo, let's get started!

But how do we reconcile these numbers? A "typical coal fired power plant," per the Union of Concerned Scientists, emits 3.5 million tons of carbon dioxide annually. If I assume they're utilizing short tons, it fits fairly well with an estimate calculated from Wikipedia that yields 2.4 megatonnes, using a one gigawatt power plant at 80% capacity factor. OK, so 50,000 plants times 3.5 million tons per plant yields 175 billion tonnes, or over five times worldwide emissions. Nothing sensible there either, clearly none of that makes sense unless the average coal fired plant is much smaller than a gigawatt plant. The Union of Concerned Scientists must be referring to a very large, gigawatt scale coal fired power plant.

OK, finally, looking through the EIA site, I can estimate that about 14 gigatonnes of COare emitted worldwide via coal combustion for energy. So the average annual emission of a plant would be 14 billion/50,000 or 280,000 tonnes per plant per year.  Does THIS make sense? The estimate in the previous paragraph of 2.4 megatonnes came from my plugging in a 1 gigawatt nameplate capacity plant at 80% capacity factor. That would mean that the "average" plant operates at (280,000/2,400,000)*800 megawatts or 93 megawatts. I don't find this to be unrealistic, there may very well be many thousands of relatively small coal fired power plants around the world.

But back to the claim that 50 pilot plants can sequester a gigatonne. That would be 20 megatonnes per plant, FAR more than the 2.4 megatonnes emitted by a large (gigawatt size) power plant. The only way for the claim to make sense is if, in contradiction to my speculation above, carbon dioxide is compressed and transported to a sequestration facility. Sorry, I doubt it. Next post: how much carbonate will be produced and what can be done with it? After that, energetics and economics.