The Solar Garage Door

The cost of solar photovoltaics keep dropping.  In fact, solar cells have been getting cheaper every year for so long that they now have their own equivalent of Moore's Law: Swanson's law:

Swanson's law is an observation that the price of solar photovoltaic modules tends to drop 20 percent for every doubling of cumulative shipped volume. At present rates, costs halve about every 10 years.

Unfortunately, a complete photovoltaic system consists of a lot more than just solar cells, and the other components of the system are not getting as cheap so quickly.

However, this does introduce an interesting possibility: It may become cost effective to install solar panels on vertical surfaces even though they won't be as effective as a rooftop installation.  You'll need more solar panels to generate the same amount of power as a rooftop installation with a better angle.  This added cost might be entirely offset by much lower installation costs, however.  As an additional bonus, vertically mounted panels will be much easier to keep clean, especially if they're installed on first floor walls.

I've been thinking about this idea for a while, but today I started wondering how far you could take the idea, and I came up with an even more absurd idea: the solar garage door.  I'm imagining a mass-produced, standard-sized garage door with integrated solar PV panels, which is a drop in replacement for many of the garage doors currently installed in houses all across the U.S.  Replacing a garage door is by far the easiest thing I can imagining doing to the outside of a house, and is well within the capabilities of the average do-it-yourselfer.  I would expect a couple of professionals to be able to replace a typical garage door in a matter of minutes.

Obviously not every garage door is a candidate, since many will be facing the wrong direction, and there are many that are too small, or oddly-sized.  I don't know how many garages there are in the United States, but I'm guessing on the order of tens of millions.  And probably about a quarter of them are south facing.  In addition, the typical garage door will not be obstructed by trees or other foliage since there will almost always be a driveway in front of it.

OK, so realistically, a standard American two-car garage door is only about 10 or 12 square meters, and you can only expect to get 100 or 200 watts per square meter even in the best circumstances.  So the solar garage door might only produce 5 or 10 kilowatt hours over the course of a day.  That's not enough to run a house or charge an electric car.  But it might be enough to pay for itself in a couple of years, especially since the greatest power production will occur during the times when electricity is the most expensive.  And certainly this idea makes more sense for Dallas than Seattle.

Five or ten kilowatt hours is hard to get excited about in most circumstances.  But there are times when it is very exciting indeed -- when the power grid is down.  Keep in mind, as I write this Florida is recovering from Hurricane Irma, Puerto Rico has just been hammered by Hurricane Maria, and Houston is still drying out from Hurricane Harvey.

Many people keep generators for dealing with prolonged power outages.  Solar PV has some potential advantages.  It can pay for itself over time since it produces electricity for free once it's installed, and it doesn't require fuel to run.  In fact it doesn't have moving parts, so it's very reliable compared to a generator which may or may not run if you haven't used it in a long time -- or possibly ever.  And a solar system doesn't preclude buying a generator as well.  In fact, after the solar system pays for itself, it can pay for the generator too.

A solar garage door will only produce a little bit of power during the day, but even a small installation can produce enough power to charge a cell phone or a laptop, and possibly even run a freezer enough to keep it from thawing out overnight.  A refrigerator may require a battery to keep it cold enough overnight, but batteries are getting cheaper too.

So anyway, my argument for the solar garage door is that it could be an insanely cheap way to retrofit solar to an existing house, its incremental savings in the electricty bill will allow it to pay for itself, and then it provides some added security in the event of a prolonged power outage.

It also provides a way for prospective solar customers to get their feet wet with minimal risk, expense, or even hassle.  And it might be a good way for a new solar company to bootstrap its way into the emerging market (well, maybe) of vertically installed solar panels.

Using Algolia's Hacker News Search to get an alternative view of the current most popular posts

I've always found the ranking mechanism on Hacker News to be somewhat opaque, especially with respect to posts which are flagged.  Sufficient flagging can kill a post in the official sense, but what seems to happen more often is that a post receives one or two flags and then gets aggressively down-ranked and dropped so far down on the popular articles feed (three or four pages or more) that it might as well be dead.  I've both flagged and vouched submissions in the past, and I can say that some submissions definitely deserve to get flagged into oblivion.  The call on a lot of other submissions is more subjective however.  So sometimes I'd like to get a view of currently popular submissions without flagging taken into account.  It turns out there's an easy way to do that.

Algolia's Hacker News search page ( provides a way to search popular articles within a date range.  One of the pre-canned options is the last 24 hours, which provides a view similar to Hacker New's front page, but not identical.  In particular it seems rank submissions purely by upvotes.


How I wish Google CEO Sundar Pichai had responded to James Damore's memo about diversity.

James Damore, who at the time was a Google employee, wrote an internal memo about diversity at Google.  It did not stay internal to Google and ultimately, as they say, it went viral on the Internet. I think Google CEO Sundar Pichai should have responded to this memo in a different way than he did.  Something kind of like this:

I have not yet made a decision about how to respond to James Damore's memo about diversity at Google.  I am going to wait for the outrage to subside, for the various members of the Twitter mob to lay down their metaphorical pitchforks and return to their homes. I do not wish to be a participant in a modern-day Internet lynching -- and neither should you.  If anything Mr. Damore has written in the memo constitutes a fireable offense (as some people have alleged), then I will, indeed take that step.  However, such a drastic action does not need to take place immediately.  If it is in fact justified, then delaying it a few days will cause no great harm.  And this little bit of extra time will allow for hurt feelings and outrage to subside, and that will in turn allow us all to approach the issue with cooler heads and sounder judgment.
-- Imaginary Sundar Pichai

Notes and References

Pichai's actual response can be found here:  And, of course, he also fired Damore:  My contention is that even if he felt he should fire Damore, he should have waited longer, because, well, the pitchforks were still out.

There are a number of different versions of the "diversity memo" floating around on the web, some of them incomplete due to missing links.  I believe that the PDF version of the memo assembled by Vice is a fairly accurate representation of the original memo.  It can be found at:  This document is linked from, which also provides some useful context.

I have also attached a copy of the PDF directly to this post, in case any of the links above should go stale.

As a final note, I am referring to the memo as the "diversity memo" whereas much of the reporting about it uses the term "anti-diversity" (including the Vice link above).  Labeling this memo as "anti-diversity" demonstrates a truly profound lack of reading comprehension, since the author flatly states that he values diversity in the very first sentence of the memo.  Conor Friedersdorf addresses this issue at length in The Atlantic:

Sage-y Cornbread

Got to the grocery store too late the day before Thanksgiving, and discovered that they're out of Stove Top Stuffing Mix? Need an emergency back-up plan? (Originally posted to Facebook ~ Thanksgiving 2016, only now getting around to posting it to the blog.)

Part 1
  • 1.5 cups corn meal
  • 0.5 cups flour
  • 1 tbsp + 1 tsp baking powder (4 tsp)
  • 2 tbsp sugar
  • 0.75 tsp salt
  • ~ 2 tbsp chopped fresh sage
Mix dry ingredients thoroughly in a mixing bowl.

Part 2
  • Cooking oil
  • 1 stick butter
  • 1 cup milk
  • 1 egg
Pour about a tbsp of cooking oil (canola, etc) in a 9x9 pyrex baking dish. Use a paper towel to thoroughly coat the inside of the dish with oil.

Put a stick of butter in the dish and
  • microwave it for 3 minutes on 10% power (soften it, don't liquify it)
Add one raw egg and one cup of milk
  • to the dry ingredients and mix them thoroughly
Add the softened butter
  • to the mixing bowl and mix it some more

Part 3

  1. I wait to preheat the oven since that gives the batter more time to rise.
  2. I preheat the (greased!) Pyrex dish with the oven to keep the cornbread from sticking later.

Stick the empty Pyrex dish in the oven and
  • preheat it to 350 degrees
Once the oven has preheated
  • remove the Pyrex dish
  • pour/scrape the batter into the dish
  • pat it down so it's basically flat
Put the dish back in the oven and bake the cornbread
  • at 350 degrees
  • for 40 minutes

Let the cornbread cool for a few minutes.

  • Typically white flour is used as the second ingredient in cornbread, but I always use spelt, which is pretty similar to ordinary whole wheat flour.
  • If you want to do a gluten-free variant, I have successfully used cornflour (more finely ground than cornmeal). My recollection is that it was somewhat crumblier than normal, but otherwise OK. I have not tried it but I suspect that rice flour would work about the same.
  • I'm not sure what would happen if you just used two cups of cornmeal. I expect the result would just be really crumbly cornbread, but if you're planning to use it as a substitute for turkey stuffing, that's probably OK.
  • The batch I just made came out pretty crumbly anyway.
  • I just eyeballed the sage. It might have been closer to 3 tbsp, I'm not sure. You could substitute dry sage, and if you do you will need a lot less, but I don't know how much exactly.
  • This should go without saying, but you can leave the sage out if you just want regular cornbread.
  • You can use less butter, no butter, or substitute canola oil if you're looking for something a little more healthy.
  • My batter comes out pretty thick, especially with the whole stick of butter. You can just add a little more milk if you find the thick batter to be an issue.
  • Astute readers will note that since I softened the butter in the pyrex dish, I could just have used butter residue to grease the dish. Usually I don't use butter at all (certainly not a whole stick) and just use a little canola oil to grease the dish.
  • As mentioned above, I wait until the batter is ready before I even start to preheat the oven. This gives the cornbread batter more time to rise, which makes a difference in my experience, but seems to be a problem that other people don't have. (Maybe my baking powder is old?)
  • Also as mentioned above, I preheat the greased pyrex dish as well as the oven. This keeps the cornbread from sticking to the dish after it's done and makes it much easier to clean the dish afterwards. However, you have to remember that the dish is still hot when you're pouring the batter into it!
  • If you're feeling ambitious, you could use the butter to saute garlic, chopped celery, chopped onions or other stuffing-like ingredients to add to the batter.
  • No matter how hard I try, I can never cut the cornbread into equal sized pieces. This bothers me more that it should.

Someday Soon "Chemtrails" May Be Real

Airplane contrails are real, but we know what they are: water vapor and small amounts of other combustion products created by jet engines.  The other pollutants may be somewhat harmful, but they are basically the same thing as produced by any other form of combustion.  So what are chemtrails?  Wikipedia sums it up nicely:

The chemtrail conspiracy theory is the unproven belief that long-lasting trails, so-called "chemtrails", are left in the sky by high-flying aircraft and that they consist of chemical or biological agents deliberately sprayed for sinister purposes undisclosed to the general public. [1]

When I say chemtrails may be real in the future, I'm really only making the claim that high-flying aircraft will be deliberately spraying chemicals that are not simply a normal by-product of jet engine operation.  However, it won't carried out for "sinister" reasons and it won't be done in secret.  Instead it will only be done after a great deal of public discussion and scientific deliberation.

The chemical in question?  Sulfur dioxide. 

In 1991 Mount Pinatubo in the Philippines produced the second largest volcanic eruption of the 20th century.  Besides massive amounts of volcanic ash, Pinatubo injected an estimated 17 million metric tons of sulfur dioxide into the atmosphere.  This caused measurable global cooling of about four-tenths of a degree Celsius from 1991 to 1993.  The effects of the eruption lasted for about three years. [2]

The Mount Pinatubo eruption and its worldwide effect on the climate has raised the possibility that we could intentionally inject sulfur dioxide into the atmosphere to counter-act the effects of global warming.  This kind of large scale intentional intervention is frequently called "geoengineering" although Wikipedia prefers the term "climate engineering". [3]

Seventeen million tons of sulfur dioxide might seem like a lot, but over one one-year period in 2013 and 2014 U.S. airlines alone consumed about 50 million tons of aviation fuel.  If jet aircraft were burning fuel (at altitude) as sulfur-heavy as marine bunker fuel (3 or 4%) then we could be talking about the equivalent of a Mount Pinatubo eruption every couple of years. [4][5][6]

A massive climate engineering project to inject sulfur dioxide into the stratosphere is clearly plausible, but is it a good idea?  We can do it, but should we?  There are two big questions we need to answer.  How useful is it? And: How risky is it?

Earth's surface has warmed by about 0.85 degrees Celsius from 1880 to 2012.  In comparison, the effects of the 1991 Mount Pinatubo eruption lasted for a couple of years and caused global cooling that was estimated to be about 0.4 degrees Celsius.  Pinatubo-scale sulfur dioxide injection -- if sustained -- could offset a large proportion of the global warming that we've already experienced.  Of course sulfur dioxide injection only treats the symptoms of global warming, not the root cause.  But it sure looks like it could provide some real value as an intermediate stop-gap solution while other more permanent solutions are brought online. [7][2]

The data from the Mount Pinatubo eruption tells us that sulfur dioxide in the stratosphere can cause cooling comparable to the global warming we've seen so far.  But it tells us something else as well: The effects of stratospheric sulfur dioxide have a limited lifetime, on the order of just a couple of years.  This is bad in the sense that to be useful, the injection program has to be sustained.  But it is good -- very, very good -- in the sense that it reduces risk.  The program could be scaled up, the impact could be measured, and, if the side-effects are too serious, it can be scaled back down again very rapidly.  This greatly reduces the risk of the undertaking.

Global warming melts polar ice packs and ice sheets, exposing darker water and land underneath.  The reduction in reflectivity results in more of the sun's energy being absorbed by the earth, resulting in warmer temperatures, resulting in more ice melting, resulting in more land and water being exposed, resulting in even warmer temperatures.  This is often incorrectly referred to as a "negative feedback loop".  In reality it is a positive feedback loop with negative consequences.  There are other feedback loops of great concern.  For example, as arctic regions get warmer, methane that has been trapped in permafrost and undersea clathrates is released.  And since methane is a powerful greenhouse gas, it too can cause a positive feedback loop. [8][9]

The offset cooling provided by stratospheric sulfur dioxide injection would interfere with these feedback loops.  This could be particularly valuable in the case of methane, which is a more powerful greenhouse gas than carbon dioxide but which also has a quite short lifetime in the atmosphere.

Stratospheric sulfur dioxide injection is not a panacea.  But what it can do is buy us time.  It can buy us time to replace fossil fuels with cleaner sources of energy that don't release carbon dioxide into the atmosphere. It can buy us time to replace less energy efficient technologies with more efficient ones. It can buy us time to deploy large scale climate engineering projects that do remove carbon dioxide from the atmosphere. It can buy us time to deal with the immediate consequences of global warming and climate change (and we are simply going to have to deal with some of them), and indeed it can buy time for developing economies to, well, develop.  Because everything we need to do is going to be easier if everybody has more money.

Now, to get back to my original point.  I don't know for sure that we're going to be using jet aircraft to inject sulfur dioxide into the atmosphere, and I'm no expert anyway.  But I think we're going to do it.  And if we do, the result will be, quite literally, "chemtrails".

  • [1]
    • The chemtrail conspiracy theory is the unproven belief that long-lasting trails, so-called "chemtrails", are left in the sky by high-flying aircraft and that they consist of chemical or biological agents deliberately sprayed for sinister purposes undisclosed to the general public.
  • [2]
    • The second-largest volcanic eruption of the 20th century, and by far the largest eruption to affect a densely populated area, occurred at Mount Pinatubo on June 15, 1991.
    • The injection of aerosols into the stratosphere is thought to have been the largest since the eruption of Krakatoa in 1883, with a total mass of SO2 of about 17,000,000 t (19,000,000 short tons) being injected—the largest volume ever recorded by modern instruments.
    • This very large stratospheric injection resulted in a reduction in the normal amount of sunlight reaching the Earth's surface by roughly 10% (see figure). This led to a decrease in northern hemisphere average temperatures of 0.5–0.6 °C (0.9–1.1 °F) and a global fall of about 0.4 °C (0.7 °F).
    • The stratospheric cloud from the eruption persisted in the atmosphere for three years after the eruption.
  • [3]
    • Some proposed climate engineering methods employ methods that have analogues in natural phenomena such as stratospheric sulfur aerosols and cloud condensation nuclei. As such, studies about the efficacy of these methods can draw on information already available from other research, such as that following the 1991 eruption of Mount Pinatubo.
    • Climate engineering, commonly referred to as geoengineering, also known as climate intervention,[1] is the deliberate and large-scale intervention in the Earth’s climatic system with the aim of limiting adverse climate change.
  • [5]
    • Governing bodies (i.e., California, European Union) around the world have established Emission Control Areas (ECA) which limit the maximum sulfur of fuels burned in their ports to limit pollution, reducing the percentage of sulfur and other particulates from 4.5% m/m to as little as .10% as of 2015 inside an ECA. As of 2013 3.5% continued to be permitted outside an ECA, but the International Maritime Organization has planned to lower the sulfur content requirement outside the ECA's to 0,5% m/m.
  • [6] Math
    • How much sulfur dioxide could be produced by burning 16.2 billion gallons of fuel which is 3.5% sulfur by weight?
      • > 16.2 billion gallons
      • > 61.3 billion liters                   ; 3.78541 liters per gallon
      • > 47.5 billion kg                       ; 775 g/l or 0.775 kg/l, the lower figure for jet fuel
      • > 47.5 million tons                     ; 1000kg per metric ton
      • > 1.66 million tons                     ; tons sulfur, assuming 3.5% sulfur by weight
      • > 3.32 million tons                     ; sulfur dioxide is about 1/2 sulfur by mass (32.06 / 64.066)
    • Answer: 3.32 million tons sulfur dioxide
      • This number is at best an estimate.  Aircraft would only burn sulfur heavy fuels at altitude, so not all fuel consumed would produce stratospheric sulfur dioxide.  On the other hand, average jet fuel density is no doubt greater than 775 g/l, and sulfur concentrations of up to 4.5% have been reported for marine bunker fuel.
      • Most importantly, U.S. air travel only accounts for a fraction of total air travel -- a large fraction, no doubt, but probably less than half.
        • > 3.32 million tons                    ; assume U.S. aircraft inject 3.32 million tons of sulfur dioxide
        • > 6.64 million tons                    ; assume European and Asian aircraft can inject a similar amount
        • > 13.3 million tons                    ; assume a 2 year time horizon
  • [7]
    • The global average (land and ocean) surface temperature shows a warming of 0.85 [0.65 to 1.06] °C in the period 1880 to 2012, based on multiple independently produced datasets.
  • [9]
    • Arctic methane release is the release of methane from seas and soils in permafrost regions of the Arctic, due to deglaciation. While a long-term natural process, it is exacerbated by global warming. This results in a positive feedback effect, as methane is itself a powerful greenhouse gas.

Self-sinking capsules and cryobots

Probing Of The Interior Layers Of The Earth With Self-sinking Capsules:

It is shown that self-sinking of a spherical probe in the form of a capsule filled with radionuclides, whose decay heats and melts the rock in its path, deep into the Earth is possible. Information on the formation, structure, and shifts deep in the Earth can be obtained by recording and analyzing acoustic signals from the recrystallization of the rock by the probe.

Similar technology for penetrating ice:

A cryobot or Philberth-probe is a robot that can penetrate water ice. A cryobot uses heat to melt the ice, and gravity to sink downward. The difference between the cryobot and a drill is that the cryobot uses less power than a drill[citation needed] and doesn't pollute the environment.

A cryobot or Philberth-probe is a robot that can penetrate water ice. A cryobot uses heat to melt the ice, and gravity to sink downward.