Gas station without pumps

2016 January 3

Solar lies

Filed under: Uncategorized — gasstationwithoutpumps @ 18:27
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Enphase, who make the microinverters I use and monitor their output, reported to me

Enphase Energy maximizes your solar energy production and keeps you informed about your system. Your monthly energy report shows how your system performed and how much you contributed to offsetting the global carbon footprint.

Week Peak Power Energy Produced
12/01/2015 – 12/07/2015 925 W 24.7 kWh
12/08/2015 – 12/14/2015 887 W 23.3 kWh
12/15/2015 – 12/21/2015 928 W 22.5 kWh
12/22/2015 – 12/28/2015 1.05 kW 26.1 kWh
12/29/2015 – 12/31/2015 873 W 13.4 kWh
December 2015 Total: 110 kWh
Previous Month Total: 140 kWh
Year to Date: 1.00 MWh

For more details on these production results, please visit your Enphase® system.

Your Carbon Offset for this month: 168 lbs

You have offset the equivalent of: 2 Trees

The total energy generated seems correct, but the carbon offset is clearly wrong.  PG&E reports emission factors in the range 0.391–0.641 lbs CO2/kWh (or 0.177–0.291 g/Wh) for their electricity generation, depending on the year.  []
That means that my generating 110kWh reduces CO2 emissions by 43–70.5 lbs (19.5–32kg), not 168 lbs.

Enphase’s computation using 1.53 lbs CO2/kWh is quite high—not worst case (lignite coal is 2.17 lbs CO2/kWh []), but much higher than the US average of 1.222 lbs CO2/kWh used by [].

Of course, household solar energy production in the summer mainly affects peaking, not baseload power generation, and that averages about 0.689551 g/Wh across the US [].  With that number, 110kWh would be 75.85kg CO2 (167 lb), so that is what Enphase is reporting—the largest number that they could conceivably justify.

But in the winter, mid-day is not peak power usage—early evening is in California, so it really isn’t justifiable to use the national, year-round average peaking generator CO2 emissions for California winter solar generation.  The annual non-CO2 emissions for non-baseload power in California is only 1.01887 lbs/kWh  (0.462 g/Wh) [], which is the largest number that Enphase could honestly claim in the summer (probably still high for PG&E, which uses a smaller proportion of fossil fuel generation than most California utilities).

Enphase is not the worst offender in inflating carbon offsets—the “Cool Campus Challenge” at UC had some really ludicrous estimates of how much CO2 would be reduced by various changes in habit. For example, they seemed to assume that turning off a computer monitor when not in use would save 200lbs of CO2 a year, which for PG&E electricity would be 300–500kWh/year, or 36–58W.  But most monitors drop into a power-save mode after being idle for half an hour, taking less than 1W, so a more honest estimate of how much CO2 would be saved is around 15kWh, or 6–10 lbs CO2.  Their estimates of 50lbs of CO2 reduction for unplugging vampire loads was similarly ludicrous—most of the power supplies in my house meet at least Level IV efficiency standards, with “vampire” loads under 0.1W. Unplugging all of them would save maybe 1w, or 3–6 lbs CO2.

I wish that people who provided carbon offset calculations would be more honest about them. It does no one any good to  think that small symbolic gestures do much to reduce their carbon footprint.

One thing that is a little more than symbolic—closing my laptop so that it sleeps reduces its power consumption by 20W, so closing it for 12 hours a day saves 88kWh/year, or about 34–56 lbs of CO2.

But almost anything I do with electricity reduction is mainly symbolic, as my biggest carbon footprint is usually for heating my house (and hot water) with natural gas: about 433 therm/year or 2300 kg CO2 (5100 lbs) [].

I expect this year to make a couple of family trips, for a total flight distance of around 14000km, adding another 2500 kg CO2 this year [] I may do another 2000 km of Amtrak train rides (about 70–90 g/km [European figures for diesel traction from]) for another 140–180 kg CO2.

Even as a bicyclist without a car, transportation contributes a lot to my carbon footprint—more than I expected.

2014 December 8

Arana Gulch Multi-Use Trail Project Dedication

Filed under: Uncategorized — gasstationwithoutpumps @ 09:18
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According to  City of Santa Cruz : City Newsroom : Save the Date: Arana Gulch Multi-Use Trail Project Dedication January 14, the Broadway-Brommer bike bridge will finally be completed (it has taken about 20 years).

The ribbon cutting will take place 2–4pm on Wed 14 Jan 2015 at the Frederick Street end of the bridge. Unfortunately, I won’t be able to go, as it is sandwiched between the two classes I need to teach that day.

The City of Santa Cruz post linked to above gives details on the parking (car and bike parking) and planned entertainment.


2013 October 3

Future with less driving?

Filed under: Uncategorized — gasstationwithoutpumps @ 19:21
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It seems that we have hit the peak of the mania for driving in the US, and have started a gradual return to sanity.  I found a graph of annual per capita miles driven for the past 40 years at SSTI to Transport Officials: Start Planning for a Future With Less Driving:

Annual, per-capita vehicle miles traveled by Americans have been declining for eight years. Image: State Smart Transportation Campaign

Annual, per-capita vehicle miles traveled by Americans have been declining for eight years.
Image: State Smart Transportation Campaign
Caption: Angie Schmitt

Note: this doesn’t mean that total driving has started heading down yet, since population is still rising. Nor can I  defend 9,500 miles per capita, since that is still a huge amount of driving, but it seems that there is a definite sustained downward trend.  It may take another 40 years to get back to more sane levels of driving (which I put at around 2,000 miles per capita per year), but I see some hope for the future.

Thanks to Richard Masoner, whose post  on pointed me to the post.

2013 May 10

National Bike Challenge

The League of American Bicyclists and California Bicycle Coalition are encouraging bicyclists to enroll in the National Bike Challenge.

Enrollment is free, and all you need to do is log your miles over the summer.  You get one point for each mile you ride and 10 points for each day that you ride at least a mile. Once you’ve earned a few points you get entered into lotteries for small prizes.

I’m not quite sure what the point of it is for LAB and CBC (perhaps, like Bike Week, it is an attempt to increase daily biking).

So far only 6 people have signed up from Santa Cruz, making out points per capita astonishingly low (57th in California).

2013 April 20

College tours around LA

Sorry I’ve not been posting this week, but I’ve been on the road with my 11th-grade son around Los Angeles for science fair and college campus tours.

On Monday and Tuesday, we had the California State Science Fair, where he had a project in the math and software high school division, and I was judging in the math and software middle-school division.  He did not expect to win anything this year, as he had a fairly straightforward engineering project—the Arduino data logger that he wrote for my circuits class to use.  The project was well done for a high school student (comparable to some senior projects I’ve seen by college students), but not flashy in the way that science fair judges like. Indeed he did not win anything at state this year, but he was one of only 11 students who had been to state science fair 6 or more times—so he shows consistent quality and perseverance, even if he never wins the lottery that science fair judging often is.  The top math and software award at the high-school level this year went to a math project (not a software project), which is a bit unusual.  I did not read the poster for it in any detail, which I now regret, as it must have been pretty good to overcome the usual judging bias in favor of software.

The middle-school math and software category had a unanimous vote for the first-place project: an ambitious image-processing project with an interesting application and pretty good code (properly commented—a rarity at the middle-school level or even the high-school level).   The order of the next few projects was more strongly debated, but all of them were very good projects, and the order ended up depending more on the tastes and persuasive abilities of the judges than on the inherent merits of the projects.

Since we were down in Los Angeles for the science fair, we decided to extend the trip by 3 days to visit three colleges in the area: Caltech, UCLA, and Harvey Mudd.  [The science fair is right by USC, but that was not our list of colleges to visit—we’ve seen the campus often enough, and the academic program did not appeal.] Originally we had planned a west-to-east sweep (UCLA, Caltech, Harvey Mudd) to minimize the transit time, but Caltech was not doing tours on Thursday and Friday (preparing for their admitted-students yield event this weekend), so we changed the order to Caltech, UCLA, Harvey Mudd. To get from the science fair to Pasadena, we took a DASH bus, the red line (subway), and the gold line (light rail).  That used 2 different transit systems (LA DOT runs the DASH buses, and Metro runs the subway, the light rail, and all the other buses that we took on this trip).

I couldn’t find any reasonably priced motels or hotels near UCLA in my on-line searches, so we stayed one night in Pasadena and two nights in Claremont, with the UCLA tour sandwiched in between the 2-hour, 2-bus Pasadena-Westwood and 3-hour (bus, subway, train) Westwood-Claremont transits.  I had originally planned to take a taxi from UCLA to Claremont (a pretty expensive ride across Los Angeles), but my son wanted to include a Metrolink commuter rail link in the trip somewhere in our trip, so we ended up taking the Metro number 2 bus from UCLA to the red line, the red line to Union Station, and Metrolink to Claremont.  The subway and commuter rail portions were fairly pleasant, but the number 2 bus was so full that we felt guilty for having luggage—Metro probably needs to run more buses on that route during rush hour.

The LA transit system is usually maligned by the locals, who claim that it is so bad that they have to drive everywhere, but it seemed pretty reasonable to us—under-utilized, perhaps, but reasonably quick and with decent connections.  Of course, just about any local bus system will only provide about 10-mile-per-hour transportation, so bicycling is almost always faster, but that is an option that is seems very , very few people choose in Los Angeles.

OK, enough on transit, what about the 3 colleges?

At Caltech we had a very small tour group (just 3 prospective students) and a friendly, barefoot tour guide.  We were shown the Caltech “houses” and the guide talked a lot about Caltech traditions.  Some of the traditions (like the honor code) seem great, but a lot of the other traditions seemed to be based mainly on rivalry, competition, and mean-spirited pranks. The social activities mentioned (like the interhouse parties) seemed to be mainly competitive events also (which house could build the most elaborate set for their party).  We saw almost no students while on the tour, no classrooms, no professors—very little other than the houses and the outsides of buildings.  The campus seemed strangely deserted for a Wednesday afternoon in the middle of the term.

The Caltech campus does have some nice-looking buildings, and there are supposedly a lot of Nobel prize winners around, but we didn’t hear much about students actually interacting with the professors—the impression was that the professors mainly kept their heads down and did research with their postdocs and grad students. My son had tried to arrange meetings with a computer science faculty member by e-mail, but the first one he contacted suggested he talk to someone else, and that person said he was too busy, but that my son should just wander down the hall and stick his head in an open door.  We ended up not talking to any Caltech faculty or even seeing any from a distance.

The one academic message that we got from Caltech was “physics”.  They teach physics at Caltech—occasionally they give it a different name (math, chemistry, computer science, engineering, … ), but when you look at the research interests of the faculty, it is almost all physics in different flavors.  My son likes physics, and would probably do ok at Caltech, but he has other interests as well, and Caltech does not seem to provide instruction or opportunities in them.  He also likes doing applied work more than theory, and Caltech (according to the student tour guide and what we could glean from the web) is very theory-oriented.  Caltech does have some theater that he could participate in, but their entire “theater and visual arts” program apparently fits in a small 2-story house and a shed at the corner of campus, and there was no one around on a Wednesday afternoon to get any information from.

UCLA was in many ways the opposite of Caltech.  It is a large, bustling campus, crowded with students the whole time we were there. Students walked or hung out in groups (very little wheeled transportation, because of the number of hills and stairs).  There did not seem to be many quiet places on campus (unlike Caltech, where the entire campus seemed to be silent).

The tour group we were with for a 2-hour walking tour was large—probably 15 students plus accompanying family members.  The tour guide showed us many buildings (including the insides of a nice library), but no residences (which are a 20-minute walk away from the academic buildings), and she told us about admissions and other generic information.  The campus tours seem to be entirely student run (the campus tours office is in the student government building and staffed entirely by students), rather than part of the admissions office.  The tour was pretty good, for a large, generic tour, and UCLA does have some nice-looking buildings (and nice-looking students, but I’m not supposed to notice that).

We had arranged a meeting with a CS faculty member, who told us about his classes and research. Undergrad computer science at UCLA has huge classes (60–80 in upper-division courses, and three times that in lower-division courses). The faculty member told us that he does not allow undergrads into his grad courses and that few undergrads get research opportunities.  He did not have numbers, but estimating from what he said, it sounds like only about 5% of CS majors at UCLA get involved in faculty research—an appallingly small number.  It sounds like it is hard for an undergrad at UCLA to get a first-rate computer science education, because they are so focused on pumping through huge numbers of OK students.

UCLA does have a great reputation in theater, so we went over to the opposite side of campus to find out whether a non-theater major could ever get roles.  We did not talk to a theater faculty member nor an administrator, but to a friendly group of theater majors.  They basically said that non-majors had essentially no chance of getting a role (or even tech work) in any theater department production—even the theater minors only got theater-appreciation classes, not acting classes.  They did say that there were some non-departmental theater productions, but that they knew almost nothing about them.  In short, it sounded like what my son wants (a really advanced computer science education with the ability to do a fair amount of acting on the side) is not available at UCLA.

I had expected Harvey Mudd to be similar to Caltech.  They both have reputations for being very techie schools with impossibly high workloads, and Harvey Mudd was started by someone with close ties to Caltech.  They both have a similar-sounding common core requirement and both have a very pure form of honor code (tests are unproctored take-home exams, with students responsible for timing themselves as well as following directions about whether notes and books are permitted).  There were a number of observable differences, though, even on a one-day visit:

  • Harvey Mudd has some of the ugliest buildings I’ve seen on any college campus.  The concrete block buildings with “warts” make UCSC’s cast concrete bunkers look stylish in contrast.  It is clear that Mudd has not been investing in the amenities wars—there is no luxury here.  The interior of the dorms look a lot like the concrete-block dorms I lived in back in the early 70s at Michigan State, but perhaps even more crowded.
  • The campus is small.  Our walking tour showed us every building on campus, including a walk through the main academic building, showing us classrooms, faculty offices, and even the wood shop and machine shop (which Mudders can use 24/7 once they have passed the safety training). The class in which students have to make a hammer to specifications from a chunk of wood and a chunk of metal seems like a good, practical course.
  • The campus is flat, so wheeled transportation is common (bikes, unicycles, skateboards, long boards, and freeline skates seemed the most popular).
  • The density of students was between that of Caltech and UCLA.  There were plenty of students around, but it was never so crowded or so loud as to be claustrophobic. A lot of the students were wearing geek T-shirts and seemed likely to be the sorts of kids my son would get along well with.
  • Faculty were clearly visible—one physics professor even kibbitzed the tour guide as he was giving the explanation of the physics core courses.
  • The admissions office gave my son a ticket for a free meal at the dining hall (and a reduced-price ticket for me).  We had lunch there, and the food was pretty good for a dining hall—more important it included several things that my son would eat on a regular basis.  We also noticed that several of the faculty ate there.  I don’t know if Harvey Mudd encourages the faculty to eat with the students (free lunch might do the trick, or the unavailability of other options), but it was good to see faculty and students in the same hall, even if at different tables.  I also noticed that none of the students were eating alone—almost everyone was in a group of 2 to 10 students. For a group of geeks, that is a rather astonishing bit of social engineering—I wonder how they accomplished it.
  • My son was also given a list of all the classes meeting at Harvey Mudd this semester and invited to sit in on any of them.  Unfortunately, we were there on a Friday, so few classes were meeting (mostly long labs).  We sat in on one of the “choice” labs for a while, and saw mainly one-on-one mentoring by the faculty member, which was good to know about, but not very exciting to watch.
  • Harvey Mudd does have an 11-course humanities, social science, and arts (HSA) requirement, about half of which has to be done at Harvey Mudd, with the rest usually being done at the other Claremont colleges.  It would be possible for him to do a theater concentration (5 theater-related courses), by taking the one Harvey Mudd theater course (simply titled “Shakespeare”) and 4 courses at Pomona.  Most of the Mudders take a fair number of courses at the other Claremont colleges—usually PE courses and courses in their HSA concentration, and cross-registration seems to be fairly straight-forward, since the Claremont colleges share a common registration system.
  • There is an aikido course at Scripps that my son could take for PE—he’s not done aikido since he was quite young, but thinks that he would enjoy picking it up again more than most PE options.
  • My son had made an appointment with a computer science faculty member and we had a good conversation with him about the Harvey Mudd requirements and opportunities in computer science.  All the computer science students have to do research or development projects and most do more than one (the senior clinic plus one or more summer research projects).  There seems to be enough depth in courses and research in the fields my son is interested in that the lack of grad courses is not really important.  Even the required common-core first course in computer science has an option for students sufficiently advanced in CS, so that he would not have to repeat stuff he’s already done.
  • The tour guide talked a lot about coöperation, mentoring, and group projects—concepts that were independently brought up by the admissions officer and by the CS faculty member.  The group projects don’t seem to be the one-person project forced on a group that most middle-school and high-school projects are, but projects big enough to benefit from multiple people working on them.  They do practice pair programming in most CS classes, which will be a new experience for my son.

Although I had expected Caltech and Harvey Mudd to be very similar schools from what I knew before the visits, I ended up with very different impressions of them.  Caltech seems to be a competitive school with a physics-centric, theoretical focus, while Harvey Mudd is a cooperative school with an applied engineering focus.  My son will probably apply to both, since getting in is largely a lottery (they both have about a 10% acceptance rate and his test scores are only average for either school), but I think that he’d end up much happier at Harvey Mudd.  UCLA looks much less attractive (other than financially), but he’ll probably apply to several of the UC schools as he is much more likely to get into them.

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