Year of Bread 2018

By the end of 2017, having lived in California for 18 years, one of the things that I most enjoyed about return visits to the East Coast was the bread. To be clear, great bread is not difficult to find on either coast, or in between. But for my taste, the average East Coast bread is more consistently warm, crusty, toothy, delicious, and just more thoughtfully prepared and served. There is lots of speculation about the reasons for this. Is it all in the water? Is it a closer connection to old world European traditions? Is it the flour or the yeast? I sought answers from The Internets, most notably r/Breadit [].

Like all internet subcultures, some themes and lingo appeared time and again. Discussions of sourdough cultures were pervasive, as were references to “Tartine” and “FWSY”, which I later decoded as Chad Robertson’s 2010 Tartine Bread [], and Ken Forkish’s 2012 Flour Water Salt Yeast []. Creating a sourdough culture seemed like a good start, so I found a few online guides, mixed up some flour and water, and experienced several failed and/or moldy starts. Eventually, I discovered @maurizio’s [] website, His excellent instructions set me on the path to creating a successful starter, which reached viability just as we were about to drive to Portland for the holiday break.

So along with our luggage, I packed my neonatal starter, which I fed in the hotel bathroom during our first night away from home. Next stop, Powell’s City of Books, where I bought the copy of Tartine Bread that would be become well worn and dusted with flour in the coming year. We stayed in a VRBO apartment for a week, so on the day after Christmas, I formed my first two loaves, which proofed while we journeyed to Pok Pok for legendary Thai fare. When I attempted to turn the loaves out of their baskets, they stuck to the liner towels (note: dust with more flour next time), and were a sticky mess. Considering them a loss, I baked them anyway to see what would happen… To our amazement, they were shockingly good! First lesson: good bread is more fault tolerant than I expected.

Robertson’s Basic Country Loaf is the cornerstone of Tartine Bread, and the variant that I practiced probably over 20 times during the year. Usually, I baked two loaves: one to eat during the week (they stay fresh for a surprisingly long time), and one to give away. My version uses 200g spelt in place of 100g whole wheat. Here’s the formula:

  • Starter: 50/50 AP/rye flour, 100% hydration. Replenished daily with about 20g of yesterday’s starter, 25-40g of water, and equal amount of 50/50 flour.
  • Levain: 100g 80F water, 20g starter, 50g AP flour, 50g spelt. Ready in about 3 hours.
  • Dough: 700g 80F water, 200g levain, 800g King Arthur bread flour, 200g Bob’s Red Mill spelt flour.
  • Process: After 25 minute autolyse, add 20g salt and another 100g water. Bulk fermentation in the oven, heat off and light bulb on, door open a bit, maintaining an 80-90F environment. Four turns, one every thirty minutes, then one more after an hour. Split and form after another hour. 25 minute bench rest. Fold to develop tension and form final loaves. Then into baskets dusted with rice/AP flour blend, and into the fridge for cold bulk fermentation overnight.
  • Bake: Place cast iron combo pans [] in the oven, set to 500F and preheat for at least an hour. A pizza stone [], covered in foil on the floor of the oven, acts as a heat sink. The built-in oven thermometer claims to be at 500F in less than a half hour, which is a lie. An Omega industrial thermocouple [] speaks the truth. When ready, remove the cast iron skillet from the oven, place the first loaf, score, return to the oven and cover with the lid. Drop the oven setting to 450F and wait 20 minutes. Remove the lid, avoid blast of steam, and bake another 22 minutes. Remove the loaf to a rack, and listen to crust crackling while resisting temptation to eat immediately. Return the cast iron to the oven, raise the oven temperature back to 500F, and wait at least 30 minutes before repeating for second loaf.

I compressed the two day process into this two minute video:

Everyone asks if my starter has a name. Well, as she was born in the City of Roses, and in the spirit of “We Can Do It” [], she is Rosie. Every day, all but about 20 grams gets moved from her countertop Weck 743 3/4 Mold Jar [] to a matching jar in the fridge. Then, I feed her 20-40 grams of a 50/50 blend of rye flour and all-purpose white flour, and an equal amount of water. I actually add the water first, mix to combine, then mix in the flour. After about a week, sufficient spent fuel has accumulated in the fridge to make pancakes [], waffles [], crepes [], or sometimes cinnamon rolls [].

Poster. “We Can Do It!” or Rosie, the Riveter. 1985.0851.05.

Just about every weekend, I baked something, usually from Tartine Bread. By year’s end, a total of 42 episodes of bread production had been completed. It became a lifestyle.

I also made the Tartine baguettes a few times, yielding elongated loaves of variable aesthetic quality, plus some dinner rolls (converted by scissors from the most #fail of the baguettes), and sometimes also pan fried English muffins. Many times, I rewatched Dan McTiernan’s YouTube instructions for shaping a baguette, and eventually achieved reasonable results. I also made the brioche a few times, best deployed as Glorious Hamburger Buns.

I’m now reading Flour Salt Water Yeast (2012), which was published after the first Tartine book, and is probably a better starting point aspiring artisan bakers. Forkish gives more details on the process, and his recipes start simple and work their way up to more complex. Next on my list is Tartine Book No. 3 [] (2013), with more advanced whole grain breads. Whatever 2019 has in store for us, it is certain not to be gluten-free. #🍞

The End of Car

Here on this very occasionally updated website, I have written a few times about my journey into the future of cars. We still own our 2012 Chevy Volt, a species soon to be extinct [] as GM is closing its factory and killing most of its sedans. In January 2017, I took delivery of one of the first ever Bolt EV’s, and wrote about my first impressions, which still hold true. But alas, I now write of the Bolt in the past tense, because it is no more. This is the story of how 2018 became my post-car future of cars.

The Incident

On the morning of May 21, 2018, I was heading southbound on I-680 on a clear day, in the usual morning traffic, and otherwise unremarkable conditions.


I was hit from behind, hard. Time expanded. What just happened? I have definitely been hit. This is not good. I’m going to be late to the study in San Carlos. They’ll have to get started without me. Hope someone else brought a camera. I have to try to stop my car. There’s a Prius in front of me. I really don’t want to hit that Prius, because that would make this situation much more complicated. Oh, good, I’m already jamming on the brake. What the hell hit me, anyway? No time to check now, must continue jamming on brake. What is that clicking noise? It’s that sound that you hear if you engage the parking brake while the car is still moving. Oh, it must be the car trying to help. Thank you car, we are working on this problem together. Will we be able to stop before hitting that Prius? No. I guess not. But it’s just a little bump, though, not too bad. Thanks for sticking with me on this, Bolt EV. We are now stopped. On the highway. In the HOV lane. Today, the daily fiasco on 680 is: ME. Maybe we should move to the shoulder. All attempts to re-energize the car fail, as a series of dire messages pass across the dashboard screen. We have entered post-apocalypse failsafe mode. I exit the car, look around, and guy that hit me is wandering about with a bloody face, apologizing. His car is a disaster, mine doesn’t look too bad. Mostly unscathed Prius has pulled over to join in the festivities. I call 911.

What follows is an ordeal of several months duration, which is hopelessly boring. Let’s just address the important points. First: PHILIP WAYNE GARZA of WEST ZEERING ROAD in Turlock, CA. According to the police report, which I obtained later, he had been driving erratically in the moments before hitting me, and his license was suspended at the time. He was going 65 mph or so, and I was slowing to about 30 mph. When I was taking pictures at the scene, he asked that I not take his picture, so I will not post it here. You’re welcome Philip Wayne Garza.

The Damage

This is what a totaled 2017 Bolt EV looks like

Fortunately, while I was both shaken and stirred, I was not seriously injured. No airbag deployments, and the damage to Bolt EV seemed to be mainly cosmetic, limited to the rear fender and quarter panels below the lift gate. As this car was leased, I had to follow the protocols prescribed by GM Financial and the insurance company. After a couple of weeks, here were the numbers:

  • $12,230.74: preliminary repair estimate, provided by the dealer recommended and insurance company approved body shop. May 25, T=+4 days.
  • $32,020.84: settlement value, the valuation of the car determined by my insurance company. May 30, T=+9 days.
  • $33,369.90: lease payoff value, determined by GM Financial. June 4, T=+13 days.
  • ($1,349.06): the difference between the settlement value and payoff value. Surprise, not in my favor.

So at this point, it would seem that the next step should be to repair the car and move on. But no, this car was leased, so the decision was not mine to make. Instead, the car was declared a Total Loss. Presumably this is because the car had a high salvage value relative to the cost of repairs, but this was never made clear to me. The settlement value would go to GM Financial, and I would be left to wonder about how the remaining $1,349.06 gets settled, and nobody could give me a straight answer on that topic. I was told that GM Financial would open a “GAP Claim”, which “would take some time to process”, during which time I should continue making my lease payments “if I wanted to protect my credit rating” (be a real shame if something happened to your credit rating, buddy). I was later told that this was not true, and I could stop making payments after the settlement check was received. With conflicting verbal advice, I asked GM Financial multiple times to give me a statement in writing, or connect me with a manager. I received nothing but unanswered or dropped calls. So I continued making payments, until I eventually received a check (with no explanation) from GM Financial that seemed to indicate the matter was closed. Here was the final score at the end:

  • $2,006.12: Total sum of lease payments made in June, July, August, and September for a car that didn’t exist.
  • ($501.53): Mysterious check received from GM Financial on October 29, in the exact amount of one lease payment, presumably because they decided they had enough of my money already.
  • ($268.27): Mysterious check received from GM Financial on November 7, presumably because the “GAP claim” was resolved. T=+170 days.
  • ($250.00): Refund of the deductible from my insurance company, presumably because (?) I don’t know why.

Subtract those three numbers from the first, and $986.32 is the punitive amount I ended up paying GM Financial after 170 days of opaque and conflicting non-communication, accounting for insurance and GAP payments. Thanks, GM Financial, for this reminder of why you are a horrible person.


I was in Europe for two weeks shortly after The Incident, and tried to buy a replacement car from afar during that time. An exact replacement. Unfortunately my reliable sales guy had vanished. And let’s just say that Chevy dealers are not equipped to handle the circumstance of a customer who wants to purchase a specific car, in exchange for actual money, via email. By the time I returned from the EU, having spent two weeks traveling by train, metro, and bus with the greatest of ease, I decided that I didn’t want a car. Instead, I set out to see just how terrible the Bay Area public transit system really is.

In summary, it is bad. However, its competition is the infuriating hellscape of a daily commute on I-680 between Pleasanton and Fremont. For a few years, I’ve been using LifeCycle [], an iPhone app that magically tracks time spent on various activities, including my commute. I exported and analyzed the data, and found that it agrees with my intuition: my transit commute takes about 50% longer on average, but the highs and lows are not too much different.

longest daily round trip commute times by week, 2016-2018

While my transit commute takes longer, those minutes are far less stressful and much more productive. For several weeks, I enjoyed biking to and from the BART station on one or both ends of my commute, which subtracted minutes while adding exercise. Then I broke my shoulder, which is another story, which I might write about some other time…

By the end of 2018, my average transit expense was about $220/month, less than half my monthly lease payment. This average benefits from some zeros, because (unlike my lease payment) my transit expenses are much lower when I’m traveling for work.

Six months into this experiment, my desire to have a car is less than ever. I have outsourced my transportation needs to BART (a.k.a. “The Tetanus Train”), ACE, Wheels, AC Transit, and Lyft, and I don’t want my driving job back. I shall continue collecting data in 2019, and maybe I’ll report back in another year or so!

2017 Bolt EV First Impressions

2017 Bolt EVThe first Bolt EV that I saw with my own eyes was the one I picked up last Saturday, and ordered a couple of months ago (before it was actually for sale). People ask me why I would buy a new car sight unseen… When I first drove a Volt, I knew it was a glimpse of the future. When I heard about the Bolt, I knew that future had arrived. Like the Volt before it, the Bolt EV is the future I want to believe in.

I first read about the 2017 Bolt about a year ago in the Wired cover story “How GM Beat Tesla to the First True Mass-Market Electric Car” []. I promptly called up Kurt at Fremont Chevrolet [], to whom I entrust all of my electric vehicle purchases, and he offered to call me back when Bolts were available to order. A few months ago, my phone rang, and after a quick meeting at the dealership to choose colors and options, my Bolt was scheduled for production. It was waiting for us upon return from Christmas vacation, when we traded in our 2010 Equinox, and drove home in a Nightfall Gray 2017 Bolt EV.

227 MilesFirst impressions: A full battery with 227 miles of range is an impressive sight to behold. Responsive, solidly built, and fun to drive. Surprisingly spacious inside and small outside. Ample headroom front and back, with seating for five. Instrument panel and large center touchscreen are clear and bright, evoking the glass flight deck of a spaceplane. Interior trim and body panels are sculpted and modern, and controls are well positioned and intuitive. An abundance of high tech options, and a corresponding array of menus and preferences.

The fly-by-wire “gear shifter” requires a special touch sequence to engage, which takes a few days to feel normal. When reverse is successfully engaged, the large center screen displays a magic drone’s eye view of the car from above, with the views from multiple cameras fused into a 360 degree view. This is a neat trick at first, and shortly thereafter an indispensable aid for obsessively centering the car parking spaces. Flip a switch on the rear view mirror (as if to deflect the high beams of trucker behind you) and a hidden digital screen projects a wide angle view behind the car. This car is like an augmented reality video game. Except it is actual reality, and the controllers are much better.

In addition to all of the cameras, the car can also monitor following distance, and check for cars in adjacent lanes. In a fast stop, when following distance closes quickly, a red light flashes on the windshield, the car mutes the entertainment system, and “beep-beep-beeps” an urgent warning. According to the manual, it will assist with breaking if the situation gets more dire (I do not plan to test this). The driver’s instrument cluster can display following distance (in tenths of a second), one indicator changes color if the following distance is less than safe, side view mirrors flash to indicate cars in the right and left blind spots, and dash indicator blinks if the car drifts out of its lane. These are passive robots that cross into active mode in case of emergency. They augment the driver’s senses and actions, but it is clear that these systems will grow up to be our fully self driving chauffeurs of the not too distant future.

I chose to lease this car (a first for me) because I have a sense that the future is approaching faster than ever. This car will supposedly receive over-the-air software updates, but I’m not expecting to find a robot-car upgrade waiting for me some random morning. Self driving (as promised by Elon for the Tesla Model 3) or a more ambitious autopilot style cruise control would require hardwire beyond the cameras and sensors in this car, but I suspect that these upgrades will be in place for new Bolt EV’s by the end of this lease.

Top five hits:

  1. Range. Any point around the SF Bay and back again with zero anxiety.
  2. Tech. Screens, cameras, iPhone CarPlay integration, Siri integration.
  3. Acceleration. Very zippy, noticeably more so than the Volt.
  4. Size. Big inside, and small outside.
  5. Rear heated seats. For my son, this would be 1,2,3,4 and 5 on the top five list.

Bottom five misses:

  1. No Homelink (integrated garage door opener). Not even an option. Why not?
  2. No power seats. Would be nice to have seat/mirror memory for different drivers.
  3. No onboard map. Maps require a plugged in iPhone, and CarPlay supports only Apple Maps (which isn’t as bad as people say, but still isn’t as good as Waze)
  4. Occasional infotainment glitches. Siri button sometimes doesn’t work, Pandora stations sometimes don’t load, volume changes mysteriously, settings sometimes revert and need to be reapplied. Many of these may be “user error”.
  5. Regenerative braking paddle. There’s a paddle on the steering wheel that engages regenerative braking, but it seems to work only in “binary” mode: either on or off, causing unpleasantly jerky deceleration. I would expect it to be variable, like a brake pedal. I don’t use it. Instead, I use the “L” drive mode, also known as one-pedal-driving or “go cart mode”, where the accelerator pedal modulates both acceleration and regenerative braking, and the brake pedal is necessary only for more urgent stops. This is delightful, especially in stop and go driving.

The Bolt EV a great car, and I think it is just the beginning. I can’t wait to see what Kurt will sell me next!

Finding Lorenzo

lorenzo-thumbnail-300In the past two weeks, I’ve been on nine flights, through seven airports in six countries, and I’ve slept in six different hotel rooms. Strange as it may seem, my busy travels have allowed for unusual stretches of uninterrupted time to think and reflect. Six to nine time zones away from my family, we didn’t have much time to talk, so a backlog of stories began to accumulate in my mind. Inspired by a friend’s good habit of writing journals when he travels to exotic locales, I started writing in the evenings, and found it to be a relaxing practice. During the trip, I met with clients, attended a conference, visited the Sicilian village of my great-great-grandfather, and the political structure of Europe had fractured possibly beyond recognition. I find that writing helps me to think, and there has been lots to think about in these two weeks.

When I got back to the US, I decided to try a self-publishing experiment. I created a book layout using the typesetting system LaTeX [], a strange and powerful markup language that I’ve been using to write proposals and reports in the last few years. From that, I created a print-on-demand version of the book using Amazon CreateSpace, and a Kindle version following the advice of Scott Nesbitt []. Instant book, published in print and online in about a day. I think Gutenberg would agree: we are living in the future.

I wrote Finding Lorenzo for my own amusement, as a time capsule to remember this eventful time. If you would like to follow my path through Scandinavia, Germany, Sicily (including Sciacca and Catania), and #BREXIT, here are some ways to obtain print or electronic copies:

Photos from my travels are in the Finding Lorenzo [] album.

Open 3D Human Anatomy

3D Printed Skeletal Right Foot. Printed using freely available 3D files from the BodyParts3D project

There isn’t much that is “open” in the proprietary world of medical device design and development. Designs are guarded, competition is spirited, employees and vendors are bound by strict non-disclosure agreements. Yet for all the varied and confidential pursuits that we undertake in this industry, we all have at least one interest in common: human anatomy. Everything we design travels through, or is placed within, some part of the human machine. A machine so ubiquitous that while I am using one at this very moment, most of you are as well at this same moment. And yet despite eons of medical study and inquiry, collaboration, and publication, it holds its secrets in plain view. The blueprints for this most essential of machine are  strangely out of reach.

Sources of 3D Models

We can freely download 70,000 technical drawings and 3D CAD models for nuts, bolts, and mechanical components from McMaster Carr [], but they don’t sell body parts, so no luck there. There are great sources for viewing 3D anatomy, like But if you want to download native 3D files, you’re going to have to pay. sells medically accurate models for animators, illustrators, and engineers. They cost hundreds or thousands of dollars, and they’re probably worth it. The good folks at Pacific Research Laboratories [] can sell you dimensionally accurate polymer based models for product testing or demonstrations, as well as 3D CAD files representing them. These things are great, but they are neither open nor free.

Modern medical imaging, including CT and MRI scanners, provides a wealth of 3D data, but it isn’t easily translated into a form that is useful for engineering. Commercial software like Mimics [] does a nice job of this, again for a price. OsiriX is an awesome open-source program for viewing medical datasets, and with considerable effort, it is possible to extract 3D structures in a format that can be used for engineering (example described in an older post, but I really should write a new post some day with details on how to create such models). OsiriX hosts a number of example DICOM data sets [], which are treasure troves of freely accessible digital human anatomy, for anyone ambitious enough to try to extract it.

Visible Human and BodyParts3D

I recently discovered the NIH/NLM Visible Human Project®, which is a public effort to develop “complete, anatomically detailed, three-dimensional representations of the normal male and female human bodies”. (The ® seems suspicious for an NIH project, doesn’t it?) The project and related initiatives, underway since 1989, have produced many gigabytes of  data, and I’m sure have entertained countless scores of grad students and post-grads. But unless I’m missing something, I can’t find any publicly available 3D solid or surface files derived from these impressive data sets. (update: the University of Iowa hosts male and female Visible Human data sets []) Refusing to be deterred though, I Googled obsessively until I hit paydirt, in an unexpected place: The Journal of Nucleic Acids Research.

In the 2008 paper BodyParts3D: 3D structure database for anatomical concepts, (abstract on PubMed, open access PDF from some ambitious researchers in Japan set out to create:

BodyParts3D, a dictionary-type database for anatomy in which anatomical concepts are represented by 3D structure data that specify corresponding segments of a 3D whole-body model for an adult human male

The project was funded by The Integrated Database Project, Ministry of Education, Culture, Sports, Science and Technology of Japan. (Arigatō!) The website alone is quite impressive, and is even translated into English (see But this project goes beyond just displaying pretty pictures… The native 3D models for thousands of carefully rendered body parts are made freely available under a Creative Commons Share-Alike license! And they can be downloaded from an FTP site, in high resolution!

Finally, a complete source of 3D digital human anatomy that is freely available, accessible, and suitable for use in with solid and surface CAD software. From Japan! The files are available in Wavefront OBJ format [], which can be imported as a 3D surface into CAD software like SolidWorks, finite element analysis (FEA) software like Abaqus or Ansys. These files can also be manipulated in open-source programs like Blender [] or Meshlab []. Either of these can also easily convert the .OBJ files into .STL files that can be printed on a 3D printer! Like a kid in a candy shop, I’ve created a few of these already, and hope that others will create more. Here’s the basic procedure that I used.

Creating STL models from BodyParts3D

  1. Download and unzip the OBJ files. The originals are at, but I’ve made a copy (as permitted by the CC-SA license) in case the originals disappear, and to avoid taxing their FTP server in case this gets popular (which I hope it does!). You can grab my copy of the 547MB zip file here: [].
  2. Find the FMA number of the body part of interest. You can do this using the web interface at or by searching the English version of the the parts list (parts_list_e.txt inside the zip file). It helps to know something about anatomy, of course. It also helps to know that many of the FMA numbers on the list refer to groups, rather than individual parts.  For example, FMA9664 “foot” contains FMA70664 “set of toes”, which contains FMA25047 “big toe”, but  you will find none of them in the list of .OBJ files. Instead, you need to find FMA230986 “middle phalanx of right little toe” and 27 other bones if you’re trying to build a complete skeletal model of the right foot.
  3. Create a new empty project in Meshlab, and import one or more .OBJ file of interest. Each .OBJ will be on a separate layer in the project, and Meshlab doesn’t make it easy to figure out how to work with layers. Hint: Filters > Layer and Attribute Management.
  4. Save the Meshlab project at this time if you think you might want to do some more work later.
  5. Merge all visible layers into one. Filters > Layer and Attribute Management > Flatten Visible Layers.
  6. Save the mesh as an STL file. File > Export Mesh > select .STL as type.
  7. Close the project without saving to preserve the layer organization for each component.

Slicing STL files

Many organic models like these are difficult to print on an Ultimaker, MakerBot, or similar 3D printer because there are no flat surfaces to build up from. So its often helpful to slice the model in half, or slice the bottom off a model. For this, I use Netfabb for Ultimaker, a commercial application that I bought with my printer. Netfabb also makes a basic version of their application available for free, and I think it will also work for slicing and repairing STL files. It is available here: My procedure:
  1. Create a new empty project in Netfabb
  2. Import the .STL file from above. Part > Add
  3. Rotate the part into a desirable orientation, so “up” is in the direction of the +Z axis. Part > Rotate
  4. Move the Z cutting plane to the desired location using the “Cuts” slider at the right. Click “Execute Cut”, then “Cut”
  5. In the parts window at the upper right, delete the part of the cut to throw away.
  6. Right click on the cut part to keep, and choose Export part > To .STL
  7. If offered the opportunity to repair the geometry, do so!
  8. Prepare for printing using your tool of choice. I’m partial to Cura [], which I use for everything.
  9. Print, and/or…
  10. Upload to Thingiverse, and tag with “bodyparts3d”


This data set is not perfect. It is derived from a single donor, and with 2mm resolution, much of the detail was subject to artistic interpretation. These models were never intended to be  anatomically perfect, but they are an excellent free and accessible resource for artists, engineers, makers, and bio-hackers. I have converted several into models suitable for printing, and you can do the same! Here are the first ones that I put up on Thingiverse:

The conclusion of this effort is inevitable… So who will be the first to reconstruct a complete 3D printed assembly of our immortal Japanese donor? The challenge is now declared! Leave a comment here when its done…

One Year of Electric Driving

I’ve driven my Chevy Volt for over a year now, and the numbers are in, with help from

  • 12,376 total miles driven
  • 9,956 battery powered electric miles (80%)
  • 2,420 gasoline generator powered miles (20%)
  • 68 gallons of gasoline
The majority of my driving is a 34 mile round trip, easily less than my fully charged range, which varies between 35 and 42 miles. About a third of the gasoline powered miles can be attributed to long distance road trips to Pinnacles (200 miles) or Los Angeles (750 miles), and the rest are day trips around the Bay Area. I’m happy to report that the Volt has been solid and reliable. It’s fun to drive in the future!

Electricity bill doubled

The number one question that people ask me about owning a Volt: “So how much has your electric bill increased?”. The answer is “its complicated”. The cost of electricity varies with usage, varies with the season, and with EV specific time-of-use rate plan that I switched to when I bought the car,  it also varies with the time of day, and day of the week. So the true costs of electricity need to be evaluated on the basis of a full year. Comparing a full 12 months of electricity costs before owning an EV with the same 12 months after buying an EV, the final score: $801/year before the Volt, and $1,564/year with the Volt. So that’s an increase of  $762, roughly doubling my electric bill.

Electric consumption increased 50%

So if my electric bill doubled, does that mean that my electricity consumption doubled with the car? Far from it. Home charging the car for a year added about 2,800 kWh, or about 233 kWh per month. That’s about a 50% increase over normal household consumption.

Household consumption is consistent and below average

Are my electric rates skewed because of high household electricity consumption (from air conditioning, or other variable demands)? No. The average annual electricity consumption in California was 6,296 kilowatt‐hours (kWh) per household in 2010, according to the 2009 California Residential Appliance Study conducted for the California Energy Commission. The chart below shows my household consumption, excluding EV charging, for 12 months before and after buying the Volt. This makes it clear that my normal household electricity usage is far from excessive, and in fact is less than average. Excluding EV charging consumption from this year, annual electric consumption is virtually identical to last year.

PG&E Rates are Crazy

PG&E’s “EA9 XB Residential Time-of-Use Service for Low Emission Vehicle Customers” provides baseline off-peak rates less than $0.05/kWh, and the Volt knows to only charge itself when the off-peak rates are in effect. So the 2,800 kWh of EV charging electricity should cost 2,800 x $0.05 = $140, right? Wrong! Instead, adding 50% to total electricity demand roughly doubles the total cost. This all happens through the combined magic of tiered rates and time-of-use rates. Tiers are typical in California electricity rate plans, including the conventional E1 residential rate plan that I used last year. With a tiered system, rates increase as usage increases, so this hits particularly hard for EV households. In the summer, I commonly reach the punitive >201% of baseline tier, with rates that can range up to 10 times the baseline. The E9A rate plan, an option specifically designed for EV households, adds another twist: rates change with the season and the time of day. So while off-peak rates can be under $0.05/kWh, they surge to $0.30/kWh or above $0.54/kWh in the summer during peak times. So the cheap electricity at night is more than offset by very expensive electricity for air conditioning on hot summer days. A typical summer electricity bill from PG&E looks like this:

Excerpt from a PG&E electric bill

My effective electric rate increased by 22%, and is 50% higher than the national average

So what are the true effective rates? Well, in the twelve months prior to owning an EV, my average rate under the standard E1 residential rate plan was $0.14/kWh. In the following twelve months, under the E9A time-of-use rate plan, my average rate increased to $0.18/kWh. From the chart below, its clear that in the winter months, the E9A plan offers effective rates that are equal to or lower than last year’s $0.14/kWh. In the summer months, though, rates are substantially higher. The EPA energy costs on the window sticker of a Volt assume the national average of $0.12/kWh, so the $0.18/kWh effective rate in PG&E’s California is 50% higher than the national average. It would be higher still if my household demand were higher than average, or if (gasp!) I owned a second EV.

Volt saves $1,180 in energy costs, compared with the car it replaced

So what’s the bottom line? How do the energy costs for a Volt compare with the gasoline costs of a conventional car? Well, that depends on the car used for comparison. My previous car required premium gas (as does the Volt) and averaged 24 mpg during the years that I drove it. Using California monthly average premium gasoline prices from the California Energy Commission, gas for my old car would have cost $2,167 for the 12,100 miles I drove in the past 12 months. That’s $18/100-miles. For the Volt, during this period, I used $293 in gas, and the incremental cost of electricity (compared with the previous year) was $767. So that’s a total of $1,059 in energy costs for the Volt, or a annual savings of $1,108. At $9/100-miles, that’s almost exactly half the energy costs for a 24 mpg conventional car.

EV energy costs vary by season

The chart above is strange. The slope of the Volt cost curve flattens out from 2,500 miles to 7,500 miles, which happens to correspond to the winter months. With E9A rate plan, the Volt energy advantage is much more impressive in winter, when a Volt operates for about 1/3 the cost of a conventional car. In the summer, the advantage is less impressive, with energy costs reaching 2/3 the costs of gasoline at times.

 What next?

With a year of data in the bag, I can get a better understanding of the costs and benefits of a solar system. This introduces yet another time-of-use rate plan option, as I described in Decoding Time of Use Rate Plans. And to make things even more interesting, PG&E plans to retire the crazy E9A rate plan, and replace it with a different crazy EV-A rate plan. The new plan was originally proposed in September 2011, and met with dozens of protests, including one from me. PG&E responded with a somewhat less objectionable proposal, which appears to have won support of the CPUC. Jack Lucero Fleck has followed these matters closely, and has a written a nice summary of the current PG&E proposal, and a letter to the CPUC with additional analysis.

We’re at the dawn of an electrified revolution that will have a profound impact on auto manufacturers, electric utilities, and the fossil fuel industry. Prospective EV buyers, and current EV owners face a shifting landscape, and considerable uncertainty about the true costs of energy. Governments and regulated utilities will stumble forward toward the inevitable future. It will be an interesting journey. I’ve been in the future for a year now, and complicated as it may be, I’m not going back!

The full year data and source charts from this post can be viewed in greater detail as a Google Spreadsheet. Comments, criticisms, and suggestions are welcome!

Open Source Human Anatomy

3D Printing Aortic Bifurcation
3D Printed Aortic Bifurcation

I first saw a MakerBot Thing-O-Matic in action at the 2011 Bay Area Maker Faire, and it was truly a thing of beauty. I’ve used rapid prototyping machines and services since the mid 90’s, but here was something that you could build yourself, and have on your own desk! Wow. Later in the year, I happened to have a free day in New York during the NYC Maker Faire, so I was drawn to revisit this hacker dreamscape. There, I met @ErikDeBruijn, one of the developers of the Ultimaker: an elegant build-it-yourself 3D printing machine capable of relatively high speeds, stunning resolution, and a comparatively large print volume. I became immediately obsessed with visions of 3D printed anatomical structures, and medical device prototypes. I asked Erik if the Ultimaker was being used commercially, and he knew of a few customers that were using it in schools, and at least one other that was offering a service making 3D prints by the hour. Medical device development, not so much. That only made me more interested.

Later that day, I saw a great talk by Bre Pettis (@Bre) of MakerBot fame (30 minute video on An icon of the open source hardware movement, Bre gave lots of examples of digitized “things” that are freely shared on sites like Thingiverse, where users can upload, download, share, modify, and combine digital objects. And now print them out, too, effectively “teleporting” physical objects among like minded citizens of the internets. Digital “mashups” of Yodas, Gantstas, and Rabbits delighted the maker-faithful in attendance, while evoking dismissive comments from the guy sitting behind me: “What’s the point?” Dismissive guy, and many like him, see a toy. Which it is. But its more than a toy.

A few quotes from Bre’s talk resonated with me:

If you’re not sharing, you’re doing it wrong!

If you’re at a company, and keeping things secret… Stop it!

Publish those things (even if they’re not done, or done done)… Just share them, because so much of the future depends on it.

These are the noble words of an open source evangelist, and the principles upon which Linux, Firefox, Wikipedia, Arduino, and countless other open source projects depend. And then there’s my professional universe of medical device design and development. An industry that relies upon proprietary designs, trade secrets, secure patents, guarded intellectual property. The opposite of open. And yet, everything that we do in my industry is directed at improving the human condition, which is very much in the common interest of all humans. Is there a way to be “open” in a “closed” industry?

It isn’t easy. I wrote about the opportunity and challenges in Open Medsystems a few of years ago.  Medical device development is expensive, and it generally isn’t going to get funded unless the investors have some confidence that they can profit from their investment. So NDA’s will be signed, secrets will be kept, patents will be filed, and knowledge will be sequestered. Brilliant engineers and designers will face the same challenges, each alone in their own respective proprietary silos, not knowing of their kinship, not benefiting from each other’s ideas or mistakes. In the end perhaps one will win, or both will lose.

But there is hope. I’ve tried to do my part by publishing Open Stent Design on, releasing Stent Calculator on Google Code. But I think there’s a bigger “open source” opportunity for the medical device community, and I’m not alone. 3D medical imaging technologies, like CT scans and MRI’s, have made amazing advances in the last decade. These increasingly ubiquitous machines create torrents of 3D data sets, each a unique atlas of human anatomy, and each an exquisite three dimensional map of  a diseased system, organ, or tissue. These medical imaging data sets hold secrets waiting to be discovered -they describe the environment in which medical devices must do their healing work. 3D imaging data, usually in DICOM format, is easily anonymized, and easily rendered and manipulated with open source software such as the excellent OsiriX []. Translating medical imaging data sets into useful 3D geometry for analysis or simulation is messy work (see segmentation [Wikipedia]). But it is important, and at least one group is working on developing a Cardiovascular and Pulmonary Model Repository [] to do just that. Sponsored by NIH, this effort will collect medical imaging data sets for several body systems, perform segmentation, and make the raw data and analysis available to the public.

Freely available 3D anatomical data + open source 3D printers = freely available (plastic) body parts! Rapid prototyping of proprietary 3D data is nothing new in the medical device development world… but 3D printing of freely available anatomical models derived from freely available anonymized medical imaging data is all kinds of awesome! 3D printed blood vessels, organs, and bones can be used to mold or cast realistic benchtop models, which can be used to test and challenge medical device concepts in a realistic environment… Or better yet, many realistic environments, reflecting the many individual humans they are designed to help. And that is some true open-source mojo at work in a closed industry, to be benefit of all.

So after honing my Ultimaker skillz on snakes, whistles, cars, and alien eggs (“What’s the point?”), I have turned my attention to the beloved OsiriX DICOM Sample Library [], and tackled the aortic bifurcation of the AMNESIX model. After some quality time with OsiriX, I had a rough export of the aorta and iliac bifurcation, which I then cleaned up in MeshLab [], sliced using Netfabb [], then printed using ReplicatorG []. And though it isn’t final, done, or done done, it is now shared as Thing:15942 on Thingiverse!


Proposed change to PG&E E9 Time-of-Use Plan

I’ve had the Volt for about a month now, and my electron-fueled travels have been perfectly fantastic. As of this afternoon, I have driven 1,002.7 miles and consumed 1.1 gallons of gas. Still, I can not yet answer the question that I get most often: “What about your electric bill?”

At the beginning of the month, I changed my service plan from the standard issue PG&E E1 residential rate plan to E-9A, a “time-of-use” plan designed for customers who charge electric vehicles at home. With this plan, rates are higher during peak times, and lower at off-peak times, thus providing a good incentive to charge up the car at night when demand on the grid is low, and there is plenty of generation capacity with electrons to spare. Complicated as this is, the Volt allows me to program in all of the rate details, and it figures out when to charge itself.

Until this month, I was able to use PG&E’s website to download daily and hourly demand history from my SmartMeter. Now that I’ve switched to a plan where this hourly usage data actually matters, it is no longer available. Thanks PG&E! So I will not know the true costs for this plan until I get the first bill in a few weeks.

Just the other day, a forum post at caught my eye: Major change in PG&E CA E9 TOU rates. It seems that PG&E proposed some “helpful” changes to the E9 plan on September 26, 2011. In Advice Letter 3910-E, they propose a new rate schedule. According to this letter, the changes will cause an overall increase in payments for 3/4 of the customers on the E9A plan. Since I had gone to the considerable trouble of Decoding TOU Rate Plans not long ago, I decided that it was time to dust off my spreadsheet and calculate the impact of the proposed change for my expected usage.

The perplexing result of this effort confirmed the same surprising conclusions of some other PG&E EV customers: the new E9 plan is substantially worse than the old E9 plan, and is actually the same or better than the standard E1 plan. The results of one year of simulated use is depicted in the figure below.

Comparing current and proposed E9 time-of-use rates with the standard E1 plan. If my situation is typical, these "helpful" proposed changes will render E9 useless, drive customers to stay on E1, and eliminate any incentive for EV owners to charge at off-peak times.

PG&E’s proposed change makes the E9 plan useless: EV owner will have no reason to choose a time-of-use plan, and will have no economic incentive to charge at off-peak times. This change seems to be completely counter to the public interest, and to PG&E’s own best interest. Go figure.

Here’s a link to my spreadsheet for calculating simulated annual billing under various confusing and convoluted rate plans. I think it’s reasonably accurate, but who knows. If you find it useful, or can make any improvements, please drop a comment here.


UPDATE (10/9/11) The Numbers Are In!

The first PG&E bill has been posted, and it is quite a whopper! Electric costs are $219 for 896 kWh compared with $122 for 683 kWh in the same period last year: An increased cost of 80%, for 31% more electrons. That’s the magic of tiered rate plans: the more you use, the higher the incremental cost. As it turns out, this billing period is historically the highest of the year for us, and this year, there were more hot days than usual – so lots of A/C during expensive peak hours. I estimate that the car should account for no more than 7 kWh/day on average, but our total usage was nearly 8.5 kWh/day higher this year. Unfortunately, it is nearly impossible to unravel the cost impact for the extra A/C from that for the Volt. So rolling everything together, in the first month, the cost of additional electricity (plus 1.1 gallons of gas) works out to 11.64 cents/mile, or a modest 31% savings relative to my old 24 MPG car. I’ll update the stats monthly, or until I get bored. Here’s a link to my Google Spreadsheet:

Volt Dollars per Mile


Decoding Time of Use Rate Plans

My roof, without solar panels

While I’m waiting for the new Volt to arrive, I’ve been researching the economics of a residential solar system. By “researching,” I actually mean geeking-out on all the technical details, and attempting to unravel and reconstruct the engineering and economics of the systems that I’m considering. There have been many discoveries along the way, some of which are explained in excruciating detail here for two reasons: 1) because Google couldn’t provide me the answers that I was seeking, and 2) I probably need some better hobbies.


My home in Pleasanton bakes in the California sun, and has an unobstructed southern facing roof that if perfectly situated for photovoltaic panels. Our electricity demand has been about 6,000 kWh per year, which isn’t too high for a house of our size in Pleasanton. The car will add about 2,400 kWh to that, and with the standard tiered rate plan, electricity costs escalate considerably with additional usage. Our friendly local utility, PG&E, is here to help. They have a lots of information on their website, including a spreadsheet to predict the economics of switching from a standard tiered rate plan (E-1) to a plug-in electric vehicle (PEV) plan with variable rates depending on time-of-use (E-9A or E-9B). Separately, they also have lots of information on solar installations, including a different time-of-use rate plan (E-6) designed to benefit residential solar customers.

Both the E-6 and  E-9 rate plans are eligible for “net-metering”, which means that the electric meter runs in both directions: the utility pays me when I generate more than I use, I pay them when the opposite is true, and we settle up on an annual basis. Since these are time-of-use (TOU) rate plans, the rate is higher during peak times (like summer afternoons), and lower during low demand times (like nights). So I sell electrons to the grid at high rates on sunny days, and buy them back for cheap at night when I charge the car. Perfect!


Since the convergence of solar and electric vehicles is a fairly new thing, nobody seems to know whether E-6 or E-9 is most beneficial for a customer that has both solar panels and an electric car. So I set out to find the answer, using the most complicated means possible. Here’s the procedure:

  1. Download 52 weeks of hourly SmartMeter data from PGE’s website. This gives me the hour-by-hour electricity demand for my own house in the course of one full year. Unfortunately, this required 52 separate downloads. Thanks, PG&E. Import into Excel, and reformat into 8,760 rows, one for each hour in the year. Add the anticipated demand from charging the Volt on a Level 2 charger: 6 kWh per hour, for two hours, starting at midnight, every weeknight.
  2. For each of the 8,760 data points, figure out which of five different rates apply for each hour, based on the month and time of day. Repeat this for E-6 and E-9 plans.
  3. Now figure out the output from my hypothetical solar system for each of those 8,760 hours. This depends on lots of things: the panel specs, number of panels, inverter, roof orientation, weather, and so on… While this may seem completely intractable, the US Government has developed an application that does all that and more. The National Renewable Energy Laboratory (NREL) has developed a software tool called System Advisor Model (SAM) that simulates the performance of systems under a wide range of conditions. I fed SAM the 8,760 data points that describe my annual usage, and it gave me back the hourly net kWh to or from the grid. Way cool.
  4. With the net energy flow pasted into the spreadsheet, I could now simulate a full year of operating a solar array and a plug-in electric car, both under the E-6 rate plan and the E-9 rate plan.


The system that I modeled consisted of 22 panels, each rated at 235W, for a total rated output of 5.17kW. For my installation, this will provide about 7,800 kWh of energy during a year, and with the car I’ll need about 9,000 kWh.  So I’ll take about 1,200 kWh more off the grid than I’ll send onto the grid. The chart below shows cumulative demand and generation throughout one full year.

The E-6 rate plan has several different rates depending on the time of day and season. The next chart shows net energy to and from the grid during the year for each of the rate categories: summer peak, summer partial-peak, summer off-peak, winter partial-peak, and winter off-peak.

Though I’m 1,200 kWh in debt by the end of year, the picture in dollars is quite different. The power that I generate during the summer peak and summer partial peak periods (the top two lines) is much pricier than the power that I have to buy during the winter periods. So with the E-6 rate plan, I finish this simulated year owing PG&E exactly $18.19.

The E-9A rate plan is similar to E-6, but the rates are more leveraged. The peak rates last for more hours during the day and evening, and the off-peak rates (though lower) last for a shorter period of time. I wanted to figure out if the higher peak rates and long peak hours would be a net benefit with solar generation. The E-9 chart shows what happens: the summer partial-peak period is very profitable, but the costs during the winter off-peak period completely offset the benefits. At the end of the year, I owe PG&E a total of $64.41.


For my circumstances, the E-6 plan is a better option than the E-9 plan, to the tune of about $40. Now you know. Your results may vary.


There are lots of great resources freely available online that are very helpful for obsessed engineers that are interested in finding ways to spend some of their free time.

  • PGE_TOU_Compare.xls ( is a version of the spreadsheet that I used to calculate all of this stuff. Unfortunately, it was too large to work natively as a Google Spreadsheet, so it has to be downloaded old-skool style.
  • NREL ( developed the System Advisor Model software, which was good for many hours of simulated enjoyment.
  • Open Energy Information ( provides crowd-sourced data on rate plans for utilities across the country. I found the data there for the E-1 plan that I currently use, updated the data for E-6, and added the data for E-9. The SAM application also interfaces directly with this database.
  • The OpenPV Project ( was also developed by NREL. It is a comprehensive database of solar installations across the country. It has detailed data on the location, size, and installed cost of PV installations across the country. Compare the statistics from your quotes with those for other systems installed in your neighborhood.
  • As I’ve been planning my system, I’ve been fortunate to work with three very reputable solar installers: Real Goods, SunWize, and REC. If I had three houses, I would buy one from each.

Buying a 2012 Chevy Volt

Silver 2012 Volt

I’ve owned mostly German and Japanese cars, so when we traded in the Subaru Legacy for a 2010 Chevy Equinox last year, it was quite a leap of faith. A Government Motors vehicle in my garage? Strange but true. We have been impressed with just about everything – utility, handling, comfort, reliability, styling. And had we not been so impressed with the ‘Nox, I don’t think I would have remotely considered such a radical new GM offering such as the Chevrolet Volt.

My current ride is a 128i, which is the minimum recommended dose of Ultimate Driving Machine that money can buy. It is an altogether great car. Fun to drive, reliable, sporty, comfortable. It is one of the most fuel efficient cars that BMW makes, but even so, I get a real world average 24 MPG driving to and from work, during commute traffic, with a grandfatherly absence of sportiness. On weekends, it sits in the garage, and we use the Equinox. The coupe format makes it difficult to get the little man in and out when I’m on pickup or dropoff duty. So the car is optimized for a degree of sportiness over efficiency that just doesn’t suit my usage.

My first opportunity to check out the Volt was at Maker Faire in May. It definitely looked bad-ass, and seemed to be everything I was hoping for. Comparable in size to my 128i, four doors, with a fit and finish that seemed even better than the already excellent Equinox. Not long after, I got in touch with Tony at Courtesy Chevrolet in San Jose. When we were shopping for the Equinox, we found Tony after being thoroughly disappointed with the sales experience at the closer Dublin Chevrolet. He gave us a great deal, and made it easy as could be. Turns out that Tony is Mr. Volt at Courtesy, and gave me the scoop on everything I wanted to know.

We took a test drive, and the deal was sealed before I drove off the lot. Clearly, the Volt is an exotic novelty of automotive technology, but 1) it drives and handles just like a normal car, and 2) if it was possible to drive an iPad, this is what it would be like. It is a remarkable combination of ordinary and transformational.  Just like an iPad connects to the same Internet as the desktop PC in my office, the Volt drives on the same roads and delivers the same functionality as an ordinary car. But the experience of driving a Volt for the first time, similar to using an iPad, is like stepping through a portal into the future. In this alternate future, some things are left behind and missed: a real keyboard, a real back seat. The shortcomings, however, are easily eclipsed by the experience offered by this new platform.

EPA Estimated Energy Costs

For my normal commute, the all-electric range of the car will get me to work and back without having to use any gasoline at all, or recharging, which is quite remarkable. I expect that I’ll gladly burn some petrol for the comforts of heat and air conditioning. Maybe I’ll be able to plug in at work and avoid the need for gas altogether. Beyond the convenience and energy efficiency, the Volt also offers an impressive array of wizardry, connectivity, and creature comforts the likes of which I haven’t seen anywhere outside of an Apple Store. So there was no doubt that I wanted to own this car.

The true cost of a Volt is not easy to discern. The sticker price for a well equipped Volt is in the range of $43,700, which certainly seems like quite a premium relative to other small cars. But that is offset by a federal tax rebate of $7,500, and possibly state incentives as well. Fuel (energy) costs are a big factor, too. I figure that the cost of electricity and gasoline for the Volt will be at least half of what it is for my 128i, with the savings greater as the cost per gallon inevitably increases. Then there’s resale value, which is a complete mystery for a new creature like the Volt. The folks at have a total cost of ownership calculator which attempts to factor in all of these things, including maintenance, fuel costs, and all the rest for a five year period. Here’s a breakdown of what they call the “true cost to own” for several cars that I might compare with the Volt.

5-Year Total Cost of Ownership (

The Courtesy Difference

This is where we need to take a brief detour to discuss the practice of Market Price Adjustments, also affectionately known as Price Gouging. There are some interesting discussions about this at, along with lots of other great information. The supply of Volts is limited and demand is high, so some dealerships have elected to avail themselves of the benefits of such market economics. Particularly in Silicon Valley, there are plenty of folks that can afford to pay whatever the dealer asks, so in some sense its hard to fault the dealer for taking their money. As of June 2011, Courtesy Chevrolet has chosen this path. By doing so, they actually have Volts available on the lot for folks that are willing to pay $5,000 or more over MSRP. I’m in no rush to buy a Volt immediately, and Courtesy wasn’t willing to sell one at MSRP, nor order one with a commitment to sell it at MSRP. Certainly they have a right to opportunistically sell Volts above sticker, but they will not sell one to me. Dealers engaging in such practices will likely suffer long term damage to their reputation and credibility for doing so. They have offended the sensibility of early-adopters and influencers, and we have a good memory.

On the other hand, there are also dealers that have elected to sell Volts at GM’s recommended sticker price. Dealers owned by AutoNation are in this category, as are others I’m sure. I recall that when my brother was in the market for a new Corvette C5, the same “opportunistic” pricing practices were prevalent, and Kerbeck Chevrolet in Atlantic City was one of the few that took the high road and gave him a fair deal. I’ve read that they are doing the same with Volts, so Kerbeck deserves the great reputation they have earned. Fortunately, I didn’t have to look as far as the East Coast for such a reputable dealer.

I contacted Fremont Chevrolet, which is about five minutes away from my office. I quickly got a call back from Kurt Mietz, their fleet sales guy, and also Volt specialist. They sell all their Volts at MSRP, so for now you have to order one and wait. It just so happens that Kurt was spec’ing out the first eight 2012 Volts allotted to Fremont, so he asked me how I wanted mine configured. I told him on the phone, and then when I stopped by later that day, he handed me the piece of paper with a tracking number. Done. Absolutely couldn’t have been easier. If you’re in Northern California and shopping for a Volt, give Kurt a ring at (510) 445-8700.

Some other things that I’ve learned… I had wanted the “Cyber Gray” color, but learned that it is not available for 2012 because the supply of the pigment was impacted by the tsunami in Japan. So I went for Silver. We expect that my Volt will be in production sometime in August, rail transportation will take about 30 days, and after that delivery will be sometime around October. Plenty of time to get a 220V charging system installed in the garage. I’ll post Part 2 once the Volt makes it home.