Which PG&E rate plan works best for EV charging?

By Robert Ellison.

We recently got an electric vehicle and unsurprisingly our electricity usage has shot up - something like 125% so far. This is of course offset by not needing to buy gas, but the PG&E bill is starting to look eye watering.

PG&E offers an exciting and nearly impenetrable number of rate plans. Right now we're on E-TOU-C which PG&E says is the best choice for us. This is a time of use plan which makes a lot of sense - electricity is cheap off peak and expensive when it's in high demand. Running the dishwasher at the end of the day saves a few cents. Charging an EV at the right time is a big deal.

I decided to simulate our bill on each plan, with and without EV charging.

This turns out to be astonishingly complicated. There is probably a significant energy saving in having the billing systems sweat a bit less. It's not just peak vs. off peak, the rates are different for summer and winter. In some plans peak is a daily occurrence and in others it doesn't apply to weekends and holidays (raising the exciting sub investigation of what PG&E considers to be a holiday). Some plans have a daily use fee. Our plan has a discount for baseline usage, others do not.

That's all just for the conventional time of use plans. The EV plans introduce a 'part-peak' period so there are three different rates based on time of day. They also have different definitions of summer.

I had imagined a quick spreadsheet but this has turned into a python exercise. The notebook is included below. If you use this you'll need to estimate your average daily EV charging needs and also your baseline details. It uses a year of data downloaded from PG&E to run the simulation, so use the year before you started charging an EV. I think I've captured most of the details but I did take a shortcut with the baseline calculations - it uses calendar months instead of billing periods. PG&E billing periods range from 28-33 days, presumably because that will be cheaper in the long run.

It would be nice if PG&E had some kind of what-if modelling but I guess that's not in their best interests. Right now the web site says I should stick on E-TOU-C, which looks like a bad idea even based on the past year of usage. All of the plans are pretty close for me based on historical usage though. Adding an EV shows a huge difference. Off peak rates are a lot cheaper but in exchange the peak rates are much higher. I'll save a lot moving to the EV2 plan, which is what I've just done. It's not clear how you should choose between the different EV oriented plans without getting into this level of detail, but they are all better than the conventional time of use options if you have better things to do.

I evaluated the E-TOU-B, E-TOU-C and E-TOU-D time of use plans and the EV Rate A, EV Rate B, EV2 and E-ELEC plans for people with an EV or other qualifying electrical thing. The chart at the top of the post shows PG&E's estimates for the past year, my estimates and then my estimates with EV charging included.

Here's the code:

{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Best PG&E Electric Rate Plan for EV\n", "\n", "Actual rate plan data in [this](https://www.pge.com/assets/rates/tariffs/Res_Inclu_TOU_Current.xlsx) Excel file. [This](https://www.pge.com/en/account/rate-plans/find-your-best-rate-plan/tiered-rate-plan.html) page has some details on the E1 tiered rate plan. TOU holidays are defined [here](https://www.pge.com/tariffs/en/rate-information/tou-holidays.html).\n", "\n", "Most plans have some minimum daily delivery, ignoring this as they are similar and not driven by usage. The tiered plans (E-1) etc just start charing more once you use more and are designed for people who can't control when power is used so not analyzing these. The remaining plans have a discount based on when you draw power, so looking at E-TOU-B, E-TOU-C and E-TOU-D which all have subtle differences. Also EVA, EVB, EV2 and E-ELEC which are targeted at EV / other electrical technology usage.\n", "\n", "Baseline is need for E-TOU-C. Information is on page 3 of the bill. I'm in baseline territory T, and my heat source is B - Not Electric (makes sense, heating is gas). For the current month my baseline is 208 kWh which is 32 days at 6.5 kWh / day. It's 32 because the billing cycle is 7/19/24 to 8/19/24 for some reason. And baseline switches from summer to winter based on month, but the billing periods are parts of months... For now, I'm using a simplified model for this. \n", "\n", "I'm also ignoring the very strange California Climate Credit ([previously](https://ithoughthecamewithyou.com/post/california-climate-credit)) which is in some plans but not others. It's a one off discount and not usuage driven. " ] }, { "cell_type": "code", "execution_count": 27, "metadata": {}, "outputs": [], "source": [ "import pandas as pd\n", "import calendar\n", "from datetime import datetime" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Plan Calculations\n", "\n", "Functions to calculate total dollars spent based on day of year, hour of day and an assumption for EV charging. " ] }, { "cell_type": "code", "execution_count": 136, "metadata": {}, "outputs": [], "source": [ "# assumption for daily charging - this will just be added at 4am each day as that's always going to be of peak\n", "dailyEvKwh = 17.8\n", "\n", "\n", "# E-TOU-C has a baseline discount, the months and billing periods are complex and so will simmplify to calendar months...\n", "# These figure are for territory T with gas heating.\n", "etoucSummerDailyBaseline = 6.5\n", "etoucWinterDailyBaseline = 7.5\n", "etoucCurrentMonth = 99\n", "etoucRemainingBaseline = 0;\n", "\n", "def isTouHoliday(date):\n", " # off peak weekends\n", " dateobj = datetime.strptime(date, '%Y-%m-%d')\n", " if dateobj.weekday() in [5, 6]:\n", " return True\n", " \n", " # off peak holidays \n", " holidays = ['2024-01-01', '2024-02-19', '2024-03-11', '2024-05-01', '2024-05-27', '2024-07-04', '2024-09-02', '2024-11-01', '2024-11-04', '2024-11-11', '2024-11-28', '2024-12-25',\n", " '2023-01-03', '2023-02-20', '2023-03-13', '2023-05-01', '2023-05-29', '2023-07-04', '2023-09-02', '2023-11-01', '2023-11-06', '2023-11-11', '2023-11-23', '2023-12-25']\n", " return date in holidays\n", "\n", "def days_in_month(date):\n", " dateobj = datetime.strptime(date, '%Y-%m-%d')\n", " # Get the number of days in the month\n", " _, num_days = calendar.monthrange(dateobj.year, dateobj.month)\n", " return num_days\n", "\n", "def evChargeKwh(hour):\n", " startHour = int(hour.split(':')[0])\n", " if (startHour == 4):\n", " return dailyEvKwh\n", " else:\n", " return 0\n", " \n", "def priceLookupThreeBand(date, hour, startPeak, endPeak, startPartPeak, endPartPeak, startSummer, endSummer, summerPeak, summerPartPeak, summerOffPeak, winterPeak, winterPartPeak, winterOffPeak):\n", " dateobj = datetime.strptime(date, '%Y-%m-%d')\n", " month = dateobj.month\n", " startHour = int(hour.split(':')[0])\n", "\n", " price = 0\n", "\n", " if month in range(startSummer, endSummer):\n", " if startHour in range(startPeak, endPeak):\n", " price = summerPeak\n", " elif startHour in range(startPartPeak, endPartPeak):\n", " price = summerPartPeak\n", " else:\n", " price = summerOffPeak\n", " else:\n", " if startHour in range(startPeak, endPeak):\n", " price = winterPeak\n", " elif startHour in range(startPartPeak, endPartPeak):\n", " price = winterPartPeak\n", " else:\n", " price = winterOffPeak\n", "\n", " return price\n", "\n", "def priceLookupTwoBand(date, hour, startPeak, endPeak, summerPeak, summerOffPeak, winterPeak, winterOffPeak, forceOffPeak):\n", " dateobj = datetime.strptime(date, '%Y-%m-%d')\n", " month = dateobj.month\n", " startHour = int(hour.split(':')[0])\n", "\n", " # summer is June-September, Winter is October-May\n", " price = 0\n", " if startHour not in range(startPeak, endPeak) or forceOffPeak:\n", " if month in range(6, 9):\n", " price = summerOffPeak\n", " else:\n", " price = winterOffPeak\n", " else:\n", " if month in range(6, 9):\n", " price = summerPeak\n", " else:\n", " price = winterPeak\n", "\n", " return price\n", "\n", "def etoub(date, hour, kwh):\n", " price = priceLookupTwoBand(date, hour, 16, 20, 0.56943, 0.44637, 0.4328, 0.394, False)\n", " return (kwh + evChargeKwh(hour)) * price\n", "\n", "def etouc(date, hour, kwh):\n", " global etoucCurrentMonth\n", " global etoucRemainingBaseline\n", "\n", " # reset baseline each month\n", " dateobj = datetime.strptime(date, '%Y-%m-%d')\n", " month = dateobj.month\n", " if (month != etoucCurrentMonth):\n", " # calculate days in month\n", " daysInMonth = days_in_month(date)\n", " if month in range(6, 9):\n", " etoucRemainingBaseline = etoucSummerDailyBaseline * daysInMonth\n", " else:\n", " etoucRemainingBaseline = etoucWinterDailyBaseline * daysInMonth\n", " etoucCurrentMonth = month\n", "\n", " # calculate discount\n", " dicountedKwh = 0\n", " if (kwh <= etoucRemainingBaseline):\n", " dicountedKwh = kwh\n", " etoucRemainingBaseline = etoucRemainingBaseline - kwh\n", " else:\n", " dicountedKwh = etoucRemainingBaseline\n", " etoucRemainingBaseline = 0\n", " discount = dicountedKwh * 0.09837\n", "\n", " price = priceLookupTwoBand(date, hour, 16, 20, 0.59342, 0.49042, 0.47926, 0.44926, False)\n", " cost = (kwh + evChargeKwh(hour)) * price\n", "\n", " # less discount\n", " cost = cost - discount\n", "\n", " # there is a daily meter fee on this plan, add this at 4am each day\n", " startHour = int(hour.split(':')[0])\n", " if (startHour == 4):\n", " cost = cost + 0.25298\n", "\n", " return cost\n", "\n", "def etoud(date, hour, kwh):\n", " forceOffPeak = isTouHoliday(date)\n", " price = priceLookupTwoBand(date, hour, 17, 19, 0.55447, 0.41951, 0.46486, 0.42625, forceOffPeak)\n", " return (kwh + evChargeKwh(hour)) * price\n", "\n", "def eva(date, hour, kwh):\n", " price = 0\n", " if isTouHoliday(date):\n", " price = priceLookupThreeBand(date, hour, 15, 18, 15, 18, 5, 10, 0.69132, 0.44721, 0.33466, 0.50872, 0.37671, 0.30498)\n", " else:\n", " price = priceLookupThreeBand(date, hour, 14, 20, 7, 22, 5, 10, 0.69132, 0.44721, 0.33466, 0.50872, 0.37671, 0.30498)\n", " return (kwh + evChargeKwh(hour)) * price\n", "\n", "def evb(date, hour, kwh):\n", " price = 0\n", " if isTouHoliday(date):\n", " price = priceLookupThreeBand(date, hour, 15, 18, 15, 18, 5, 10, 0.68841, 0.4443, 0.33175, 0.50587, 0.37386, 0.30213)\n", " else:\n", " price = priceLookupThreeBand(date, hour, 14, 20, 7, 22, 5, 10, 0.68841, 0.4443, 0.33175, 0.50587, 0.37386, 0.30213)\n", " cost = (kwh + evChargeKwh(hour)) * price\n", " # there is a daily meter fee on this plan, add this at 4am each day\n", " startHour = int(hour.split(':')[0])\n", " if (startHour == 4):\n", " cost = cost + 0.04928\n", " return cost\n", "\n", "def ev2(date, hour, kwh):\n", " price = priceLookupThreeBand(date, hour, 16, 21, 15, 23, 6, 9, 0.62402, 0.51353, 0.31151, 0.49691, 0.48021, 0.31151)\n", " return (kwh + evChargeKwh(hour)) * price\n", "\n", "def eelec(date, hour, kwh):\n", " price = priceLookupThreeBand(date, hour, 16, 21, 15, 23, 6, 9, 0.6028, 0.44092, 0.38424, 0.37129, 0.3492, 0.33534)\n", " cost = (kwh + evChargeKwh(hour)) * price\n", " # there is a daily meter fee on this plan, add this at 4am each day\n", " startHour = int(hour.split(':')[0])\n", " if (startHour == 4):\n", " cost = cost + 0.49281\n", " return cost" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "etoucCurrentMonth = 99 # reset to make sure we calculate the first month\n", "\n", "print(etoub('2024-09-01', '23:00', 0.67))\n", "print(etouc('2024-09-01', '23:00', 0.67))\n", "print(etoud('2024-09-01', '23:00', 0.67))\n", "print(eva('2024-09-01', '23:00', 0.67))\n", "print(evb('2024-09-01', '23:00', 0.67))\n", "print(ev2('2024-09-01', '23:00', 0.67))\n", "print(eelec('2024-09-01', '23:00', 0.67))" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Simulate Bill\n", "\n", "Use real data to simulate possible bills. This uses a PG&E expert for the 12 months before I started charging an EV. So the simulation should show how the average existing usage will change cost based on the various plan rules while adding an off-peak EV charge each day." ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "df = pd.read_csv('pge1yr.csv', skiprows=6)\n", "df.head()" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "etoucCurrentMonth = 99 # reset to make sure we calculate the first month\n", "\n", "# possible bills\n", "etoubTotal = 0\n", "etoucTotal = 0\n", "etoudTotal = 0\n", "evaTotal = 0\n", "evbTotal = 0\n", "ev2Total = 0\n", "eelecTotal = 0\n", "\n", "# process historical data\n", "for index, row in df.iterrows():\n", " etoubTotal = etoubTotal + etoub(row['DATE'], row['START TIME'], row['USAGE (kWh)'])\n", " etoucTotal = etoucTotal + etouc(row['DATE'], row['START TIME'], row['USAGE (kWh)'])\n", " etoudTotal = etoudTotal + etoud(row['DATE'], row['START TIME'], row['USAGE (kWh)'])\n", " evaTotal = evaTotal + eva(row['DATE'], row['START TIME'], row['USAGE (kWh)'])\n", " evbTotal = evbTotal + evb(row['DATE'], row['START TIME'], row['USAGE (kWh)'])\n", " ev2Total = ev2Total + ev2(row['DATE'], row['START TIME'], row['USAGE (kWh)'])\n", " eelecTotal = eelecTotal + eelec(row['DATE'], row['START TIME'], row['USAGE (kWh)'])\n", " \n", "print(f\"E-TOU-B Total: ${etoubTotal:,.2f}\")\n", "print(f\"E-TOU-C Total: ${etoucTotal:,.2f}\")\n", "print(f\"E-TOU-D Total: ${etoudTotal:,.2f}\")\n", "print(f\"EV Rate A Total: ${evaTotal:,.2f}\")\n", "print(f\"EV Rate B Total: ${evbTotal:,.2f}\")\n", "print(f\"EV-2 Total: ${ev2Total:,.2f}\")\n", "print(f\"E-ELEC Total: ${eelecTotal:,.2f}\")" ] } ], "metadata": { "kernelspec": { "display_name": ".venv", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.12.5" } }, "nbformat": 4, "nbformat_minor": 2 }

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(Published to the Fediverse as: Which PG&E rate plan works best for EV charging? #code #pge #electricity #ev #python Simulating PG&E bills with and without EV charging across 7 rate plans to discover the cheapest option (Python). )

code, pge, electricity, ev, python

Autumnal Equinox 2024

By Robert Ellison.

The exact moment of Autumnal Equinox (12:44 UTC on September 22, 2024), rendered in Catfood Earth.

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(Published to the Fediverse as: Autumnal Equinox 2024 #code #catfood #earth #equinox #autumnal Autumnal Equinox 2024 (12:44 UTC September 22, 2024) in Catfood Earth )

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Hudson Yards

By Robert Ellison.

Google Pixel 8 Pro 2mm f2.0 1/3,817s ISO43

Photo of the Long Island Railroad storage facility in front of Hudson Yards in New York City (one end of the High Line park).

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(Published to the Fediverse as: Hudson Yards #photo #newyork #hudsonyards #lirr #highline View of LIRR storage and Hudson Yards from the north end of the High Line in New York )

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SFO EWR

By Robert Ellison.

Google Pixel 8 Pro 7mm f1.7 1/25s ISO667

AS384

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(Published to the Fediverse as: SFO EWR #photo #flight #sfo #ewr SFO EWR )

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ITHCWY Newsletter for August 2024

By Robert Ellison.

Generated image of some random politicians with good hair.

Google has been sending me increasingly threatening emails about upgrading my Android apps and so August has been all about that. Helpfully Microsoft has also deprecated Xamarin (a tool I used to write software for Android) and so I also had to do a crash course in MAUI. Thank goodness for ChatGPT and GitHub Copilot. I also took this opportunity to figure out adaptive icons and generally update the look and feel of the apps.

Catfood Earth for Android has a new volcanoes layer and support for showing where you are on the satellite image.

Fortune Cookies for Android just works again, but that's not nothing.

I also made this timelapse of Fogust - San Francisco enveloped in fog - and this new to me hike in Pacifica has a nice hyperlapse (and some fog).

Previously:

2023: Is Sortition Having a Random Moment?
2022: Control LIFX WiFi light bulbs from Google Apps Script
2021: Every Coronavirus Article

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Catfood Earth for Android 4.40

By Robert Ellison. Updated on Sunday, September 29, 2024.

Catfood Earth for Android 4.40 is now available on Google Play.

Earth has an updated look and feel and two new features.

The volcanoes layer has been ported over from the Windows version of Catfood Earth. When enabled this will show volcanoes that have recent activity (within the past week) using data from the Smithsonian Institution's Global Volcanism Program.

It's now possible to show your current location on the map. I'm not sure it's a replacement for Google Maps just yet but it does help you find where you are on the satellite image.

The release was prompted by Google requiring API level 34 support... completing this for Fortune Cookies was a nightmare but having learnt from that experience Earth made the jump to MAUI pretty smoothly.

If you already use Earth for Android you should get the new version shortly. If not, this is what Android live wallpaper was made for so give it a try!

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Fortune Cookies for Android 1.50

By Robert Ellison.

Fortune Cookies for Android 1.50 is now available in the Google Play Store.

This update was driven by Google insisting that I target API level 34. Which is fair enough and I figured this would be a five minute task followed by a smooth release. I should have known better.

Of course the starting point is updating Visual Studio, updating the Android SDK, learning that my emulator won't launch any more and eventually coaxing it back to life. That's a couple of hours. Why this doesn't just happen when I'm doing other things I don't know, but for dev tools this has to be a ceremony.

Once all of that was done I learned that Xamarin was officially deprecated in May. I'm going to have to figure out MAUI.

There is a helpful migration page with this gob smacking advice:

"Once your dependencies are resolved and your code and resource files are added to your .NET native project, you should build your project. Any errors will guide you towards next steps."

I think they hired Yoda:

"Errors, they are. Guide you, they will, towards your next steps. Warnings, hmm, check them out you must... eventually. But information issues? Merely whispers they are, nudging you towards shiny new platform features, yes! Listen, you might, if time you have."

Anyway... the actual mechanics of getting this working in MAUI were not that bad. It could be that I need to reinstall my system with extreme prejudice but the platform itself seems to be very unstable. I constantly got Visual Studio and cryptic compile errors that went away on rebuild or a restart. Starting the android emulator has completely frozen my system several times requiring a hard reboot. I don't think I've had that experience since the Clinton administration.

Once it was finally working the Google Play Developer console wanted my "private" key, which I gave it; and to have a conversation about my tax situation in Cuba, which I'm ignoring for now.

As well as a brand new API target Fortune has a nifty new color scheme, a floating action button with a little fortune cookie on it, and will ask you nicely for permission to send notifications.

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(Published to the Fediverse as: Fortune Cookies for Android 1.50 #code #fortune #software #cookie #catfood #xamarin #maui Catfood Fortune for Android is based on the UNIX command of the same name and will display a random and possibly no longer socially acceptable fortune from a less civilized era. )

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Fogust

By Robert Ellison.

San Francisco gets a lot of fog in the summer. This brief time lapse, shot from Mount Tamalpais and the Marin Headlands shows just how much.

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(Published to the Fediverse as: Fogust #timelapse #video #fog #sanfrancisco #karlthefog #fogust Time Lapse of San Francisco Fog in August (Fogust) )

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Milagra Ridge

By Robert Ellison.

Starting from this parking area makes for a brisk walk up to Milagra Ridge and then a nice loop at the top before returning by the same trail. Milagra Ridge used to be a Nike missile site (SF-51), still has some WWII remains (Battery #244) and a reservoir. I thought it looked like a nice enough day to brave Pacifica but by the time I'd loaded the dog and driven down the fog had swept in. Still a pleasant 3 mile hike.

Hike starts at: 37.643146, -122.488815. View in Google Earth.

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(Published to the Fediverse as: Milagra Ridge #hike #video #pacifica #sfdogwalk #hikevid #map A 3 mile loop hike at Milagra Ridge (GGNRA) in Pacifica, California )

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ITHCWY Newsletter for July 2024

By Robert Ellison.

Federation

I have wanted a decentralized social network for a long time. Maybe this Fediverse thing is starting to get legs. Bluesky and Mastodon can now talk to each other via Bridgy Fed. Threads can post to Mastodon. ITHCWY has been on ActivityPub for a year now and it's become a significant source of traffic and comments. If you are on Mastodon or a federated service you can follow me at @[email protected]. I plan to get even more federated over the next year.

I waded foolishly into the debate around turning the Great Highway in San Francisco into a park, and found that the data doesn't support the fear of carnage in the Sunset when this road is closed. I also made a custom GPT to discuss the San Francisco budget with, and had to spend some time writing the missing manual to even know what to ask. Too late now, but here's a guide to the March ballot measures (watch this space for November) On a national level I got to update my NPVIC page now that Maine has joined.

Some photos... I knew that black bears could be brown, this one is very brown. Some humpback whales. The first commercially available glow-in-the-dark plant.

Milky Way timelapse from Canada. Partial Solar Eclipse from Inverness (CA).

Tunnel Mountain is a great hike in Banff (start from anywhere in town). Bolinas Point Loop is better if you're closer to Bolinas (which I mostly am).

Previously:

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