solar tesla

How PG&E’s “EV” rate schedule benefits solar homeowners

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We have had the fortune of helping more than 50 electric vehicle owners go solar. As shared in prior posts, fueling your car with solar electricity is the least expensive form of (automotive) transport: Your amortized cost to generate solar electricity is ~8 cents per kWh, and you yield about four miles per kWh of electricity. Trite but true: Driving on sunshine makes sense.

Better yet, when you enjoy an electric vehicle you can employ PG&E’s “EV” rate schedule. This time-of-use rate program incents EV drivers to charge their car (and shift other electricity demand) to “off-peak” hours, namely 11 pm to 7 am, Monday through Friday, and all weekend/holiday hours, sans 3-7 pm.

Here are PG&E’s “EV” rates per kWh:

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  • Peak (2-9 pm, M-F): $0.33 (winter); $0.48 (summer)

  • Part Peak (7am-2pm; 9-11pm M-F): $0.20 (winter); $0.26 (summer)

  • Off Peak (11pm-7am M-F; weekends/holidays all hours except 3-7pm): $0.13

When your solar panels make more energy than your home uses, you are credited by PG&E via their net-metering program. Hence, the greater the delta (solar generation less household consumption) during “peak” periods, your monetary credits are amplified.

Generally, Repower homeowners who enroll in PG&E’s EV rate schedule only generate ~80% of the electricity they use to cover 100% of their electricity costs. This is simply due to the time-of-use rate schedule and the advantage of buying electricity at a low rate and getting credited at nearly 4x. Very cool.

With apologies for the bevy of metrics, let’s review an example. Below is the electricity use for a fairly standard Davis homeowner who charges their electric vehicle 12,000 miles per year at home.

Pre-solar electricity use and costs (on PG&E’s “E-1” program):

E1 use.png

We then sized and modeled a solar system to eliminate the homeowner’s electricity bill: A 4.8 kW, 15-panel system installed at 270-degree azimuth (due west), no shading. The solar panels are projected to generate 6,493 kWh in year one, thus covering 70% of the homeowner’s electricity use.

If the homeowner did not own an electric vehicle, they would (upon going solar) enroll in PG&E’s “TOU-A” rate schedule. Like the EV rate, TOU-A values electricity based on demand (“peak” period is 3-8 pm), but there’s little difference between peak and off-peak periods.

Solar economics under the default E-TOU (A) rate schedule:

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The homeowner’s year-end, true-up cost would be $645 — the solar system is too small. This is not bad, but …

… under the EV rate schedule, the homeowner generates significant time-of-generation credits/leverage. Their year-end bill would be $108.

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Simple but lucrative: The homeowner will save an additional $500 per year through the EV rate schedule. Contact us today with questions and/or if you’d like a free solar assessment.

Tesla Model S vs. 3: First Impressions


Aunt Laurie and Uncle Clif reside in Portland. They're car peeps, specifically (emphatically) Tesla junkies. In 2013 they registered the first Tesla (a Model S) in Oregon. A few years later, they welcomed a Model X, and quickly jumped in line (and vaulted me to the front, riding shotgun courtesy of their second reservation) when Elon announced the Model 3. 

Laurie and Clif have drank the Tesla kool aide ... they are fanatics. To wit, here's a 48-hours-after-souped-up-Model-3-purchase recap from Aunt Lor:

Something felt odd to me about the 3 so I've had to give it some thought. l think I understand now ...

I got spoiled by the S.

3 not as fancy by far, but heck, it's at least $45k cheaper! (Even tho we bot the interior upgrade, fancier paint, rims, & long range 310 mi battery.)

Positives: It's more nimble, it's shorter by 11", so easier to maneuver round town. It does have more headroom as it is taller. It has spunk for sure, auto park & auto drive features. Simpler controls. Odd no driver dash gages, only an ipad like screen that is placed near center of dash? But now I get it. 

After 1 day I realize that simple design is clearly paving way for no driver & autonomous. Simple steering wheel "almost" feels superfluous in design. iPhone acts as one's fob, like calling Uber.

Clean lines w/smooth front. Elon no longer has to make cars look like other autos to be accepted; I predict more space age looks in near future.

So my conclusion:

The S is the brilliant stepping stone from normal luxury cars to electric luxury cars.

The 3 is stepping stone from human driver elec cars to elec autonomous vehicles. 

Just wait until 200,000 are on the road.

The future 


IMPORTANT to include enhanced autopilot hardware on your order. It incorporates the eight cameras & smart brains that enable lots of future software upgrades. 

W/o it the car won't be sought after on resale. 

The fully autonomous can be added later. 

Electric cars + solar panels: Does 1+1=3?

A quick note of thanks to The Enterprise for publishing the below article online today and in tomorrow's print edition. You can access the story here, and below is the prose.

A few times each week, we tender conversations with homeowners who own (or are considering purchasing) an electric vehicle and are thereby contemplating installing solar panels.

The psychology is similar: Electric cars (and solar) are good for the environment, and electric cars (and solar) are pragmatic/less expensive than the alternatives. Seems like a no-brainer – power your electric vehicle with cheap, clean energy generated by your solar panels.

But, is it?

Since 2010, nearly half of all plug-in electric vehicles sold in the United States are registered in California; the top-three models — Chevrolet’s Volt, Nissan’s Leaf and Tesla’s Model S — dominate the electric highway.

(And, many see the advent of Chevy’s all-electric Bolt in late 2016 and Tesla’s Model 3 — my deposit is in; please, Elon, late 2017? — as a tipping point for electric vehicles.)

Similarly, nearly half of all solar electric systems in the U.S. sit atop California households. (As we’ve shared, nearly one in four single-family residences in Davis now has a solar electric system, far out-pacing an estimated 5-percent penetration in PG&E territory.)

As transportation is increasingly electrified and energy generation is decentralized (from carbon-based, utility delivery to solar-generated, homeowner systems), does going solar to power your home and transport make sense? Let’s do the math.

Electricity costs
We have had the fortune of helping several hundred Yolo County homeowners evaluate solar. What we’ve learned: Their average cost of PG&E electricity is 25 cents per kWh, and their median monthly electricity bill is $185. Conversely, their cost to generate solar electricity averages 8 cents per kilowatt hour (kWh), amortized over the warrantied life of their solar panels. Solar saves money.

Transportation costs
For comparison, let’s assume an average car is driven 12,000 miles each year. If the car averages 25 miles per gallon, powered by petroleum, it will guzzle 480 gallons of gas annually. At $2.50 per gallon, annual fuel costs are $1,200, or 10 cents per mile.

Electric vehicles yield, on average, 4 miles of range per kWh. Hence, you will consume 3,000 kWh to drive 12,000 miles. If you are purchasing electricity from PG&E, your annual “fuel” cost is $750 (or, 6 cents per mile). If your electric car is powered by solar, your annual cost is $240 (2 cents per mile).

And, of course, if you charge at your workplace or one of a half-dozen free sites downtown, your cost is lower.

Environmental benefits
I can’t conceive an environmental virtue of driving a gas-powered car, though admittedly my family owns three (along with an all-electric vehicle). The environmental outcomes of electrifying your transportation with solar, though, are striking.

According to the EPA, over three years (36,000 miles) the greenhouse gas equivalents of clean transportation are:

* Retirement of 12.84 metric tons of carbon dioxide;
* Planting 320 tree seedlings, grown for 10 years; or,
* Averting 4.08 tons of waste sent to a landfill.

Many suns will set before electric vehicles become mainstream. Though cool and cheap and clean, their drawbacks are obvious: Range anxiety (Can I get from here to there?), charging anxiety (Do I need to charge it?), technology phobia (Is it too early/will it work?).

Danny Kennedy, managing director of California Clean Energy Fund, recently opined, “We’re now in a tech world, rather than a resource world. Resources are bound by scarcity — the more you use them, the more expensive they become. With tech, the more you use it, the cheaper it becomes.”

As the cost of solar and electric cars continue to descend, as the efficacy of both improve, and as PG&E rates further escalate, it will become increasingly difficult to dispute solar-fueled transportation.

The future is bright.