Expanding your solar system to charge an electric vehicle

Increasingly — at least once each week — we are contacted by solar homeowners who recently purchased, or are contemplating buying, an electric vehicle (eV). To wit, they are interested in adding panels to their current solar system to cover fueling (charging!) their new eV.

The good news: Solar-charged electric vehicles are the least expensive form of four-wheel transportation, let alone the virtue of aborting fossil fuels. For RepowerYolo homeowners, the average cost to generate solar electricity on their rooftop is 8 cents per kilowatt hour (kWh). For every kWh of charge, eV owners garner ~4 miles of range. Hence, if you have an electric car that’s powered by sunshine, your cost to drive is ~2 cents per mile.

The challenge: While it’s technically (almost lego-esque) easy to add solar panels to a system, the process is, unfortunately, somewhat pricey. There are two scenarios:

1. Your current inverter has sufficient capacity to accommodate additional panels. If this is the case, then the challenge is locating and purchasing comparable (wattage) solar panels. Depending on the vintage of your current system, this could be simple, or it may be that you need to purchase used/refurbished panels.

2. Your current inverter cannot accommodate additional solar panels. Thereby — this is what I did when I added nine panels on my roof to charge my Leaf — you need to either add a second inverter or proceed with micro-inverters. Again, securing compatible panels is the next step.

In both scenarios, we are required to perform full design-engineering-permitting for your additional solar capacity. Though this is not complicated, it adds to the cost; it’s not simply lego-esque, snap-a-few-panels-in-and-go.

An additional caveat: Homeowners can only claim the 30% Federal tax credit once every five years. So, if you went solar in the past five years, you may want to wait until you re-qualify for the credit. 

Net-net, we’re happy to help. There’s no cost to receive an assessment of your current system, analysis of your historical net-energy use, modeling of your future electricity demand (for your eV), and an analysis + recommendations for your additional solar capacity. Feel free to contact us or swing my our workspace.

A clean solar panel is a happy solar panel: Simple tips for cleaning your solar panels

In mid-June it rained. Hard. In Davis, California. Call it what you’d like: Weird weather, climate change, global warming. One thing’s for sure with the unseasonal rains: Solar panels (and their owners) were smiling on a rainy June day. Now that the rains have subsided and peak-solar generation season is in full swing, our solar panels are collecting dust and pollen and bird droppings. The panels are increasingly frowning.

What’s a solar owner to do?

Solar PV systems require modest maintenance (read: cleaning) to maximize production efficiency. Below are a few tips that will help guide your steps over the life of the system. First, the warnings: exercise great care in accessing the panels. Roof materials get unexpectedly slick. And it’s easy to damage many roofs.

Keep in mind that many owners do nothing for the entire time they own the system. Equipment failures are rare and when they occur, it’s within six months of the installation. Panels are designed to last 25-years or more; inverters last at least 12 years. In short, none of the conditions mentioned below impacts many owners. Still, for those seeking full information, keep reading.

If your home or business is powered by solar, there are three options:

1. Do nothing (i.e., let the rain cleanse your panels).

2. Do it yourself (periodically clean your panels).

3. Hire a cleaning service.

Option #1 (do nothing), obviously, generates the least amount of electricity. Option #3 (hire a professional to clean your panels) optimizes efficiency, but can be quite expensive; the cost of doing so oftentimes exceeds the value of your increased solar generation. (Researchers at UC San Diego concluded, “You definitely wouldn’t get your money back after hiring someone to wash your rooftop panels.”) Herein we focus on the most common alternative: Do it yourself.

As solar panels have no moving parts, the main area of maintenance is to keep them clean. We recommend to check the panels periodically especially during dry periods when precipitating dust occurs with the morning dew. Dirty panels can reduce electricity production as much as 8-12% (results from Department of Energy studies vary). Most dirt can be easily removed with water sprayed from a hose or from rainfall. (Do NOT use high-pressure sprayers as it can damage the seals around the frame.) Important: Wash/spray the panels in the morning to reduce drastic temperature changes. If you cannot ascend your roof, simply spray from the ground and let gravity do the trick … a small wave of water will cleanse most dust. Do not scrub the panels with any harsh materials. If a brush is needed, make sure it has soft bristles, or opt for a common window squeegee. If you notice rapid dirt build up—or bird droppings—then more frequent cleanings are warranted.

Generally, we recommend cleaning your panels every six weeks, commencing in early June (given that our last rains, typically, occur around Picnic Day) and continuing through early September. Hence, 3-4 cleanings every six weeks will suffice.

We monitor the production of 100+ solar systems in our community. Thereby, we can tell when a homeowner has cleaned their panels … solar production increases 5-6%, and then gradually decreases. In addition to our general rule-of-thumb — cleaning every six weeks during peak production season (late May through mid-September — it’s worthy to keep an eye on your web-based monitoring system to gauge if/when your panels would like a bath.

And, of course, feel free to contact us if you have questions.

Evaluating solar options? The Model T days are over; four key considerations.

You've decided it's time to (re)-investigate installing solar. Your hesitancy may be logical: You do not need to go solar, and you’re unsure how to assess and assemble the pieces, let alone compare offerings. It can be puzzling. Your caution (and even procrastination) actually positions you well. The solar industry has improved dramatically from the Model T days.

Early car buyers had similar concerns: Do I buy internal combustion engine, electric, or steam? What starter makes sense? What about the brakes, or the dashboard, or the tire lifetime? Do I need a car? If so, who can I trust and will it work/be dependable?

Homeowners who went solar in the early days had to consider panel composition, wiring, inverter design, roof attachments, warranties, and even potential fire hazards. Fortunately, solar equipment is now similar to automotive offers from the early ‘80s. We no longer need to ask about where the engine was made, the engine compression, the electrical system, etc. For cars, we now shop for benefits and outcomes, and we have specific metrics to help gauge alternatives: fuel efficiency, acceleration (zero-to-60), safety test results, stopping distance plus all the new features and benefits available.

For solar, here's what matters most on the equipment front (i.e., questions you should engage and pose to your solar provider):

  1. What is the likelihood the system will generate the annual energy forecasted? Thereby, can the solar company point to a significant group of local, monitored homes and compare forecast to actual generation? A simple metric to calculate system productivity: total annual electricity (kWh)/system size (kW-DC). For south-facing systems with no shade, this number should be about 1,500 kWh/kW. East- and west-facing systems produce ~8% less. (The likelihood of actually generating the energy promised falls dramatically as the actual productivity value increases above this threshold.) And, don’t get confused by panel efficiency: It simply reduces the area required for a system, and has a modest impact on the system’s production.
  2. Does the equipment come from Tier-1, investment-grade suppliers? For solar panels: Canadian Solar, SunPower, LG and a handful of others qualify. For inverters: SMA, SolarEdge, and ABB.
  3. What is the likelihood my product warranties will be valid? Amplifying the above point, the current and future financial stability of the manufacturer is imperative. A 25-year warranty is only as good as the company behind it; do your homework (or, better yet, press your solar provider to evidence the manufacturers’ solvency).
  4. How do I know I’m getting a fair price? One way to standardize pricing for an apples-to-apples assessment: Divide system cost by the the system size (watts), so you have the cost per watt. The gross investment (pre-tax credit) for most home systems today should be $3.50 per watt or less for a Tier-1 system installed by a first-rate contractor.

Solar is transitioning from an art form to science. In so doing, your task is simplified as you endeavor to generate your own power. (And, solar, in our opinion, is the only investment in your home that generates a reliable return.)

Thank you

Yesterday we were named the Best Solar Company in Yolo County by Davis Enterprise readers.


We are honored. We are humbled. And, we are more committed than ever to help members of our community evaluate and go solar.

Above all, thank you to property owners who have trusted us to shepherd their solar process. More than 7,000 Repower solar panels smile at the sun today thanks to you. 

Thanks too to our parents who raised us, our wives who support us, our children who keep it real, and our friends — be it over a beer or bite, on the tennis courts or golf course, or in the boxing ring or gym — for keeping our egos in check!

And thank you to the dozens of community and nonprofit organizations we collaborate with. Since we have not spent a dime on advertising or marketing — and we do not employ salespeople — the organic word-of-mouth of our comrades has been imperative to our growth. Thereby, we are proud to have donated more than $40,000 to local nonprofits through our YoloShines program.

This is the first year the Enterprise entertained votes for Best Solar Company in Yolo County. Some say, "it's about time solar got its due." We believe it's a signal solar has come of age, particularly since one-in-four Davis homeowners now have solar PV systems.

Best is an superlative, subjective adjective. At risk of sounding trite, here's what we do to earn the trust of our community: Deliver high-quality solar systems installed by a first-rate contractor at a competitive price. Thereby, ensure property owners get what they paid for, and make sure the solar system does what it’s supposed to. We are there every step of the way — from initial assessment to financing to design and engineering to permitting to installation to PG&E interconnection to solar system monitoring. That’s our job, and we both love it and take it seriously.

Finally (and importantly!), congratulations to our friends who also were honored as Best in Yolo County … we’ll have beers soon to celebrate:

It’s a pleasure to do business with you and collectively serve our community.

PG&E just raised its rates (again!); what’s going on and what can I do?

Effective March 1, PG&E condensed the tiers of its E-1 residential rate schedule (the tariff most homeowners employ). And, again, electricity rates went up, this time by ~8%. What’s the story and what can I do, if anything?

First, a little background. Every few years, PG&E submits a three-year budget to the California Public Utilities Corp (CPUC), aka, their “rate case”. Therein, they propose myriad rate schedules for commercial, agricultural, residential and other customer groups. The CPUC eventually approves PG&E’s budget, but that’s not the end; over the ensuing three-year period, rate schedules are modified (read: rates are increased) to reflect contemporary PG&E expenses. Over the past two years, PG&E’s residential rates have increased ~43%. Ouch.

Like it or not, inflationary pressures on PG&E’s rates are somewhat just:

  • Replacement of aged infrastructure (e.g., natural gas lines; updated the grid);
  • Retirement of idled assets (e.g., “peaker” power plants; Diablo Canyon);
  • Reduction in generation of inexpensive hydro electricity (due to the drought);
  • AB 32 and the Renewable Portfolio Standard (RPS); and,
  • Long-term power purchase contracts.

And, living here, we have no choice but to love the one we’re with, at least until Valley Clean Energy Alliance (VCEA) launches. (Side note: PG&E has commenced its fear-and-smear campaign regarding VCEA and community choice energy … it’s gonna get ugly.)

Homeowners have four rate schedules to choose from:

  • E1 (the most common rate): Electricity is priced based on tiers (monthly usage).
  • EV: Time-of-use pricing for electric vehicle owners.
  • E-TOU (A): Time-of-use pricing, with “peak” periods from 3:00-8:00 p.m., Monday through Friday.
  • E-TOU (B): Also time-of-use, with peak pricing from 4:00-9:00 p.m.

So, what’s a homeowner to do? Here are a few simple ways to reduce your utility costs:

1. Go to PG&E’s website, log in to your (or create an) account and select “Compare Rate Plans” in the right column. Based on the time and volume of your electricity use, PG&E — such kind souls! — will quantify your costs under the above scenarios and suggest the least expensive rate schedule. More than likely, one of the time-of-use plans will reduce your bill.

2. Change your behavior. No, not your comfort (or the way you live), but your electricity use. Simple things like doing laundry in the morning, on weekends, or after 9:00 p.m. will lower your costs. So too, if you have a pool, will changing the time your pump runs; start it at 11:00 p.m. And, in the summer cool your home in the morning and early afternoon, then turn off your AC at 3:00.

3. Replace incandescent and CFL bulbs with LEDs. This is not even low hanging fruit in the energy savings world; it’s fruit laying on the ground. 

4. If you have a swimming pool, install a variable speed pool pump. Thereby you can reduce the electricity consumed by your pool by ~70%. Davis Home Trends, Leslies and several other stores can lend a hand.

5. If you haven’t done so already, go solar and insulate yourself from future PG&E rate increases. (No duh, eh?)

And, of course, feel free to contact us or stop by. As Jackson Browne once mused, we may not have the answer, but we believe we’ve got a plan.

The coolest organization in our cool city

Sunday, in arms with our comrades Indigo, we had the great honor of hosting Cool Davis’ annual donor celebration. Magnificent vino was poured by Senders Wines and tasty eats were tendered by ChickPeas, tantalizing the palettes of several dozen community leaders. In addition to honoring those committed to enhancing the sustainability of our community, we toasted Indigo's wonderful abode, the first zero net-energy commercial building in Davis (now boasting a beautiful, 46-panel solar array!). A good time was had by all, with special thanks to Judy Moores, Lynne Nittler, Chris Granger and Kerry Daane Loux for their orchestration.

During the event, we shared an update regarding RepowerYolo’s impact, in concert with Cool Davis’ Double Up on Solar Davis campaign. Over the past few years, Repower has helped homeowners install more than 5,500 solar panels. Panel by panel, home by home, the aggregate clean energy impact is pretty cool. Namely, the clean electricity generated by Repower homeowners is the equivalent of: 

- eliminating 16,696 metric tons of carbon dioxide;

- taking 3,519 cars off the road; and,

- planting 429,224 trees

To boot, Repower homeowners are projected to save a cumulative $9,804,774 in PG&E expenses. That makes us smile, and we deeply appreciate the support and confidence of the community.

Back to the coolest organization in our cool city. Cool Davis is the little engine that IS making a difference, proactively fulfilling its mission to "inspire our community to reduce greenhouse gas emissions, adapt to a changing climate, and improve the quality of life for all.”

Here’s how you can get involved:

1. Act: If you would like a hand reducing your carbon footprint, here are a few examples of how you can take action.

2. Donate: Like all nonprofit organizations, Cool Davis can use your support and we engage you to join Repower in making a contribution. Our assurance: Every dollar Cool Davis raises is invested in pragmatic, impactful measures. 

3. Volunteer: There are myriad ways to get involved, beginning with Cool Davis’ Coalition and Partner forum. Attend and you’ll learn more about last year’s Sustainability Summit, along with recent post election community gatherings on Environmental Justice and Climate Change. Come prepared to work on planning forums, and forming working groups on local policy dialogue and discussing new collaborative projects.

4. Learn: Cool Davis’ website has a wealth of useful tips and tools … click here for the latest news, and here to explore resources.

We are grateful for our collaboration with Cool Davis and their mutual commitment to make Davis a more sustainable place. The time to act is now. Please join us!

$500 rebate from PG&E for electric vehicle owners

Occasionally, we'll stumble upon something that sounds too good to be true. Not fake news, but are-you-kidding-me offers. This one's good and real: A $500 rebate from PG&E to any current electric vehicle owner. No joke, no strings attached. The program commenced yesterday; here's an excerpt from Green Car Reports story:

Pacific Gas & Electric (PG&E) now offers a $500 "Clean Fuel Rebate" for customers with electric cars.

The program, which just launched yesterday, is the result of California's Low Carbon Fuel Standard, which among other provisions, gives credits to utilities whose customers use home electricity to charge electric cars.

PG&E hopes to pass the value of those credits back to those customers, according to a company press release.

To be eligible, customers simply need an active PG&E residential account.

Customers can apply for a rebate for their own electric cars, or apply on behalf of an electric-car owner in their household (or a tenant, in multi-family households), after gaining that owner's permission.

Applicants need only a PG&E account number and a scanned image of the car's registration or sales/lease agreement, which can be be submitted through a web page set up for the program.

Feel free to contact us if you have questions or have trouble securing your rebate. And, for a day, we can all smile when we think about PG&E!

Thinking about going solar? Five key considerations

There’s a lot of sunshine being monetized by our community. In Davis alone, one in four single family residences have solar PV systems (versus approximately 5% in PG&E territory). Such rapid adoption is driven by four factors: PG&E’s ever-escalating electricity rates, a sharp decline in the cost of solar systems, the 30% federal tax credit, and (increasingly) grand concerns about our climate and planet.

The formative stage of the Repower program involved extensive research. We assessed the quality, reliability and pricing of solar equipment; the efficacy of solar installation contractors; the pricing (through a group purchase program) of solar; the most viable financing options; and, the most systematic installation methodology. Since pulling the pieces together and enabling the Repower program, we have had the fortune of helping more homeowners in our community invest in solar than any other solar provider.

If you are pondering going solar, here are five key considerations:

1. How long do you intend to reside in your home? If your horizon is less than five years, think twice; if more than five (and given you have a de facto agreement with PG&E to purchase electricity), dig deep.

2. What is the condition (and remaining life) of your roof? Solar systems have a 25-year production warranty. Though it is possible (and common) to replace a roof with an existing solar system, if your roof’s remaining life is less than 10 years, you should consider replacing all or part (i.e., the portion under the solar panels) of your roof.

3. What are the installation contractor’s qualifications? Thereby, it’s critical to speak with local homeowners who have worked with the contractor. Furthermore, you should seek a 10-year workmanship warranty and ensure the installation contractor is financially solvent. Finally, the contractor’s experience with your type of roof is paramount.

4. Who manufacturers the solar panels and inverter(s)? The assessment herein is twofold: What is the efficacy and reliability of the products, and what is the financial solvency (i.e., strength of balance sheet) of the manufacturer, and thus the validity of their performance warranty. Bloomberg qualifies a dozen or so solar panel manufacturers as “Tier 1” or “investment grade” … make sure you’re purchasing a product from this class.

5. Who will own the system and/or how will you pay for it? Frankly, leasing a solar system — whereby your solar panels are owned by a third-party, tax equity fund — is a raw deal for homeowners. You should own your system. Many homeowners employ a home equity line of credit (HELOC) or credit union financing (Yolo Federal Credit Union) to finance their solar system. (Contact us if you would like to learn more about Property Assessed Clean Energy [PACE] financing … we helped developed the first PACE programs in Sacramento and Yolo counties.)


At the end of the day, you'd like to know the likelihood your solar system will meet or exceed its energy forecast. Most solar companies use the same forecasting tools. It's the assumptions that feed these models that vary. You should feel confident the forecast presented is reasonable and not some pie-in-the-sky result. Hence, ask solar companies the proportion of systems installed that meet or exceed the originally forecast energy generation. (You should also ask the number of systems monitored to ensure it's a meaningful proportion.)

We do not have all the answers — there is no surefire, perfect solar solution — but we do have strong opinions and extensive experience in our community. Nobody wants to get a bad deal or make a short-sighted decision; filtering through the noise of pesky solar solicitations can be migraine-inducing. To wit, feel free to contact us if you need a hand.

President-elect Tump + the future of solar

So, it happened. President-elect Donald Trump. The ramifications are yet to be seen, but based on more than one-dozen conversations since the election with prospective solar investors (residential and commercial property owners), a valid concern has been floated: What will happen to the 30% federal solar (renewable energy) tax credit?

First, what we know: Mr. Trump has bemoaned climate change as a “hoax.” He has committed to revitalizing the coal industry and boosting national development of non-clean (read: natural gas and oil) energy sources. And, he has — for selfish reasons, given his on-the-coast golf course in the UK — denounced wind farms. Furthermore, he has floated climate science denier Myron Ebell as a potential director of the Environmental Protection Agency. Clean air, clean water, viable species, and solar tax credits be damned.

But, in my conversations with concerned folk, I’m trying to apply logic and common sense. First, the solar industry has created more jobs in the US over the past five years than any other industry, and it’s the fastest growing sector in the economy -- more than 200,000 patriots are employed in the solar industry. The solar industry is growing 12x faster than the overall economy. Solar creates jobs; republicans like job growth. Second, when property owners opt to invest in and create their own energy, they are exercising their (energy and investment) independence. Who’s to argue with an individual’s right to create their own energy? Decentralization of energy — creation, distribution, investment — is something both sides of the aisle should logically agree with. (Fact: 85% of Americans and 84% of republicans support solar.)

My fear: Uneducated idealism will trump logic, facts, statistics and applied common sense. The reality that the fossil fuels industry receives more than 10x the incentives (tax credits included) of renewable energy will be cast aside by powerful coal and gas industries. 

My hope: Renewable energy (and solar in particular) is a roaring bonfire in our country that ideologues and industrialists can’t stop. Our economy and our environment benefit every time a property owner opts to invest in clean energy. It’s their choice, and it makes sense; if it did not, they would not do it.

The reality: Those of us who believe in and champion clean energy investment cannot simply apply logic and common sense. We will need to fight, use facts, and trumpet the job-percolating, economic-resonating virtues of our profession and passion. Solar is now and it is happening … we cannot allow the momentum to become no-mentum.

The oh-so-beautiful Tesla solar roof: Trophy wife or trusted companion?

I want a Tesla solar roof.

There, I said it. And I admit I’m under the spell of Elon (with a capital E). He’s enchanting and innovative, a visionary with extraordinary aesthetic taste. He is hell-bent on building THE sustainable energy company of the future. Elon rocks.

I spent 15 minutes Friday night fixated on Tesla’s solar roof (and Powerwall) announcement. Set at Universal Studios, it was like a scene out of Truman Show: Was it real? Time will tell. Here's the video.

Enchantment to the side, I have a few questions for Elon prior to pulling the trigger on a Tesla solar roof (in addition to recommending the solution for friends and neighbors). Elon, I will buy and recommend your roof if:

1. As you stated, the cost is the same or less than installing a new roof and traditional solar PV system.

2. The solar shingles’ electricity generation capacity is proven and backed by a 25-year, third-party warranty.

3. The quality of the roof is the same or superior to traditional roofs, both its insulating capacity and protection versus leaks.

4. It’s easy to install and replace the singles (versus Dow’s recently-killed Powerhouse solar shingle).

5. The roof can endure standard stomping and pounding, be it a person walking or a tree limb tumbling.

6. My local jurisdiction will permit its installation.

7. It can be installed by a reputable, third-party contractor; as you know, Elon, SolarCity is not known for their quality workmanship.

8. It qualifies for the 30% federal tax credit.

9. I can insure it.

Elon, if you nail the above you will be well along your way in building a sustainable and profitable, end-to-end clean energy juggernaut. Until then, please focus on ramping production of the Model 3 ... my $1,000 deposit is burning a mini hole in your pocket!

RepowerYolo siting (in Morocco!)

We believe an unofficial world record was set this weekend: The farthest distance -- 5,990 miles -- traveled by a RepowerYolo t-shirt! Our colleague, friend, fellow sustainability advocate, Davis resident, and (hah!) international correspondent Yvonne Hunter reported in from Ourazette, Morocco.

Greetings from Morocco. My Repower tee shirt went along on the trip and was worn today in the city of Ourazette - in the Sahara.  

Lots and lots of solar PV all over Morocco and imagine my surprise at seeing that a solar festival is here now.  No chance to attend but the poster and outside signs were nifty.  In French and Arabic!

Many thanks to Yvonne for sharing the solar love in the Sahara! (And, hopefully, she did not hug a solar panel.) 

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.

To Bolt or not to Bolt

Over the past 10 days, we've had a dozen or so conversations about Chevrolet's soon-to-be-released, all-electric Bolt. Concurrently, my wife is pondering a new car that's efficient, economical and suitable for a Davis-to-UCDMC commute. To wit, to Bolt or not to Bolt?

After all, what's not to like? Significant -- 238 miles -- all-electric range, a decently sporty design, and a good price tag (less than $40k before $7,500 in federal and $2,500 in state incentives). Pundits have proclaimed General Motors (with the Bolt) has beat Tesla (with its Model 3) to the dance.

General take through our lens: Electric vehicles powered by solar-generated electricity make great economic and environmental sense. Quick 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 $0.25 per kWh, and their median monthly electricity bill is $185. Conversely, their cost to generate solar electricity averages $0.08 per kilowatt hour (kWh), amortized over the warrantied life of their solar panels. 

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 $0.10/mile.

Electric vehicles yield, on average, four 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, $0.06/mile). If your electric car is powered by solar, your annual cost is $240 ($0.02/mile). (And, of course, if you charge at your workplace or one of a half-dozen free sites downtown, your cost is lower.)

Back to the Bolt. A few takes floated over the past week:

- Business Insider: The Chevy Bolt still doesn't compare to Tesla's Model 3

- Electrek: The very good Chevy Bolt reviews are in ... everyone forgot to ask the most important question

The latter from Electrek hits -- aside from design/style/brand cache/Elon-halo-effect virtues -- Tesla's sustainable competitive advantage. General Motors (and other automakers) need to get off their collective rears and solve the charging challenge. Their networks are established: Dealerships are sensible locations for super-charger stations.

Until then, the Bolt will be a bit better than my Leaf: Great for local transport and perhaps a trip to the Bay Area or Tahoe, but nonsensical to take to Oregon or Southern California. Here's hoping General Motors and others will tackle the simple (technology) but complex (logistical) challenge of building a charging network.


Postscript: Great comparison of the Bolt and Model 3 in today's Clean Technica, echoing and amplifying many of our thoughts.

YoloShines: NAMI-Yolo

There are a lot of rewarding and fun virtues of doing what we do: Helping friends and neighbors achieve energy independence (while slashing their carbon footprint and saving thousands of dollars) is extremely gratifying. At the top (of the Repower fun/rewarding list) may be when we ask homeowners to select a local nonprofit for our YoloShines program.

And, this time we have a new twist. Repower homeowners John and Alice Provost asked if we could split our $500 donation among two organizations. Of course.

John and Alice selected the Davis School Arts Foundation (read more about our prior support of DSAF here) and Yolo-NAMI, a new organization in our basket of beneficiaries. Here's what John and Alice had to say about Yolo-NAMI:

The National Alliance for the Mentally Ill is a national organization with local chapters throughout the country, including one in Yolo County. Yolo NAMI works with cities and counties in Yolo County as well as private organizations that provide services to residents of Yolo County who suffer from some type of mental illness. This is a population that is greatly underserved and often suffers in isolation due to the nature of their illnesses. Yolo NAMI provides much needed assistance to these individuals and is a very worthy organization to support.

Thank you, John and Alice, for making our community a better place.

YoloShines: Yolo Farm to Fork

As we've shared, Yolo Farm to Fork is one of our favorite (most appetizing?) nonprofits. Like many small, scrappy organizations, F2F does a lot with a little, and their impact spans generations.

With our YoloShines program, Repower homeowners select a local nonprofit organization to which we donate $500. When the selected organization is one of our faves, our donation has even more meaning.

To wit, we would like to thank Davis resident Kirk Mills and his family for choosing Yolo Farm to Fork, and we are proud to donate $500. Here's an encapsulation of why the Mills family selected F2F:

The video on Yolo Farm to Fork's website really spoke to our family. We value buying local produce because it's delicious (mostly), but also because we know it has only traveled a short distance to our local store thereby creating less pollution in the traveling process. The idea of schools using local produce is so exciting. Even more exciting is the concept of school gardens. We know first hand how excited our son gets about our garden at home and how it makes him want to eat what he grows. It is truly a gift to see our son so excited about something so beneficial and positive that he will carry through his whole life.

Thank you, Kirk, for making a difference in our community. Please join the Mills family and Repower in supporting Yolo Farm to Fork.