How many PV+EV miles could you be banking?


editors-blog-entry3We hit 1,000 kWh of banked Sun Miles™ – what we at SolarChargedDriving.Com describe as solar-powered miles driven by an electric vehicle (EV) or plug-in hybrid electric vehicle (PHEV) whose batteries have been charged using solar energy – earlier this week on our 47th Colorado day with a 5.59 kW solar system on our perfect-for-solar, south-facing roof.

How we worked around our utility’s 120 percent rule on home solar system size

dlWe were able to finesse Xcel Energy’s Solar Rewards rebate, which Xcel refuses to award to people who put up a solar system that produces more than 120 percent of annual household electricity use. Our intent in doing so wasn’t to bilk the system — although we do think it is unfair. It was simply to build a solar system that would cover 100 percent of our home electric use with an electric car.

Here’s how we beat Colorado’s Public Utility Commission’s (PUC) 120 percent rule:

We signed on for a 5.59 kW system in Aug. of 2009, but indicated to REC Solar, and to Xcel, that we would not have it installed until June 2010. We did so in order to give ourselves time to save up money to pay for the system, not to beat the Xcel 120-percent rule. However, it turns out that this extra time was exactly what we needed in order to beat the 120-percent rule. That’s because Xcel measures annual household electricity use back exactly a year from the date of your solar system installation.

In Oct. of 2009, Xcel rejected our application for a 5.59 kW system and we were forced to resubmit an application for a 2.8 kW system. However, because we had 7 months until installation of the system and because Xcel ultimately measures annual household electric use exactly a year back from the date of installation, we had these months to increase our electricity use so that the 5.59 kW system would not put us in violation of the 120 percent rule.

We did in fact up our electricity use while simultaneously reducing our natural gas use. We did this by shifting a good portion of our winter heating from natural gas to electric. We covered much of our heating with several 400-watt high efficiency electric heaters from E-heat.Com (which use far less energy than the standard 1,500 watt $30 space heaters you get at Home Depot). And we managed to push our June 2009 – May 2010 electricity use to 6,900 kWh.

ckThis meant the 5.59 kW system (output = 8,000 kWh per year) would produce 115 percent of our annual household use – and Xcel okayed a reapplication for that 5.59 kW system (with the $3.50 per watt rebate from the fall of 2009) in May of this year. Of course, while we will still use the E-heat heaters this winter, we won’t use them as much as last winter. In short, we’ll be dropping our electricity use from last year – which we inflated temporarily to get the 5.59 kW system that would be big enough to power a future electric car. At that point, it will no longer be “too” big.

One-thousand kWh hours = 4,000 miles worth of gasoline free, air pollution free driving in an electric vehicle – which we don’t yet have but which we will within the next year and a half or so. And, for those of you more motivated by dollar green than environmental green, 4,000 Sun Miles™ = more than $600 worth of gasoline savings (at $3 per gallon and 20 m.p.g.). Add to that the $52 we’ve saved in terms of the electricity we’ve used in our home over those 47 days and we’re talking about $650 worth of savings generated — in just 47 days!

Yes, we will end up paying around $8,500 out of pocket for our solar system (we’re still waiting on the 30 percent Federal Tax Credit, which we can’t capitalize on until April 2011). But, as I’ve written elsewhere, $8,500 is a steal compared to the long-term home electric and gasoline savings we will generate. I’m not going to discuss these savings in detail here because I’ve already done so in another entry, which I encourage you to read if you’re interested in learning just how much money solar-charged driving could potentially save you.

Is 1,000 banked kWh in 47 days reach-able for most people?
Instead, I’m going to concentrate on something you might be asking right now: Is this guy’s experience really representative? Is it something I can do – and reap just as much savings just as quickly as he has?

The “definitive” answer from yours truly is maybe.

Here’s what you need in order to generate a scenario almost identical to ours – a house next door 😉

But, in all seriousness, I know not everyone can be – or wants to be – our neighbor, though I do wish some of our current neighbors with those perfect-for-solar roofs, especially those that have even better-for-solar roofs than ours (yes, these do exist!), would go solar.

In the interest of being helpful, realistic and of coming “clean” about our own developing solar-charged driving story (we’re halfway there, with the solar system in place, but no electric car yet), here’s a list of things you would need to do in order to generate 1,000 extra kWh in the span of 47 days, as we have been able to do so far:

  1. Live in a state and an area with excellent utility and/or state rebates and/or Solar Renewable Energy Credits (SRECs). We live in Colorado and in Xcel Energy territory. When we signed on the dotted line for our 5.59 kW solar system in Aug. of 2009, we locked in a $3.50 per watt Xcel Energy Solar Rewards rebate. This rebate lopped off 60 percent of the cost of our system. In fact, the Xcel per watt rebate has since dropped to $2.75 per watt. This means by buying at the ‘right time’, we paid about $4,000 less for our system than a Colorado buyer in Xcel territory might pay right now. In theory, decreases in the cost of solar panels should offset declines in utility rebates. But in reality, they haven’t kept pace – at least not here in Colorado. Still, $2.75 per watt takes a decent chunk off the cost of a solar system, and is considered a good rebate. In terms of state and/or utility rebates and SRECs, the best places in the U.S. right now are, according to our friends at SolarPowerRocks.Com: New Jersey, New York, Massachusetts, Maryland, Pennsylvania, Oregon, Washington, D.C., Illinois and Delaware.
  1. Live in a house with a roof that can support a solar system which produces more electricity than your current household use. Most fundamentally, what you need here is a favorable ratio between your rooftop solar potential and your home electricity consumption practices and ethic. If you have great solar rooftop potential (lots of un-shaded, south-facing roof space) plus you live in a great-for-solar area of the U.S. (about three-quarters of the continental U.S. is very good for solar, with the American West the true hotspot for solar PV — check out this map to see what the solar potential is where you live), and you are truly electricity conservation oriented, you are potentially in excellent position to realize an excess solar production success story like ours.
  2. Live in a climate and house that are favorable to energy conservation – and are truly committed to energy conservation. Our combination of geographic location (Colorado’s comparatively temperate Front Range), individual house location (trees and a neighbor’s house shade the west side of our home in the late afternoon), house design (a welcome-to-our-roof south-facing roof and only two south-facing windows, neither of which let in direct sunlight in the summer, but which allow the sun to pour in in the winter), energy conservation ethic (I’ve put in extra insulation, etc.), and a willingness to “endure” indoor temperatures up to about 82 degrees in the summer and down to about 62 degrees in the winter, all add up to comparatively low electricity (and natural gas) use, on our part (we are a four person family).
  3. ciLive in a state and utility area where solar PV rebates are not tied to 100 percent of annual electricity use (in many places, unfortunately, they are) – or are able to finesse the rebate system to get a solar system on your home’s roof that exceeds your household annual electric use. Solar PV rebates are a complex maze in the U.S. That makes it pretty much impossible to list which states and utilities tie their rebates to household annual electricity use and which ones do not. If you want to determine exactly what rebates are available in your area and what preconditions apply in terms of rebate eligibility, check out and Suffice to say, if your state and/or utility will not pay out a solar rebate to you (or your solar company) if you install a system that produces more than 100 percent of your home electric use, you probably are not in good position to repeat our 1,000 extra kWh produced in just 47 days story. However, if solar rebates where you live are not tied to 100 percent of annual household use, you may be in good position to repeat our success story.

Even if you do face a rebate-tied-to-household-electricity-use situation, you may be able to finesse yourself to a solar system that produces more than 100 percent of your annual use while still earning yourself the full rebate. The easiest way to do this is to temporarily increase your electricity use before you sign with a solar installation company – or by giving yourself a multi-month lag time between the time you sign the contract with your solar company and the time you get it installed to temporarily up your home electric use. Most likely, you would be doing so knowing that you would immediately drop your household electricity use after your solar system has been installed and after you are officially on the grid with your system.

solar-panel-for-big-better2Why would you do this?

It could save you money in the long run by allowing you to put up a solar system – with a good per watt rebate – that’s big enough to bank future EV miles in a manner like we are now. Extra kWh used as fuel for an EV are extremely valuable, much more valuable than for any other use. In fact, the 1,000 extra kWh we’ve generated in 47 days with solar and which = about $600 worth of gasoline would generate a check from Xcel Energy of somewhere between $50 and $70!

Sun Miles savings could be yours too
So, is our 1,000 extra kWh in just 47 days a complete anomaly? Will anyone else be able to do this?

The answer is you may be able to do it – but you’ll need the right things to come together for you in order for it to happen.

<div style="float:left; margin-right: 10px;">
<script type="text/javascript"><!--
google_ad_client = "pub-7703542917199961";
/* 200x200,
created 12/8/09 */
google_ad_slot = "7950368454";
= 200;
google_ad_height = 200;

I’m confident there are lots of people in the U.S. who could see it all come together for them as it has for us, and who could be pumping out the future Sun Miles™ savings at a rate close to ours.

However, even if you can’t quite hit our rate of kWh banking – 21.7 kWh per day so far — there’s a decent chance you’ll be able to begin to amass some Sun Miles™ with a home solar system while you eagerly wait to replace that filthy, fume spewing gas car with an air pollution, EV savings machine. This is especially true if you’re willing to do a few things to cut back on your electricity use after you have the solar system installed. These might range from reducing your use of home air conditioning, or at least increasing the temperature you set it at to hanging out some of your clothes to dry rather than tossing them in the dryer.

green-green-sky1Reducing your AC use and hanging some of your clothes out to dry might seem like “extreme” measures at first glance – who can “survive” an indoor temperature of 79?! As one of my neighbors put it when I told him we rarely use our central AC, there is certainly the attitude that you “gotta live”, and that in order to “live” your home must always be at 72 degrees. However, when you begin to calculate how much gasoline savings you could achieve if, after you get solar for your home, you dial the AC temp up, and take a few extra minutes to hang clothes outside, it will become quite clear that the payoff is worth it.

The bottom line is that a kWh is worth a lot more money as a gasoline replacement than as a source of fuel for your home’s central air conditioner or for your clothes dryer.

Related articles–>

prius-resources-page-image Like this story? Interested in the solar EV/PHEV synergy? Join our Sun Miles™ Club and start meeting & interacting with other people around the world who want to drive, or already are driving, their cars on sun! Register to join us today!