Category Archives: Solar Power

A Call for Perspective

Wind turbines in Denmark. The nation has strong government support for wind power, and at times generates over 100% of its electricity from wind.

Wind turbines in Denmark. The nation has strong government support for wind power, and at times generates over 100% of its electricity from wind.

(Note: This is my letter to the editor that was printed in the Addison Independent this week, though they changed the title from my original above. Several of you have asked for an electronic copy or link, so here it is.)

For the last few years I have been carefully following the debate about Vermont’s solar and wind development. There have been many valid points brought up by both advocates and opponents, and there seems to be a consensus opinion forming that revolves around a middle ground of sorts. Most Vermonters do agree that we need to transition toward a renewable-energy economy, but also that common-sense guidelines should be developed with regard to the approval and siting of wind turbines, solar arrays, and their distribution networks. I do sometimes wonder, however, if the body politic is occasionally losing sight of the forest for the trees, especially when I see the tiniest of details about specific projects being debated in various public forums.

In light of this, let me attempt to bring us all back a step. In the last several centuries, we humans have benefited tremendously from the use of fossil fuels; the power they contain has underpinned most of the world’s development and wealth creation. This energy source has also enabled human populations to mushroom, and, despite a gradual slowdown, world population is still increasing by about a million people every four days. The pressures that 7 billion-plus humans are putting on the planet are beginning to break it, as oceans acidify, the planet warms, wildlife habitats shrink, soil washes away, species vanish, pollution accumulates, and sea levels rise. Though the problems are many and disparate, a good portion of them are related to the use of fossil fuels, because using them has in some ways been a bargain with the devil. Despite the benefits that these fuels have given to mankind, we now better understand that they have dangers as well, and realize that burning them is not without cost, particularly with regard to CO2 emissions. Despite efficiency improvements across the board, CO2 levels in the atmosphere are still climbing steadily, and have now passed 400-parts-per-million—higher than any time in the last four million years. Worse, these higher levels hold a hidden danger, as atmospheric CO2 is quite stable, and continues to cause warming for centuries. This warming of the planet is also likely to exacerbate all of the other problems that we humans are causing, and many of them could become mutually reinforcing, or even spiral out of control in future decades. Mankind has unknowingly, and then knowingly, been playing a very dangerous game.

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A Tale of Two Energy Futures

Te Apiti wind farm in New Zealand.

The Te Apiti wind farm in New Zealand. About 80% of New Zealand’s electrical power is generated from renewables, making it an example for the world.

I often joke with Mr. X that “I can see the future”. Yes, I’m usually kidding, but the other day I was thinking about an article about energy that I had read, and the future did indeed seem to me to be as clear as a bell. To back up a bit here, the article is by John Mauldin, an economic analyst, and it is his take on low oil prices, entitled “Riding the Energy Wave to the Future“. It’s well worth reading, but if you want the quick summary, here’s my very-short paraphrasing—

Marked improvements in oil and gas production technology (especially fracking technology) are largely responsible for today’s low oil prices, and these improvement trends are likely to continue. As such, prices for oil and gas are likely to remain low. BUT, the same types of innovation are also causing prices to drop in the renewable energy field, especially solar and wind, and the prices there WILL DROP EVEN FASTER. The likely outcome of this, according to Mauldin, is that future energy prices are likely to be low across the board, and that natural gas will continue to eclipse coal and is likely to become a “bridge” fuel between fossil fuels and renewables.

Now, I think that Mauldin’s article is basically on the right track (I wrote about a closely related topic, grid parity, here).

(And now for an aside—this, as opposed to another article I read this week, that I won’t link to, that went on and on, seemingly supported by all the relevant statistics and graphs and written by someone with all the proper credentials, about how low oil prices are a sign that resources have run out and global growth is permanently slowing and will soon collapse. There are thinkers in the peak oil and similar movements who confidently swear that collapse is imminent every single year. Continue reading

Bruhl Net-Zero Project– Early Results

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I overheard one of my students ask a classmate today, “Why are they doing so much solar in Vermont, when it’s so much cloudier here than in other parts of the country?” This was on my mind when it occurred to me that that her comment might be more meaningful if rephrased— “Since solar is working in Vermont (and Germany), where it’s relatively cloudy, imagine how it would work even better in other states?” Because, solar does work here in Vermont, and the data so far from my net-zero project is bearing witness to that fact, here in my little corner of the state.

When I last wrote about the project, as I was just finishing the barn panels (post: “Just in the Nick of Time“), the snow had arrived and the days were near their shortest. The snow is mostly gone now, though, the days are getting longer, and the solar production is ramping steadily up. The image above is from my March report from Enphase (the company tracks the performance of each individual invertor and panel via the internet, and sends these nifty monthly reports). The panels on the barn, according to Enphase, have offset nearly a ton of carbon emissions, and have produced well over a megawatt hour of clean, renewable power, in the month of March alone.

Enphase report from a sunny day last month-- nearly 70 kwh produced.

Enphase report from a sunny day last month– nearly 70 kwh produced.

Eventually I’ll get the whole system online, and I’ll work up the numbers for the system’s performance over the course of a whole year. But for now, it appears that my preliminary cost projections are working out as planned— the monthly savings from the project (in propane, generator fuel, electricity to charge the electric cars, and, in a side benefit, cheaper internet due to the coax we ran in with the underground power) nearly completely offset the loan payment. So it still looks like the project will pay for itself in 11 or 12 years, and then provide a large savings every month after that.

As for the net-zero aspect, my goal was to completely power the house, AND the two electric cars, with solar. I can’t quite tell on this one, but I believe we’re close to this goal. I’ll need a few more months of data—our usage for the cars will be higher in the winter months (due to using the heaters, having snow tires on, and the lower efficiency of the batteries in cold weather), while the solar production will be higher in the summer. I’m also not quite finished putting all the panels back on-line; the new ones on the barn roof are finished, but I need to reinstall all the panels we were using when we were off-grid. This should bump up the solar production another 20 or 30 percent.

So, it’s too soon for me to do a complete report, but the results so far are good. We are net-zero, we’re driving 90 miles or more every day on mostly solar power, and we’re going to save money in the long run. It’s time for everyone to jump on this bandwagon.

Just in the Nick of Time

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The new solar array, powered up (and nearly invisible) just as the first snowfall begins.

And… we just powered up the new solar system. 10,000 watts of solar, feeding into the grid. Though, quite a bit less than that at this very moment, because it’s snowing hard and the snow is piling up. So, I got the project (mostly) completed just in the nick of time. I still have some inside work to do with the water heater (post: “An Efficiency No-Brainer“), and a few odds and ends here and there, but the bulk of it is finished. Some photos of “Phase Two”—

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Thirty-six Enphase micro-inverters. Each panel gets its own inverter, and feeds 220-volt power into a trunk line, and from there through a meter and into our main sub-panel.

 

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Step one– putting up the rails.

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The rails are held to the roof with brackets that are attached with 3 1/2- inch lag screws. I got lucky with the purlin spacing, and only had to add one, the new wood is visible here. I also had to add an extra block of wood under each bracket to give the bracket screws enough material to grab onto. Each rail had 11 brackets, so that meant 66 blocks that had to be added. It took a while; I was glad when I had them all in.

 

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Our interim power solution while we were between systems, two Honda 2000-watt ultra-quiet generators, tied with a patch-cord to combine their outputs. The 30-amp plug is tied through a transfer switch inside to the load center in the house. Our biggest load is the well pump, which appeared to draw 2300 watts. One generator is mine, the other is my neighbor’s; he was gracious enough to let us borrow it for a few weeks. This setup proved quite flexible– we could run one generator, or both, or one and not the other, depending on how many loads we wanted on. The generators also idle way down in “eco” mode; better than listening to a large generator yammering away.

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Midway through the roof work, Green Mountain Power came and pulled the power in. Here’s the transformer cabinet in front of the barn.

 

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The combiner box. Each row of 12 panels feeds a trunk line that ends up at one of these 220-volt breakers. From here the combined power of all the panels feeds into the solar meter.

 

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It turned out to be easier to bolt up all the invertors before the panels. High winds were hampering my panel installation efforts, anyway.

 

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The “Sola-deck” box flashed into the roof. The three trunk lines terminate here, and are tied to THHN wire to go through the conduit and down to the combiner box. It is also possible to use the Sola-deck box as the combiner, but we didn’t wire it that way.

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Finally, a nice day to install panels last Sunday. I worked non-stop and got nearly all of them up in one day. I made a jig to hold each bottom panel while I connected it. There’s probably a better way, but I was working by myself.

So, the bulk of the project done. Each inverter reports data to the internet; I’ll keep track of the input. If all goes well, we’ll be powering the house and the cars and still have some left over. Material for a future post…

Project Photos, Phase One

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The meter sockets. The one on the right is the “gross meter” to record solar input to the grid. So far my wiring has passed muster with only a few minor changes needed. A small change required here; the equipment ground in the solar meter can’t go straight to the ground rod.

Well, I think I’m roughly on track with the add-a-bunch-more-solar project (if you missed it, see post from the other week “And the Project Begins“). I gave myself a month to complete the conduit runs underground, and we finished that today; almost two-thirds of a mile of conduit. Green Mountain Power is still waiting on one easement from a neighbor (a pole on their property will need an additional stay), so they can’t pull the high voltage wire in yet. But, my part is done, so it’s on to the solar panels on the barn roof. Some photos of this portion–

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The conduit at the house end of the run from the barn to the house. The main breaker is at the barn, so this is secondary power coming in to a 100-amp subpanel. The conduit on the right is for internet, with 500-lb strength pull cord getting pulled through as it gets put together.

 

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All the dogs, having a good romp.

 

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The main trench to the road; 42-inches deep. The high-voltage line will get pulled through this conduit; 7,000 volts in a single large co-axial cable, to a transformer at the barn. For this portion of the run we put the communications/internet conduit one foot above this one as we backfilled.

 

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The goal– to get to this stake. A single pole goes here, near the road, before the run goes underground. The last few feet can’t be dug until the pole is set, and then it has to be backfilled immediately and tamped.

 

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The deep well for the transformer (cabinet visible behind the dirt pile), and the internet conduits stubbed up in the foreground. The internet run splits from the power run at both cabinets; communications cables must be at least five feet from the high-voltage cabinets.

 

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The view down the valley as we work. It’s been reasonably pleasant so far, but I’m definitely racing winter; a bit of snow the other evening was a reminder…

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The new 225-amp load center in the barn, with the solar feed coming in at the top, the grid power coming in from the left, and the feed to the house going out toward the bottom (not all of the cables are attached in this photo).

Anyway, last night I unpacked all the invertors and racking and other parts for the solar modules on the roof, and I’ll just call that part “Phase Two”. I’ve given myself a month to get that part in place; I’ll post pictures.

 

And the Project Begins…

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After ten years off-grid, in comes the power…

Ok, a post about the project here. We built our house ten years ago, and have powered it ever since with wind and solar. Almost. During the short, cloudy days of November and December, and other times when we get a string of stormy days, we sometimes need to run a gas-powered backup generator. For years I’ve thought about adding enough solar to completely free us from the generator and fossil fuels, but in an off-grid setup the system becomes more and more inefficient as you add more panels, because you’re adding generation that you might only need to use 5% of the time. The other 95% of the time, all that potential power goes unused (for more about this inefficiency, see my post “Not Sexy” ). But, we were very close to net-zero despite the generator use, and I wasn’t quite sure how to change the system in a way that would make economic sense.

Then we got the electric cars. Which we love. And then I started wondering about powering not just the house with solar, but the cars, too. Suddenly, the thought of tying to the grid for more efficiency began to seem like a practical path forward. Then, I realized that a number of renewable energy rebates and incentives are set to expire at the end of this year, so it seemed like a good time to push ahead with the entire grid-tie, add-more-solar plan.

So, that plan, now underway, is to bring in the grid power in from the road, underground, to the barn. Then, I’ll reverse the cable run that currently takes power from the house to the barn, and use it to bring power the other way, from the barn to the house (the barn is between the house and the road). Then, I’ll add 10,000 watts of panels to the barn roof, and grid-tie them with Enphase micro-inverters. The current PV system, with the inverter in the basement, will stay largely intact, but will become a fairly robust PV and battery backup system for those times every year when the grid power goes down.

That’s the very short version, anyway. Oh, and then we’ll replace the propane hot water heater with a new, highly efficient electric heat pump water heater, which will virtually eliminate the propane bill.

If all goes well, monthly cash flow should about even out. We’ll pay for the home-improvement loan, but we’ll be able to mostly quit buying propane (we’ll still keep the propane range-top, for now), we won’t have to buy fuel for the generator, and we can charge the cars here and save the money that we normally reimburse my wife’s place of work. On the practical side, I can also quit fueling and maintaining the generator, and can quit climbing up on the scaffolding next to the barn all winter to rake the snow off the solar panels.

Then, after fifteen years the system should be paid for. After that—virtually free utilities and transportation energy, for decades.

That’s the rough outline, anyway. There’s actually a lot more to it, but I’ll discuss the details as they come along. Until then, I’ve got plenty to do…

 

Grid Parity

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A graph put together by Deutsche Bank—solar is likely to be cheaper than grid power in the relatively near future. Other forecasts vary a bit, but all tell this same basic story.

If you aren’t familiar with the term “grid parity”, then perhaps you need to be, because it might change your life. Here’s the simple version—electricity created by solar panels is, in most cases, more expensive today than what most Americans pay for grid power, even when calculated out over the life of a photovoltaic system. But, prices for conventionally-produced grid power are slowly rising, and prices for solar are steadily dropping. At some point in the relatively near future, solar power is going to be the same price as grid power—“grid parity”. And after that? Solar will be cheaper, and this likelihood has some large implications. I recently heard Alec Guettel, co-founder of Sungevity, Inc, say that “Solar has won, but the world just doesn’t know it yet”. I think he might be right.

Now, it’s a bit hard to truly pin down “grid parity”, because, like everything else, it’s complicated. Not every region of the country will get to grid parity at the same time; a number of factors affect when those two lines in the graph above will cross. Key among them—the price of grid-power in a particular location, how sunny it tends to be there, how much it costs to get solar installed (those that can do it themselves might save enough to be at grid parity now…), whether or not the system is financed (and at what interest rate), whether the electric company offers time-of-use pricing, and whether there are subsidies or tax credits available. Sunnier locales with relatively high utility rates will hit grid parity first (or have already). In the U.S., places like Hawaii, southern California, and Arizona are already at or very near grid parity even without tax credits. In the slightly-less-sunny Northeast, the federal 30% income-tax credit on solar installations, or third-party ownership models, like those offered by Sun Common and others, make solar pay here, too, in many cases.

Here’s an example of a form of grid-parity that pertains to my post the other week about commercial solar installations (post: “Rooftops Please”). Even here in slightly-less-sunny Vermont, a combination of federal tax credits, accelerated depreciation, the value of Renewable Energy Credits (RECs) and a form of time-of-use pricing offered by Green Mountain Power make large-scale solar arrays, like those in open fields like I was discussing the other week, pay off. (GMP offers a 6-cent premium on each Kwh of electricity from grid-tied solar installations, an “adder”, paid because solar is produced at or near peak demand on sunny days, when wholesale electricity on the spot market is expensive). In these situations, grid parity has been more than reached, which is why you see these installations springing up all over the place—somebody’s making some money.

And, virtually everywhere, if you are able to install solar yourself, on a roof that you already own, you are likely already at grid parity. In my case, building a house that was 1500 feet from the power lines, solar made sense even ten years ago due to the cost of the bringing in the power lines, which is why we’ve been off-grid all of this time. (Though that’s set to change; I’m about to dramatically expand our solar production to run the EV’s on solar power, which will entail grid-tying. More about this project in a future post.)

Now, about those implications—some thinkers worry that grid parity will result in a death-spiral for utility companies, as more and more customers abandon the utilities and put up their own systems, which would raise the cost of transmission for the remaining customers, and thus rates, resulting in still more customers pulling the plug. I don’t actually think this is likely—grid-tied systems are actually quite a bit more efficient than off-grid ones (see my post, “Not Sexy” ). In addition, large urban areas and manufacturing facilities will always rely on the surrounding countryside for renewable power, which will entail a grid. Rather, I think the most likely implications are actually good for the planet—it’s likely that solar power will truly boom in the coming years as it gets cheaper and cheaper, and we will actually begin to fully transition to an economy powered by clean, renewable power. That’s some truly good news. As for personal implications—keep your eyes open out there, because you might be able to install solar and come out way ahead, and it might be sooner than you think.

Graph credit: Deutsche Bank

Rooftops Please

solar arrays

Clean energy, but I’d rather see it sited somewhere else.

We all love solar, but I’m a little concerned with a trend I see here in Vermont lately—too much solar going up in beautiful farm fields, and not enough going up on people’s roofs. It’s no mystery why this is happening—it’s cheaper to install arrays on racks in open fields than to install them in any other configuration. Though the price of solar panels is steadily dropping, the profit margin for arrays like the one in the image above is still thin, despite favorable federal and state tax policies. The arrays wouldn’t pay off for investors if the costs of installation were much higher, and putting arrays on rooftops can be complicated and expensive.

I’m on the board of directors for the Acorn Energy Co-op in Middlebury, VT, and we’ve been struggling with this issue. Despite a strong preference among the board to support rooftop arrays, it’s been very difficult to get large rooftop projects past the planning stages. The problems are myriad. As opposed to a flat field, every rooftop is different, so projects must be individually designed. Labor costs of these projects are higher, as well, and all involve rooftop penetrations, a potential source of leaks.

Our group has tried multiple times to support projects on the largest roofs around—dairy barns. These huge, flat, slightly-angled roofs nearly scream for solar installation. But, we’ve found that most of these types of buildings haven’t been designed to support any additional roof weight beyond code-required snow and wind loads. As such, insurance companies won’t insure the projects. The difference in weight requirements is so small as to be almost laughable– in most cases a few extra pounds of dead load per square foot. These building are usually built with trusses, and the trusses are computer-designed for each building to be only as strong as required. With prior planning, most roofs could be made stronger, during construction, for a tiny percentage of the roof cost. (We’re currently working with structural engineers and roof truss suppliers to get actual cost figures). However, to retrofit existing roofs costs enough to derail most of these projects. The whole situation reminds me of that old nursery rhyme, “For the want of a nail the shoe was lost…”

Other factors also push the projects onto open agricultural land. First, there is often tremendous opposition to the cutting of trees, either from the landowner, or neighbors, which makes open areas more suited than wooded ones. Then, a whole host of laws prevents development on wetlands (for good reason), so potential sites must be dry. Then, if the soil is too rocky and doesn’t support digging, then that too incurs extra costs. So, when all is said and done, the arrays usually end up sited in farm fields. This isn’t catastrophic—we’re going to need a lot of solar, and the arrays don’t permanently damage the land. When their lifetime usefulness is past, the posts can be pulled and farming could recommence, or the land could revert to an undeveloped state. But if we’re not careful, there’s going to be a public backlash against solar. It’s by far the most promising technology we have to avert climate change and shift our paradigms around energy use, so we can ill-afford such pushback.

So, my personal opinion here—it would be better to utilize all those big empty roofs. Barn roofs, warehouse roofs, school roofs, the roofs of big-box stores, the space above parking lots, the roofs of every house… We need to change building codes to require the few extra pounds of load carrying capability that solar arrays would add, and we need to raise awareness about the future value of such rooftop space, so as to encourage roof designs that support future solar installations. Those things alone won’t solve the problem; I’m not sure how to completely change the economics that make arrays in agricultural fields more profitable. But, we might need to refine our mindsets with regard to solar installations. Rooftops first, please.

Top image copyright: vencavolrab78 / 123RF Stock Photo

The Real Reason Why EV’s Matter

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An example of one of the many new EVs on the market; a screenshot from Organic Transit’s webpage, about the ELF. According to the company, the ELF gets the equivalent of 1800 mpg.

I was at this year’s Solarfest this past weekend, and helped present two workshops about electric vehicles. The first one was a panel discussion hosted by Drive Electric Vermont, and the second was a presentation I did, entitled “Electric Vehicles: Beyond the Basics”. I think that my thesis, so to speak, is worth thinking about, so I thought I’d recap the presentation here as a blog post.

The quite-short-version, starting with some basics—

1) Whereas a few years ago there were essentially four mainstream production EV’s, (the Volt, Leaf, Tesla Model S, and the plug-in Prius) there are now about twenty, with many more on the way. The biggest recent news is perhaps BMW’s i3, a $40,000 car that is the most efficient in its class, partly due to its lightweight carbon-fiber cabin. The car has gotten extremely high customer-satisfaction ratings, and has been successful enough that Tesla just announced last week that is would be putting together a “Model 3” that will be quite similar. And, EV’s now encompass far more than just cars. There are electric motorcycles, electric pickup trucks, buses, bikes, scooters, school buses, tractor-trailer trucks, and more.

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Zero Motorcycles, perhaps the leader in electric motorcycles.

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Bus-maker Proterra already has buses operation in several U.S. cities, including Reno, NV. With “One-fifth the fuel expense and one-third the maintenance”, these more-expensive buses can pay for themselves in two to five years.

EV owners’ customer satisfaction has been quite high; the Volt and the Tesla Model S have led Consumer Reports’ rating for the last three years.

2) Adoption rates have been brisk, though not quite as brisk as some predicted in years past. The number of EV’s on the road has roughly doubled each year since 2010, and that trend is expected to continue into the foreseeable future. There are currently about 250,000 EVs on the road today in the U.S., and about 500,000 worldwide. To keep those numbers in perspective, though, EV’s currently make up less than 1% of the cars being sold.

3) Charging infrastructure has grown at an extremely rapid pace, from less than 2,000 public charging stations in the U.S. in 2011, to well over 20,000 today, with many more coming into service daily. This has included a huge rise in the number of DC fast chargers, which can charge a vehicle like a Leaf to about 80% in about 30 minutes. A year ago Vermont had zero of these fast chargers, but today we have six, with more on the way. Further advances in charging technology are also on the way, one being inductive charging, which can charge an EV without a direct connection to the vehicle. As demonstrated by a bus system in operation in Seoul, South Korea, inductive charging systems can also be embedded in roadways and function while the vehicles driving above it are in motion.

4) Most EV’s are powered by lithium-ion batteries, and the price for these batteries has fallen dramatically in the past five years, from well over $1,000 per kwh, to about $500 per kwh today. Prices are expected to continue to drop, partly due to Tesla’s new “Gigafactory”, currently under construction. Tesla’s founder, Elon Musk, has predicted Li-ion battery prices in the $250/kwh range by 2015. (Nissan just announced $270/kwh prices for replacement Leaf battery packs.) Combined with economies of scale as EV production increases, I suspect that EV’s will approach outright cost-parity with gas-mobiles in the decade to come. Research is currently proceeding apace on all manner of battery technology, and these advancements have the potential to disrupt power companies, as well as automobile markets.

5) No battery lasts forever, but indications so far seem to show that EV batteries are exceeding expectations. Battery longevity is strongly influenced by many factors, such as average battery temperature, charging and discharge rates, depth-of-discharge, and the average state-of-charge during storage, and some of these are factors that owners can control. When the capacity of EV battery packs does drop below what is considered usable (typically considered to be 70% of its original capacity), power companies have working prototypes of grid-storage options that utilize used EV battery packs. Then, when EV batteries finally do reach the end of their useful life, virtually 100% of the materials in them can be recycled. Today the market value of lithium is such that it is not currently recovered, though the nickel and cadmium and other metals are. I suspect that this will change in years to come, though world reserves of lithium are quite ample, with the bulk of them in the “ABC Triangle”, an area in Argentina, Bolivia, and Chile. (See article “The Lithium Battery Recycling Challenge”).

6) It is becoming easier and easier to build net-zero homes (post- “Net-Zero is Possible”), but what’s really exciting is that it’s now quite possible to build a home that produces enough power for both the house AND for electric-powered transportation. In fact, I currently know of at least three houses that fall into this category. With building and transportation together making up nearly 90% of U.S. energy use, this is truly an exciting development. And since PV panels operate with DC electricity, as do EV batteries, companies like Honda are working on equipment that allows EVs to charge with DC from PV panels, which avoids the conversion losses incurred by inverters.

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Structures that produce most or all of the energy they require are now quite common. Leslie Science Center Nature House, Ann Arbor, MI.

7) EV’s have a huge potential role with regard to how sustainable power grids will function in the future. This is sometimes called “Vehicle-to-grid”, or “V2G”. A starting point for this is charging equipment that allows power from an EV to go in two directions, either into the vehicle to charge the battery, or out of the vehicle to power the house or grid. Several companies, including Nissan, already have such products on the market. With such a connection, an EV can serve as backup power during a power outage. Then, when this technology is coupled with smart meters, EV’s can serve a key role in reducing generation costs for power companies. In times of peak demand, a power company could remotely stop EV’s from charging, in order to lower peak demand, or, conversely, turn on chargers to soak up excess generation during off-peak hours. Power companies will likely pay customers for the right to control their chargers and EVs in this way, and several pilot projects are already underway. V2G capability also opens up the possibility that EV owners can charge their cars with cheap off-peak power, and sell this power back to the grid during hours of peak-demand.

8) Now, a bit of an aside, but I’ll come back to EV’s in just a bit—as we get higher and higher penetration rates of renewable power into the grid in the years to come, the nature of electricity pricing will steadily change. In the 1970’s it was thought that nuclear power would make electricity “too cheap to meter”. That did not happen, but it has indeed happened recently due to solar. Germany, with its huge amount of solar and wind production, has already seen wholesale electricity prices on sunny days dip into the negative. As these power production curves shift, it will present challenges to power companies. A visual of these upcoming changes was recently released by California ISO (ISO’s, or “Independent System Operators”, are groups that manage grid-power in particular regions), in the now-infamous “duck graph”—

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The infamous California ISO “duck graph”. Shaded areas represent steadily increasing amounts of solar generation.

Proponents of renewable power delight in this graph, seeing steadily decreasing peak energy prices and less fossil-fuel use, whereas Continue reading

For Those With Shady Yards…

The Community Solar array in Rutland, VT.

The 150 kw Community Solar array in Rutland, VT.

The other day I, when I wrote about how it’s “Not So Complicated” for individuals to install solar arrays to power their homes and vehicles, I’m sure there were some readers out there who raised their eyebrows. Some of them must have thought that it can’t be quite as easy as I made it out to be. In some cases it is exactly that easy, but there are exceptions, because there are instances where it would be difficult or impossible to make a solar PV system work. A few of these situations come to mind right away—people who rent, instead of owning their home, or, people that own condominiums. Or, a house on the north side of a big hill (or the south side in the southern hemisphere), or a house with huge trees that shade the roof but that are too beautiful to cut down, or a house with a roof design that doesn’t lend itself well to the installation of solar panels. But, innovation to the rescue—there are new projects coming online that solve these very problems.

In fact, I drive past one of them nearly every day (picture above). It’s called a “CSA”, or “Community Solar Array”, and it was just recently built by NRG, in conjunction with Green Mountain Power (more info at NRG’s Community Solar page). The idea is fairly simple—people who want solar power but choose not to install it on their property can buy a “share” of a large array that is located nearby, and the power that is produced is tied to their house via net-metering. The financial arrangements vary from project to project, but the customer typically either buys a portion of the array outright, or leases a portion of it for a given period of time. In the array above, fifty GMP customers share the power, through a variety of lease options.

So, do you have a roof shaded by beautiful trees? Or do you rent? In more and more locations you can do solar anyway, though your “personal array” might be three blocks away and right next to 49 others. Hopefully, eventually, that option will be available to every utility customer, everywhere.