Category Archives: Energy

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

Grid Parity


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

Not Sexy

La Bastilla Ecolodge cropped

Off-grid or grid-tied—that is the question. La Bastilla Ecolodge, Nicaragua. Hmmm, there’s no ice there…

Something’s become more and more apparent to me lately as I ponder our off-grid setup—being grid-tied is inherently more efficient than being off-grid. I know, nothing too sexy here with this technical point, but it’s an important realization, and it has implications for the larger systems that nations need to be working toward.

In my case, as I add generation to approach net-zero, each additional kilowatt of capacity will be needed less and less. Some numbers to illustrate—we are off-grid, and have about 3 kw of solar PV installed in two large arrays. On a sunny day in the summer, when the days are long and the sun is high, the system can produce over 20 kwh’s of power. We tend to use about 7 kwh a day, which means that in the summer we’re often making about three times the amount that we use or can effectively store. The batteries tend to be full by 10:30 in the morning on such days, and then the panels do very little for the rest of the day. In December, however, it’s quite the opposite, with much shorter days and a lower sun angle. At that time of year we only average about 4 or 5 kwh’s of generation each day, which is a bit shy of what we need, and so we run the gas-powered generator off and on, especially in November and December. Usually by mid-January the skies are clearer and the days start lengthening a bit, and we start breaking even again, and continue that way for the next ten months.

So, our house is close to net-zero, but I’d like to completely eliminate those hours where we need to run the gas-powered generator. If I added 2 more kw’s of PV capacity, I’d probably get really close. BUT—that investment (probably $4,000 if I did it myself) would only be needed for about two months a year. Thus, for about 80% of the year it would just sit there essentially unused, which would equate to hundreds of kwh’s of uncollected, and therefore lost, power. In short, the closer I approach being fully net-zero in the off-grid setup, the less efficient the total system becomes. Needless to say, this isn’t good—in addition to the expense, everything has environmental costs when produced, even technology that we need more of like solar PV, so it seems like it would be a case of not using our resources wisely.

If our house was grid-tied (which it never has been, due to the potential expense, because we’re something like 1,500 feet from the power lines), the story would be dramatically different. All those hundreds of kwh’s that I currently am forced to waste would flow into the grid, which would enable to power company to generate less. At other times, when our demand exceeded our production, I would draw these “banked” hours back from the grid. This is actually another of those win/win/win situations. It would be more efficient—it would keep my solar production from being wasted, the losses incurred by transforming power to and from a chemical state in the batteries would be avoided, and when generation is required, it would be done by the power company’s much-more-efficient stationary natural gas plants, or by grid-scale wind or hydro.

Yet another win/win---power companies on both the Canadian and U.S. sides of Niagara Falls generate 4.4 gigawatts of hydroelectric power, without destroying the beauty of the falls.

Yet another win/win situation—power companies on both the Canadian and U.S. sides of Niagara Falls use the river to generate 4.4 gigawatts of hydroelectric power, without destroying the beauty of the falls. This is the equivalent of about four nuclear power plants.

The power company benefits as well—peak solar hours often overlap with peak grid demand, so grid-tied solar inputs tend to reduce peak demand on the grid. The opposite tends to be true when grid-tied homes are pulling from the grid, say, in the middle of the night to charge EV’s, during times of very low demand. The net effect is that grid-tied systems help level the grid. Many power companies, like Green Mountain Power (GMP) here in Vermont, seem to be embracing distributed generation for another reason—taking the long view, they seem to recognize that the role of power companies is and will be changing, away from the old idea of generating power and distributing it in one direction for a single price, and to the model of the power company as a manager of a complex grid that buys power from many sources and distributes it, as needed, in all directions, perhaps with time-of-use (TOU) pricing. (See earlier post “Cloudy Day Pause” for more about how grids might function in the future.)

Remarkably, being grid-tied would probably be a better choice even if I had to use a power company, like some in the Midwest, that rely nearly 100% on coal. Being grid-tied does not change the total amount of fossil fuel that is burned—the companies burn less when grid-tied homes are feeding power in, and then burn more later, when such homes are pulling power out.

Now, while being grid-tied is more efficient when viewed system-wide, what would happen if everyone was grid-tied, in a future situation where fossil fuels might be nearly totally phased out? It’s easy enough to see how the grid can work as a virtual (and unlimited) “battery” for a small proportion of customers, but where is the upper limit? The short version—we’re not quite sure. One thing is for sure, though—U.S. power companies are nowhere close to this limit. In Vermont the electric utilities are currently allowed by law to have up to 4% of their generation from grid-tied systems, but that number was established somewhat arbitrarily in years past, and the legislature is currently expected to soon raise it to 15%, a move that is being welcomed by most of the power companies. A better case study of high RE penetration would be the situation in Germany, though it’s complicated enough that the topic really warrants its own post. Short version—their solar feed-in is around 35% on sunny days, and due to vagaries in the international coal market (coal has become cheaper due to plentiful supplies of natural gas in the U.S.) it has caused disruption in the business models of German power companies, which has had economic costs and, as of yet, fewer than expected CO2 reductions (see Economist article, “How to Lose Half a Trillion Euros“. I personally think The Economist is quite one-sided in this article, but that, again, would probably be a whole other post.) Eventually grids worldwide will need to move toward 100% RE generation as we phase out fossil fuels, and much of this will be distributed generation from point sources. But, 1) we’re not even close enough to worry about it now, at least in the U.S., and 2) power companies will change their business models over time. Indeed, companies like GMP have already started. Fortunately, moving to a smarter grid isn’t an all-or-nothing propostion, but rather evolutionary change over time. (Again, previous post “Cloudy Day Pause” discusses some of this in more detail).

So, back to where I started—it isn’t sexy, but the higher efficiency of grid-tied systems is an important point as we work out our workable vision of the future. We’ll eventually need a smart, flexible grid that efficiently connects renewable generation from million of sources to millions of destinations. In the much shorter term for me, tying to the grid might be the easiest, if not the cheapest, way to achieve net-zero. Much to ponder…

Top image by La Bastilla Ecolodge/Creative Commons at, image has been cropped.
Niagara Falls image credit: pierdelune / 123RF Stock Photo

Net-Zero is Possible

An interior view of Middlebury College's 2013 Solar Decathlon entry, a net-zero house.

An interior view of Middlebury College’s 2013 Solar Decathlon entry, a net-zero house.

Until this past summer, I had more or less assumed that a net-zero house, one that didn’t use any fossil fuel to function, could really only be achieved in some ridiculously expensive research and development setting. That may have been true a decade ago, but it isn’t true now. A combination of technical advances and cost reductions has now put a net-zero house within the reach of nearly everyone. Even better, net-zero can be achieved in most buildings in stages, and are investments that are likely to outperform the market in today’s investment climate. The result is a win-win-win situation.

First, what exactly is “net-zero”? There isn’t a hard-and-fast definition, but, in general, net-zero buildings create as much energy as they consume. They typically combine highly efficient construction and appliances with some form of renewable energy generation, usually on-site. But, this can be done in different ways, and sometimes with different goals in mind, and the result is a wide variety of net-zero terms, as delineated in this list from a designer in Waitsfield, VT (his house is in the list below)—

“Net-zero carbon, net-zero cost, net-zero source, net-zero site, near net-zero, net-zero ready…there are many terms used to describe a certain category of buildings that are referred to as “net-zero energy buildings” (or NZEBs).”

In the last six months I have seen or heard about no less than six examples of net-zero buildings, and the variety of approaches in these buildings will give you some sense of the term, I think. (Some of these details are from memory, so forgive me out there if I get something wrong).

Building #1— Kim Quirk is the owner of Enfield Energy Emporium in Enfield, CT, an architectural firm, and she bought and renovated this house and has turned it into a net-zero office space and living quarters. I saw her presentation about this at Solarfest this past summer, and if I recall, the house was originally built in the mid-19th century, and was mostly gutted when she bought it. She had the basement foamed, and did a deep-energy retrofit that included increasing the thickness of the exterior walls and filling them with cellulose insulation. She added a 5kw PV system in the yard, which is net-metered. And here’s the unusual part—for heating, she dug a huge hole under her driveway, about 10 x 12 feet by 10 feet deep, lined the sides with a liner and foam, filled it with sand, water, and tubing, and then buried it. (My rough calculations—about 60 tons of insulated mass). This thermal mass is a huge “Thermos” that can store an entire summer’s worth of heat gathered by a largish array of evacuated-tube thermal collectors. So all summer long they run and pump hot water through this thermal mass (pics here), which brings the temperature up to something like 180 degrees. In the winter another set of tubing pulls the heat out, where it’s radiated into the house in a system of low-temperature (90 degree F) baseboard heat. An interesting approach. One of her goals was zero-combustion in addition to net-zero, and from her talk this summer it sounded as if the building was on its way to achieving her design goals.

Building #2— Architect Bill Maclay’s Dartt House, in Waitsfield, VT. I saw Bill give a presentation about this building last week at Renewable Energy Vermont’s Expo in Burlington. This is another older structure, renovated in much the same way as Kim Quirk’s house. It is actually two or three net-zero projects together—a building that serves as an office, and an adjoining building that he been turned into two apartments. Unlike Kim Quirk’s solar-heated thermal mass method, these buildings use air-to-air heat pumps for both heat and cooling, all powered by a combination of larger PV arrays—one 17kw array that serves as the roof of a carport (last pic on this page), smaller arrays to the rear of the house, and another large net-metered array that is off-site.

Our house, under construction in 2004. Timber-frame construction with R-40 walls and R-60 roof panels.

Our house, under construction in 2004. Timber-frame construction with R-25 walls and R-32 roof panels.

Building #3— Oddly enough—our house. Technically a “near-net-zero building” as it is now, as we still use propane for hot water. But we’re on our way to net-zero, via yet a third approach—using sustainably-gathered biomass for heat. In our case, cordwood. Our house is off-grid, with a 3kw PV system and a 1kw wind turbine. With the addition of a bit more PV and solar hot water, we should get all the way to net-zero. Even as is, the building uses only a fraction of the fossil fuel that most Americans use. The house also has a fair amount of passive-solar design features—it is oriented to the south, and most windows and living areas are on that side of the building, and closets and utility areas are on the north. The site is shielded to the north by hills and trees, and open to the south. The building has performed admirably—on sunny days in the winter I can leave home for work with the house at 63 degrees, and come home to a house that is well above 70, all with no heat on, even if outside temps are in the 20’s. We typically use about 2 1/2 cords of wood per winter for heat, which we burn in a single wood stove on the main floor of the open-floor-plan design.

Building #4— Well, “buildings”, plural. A company called Vermod is making net-zero single-wide modular homes to address the need for efficient low-cost housing in the state. With 12-inch-thick walls and triple-pane windows, and a 6kw PV system on the roof, Continue reading

Cree Bulbs for the Bruhl’s

Cree bulb cropped

Want to know how a government policy can effect real change? Here’s an example—I have been meaning to start switching over to LED bulbs in the house, even more so since I read a piece last summer by Marc Gunther about the newest generation of LED bulbs (“A Better Light Bulb. Again“). We’ve purchased a few LED bulbs in the last year for specific applications (in one case, some pendulum lights where we needed lots of light output but limited heat), but those bulbs have been expensive, costing up to $35 each. Then, a month ago while walking through Home Depot I saw the Cree bulbs, that were referenced in the article, selling for $9 apiece. That’s still expensive, but not so expensive that I wouldn’t consider buying a few at a time and replacing the compact fluorescent (CFL) bulbs that we currently use in the house. But, I didn’t buy any then, because I wanted to compare energy usage among the different brands of LED bulbs, as I suspected that they weren’t all equally efficient.

Fast-forward to last weekend, when I was again walking through Home Depot and saw the bulbs, but this time for $4.98 apiece, a much lower price than I expected. This turned out to be due to a promotion by Efficiency Vermont, a program funded in part by the state, that is underwriting the cost of the bulbs. At this price I bought eight bulbs instead of just a few, and took them home to try them out. I like them. They are bright, they have a warm tone, they come on instantly, they should last nearly forever, and, as my son and I accidentally dropped one and it didn’t break, they seem to be quite a bit tougher than the curlicue CFLs. But here’s the biggest bonus—the new bulbs use only 9.5 watts apiece, and we were replacing CFL’s that were rated at 13, 18, 20, and 26 watts. In the case of the first three the light output seemed the same or better, and was close even in the case of the 26-watt CFL (marketed as a 100w replacement). So, in one fell swoop we reduced our energy use for these eight bulbs by at least 50%, and possibly more, even over the CFLs, which are already many times more efficient than the old incandescents. That’s substantial.


Some of the replaced bubs, which we gave away for reuse.

Then, it struck me that this remarkable incentive program wouldn’t last forever, so I stopped back by Home Depot after work the other day and bought 25 more bulbs, enough to finish replacing nearly every bulb in the house. Lighting accounts for about 20% of electrical use in the average American home, and I suspect it’s an even higher proportion in our off-grid setup. In winter months we don’t currently make quite enough solar power to get by (relying occasionally on the gas-powered generator), and if the new bulbs help reduce this energy gap, then it will result in a direct savings in burning fossil fuel. A good deal.

So back to where I started, this is a good case of supply and demand principles at work. The government underwrote an incentive, and that incentive increased demand for the bulbs, and energy was saved as a result. (And judging from the near-empty racks of bulbs at the store, I wasn’t the only one who has been swayed by the low prices into purchasing more). So, a public thank-you to Efficiency Vermont, and another public thank-you to some forward-thinking legislators who set up and voted to fund the state’s efficiency programs. Demand for bulbs like these will eventually reduce their costs, and the products will stand on their own merit. The same is true for electric vehicle incentives, and a whole host of other efficiency incentives I can think of. This is money well spent, it is smart policy, and it is part of that “better path forward”. In a world where real change sometimes seems hard to achieve, here’s a program that works.



Seeking A Friend For The End Of The World


I sometimes run across news that I find depressing, and this last week or so I seem to have come across a whole string of such stories with regard to energy use. It seems sometimes like any hope of a sustainable future is on the verge of being overcome by the growth and momentum of the system. Thus, the bit of hyperbole in this post’s title, and my original intent to write about this gloomy side to humankind’s precarious situation, or at least about how we need to step up our efforts. I was thinking that perhaps we are indeed like characters in a disaster movie where an asteroid is set to destroy the planet, and we should all just accept it, concentrate on enjoying our last days, and just quit worrying about renewable power, permaculture, recycling, and adopting more sustainable lifestyles.

But, as I set out to bolster my negativism with facts, I ended up with a more-nuanced thesis. On the whole, it might not be as bad as I thought. Much of the info that gave me this perspective comes from a research company called Enerdata, a large and seemingly well-respected European research company, and, more specifically, their online interactive “Yearbook” about worldwide energy production and use. It’s a fascinating site.

So how are we doing, when you look at the actual numbers about energy? Here’s my admittedly-rough impression of their data, from 1990 to present, a period of almost a quarter of a century. I’ll include links to the graphs, so you can judge for yourself.

Crude oil production— Over the last quarter century, not much change. A slight upward trend from 3,000 megatons to about 4,000 megatons overall, but roughly flat for the last decade, with no visible “peak”, and no dramatic hockey-stick-like exponential growth. On the whole, it doesn’t appear out of control in any way (other than the fact that we’re still burning an awful lot of oil).

oil platform south thailand

Oil and gas production south of Thailand.

Natural gas production— A steady increase in production, from about 3,000 bcm (billion cubic meters) to about 3,500 bcm. The recent boom in U.S. production isn’t overly visible on the graph. From the point of view of sustainability, there could be worse news—burning natural gas creates only about half the CO2 emissions than burning coal does.

Electricity production— Like oil, a steady increase, from about 10,000 twh (terrawatt hours) to about 20,000 twh over the 23-year period, with perhaps even a slight leveling-off as of late. Like oil, it doesn’t appear that growth is out of control. In all of these cases, growth appears linear rather than exponential, and, in the case of oil and electricity, might even be tapering off a bit.

Coal production— Flat until about 2002, then steady uptick from about 4,500 mt to about 7,500 mt today. Most of this was due to increased consumption in China, BUT—the sub-heading on this page reads “Sharp slowdown in global growth mainly due to the slackening pace in China”. This graph isn’t great news for the planet, but again, the growth doesn’t look exponential.

All of these are just portions of the world’s total energy production, (and this graph isn’t just a compilation of the previous graphs, because some of the fossil fuels are used to make the electricity) which shows steady growth from about 8,000 Mtoe (million tons of oil equivalent) to about 13,000 Mtoe.

But, what of renewable generation? The proportion of electricity from renewable sources has been steady as a percentage of total production over the entire period. At first glance this makes it look like we aren’t making progress, but when you take into account that electricity production has gone up 10,000 twh’s, math dictates that the sum total of the increase in renewable generation has been tremendous. (Hydroelectric power is included in these numbers). We aren’t decarbonizing (yet), but renewables seem to be holding their own, at least in terms of percentages.

A thermal solar system, or SEGS, (solar energy generating system).

A thermal solar system, or SEGS, (solar energy generating system).

The result of all of the world’s fossil-fuel consumption is CO2 emissions, and this data is also included on the site. On the whole, another relatively flat graph. The world emitted about 20,000 mt of CO2 in 1990, and that number is about 30,000 mt today, but it isn’t increasing fast, and almost appears to be starting to level off. In the U.S., total CO2 emissions declined by 3.5% in 2012 (and CO2 from coal declined by over 12%). In fact, net CO2 emissions have declined in many industrialized countries, including Australia, Canada, and parts of Europe. While all is not rosy in this data as a whole, there’s no denying that these net declines are good news.

It is important to note that world population has increased steadily over the entire period that these graphs cover (world population was about 5.2 billion in 1990, and is almost 7.2 billion today). World population goes up by about a million people every 3 1/2 days, and has been this way for decades. (WorldMeter population ticker here.) So, when we place these energy graphs against the backdrop of a population that has grown by nearly 2 billion over the same time period, another positive trend is evident—relative decoupling. We’re still increasing damage to the planet, but we’re doing slightly better than we were, through efficiency and conservation. The Enerdata site graphs this, too, in a graph of “carbon intensity”—how much atmospheric CO2 we create for each unit of economic output. The news here is good—carbon intensity is falling steadily, and has been for decades. We are getting more efficient in how we use energy, and it shows. In more developed countries, carbon intensity has dropped by 40% since 1990. This is good news.

We’re not out of the woods, though. Our increased efficiency is a force in the right direction, but it is counteracted by two other forces—the demands of an ever-increasing population, and the demands of a world that is getting wealthier. Population is on track to begin to plateau, though it will be decades before it begins to level off appreciably. And millions being raised out of poverty (link to a good overview in The Economist) is a good thing, and hopefully this can be achieved for all of the people in the world. But this is why overall energy use continues to rise despite dramatic efficiency gains—it just takes more energy for ever more people to live more materially secure lives. We also aren’t out of the woods just yet because the human footprint is larger than some of these numbers show; recent studies have shown that when all impacts are taken into account, that we aren’t achieving as much as we might think we are in the way of decoupling. 

But, what the numbers do show, I think, is that we’re making some progress, even though we have a long way to go. And related to energy, which still largely comes from fossil fuel, recent information seems to suggest that perhaps the atmosphere isn’t quite as sensitive to CO2 as we thought, which might buy humankind a bit of time. There’s plenty of bad news out there, but with regard to that metaphorical asteroid, perhaps, just perhaps, it might not hit planet Earth. It’s going to be a close call, though. I’ll be checking back in with this Enerdata site next year, to keep watch on how we’re doing.

Image credit: tolotola / 123RF Stock Photo
Image credit: pancaketom / 123RF Stock Photo


Fast Reactors—No Free Lunch

nuke plant cropped

Cooling towers at a thermal reactor plant.

(A slightly technical post; but I find this subject pretty fascinating. This post is more-or-less an extension of my last post, “The Nuke Post” ; I’m going to assume that readers have read that first.)

As I alluded to in my last post and comments, whether breeder reactors are affordable or possible is perhaps a key to the question of the practicality and desirability of nuclear power as we go forward. So, the following is my take on the current state of the field, gleaned from quite a few different sources. Bottom line—1) they do exist and can be built, and 2) we probably can’t afford too many of them.

Breeder reactors are more appropriately called “fast reactors”, so I’m going to use that terminology. And to understand why they’re called fast reactors, we have to step back just a bit and look at “standard” nuclear reactors that are used to generate electricity, the vast majority of which are one form or another of a light-water reactor (LWR). (The “light” refers to regular water, instead of “heavy” water, the latter of which is a different molecular structure that doesn’t naturally occur in large quantities.) These reactors use fuel rods that are enriched to 3%-5% U-235, which are typically interspersed with graphite or carbon control rods, which can be slid in and out of the core to control the speed of the reaction. When they are slid out, the fissile elements (typically U-235) approach critical mass, with neutrons being released that cause, in turn, more neutrons to be released.

Fuel pellet. Reactor fuel is typically enriched to 3%-5% U-235.

Fuel pellet. Reactor fuel is typically enriched to 3%-5% U-235.

Now, in case you’re wondering why the chain-reaction doesn’t accelerate out of control—there are different degrees of critical mass, such as sub-critical, delayed subcritical, and prompt-critical. In most nuclear chain-reactions, some of the neutrons released have a delay that ranges from a few milliseconds to several minutes. In a power reactor this allows control rods time to control the reaction. Fuel in a power generation reactor could never reach a prompt-critical state (necessary for a nuclear explosion), even if the control rods were pulled and left out. The reactor would suffer a melt-down, or even a small explosion, but it wouldn’t be a nuclear explosion, per se. Nuclear weapons typically use plutonium, combined with conventional explosives, to achieve a prompt-critical state.

But back to light-water reactors—when a nuclear chain-reaction begins, the neutrons released have so much energy that they don’t tend to cause fission when they hit other U-235 atoms. They do this much better if they are slowed down, or “moderated”. Thus, the importance of water as a coolant, because water (light or heavy) is an excellent moderator. In LWR’s, water flows through the core, moderating the neutrons, and enabling them to more effectively split other U-235 atoms. A moderated neutron is sometimes called a “thermal” neutron, because its temperature (and therefore energy) has been reduced to that of the coolant. Thus, LWR’s are sometimes called “thermal reactors”.

Idaho National Laboratory's Advanced Test Reactor, a light-water reactor (LWR)

Idaho National Laboratory’s Advanced Test Reactor, a light-water reactor (LWR)

So, that’s that. LWR’s are pretty standard, make quite a bit of electricity around the world, and, unfortunately, leave a lot of high-level nuclear waste behind, as much as 27 tons a year for a 1 GW reactor. Typically about 97% of the original uranium remains in a “spent” fuel rod, along with those fission products I discussed in the last post. In fact, that’s one reason the rod is considered spent—the fission products are all excellent neutron absorbers, and as they build up, the reactor works less and less well, until it has to be shut down and the rods replaced (typically done in thirds, each rod spending three years total in the reactor, but with a third of the rods replaced each year).

This form of operation is considered an “open fuel cycle”; the rods are used once and then disposed of. (In the U.S., no one wants them, so each reactor facility stores them, first in pools of water until their radioactivity subsides some, and then in casks on-site) Now, many consider this to be a total waste, as it is possible for the spent rods to be reprocessed and the fission products removed, and the remainder mixed with new uranium and reused. But, plutonium is typically separated out as part of reprocessing, and proliferation fears caused a ban on reprocessing during the Carter administration in the 1977, and this ban still stands.

So, back to where we began, to fast reactors. They’re called fast reactors because, unlike all of those LWR’s, they don’t moderate the fast neutrons. By letting the neutrons keep their energy, they are much more likely to hit a fertile (but not fissile) U-238 atom, and transform it into fissile P-239. Thus, potentially making more fuel than they use. (Though it’s not some sort of free-lunch—they still need to be fueled with U-238). The cores have to use highly-enriched (17%-26%) uranium, or plutonium, (called “start-up fuel”) and then the core is surrounded with a “blanket” of fertile U-238 where the plutonium is made. That plutonium can’t be used for power until the blanket is reprocessed, though, but I’ll get to this is a bit. Continue reading

Cloudy Day Pause

snowy DC

Gray days to deal with.

Mr. X thinks my vision of a future without nuclear power is “too hard” (“Needed: The Hard Path“). I was all set to write a post arguing about it, but something that’s not too uncommon here has given me pause—a dark and cloudy day. This is because a big part of the entire argument of whether we need nuclear power hinges, for most people, on whether or not we can make enough power from renewable sources. And THAT entire argument hinges on the question of intermittency, which is what the cloudy day reminded me of. Solar arrays can make plenty of power on a sunny day, and wind turbines can make plenty of power on a windy day, but what about all those other times? If we depended entirely on wind and solar and hydroelectric, what would we do on short winter days when the entire East coast might be having a cloudy and windless day? Or worse, a week of such days? If the energy constraints in such a system were dramatic, or if such a system was too difficult to build, it might result in that path that would be “too hard”.

So, Mr. X had a variety of points, but his main ones, including whether or not I was being consistent in my thinking, hinge around this “too hard” piece. In general, there are two broad lines of thinking here-

Line-of-thinking #1—We will need nuclear power as we move toward carbon-free sources, because wind and solar and other renewable sources are intermittent, and we will need nuclear power for baseload power. Or, related, we will need nuclear power as a transitional power source, until we build out enough wind and solar and/or develop grid-scale storage capacity.

Line-of-thinking #2—We can indeed switch over to renewable power, and the intermittency problems can be solved, and the money we would have had to spend developing safer “Gen IV” nuclear power would have been better spent on developing the truly safe and sustainable renewable system that we will need for the long term.

So, who is right? Could we make the system work with just renewable power? After some contemplation, I’ve decided that we probably can, though I admit that it will be difficult, as it will involve some fundamental changes. Some factors that make me lean in this direction—

— I think we need to undergo a paradigm shift with regard to how people expect their electricity to be delivered; the new systems will not just mimic the old. Customers today expect electricity to be generated by the utility and made continually available, in any amount, at a set rate. The system of the future might function dramatically differently from this, with the utility companies buying power from thousands or tens of thousands of producers, aggregating that power, and then making it available at a continually varying spot price. Consumers will be able to monitor this price via smart meters, and will be able to use this information to shift their demand.  And, they will indeed shift their demand, because prices might vary dramatically. (And, because the generation is so dispersed, it will help moderate demands on transmission infrastructure.) This change alone would go a long way toward solving the intermittency problem—we might someday see tremendous electricity consumption during sunny hours, as people choose that time when power is plentiful (and cheap) to charge their EV’s, heat or cool their homes, run their water heaters, run their air conditioners, or, factories choose that time to conduct energy-intensive operations.

— Wind and solar complement each other really well. Germany is a good example of this—the country has 32 gw of installed solar, and about 30 gw of wind. Their solar peaks in spring and summer months, when daily solar production is about eight times higher than in December and January. But wind production is nearly the exact opposite, and the seasonal fluctuations largely balance out. (For a visual of this, see pages 13,14, and 16 of this presentation. It takes half a minute or so to load this page, but worth the wait.) Other factors also help, such as the fact that daily demand peaks in most systems during midday hours, and seasonally during the summer, exactly when solar production peaks.

Kaprun hydro-electric dam, Salzburg, Austria.

Kaprun hydroelectric dam, Salzburg, Austria.

— Hydroelectric power could be held back during the day, when solar power is at its maximum, and used during nighttime hours. In many locations it can even be held back seasonally, if required. Pumped-storage systems are used in similar ways; filled when power is cheap, then used for generation when power is expensive. Other forms of utility-scale storage are being developed at a rapid rate, from compressed air storage in abandoned mines, to grid-scale liquid-metal batteries, to ideas about lifting whole mountains (TEDx Talk here), or putting together used EV battery packs in stationary locations for grid-scale battery storage. In all storage situations, the higher the difference between low and high electricity rates, the more profitable the storage—another prime situation where market-forces will help to solve a problem.

— Roofs everywhere need solar panels, even if they don’t have optimum orientations. Panels facing east and west on rooftops (and not just south) spread solar production more evenly across the course of the day (…though in the Southern Hemisphere they put solar on the northern sides of their roofs).

— The larger the geographic area that is tied together by a smart grid, the easier it is to balance power and loads. Over large areas, solar insolation averages out, as does wind production. DC transmission lines are capable of delivering power for well over 1,000 miles, and such transmission corridors could link the production from the windiest areas in the Midwest and offshore to urban centers where it would be needed, and from the sunniest parts of the country to the less-sunny (see post “This is Interesting…“). Continue reading

Oh My


Mr. X has taken me roundly to task for my Vermont Yankee post. He has some strong points, and suggests that my entire line of thought, throughout my posts, is in danger of contradicting itself. I think he’s wrong, but I’m going to have to do some thinking in order to explain why.

In the meantime, I turn on the computer this morning and see a shocking article on CNN written by an international nuclear consultant, “Why Fukushima is Worse Than You Think“. Oh my, indeed.

I haven’t followed the Fukushima story particularly closely, but my rough understanding of the incident before I read the article was this—after the tsunami the reactors lost power, which caused the cores to begin to overheat, and TEPCO eventually, at great risk to some workers, was able to pump water onto the cores to stabilize them, power was eventually restored to the area and total meltdown was avoided, but the water had become radioactive and had run into the basements, and had to be pumped into temporary holding tanks. Meanwhile, airborne releases of radioactivity did waft over hundreds of square miles, but mandatory evacuations kept most of the population there from being exposed. The incident caused no deaths, and recent reports have shown that radiation exposure to the Japanese population was minimal.

Indeed, everyone seems to discuss Fukushima in the past tense, as in this passage from a Time Magazine article, “According to a recent U.N. report, there will likely be no detectable health impacts from the radiation released by the Fukushima meltdown. The  biggest catastrophe in nuclear power since Chernobyl has turned out less catastrophic than it seemed.”

Well, apparently we haven’t been following this closely enough. If the CNN article is to be believed, and it certainly appears to have been written by someone who clearly knows what he’s talking about, Fukushima is far from over. The pumping of the cooling water has never stopped, and highly radioactive water still runs through the melted cores and into the basements at a rate of 400 tons a day. It is pumped from there to temporary tanks on-site, which currently store 400,000 tons of water. Some of the tanks and hoses leak, and hundreds of tons of radioactive water have soaked into the ground or run into the Pacific. No one can enter the reactors because the radiation is lethal, no one knows how far the containment was breached, and if they stop pumping the water the spent fuel would heat up and ignite, causing a release of radiation “dozens of times worse than Chernobyl.” Worse, I get the impression that no one quite knows how to fix it, and the author of the article is calling for an international crisis team to be assembled.

So, I’ll do some thinking about the “hard path” I outlined in the Vermont Yankee post, but this only reinforces my gut feeling that I’d rather live a simpler life powered by clean wind and solar, than an extravagant one powered at the risk of disasters like Fukushima.

In the balance, a better option.

In the balance, a better option.

9 Sept 13- Clarification— Apparently part of the 400 tons of water that accrues each day comes from groundwater flowing into the basements, where it mixes with the radioactive water that is already there, which is what the “ice wall” that has been in the news is designed to stop. The reactor cores themselves have been in “cold shutdown” since Dec. 2011, and part of the delay seems to be a normal multi-year pause before decommissioning begins, to allow radiation levels in the cores to stabilize. However, water must be maintained in the reactors cores and the spent fuel pools, and apparently some of the containments still leak into the basement. How much of the 400 tons a day comes from which source I can’t seem to figure out, but either way it’s a mess.

Image credit: swisshippo / 123RF Stock Photo
Image credit: tonarinokeroro / 123RF Stock Photo

Needed: The Hard Path

Vermont Yankee.

Vermont Yankee.

Vermont Yankee is closing. While I normally have no real shortage of opinions on many issues, I don’t really have an opinion about this one.

If you aren’t aware, Vermont Yankee is an aging, 540-megawatt reactor in Vernon, Vermont, on the banks of the Connecticut River. It has been a lightning rod for those who oppose nuclear power in the Northeast, and the site of numerous spills, leaks, and small mishaps (though many would argue that opponents regularly make mountains out of molehills whenever this particular plant is concerned). The drive to shut it down has moved to the courts, and the battles there are ongoing. But, in the midst of this, low U.S. natural gas prices (themselves largely the result of another controversial arena, fracking) seem to have sealed Yankee’s fate, and owner Entergy just announced that the plant will be closed next year.

And here the mixed feelings begin. On one hand, nuclear power plants seem vulnerable to terrorism, have the potential to wreak havoc on huge areas (think Fukushima, Chernobyl), use fuel that is non-renewable and difficult to extract, and produce waste that is problematic. On the other hand, they have, on the whole, solid safety records, small footprints, and produce carbon-free power. Then, there is even more potential benefit when you move beyond considering just current reactors (so-called “Generation II” and “Generation III” reactors) and look at newer designs that could be built to shut themselves down if things go wrong, or, like fast-breeder-reactors, use fuel much more efficiently. (A good Time Magazine article here.)

If CO2 emissions and the resulting warming are serious problems, and if the energy in fossil fuels is difficult to replace with renewable power (posts: “A Matter of Limits” and “The Magic-Wand Question“), then nuclear power might, just perhaps, be a big part of the solution. More than a few former critics of nuclear power have come to this conclusion, and have become supporters. A recently released documentary by Robert Stone, “Pandora’s Promise”, focuses on some of these individuals. Trailer–

Not everyone agrees with this viewpoint, and the reviews of the film have been mixed. Brian Walsh of Time, whose opinion I tend to respect, feels that it is important, and writes that it should be seen, especially by environmentalists. Others are more critical. I haven’t seen the film yet, but I get the gist of it.

So all of this gives me some things to ponder.

First, some issues are just complex and difficult to be definitive about, issues where all-or-nothing pronouncements tend to be intellectually dishonest. I’d put nuclear power into this group, along with fracking and GMOs. All are problematic, yet all have the potential to be part of the solution.

Second, there is the issue of whether R&D money put into nuclear power wouldn’t be better spent elsewhere. The “promise” of nuclear power hasn’t been fully realized; newer “Gen IV” designs are not ready to go into full production, and much investment would be required. These billions might be better spent doing research on permaculture, or utility scale storage, or any of a thousand other needed efforts.

But third, call me crazy, but we need the curtailment that will come with switching to renewables. It will impose self-discipline; the comparative scarcity of this power will force efficiency and conservation. Humanity has huge problems in addition to energy, like deforestation and pollution and overfishing and groundwater depletion, and many of these can only be solved by reducing the human footprint on the planet (at least until we decouple; see post “Free Lunch and the Holy Grail“); which will require true paradigm shifts with regard to human behavior. If by some miracle we could actually provide what the nuclear supporters of the 70’s envisioned, “electricity too cheap to meter”, I’m afraid it would just allow humanity to plow ahead with profligate wastefulness and business-as-usual.

So in the end, perhaps I do have an opinion. I’m afraid, though, that it is an opinion that might not be popular. Hard paths never are. We must be disciplined, we must be focused, and if we are going to work hard, we might as well think big, and work toward a planet powered by clean, renewable power, with reduced consumption and a reduced focus on material things; a world of wind turbines, solar panels, permaculture, highly-efficient buildings, and more intentional living. That’s the clean, safe, healthy future we need.

 Image credit: Wikimedia Commons