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It's Time to Admit We're Already Geoengineering

Geoengineering, or large-scale modification of the Earth's environment, is a contentious topic among people debating the right response to climate change.

On the one hand, some people believe that efforts to reduce greenhouse emissions are probably going to be too little and too late to prevent major changes to the Earth's climate with substantial impacts to human activities. This group thinks the only way to preserve the current climate is to begin large-scale projects to actively counteract human greenhouse gas emissions. These people are probably right.

On the other hand, other people believe that countering greenhouse gas emissions with active geoengineering is a poor solution to the long-term climate problem. It would be a band-aid at best, temporarily covering up the underlying problem with a short-term solution with unknown side-effects. Worse, it would relieve the urgency to find a real solution, so if we ever stopped geoengineering it could lead to even larger and faster changes in the global climate. These people are probably also right.

As I see it, what both groups are missing is the fact that we humans are already geoengineering. We're just doing it in the stupidest possible way, without any goals or planning and only the vaguest understanding of the consequences of our actions.

So the real argument isn't over whether we should geoengineer the Earth's climate. The time to have that debate was 50-100 years ago, when scientists first began to understand that burning enough fossil fuels would lead to a warming planet. But at the time the problem didn't seem real or urgent, and nobody was paying attention.

Now that we are firmly established on the path of modifying our climate on a global scale, the debates need to be over how and to what ends we are going to engineer the Earth. And these debates won't be easy.

To begin with, it's not clear what the objectives of geoengineering should be. Preventing short-term catastrophe is a good start. But beyond that, there's an implicit assumption on all sides of the climate debate that the goal should be preserving (or restoring) the status quo. I don't think it's that simple, though: we may have changed things too much already for a return to the status quo to be a viable goal.

What's more, there's other possible goals for a geoengineering program which might be even better than just returning to the status quo:

  • We may want to have the ability to reduce the impact of major natural disasters. For example, every few hundred years there's a volcanic eruption big enough to cool the Earth for a few years and cause crop failures, famine, and suffering. It may be within our reach to mitigate this.
  • We may want to stabilize the Earth's natural climate changes over long periods of time. If we have the ability to prevent another ice age, do we want to use it? (Some scientists think we've already done this, just not intentionally.)
  • There will be some winners to the current global warming. Miami isn't going to fare so well, but here in Minneapolis we may appreciate our warmer winters and longer growing seasons. Perhaps there's a way to keep things a little warmer up here but save coastal cities from flooding.

There's a number of geoengineering schemes which have been proposed, but most of them seem a little harebrained. It's true that seeding the stratosphere with particulates or spraying saltwater in the air over oceans seem like plausible ways to cool the climate relatively inexpensively. But we don't really know how well they will work, what the side-effects will be, and what the distribution of regional and global changes will be. Some of these ideas might even backfire.

What's needed is an actual engineering approach to geoengineering. We need to be testing and evaluating the effectiveness, costs, benefits, and side-effects of different ideas. We need to have the difficult political debate about the goals that we, as a species, want to accomplish with our geoengineering efforts. And in the end, we need to develop a set of tools for both short-term and long-term management of the Earth's climate so that we can control the level of greenhouse gasses in the atmosphere in a way that's going to achieve our objectives.

As I've written before, I'm cautiously optimistic that we will somehow muddle through. It won't be easy to get to the point where we're properly engineering our climate for the long-term benefit of humanity and the rest of the species on the planet. It may take a century or longer before the technological and political pieces are all in place, and in the meanwhile there will probably be some major disruptions.

But we really have no choice, since the alternative--just letting things take their course--isn't a recipe for long-term success or survival.

Political Reforms in the Post-Trump Era: Tax Disclosure


The Post-Trump Era of American politics will be on us sooner than we think. Six years and change (at the longest) is not that long in the grand scheme of things, and there's plenty of scenarios where the Post-Trump Era could begin much sooner than that.

Depending on how the end of the Trump presidency plays out, it's entirely possible that the country will be in the mood for significant reforms to our political system. It's been a surprisingly long time since that's happened: on average, we amended the U.S. Constitution on average about once every 12 years between the Bill of Rights and the end of the Nixon administration. In the past 45 years, however, there's been only one amendment ratified, and that one was originally proposed in 1789. So we're long overdue for some tweaks.

I've been thinking lately about what sorts of reforms would make sense, given all that's happened since the ratification of the 26th amendment (which gave 18-year-olds the right to vote) in 1971. There's no lack of proposals out there, with the most common one being a constitutional amendment to overturn the Supreme Court decision in Citizens United. But I'd like to give some serious thought to what sorts of reforms might actually improve the way our system works, and also have the kind of nonpartisan and broad appeal that make for a reform which will be widely accepted.

My first idea is a small one, requiring presidential candidates (and perhaps all candidates for federal office) to disclose their personal finances in detail. Since Nixon, all presidential candidates have done this voluntarily until Donald Trump. Until 2016 the tradition of releasing a candidate's tax forms was so firmly established that I think some people believed it already was a legal requirement.

This sort of financial disclosure is important because it shows where a candidate could have conflicts of interest, and it also demonstrated a candidate's willingness to put service to the country ahead of personal enrichment--both areas where our current president could use some improvement. It's not going to fix a lot of problems by itself, but it would at least raise the level of transparency and make it harder for an officeholder to engage in blatantly corrupt behavior.

But while this reform is small, it would also be easy to enact. Each state has its own rules about who is eligible to be on the ballot, and if just a few states (maybe even just one state) began requiring candidates to release their tax forms in order to get on the ballot for President or Vice President, then it would immediately become a de-facto requirement for the major party candidates. Neither party wants its candidate for President left off the ballot anywhere, and releasing your tax forms in California (or Vermont, or South Dakota) is as good as releasing them everywhere.

Bitcoin and Flying Taxis and Hyperloop, Oh My!

We seem to be living in an age filled with wildly hyped technologies that have nearly zero chance of succeeding in any meaningful way.

I'll be the first to admit that my record of picking technology winners and losers is spotty at best. I've gotten some things right (solar power), and some things wrong (I was skeptical about WiFi for a long time). But the current crop of technology hype seems to have an unusually rich streak of fundamentally flawed ideas which, nevertheless, are attracting substantial amounts of money and attention.


When I last wrote about Bitcoin I cheekily began my description of Bitcoin with, "for anyone reading this years in the future when Bitcoin has disappeared." Well, it's now years in the future and it's safe to say that Bitcoin is still very much around. My thesis then was that Bitcoin would never achieve success as a replacement for actual money because it solves the wrong problem.

Looking back, I think I can call that an accurate prediction: very few people are still claiming that Bitcoin will ever take the place of dollars or Euros anymore. Instead, thoughtful Bitcoin enthusiasts have moved on to talking about blockchain, the technology underlying bitcoin, as the thing that will change the world. I think there's some merit to this, since blockchain solves some interesting and tricky problems, but so far most of the real world applications I've seen for blockchain don't seem to have many advantages over traditional solutions.

But it's still Bitcoin that gets most of the hype and attention, especially after its spectacular 10x runup in value in 2017. And Bitcoin has proven to be insanely unscalable (one estimate claims that the energy to process a single Bitcoin transaction would power a typical American house for days or weeks) at the same time it doesn't seem to have many advantages over more traditional financial instruments.

Flying Taxis

Flying cars have been a staple of science fiction for almost as long as there's been science fiction, but every attempt to build one has been a massive commercial failure. For good reason: it turns out that a flying car is neither a very good airplane nor a very good car. But the idea keeps coming back, and the 2018 version is the fully autonomous flying drone-taxi. I've read articles about several such projects, but the one Airbus is working on is perhaps the most credible given Airbus' experience making actual airplanes.

The concept is that we can use autonomous flying drones to get above the street level congestion in big cities. But if you think about this for even a moment it's obvious that it's not practical to have large numbers of aircraft like this in the air at any moment in a given downtown area. Aside from the obvious safety considerations--drones will need to have hundreds of feet of vertical and horizontal separation to avoid wake turbulence, and flying between buildings is just a dumb idea--there's the fact that these thing are loud. Inevitably, intolerably loud. Nobody has ever built a powered heavier-than-air aircraft that could be called anything close to quiet, and multirotor VTOL drones are among the worst.

You've probably experienced the noise from someone flying a toy drone around a park. Now imagine a similar drone that's a thousand times heavier and probably a thousand times louder (at least). Now imagine a sky filled with hundreds of them. Now you know why it will never happen. At most there might be a handful of flying drone-taxis to carry the top 1% of the top 1% above the common folk. But that's hardly a revolution.


Hyperloop is the transportation concept so wacky that even Elon Musk originally took a pass on actually building it. But it's still around, and more than one company is still trying to develop the idea. Tellingly, after many years there's still no meaningful prototype, and no reason to believe that the costs will be even remotely competitive to existing technology.

And yet...the hype marches on. The latest, according to a February 2018 article in Wired, is that Musk is back in the game and wants to have the first working Hyperloop line in service by 2020. At least we won't have to wait long to see whether than target will be met.

Oh My

There's lots of other examples. Fusion energy is back in the news (it's only 20 years away, and always will be). Robocars have made great technical strides in the past few years even as the business case seems as murky as ever. And who can forget Theranos, the massively hyped medical testing company which raised the better part of a billion dollars and turned out to be a straight-up fraud.

Having lived through the dot-com bubble, this moment feels very different to me. The Internet was obviously a big deal, and while there was a lot of silliness in the air, it was also clear that big changes were coming even if we didn't yet know exactly what would change.

Today it seems more like there's lots of very speculative money chasing a wide range of crazy ideas with no underlying theme other than the desire to find the Next Big Thing. And it could well be that there is no Next Big Thing on the near-term horizon: one Internet revolution is all we get for a while. Not that there won't be new ideas and big companies, but I'm skeptical that robocars, blockchain, and the rest of the current crop of "revolutions" will have the same impact on our daily lives as the Internet. Even ridesharing, arguably the most impactful recent development, isn't much more than a better way to deliver the same taxi services we had before.

Moving from Closed to Open


My new Prusa 3D printer kit is supposed to arrive next week, about three months after I preordered it.

During that long wait I've been learning some of the software used in the open source printer world, including Slic3r, the slicer that's been customized to work with the Prusa printers. Fortunately, TierTime recently opened up their hobby printers to accept gcode from other software, allowing me to experiment with using Slic3r with my existing printers.

(For those not familiar with 3D printing lingo, the "slicer" is the program which takes a 3D model and turns it into gcode instructions for the printer, sort of like a print driver in the 2D printing world. "Gcode" is a nearly-universal format for the printing instructions.)

One huge advantage of stepping into the open source printing world is I now have access to tools and accessories I couldn't use before. A case in point is the Palette+, a filament splicer for making prints with multiple colors and materials.

I bought a Palette+ to give me more options for multicolor printing than just the Multi-Material Upgrade by Prusa. There have been some customers reporting significant problems with Prusa's older model of MMU, and it seems like it's still very experimental. One nice thing about the Palette+ is that it can be used with more than one printer, so I've been experimenting with getting it to work with my Cetus.

And after a couple weeks, and convincing the Palette's manufacturer that they really should support the TierTime printers, it works. Thanks to the magic of open standards, I was able to add multicolor capability to my old single-extruder printer.

First two-color test print
My first successful two-color print from a Cetus3D printer and a Palette+ filament splicer.

Getting the Palette+ to work properly took more effort than it should have, mostly because TierTime has some nonstandard stuff in their gcode processor. That's a good argument for why standards should be, well, standard.

New Adventures in 3D Printing


It's been almost exactly six years since I bought my first 3D printer. In that time I've owned three 3D printers, all of which still work, and two of which I still own and use fairly constantly.

To date all of my printers have been fully-built models from the Chinese manufacturer TierTime. I've decided that it's time to take the next step and build my own printer.

So I've placed a preorder for a Prusa I3 MK3 kit, which I hope to receive around the beginning of February. I've also preordered the multi-material upgrade, which might show up around April.

With my six years of experience 3D printing, I think it's fair to call myself at least a highly competent journeyman. But I'm already learning that the open source world does some things very differently from what I'm used to in TierTime's products.

For example, TierTime's slicer provides only a handful of print settings: layer height, infill, print quality (one of three options), whether you want a raft, and a few parameters for the amount of support material. Slic3r Prusa Edition has around 65 different print settings, not counting the ones under the "Advanced" menu. This clearly represents not just a steeper learning curve, but an entirely different philosophy of how 3D printing should work from the user perspective. While I can see the value of the extra control, I've also managed to get by just fine so far with one tenth the number of parameters to adjust.

Another big, and surprising, difference is how the RepRap world still seems to be struggling with support and rafts. Six years ago, the Up's break-away supports were a major point in their favor (and one of the reasons I didn't go with something like a Makerbot back in 2011). While it's not always perfect, the support material I print with my current printers is generally fairly easy to remove, and the resulting surface of the print after the support is removed usually ranges from pretty good to perfect. But from reading online discussion, it seems that a lot of people still struggle with getting their printers to print supports that are easy to remove and don't leave ugly surfaces behind. I expected the open source community would have figured this out by now--and it's disappointing because not having reliable support and rafts really does limit what you can print and how you can print it.

On the other hand, the limited controls TierTime has given me for the materials (I can only set the extruder and bed temperature on my Up, vs. 15 different material parameters in Slic3r) has limited some of my printing options. I haven't been able to get some interesting filaments (like flexible filament) to work well, or even at all. And being able to print with four different plastics in a single print, as the multi-material upgrade allows, will be a real treat. Even if one of those materials winds up being soluble support because of the problems with break-away supports.

I'm sure I've only just begun to scratch the surface. Being an experienced 3D printer taking my first steps into the world of open source printers is guaranteed to be an interesting adventure.

The Coming Energy Glut


Renewable energy prices continue to plummet, with a recent solar contract in Mexico coming in well under $0.02 per kWh for power to be delivered to the grid starting in 2020. It's entirely possible that within the next few years we could see a renewable energy contract come in under a penny somewhere on the planet.

Even setting aside the headline-grabbing outliers, solar and wind power are now the cheapest ways to generate electricity in the United States, at least for new capacity.

This fact, plus the unique characteristics of solar and wind power, means that over the next few decades pure economic forces are likely to flip power markets upside down and lead to a glut of energy.

Solar and Wind Will Be Overbuilt

Solar and wind power are different from traditional sources of electricity because:

  1. Nearly all the cost is upfront capital expenditure, and there is no cost savings in curtailing overproduction (vs. coal or gas plants, where the cost of fuel is significant and reducing output when demand is low will save money).
  2. Power output is variable and can't be increased to match demand.
  3. The lifetime cost of power from a solar or wind facility is cheaper than any other power source, and solar and wind are getting cheaper over time.

This combination of factors means that when a power company needs to add generating capacity (whether because of demand growth or because older plants are being retired), it's generally going to be cheaper to build renewables rather than a coal, gas, or nuclear plant. And because of the low cost and variable output of solar and wind, it will be cheaper to overbuild renewable capacity by some percentage, to allow the low cost renewable power to displace more of the (relatively) expensive coal and gas power even when the renewables aren't producing full power.

Once the solar and wind generation capacity is in place, the direct cost of generating power from these sources is very close to zero. The most rational, profit-maximizing approach to building future power generation is one which will inevitably lead to times when more power is being produced than consumed, at zero marginal cost to the utility. If the utility can find any buyer for this power at any price larger than zero, it can make a profit.

In other words, a glut.

(On a side note, utilities overbuild their capacity in traditional power plants, too, so that there's enough power for peak demand or when a power plant goes offline. But this peaking and reserve generation capacity sits idle until it's actually needed, since the fuel costs money. Solar and wind are unique in that they don't cost anything to generate once the plant is built.)

There have already been a few times when wholesale electricity prices have dropped to zero in certain places because of the overproduction of renewable energy. The world is only just getting started in building out the 21st century renewable energy grid, and before we're done, excess power production will be a daily occurrence in many parts of the world.

Demand Response and New Uses

The idea of an energy glut is all very weird to me. I grew up in the 70's and 80's in the shadow of energy crises, high gas prices, and 55 MPH speed limits.

One likely change is that we'll see a lot power use shift to times when there's excess electricity. Even though electricity needs to be generated at the time it's used (unless someone stores it in a battery--which is getting cheaper, but will always be more expensive than using it when generated), it turns out that many uses for electricity don't have to happen at a particular time. Heating and cooling is probably the best example, since heat (or cool) is easy to store for a few hours and a significant fraction of electricity use goes to climate control.

It's easy to imagine a smart thermostat that notices when the price of electricity is low and cranks the thermostat a few degrees (warmer or cooler, depending on where you live) so it doesn't need to run as much the rest of the day. Or a smart water heater that takes advantage of cheap power to heat up some extra hot water in the tank.

The technical term for this is Demand Response, and it's already starting to become a thing. In a few years it's likely to become a really big thing, especially in commercial and industrial applications where user can shift large amounts of consumption and realize substantial cost savings.

It's also going to be interesting to see what new uses for electricity become important. At today's prices, for example, electric cars are more expensive than gasoline but cheaper to drive--over the lifetime of the vehicle, the electric car is still somewhat more expensive. But that might change if you could recharge your EV at one-tenth the retail price of electricity as long as you did it when there's a glut of electricity.

Seasonal Storage

The hard problem in renewable power has been and continues to be, seasonal storage. Batteries can store electricity for a few hours or weeks, but even the cheapest batteries are still many times the cost of generating the power when needed (though this is starting to change: in some electricity markets it is now cheaper to use large batteries to meet peak power demand than to use expensive "peaking" plants powered by natural gas).

In many places renewable power production varies considerably not just throughout the day, but over the course of the year. In Minnesota, on average, we get only around a tenth as much solar power in the darkest month of the year as in the sunniest. It's not uncommon for us to go weeks without seeing the sun in November and December. Batteries just don't have the ability to store electricity from June to use in November.

One exciting possibility for the coming energy glut is that it may enable solutions to the seasonal storage problem. If electricity is cheap enough and plentiful enough during the gluts, it may actually become economical to do things like synthesize liquid fuel using renewable energy. These ideas are being pursued in research labs, but in today's energy markets they are much too expensive to be worthwhile.

The World Is Changing

It seems almost inevitable that, if current trends continue (and there seems to be no obvious reason why they shouldn't), we will find ourselves with intermittent gluts of energy rather than shortages. This is going to be a very different world than the one we live in today, where the challenges will not be in finding enough energy, but in getting the energy to the times and places where it's needed.

Welcome Back to the Frozen North


I've been neglecting this blog more than a little the past few years. Got busy, life was getting complicated, and so forth. And after a while I got to experience the joy of overwhelming technical debt firsthand, when the version of Drupal I was running became so out of date that it was hard to keep running and a big project to upgrade.

But I finally got around to updating, leapfrogging from Drupal 6 to Drupal 8. I didn't take the time to do much customization: I only did enough to get my basic content moved over and put together a completely vanilla blog site. I'm not perfectly happy with where it stands, but considering the amount of work I didn't do to get here, it's not too bad.

With luck, having an updated and maintainable blog will encourage me to write more often again. Reading through some of my old articles has been interesting. And with a few tweaks here and there, I should be able to gradually get some of the layout and display features closer to what I want.

A lot has changed in the almost three year hiatus this blog has taken. Kids are leaving the nest, business is evolving, and dear God don't get me started on politics.

I write this blog mainly for myself, as way to express my thoughts and ideas. I don't expect anyone has been terribly disappointed, or even noticed, that it hasn't been updated. Nor do I expect anyone will notice or care if I write again. But I care, and perhaps some of the breadcrumbs I leave here might help someone just a little bit down the road.

Half a Year of Solar (almost)


Our solar panels were activated five months ago, at the end of July. That was a couple months later than we had been hoping, but the modules we ordered were in short supply at the time.

Since then, perhaps the most remarkable thing about living with solar power is just how drama-free the whole thing is. It took a fair amount of effort and planning to get the system installed. But now that it's in place, it just sort of sits there and generates power.

Now that we've had the solar panels in place for almost half a year, here are a few observations in no particular order:

  • Probably the coolest part of the whole system is not the solar panels but the power monitoring system. This lets us view, in real time, how much power we're using and how much we're generating. This turns out to be a great motivator to turn off lights when we leave the room and otherwise look for ways to save energy. We have cut our household energy consumption by about 10% just thanks to having this tool.
  • The TenK modules are performing as advertised when we have partial shade. One reason for selecting this brand was that the roof over our garage (which is where half the solar panels were installed) gets a lot of dappled shade in the winter months, and TenK modules are designed to be highly shade tolerant. Most solar panels will lose a large fraction of their power output if there's even a small patch of shade, but the TenK modules keep generating under these conditions.
  • Speaking of panels don't generate much power when it's cloudy, and we're in the middle of the cloudiest stretch of weather in Minneapolis since the 1960's. November and December are normally the cloudiest and darkest months of the year, but we have literally had only two even partly sunny days in the past three weeks.
  • However, despite the clouds we have had relatively little snow cover. Since it's impossible to clear the snow off half of the solar panels, persistent snow cover is also pretty bad for our power production.
  • Speaking of snow, when the panels are covered in snow and the temperature gets above freezing for a few hours, all the snow and ice tends to slide off in a big clump. From inside the house it sounds like being underneath an avalanche (which is pretty much what it is).
  • We've had a few neighbors ask about solar, but it happens that ours is one of the few houses in the neighborhood that's suitable for solar panels. That's the downside to living in an area with a lot of big trees.

Our Solar System Takes Shape


In the past few months we have finalized the basic design of our solar power installation.

Our system will have two arrays, one over the garage and one on the main part of the house. Each array will have eight 410-watt solar panels from a local manufacturer called  TenK. These will feed 12 microinverters made by Altenergy Power Systems. The total nameplate capacity of the system is 6.56kw, but because the two arrays will face different directions it will never produce that much power at any given time. Instead, with a southwest and a southeast array, one will catch more morning sun, and the other will catch more afternoon sun.

The estimate is that this system will produce, on average, about 5,800 kWh per year. This is relatively low production for a system this size in this area, and the lower production is mostly because of partial shading on the arrays, especially in winter. The garage array, in particular, is estimated to produce almost no power in the month of December because the garage roof will be mostly shaded by the rest of the house. That's not such a great loss, though, since Minnesota gets relatively little solar energy in December anyway.

We chose this system because of a very generous incentive program Minnesota is offering for solar panels made in Minnesota. For the first ten years the system is in production, we will get an incentive payment of $0.29/kWh for all the power it produces. This is in addition to the net metering credit which is currently about $0.12/kWh and will increase as electric rates go up. The Made in Minnesota incentive is paid for through a conservation program established several years ago by the state which requires electric utilities to set aside a small percentage of their revenue towards energy conservation programs.

The Made in Minnesota incentive is so generous that we expect this system to pay for itself in under ten years, despite the shading on our site and the slightly more expensive panels from TenK. Our benchmark for making solar worthwhile is that the system pays for itself within its lifetime (25-30 years), so this system meets that threshold by a large margin.

TenK Modules

The TenK solar modules are a new and innovative product, which was another reason I liked this option. Some people might read "new and innovative" to mean "unproven and risky," especially for a major capital investment expected to last decades. For us, however, since one of our goals is to learn and explore solar energy, the chance to work with a product taking a new approach to solar power is definitely a bonus.

Traditionally, solar panels are very dumb devices. The basic solar module consists of a few dozen photovoltaic cells sealed in a weatherproof enclosure and wired together with a couple diodes. In many cases, the panel manufacturer doesn't even make the solar cells, they just buy the components and assemble them into the final package. That's part of the reason why there are so many solar panel manufacturers and it's such a low margin business. There's been fairly little technology in the module itself, and all the magic happens in manufacturing the photovoltaic cells and in the inverters and controllers.

TenK, on the other hand, takes a very different approach. They sell "smart" panels which incorporate the MPPT electronics (which maximizes the harvest of power from the solar cells) into the module itself, and do a DC-to-DC power conversion to control the output of the module.

This allows them to get more power from the system in situations where a traditional module performs poorly (such as when half the module is shaded and the other half is in the sun). It also allows them to use a power bus for connecting the modules to the inverters, which makes it practical to generate a lot of power but keep the DC voltage at or below 60V.

The low voltage DC bus is important because high voltage DC (traditional photovoltaic strings can operate at hundreds of volts) is dangerous and requires special equipment to manage. The TenK modules also have built in ground fault protection, so if there's a short circuit in the power bus the modules shut down automatically.

So (in theory) the TenK "smart" modules should allow us to get more power from our system (especially in December), and while the modules themselves are more expensive, the rest of the installation is simpler. The total system price quoted by our installer for the TenK system was about 10% higher per watt than what we were quoted for a more traditional system built around "dumb" panels, but it's possible we will actually get 10% more power from this system than from a similarly sized array from another manufacturer

The risk, of course, is that TenK goes out of business and our modules break earlier than expected. With a more complex module there's more risk something will go wrong and the system will need to be repaired; and the solar module business is notoriously brutal.

In the near term, TenK seems fairly stable since they very recently raised a substantial amount of money from investors. I spoke to some of the company's early customers and they were all pleased, so I'm comfortable that they will be around to fix any problems which develop in the first few years.

Next Steps

One downside to the TenK modules is that the product is currently in short supply. Our installer advised us that we can expect the modules to be available in June, which is 2-3 months from now. We're hoping that won't get further delayed, since we want to take advantage of the most productive solar months of the year.

In the meanwhile, we're starting on the paperwork for the utility approvals and the solar incentive program, and looking at what work we can get done in advance so that when the solar panels arrive we can get into production as fast as possible.

Energy Storage: Potential Game-Changer for Renewables


Solar power has reached the point where, for ordinary consumers, it's generally about the same price as power from the electric company.

Wind energy has reached the point where, for utilities, it's generally about the same price as generating power from fossil fuels.

Not surprisingly, then, both residential solar and utility wind power are growing very fast in the U.S. I've seen some analysis showing that essentially all the net new generating capacity being built in this country is coming from renewable sources. I don't know how credible this is, but whether it's true or not today, it will be true in the not very distant future.

Solar and wind energy can continue to grow like this for many years, since they still represent a very small portion of our total electric generation. But the growth of renewable energy will eventually be limited by the fact that these energy sources are inherently intermittent. The sun doesn't always shine, and the wind doesn't always blow, and there's no way to control when you get power.

The problem is that electricity needs to be generated at the same time it is consumed. The power grid doesn't store power, it just moves it from one place to another.

Right now, storing electricity is a lot more expensive than generating it. In our neighborhood, it costs about $0.12/kWh to buy power from the electric company. Rechargeable batteries, on the other hand, cost (on the cheap end) around $0.50 for every kWh you use because the battery has a limited number of charge cycles before it needs to be replaced.

Given the cost of storage technology today, it is almost never economical to store excess renewable power for later use, even if the power is free (the only exception is if there are no other power generation options available--for example, a cabin in the woods). That means that, with today's technology, wind and solar power can't supply anything close to the majority of our electrical needs, since the power simply won't be generated at the right time.

An inexpensive way to store excess power for later use would radically change the economics of renewable energy. Lots of smart people are working on this problem, and there are several different approaches which could bear fruit.

Improvements in Battery Technology

Traditional batteries are the simplest way to store electricity for future use, but today's technology is simply too expensive for large quantities of power (except in specialty applications like electric cars). There's a lot of research into novel chemistry, better physical designs (including lots of nanotechnology), refinement of approaches like flow batteries, and so forth.

In order to become economical, there needs to be at least an order of magnitude improvement in the cost of large batteries per lifetime kWh (where the lifetime kWh is the capacity of the battery multiplied by the number of charge cycles before the battery has to be replaced). The good news is that there doesn't seem to be any fundamental limitation to getting there--it's possible to build rechargeable batteries from relatively cheap and abundant raw materials. The bad news is that the cost of battery technology seems to be dropping only relatively slowly, and it will take a long time to cut the price by an order of magnitude without a major breakthrough.

Non-Chemical Energy Storage Media

There have also been a lot of novel energy storage approaches proposed, including:

  • Pumping water up a hill and using it to generate hydroelectricity
  • Filling giant underground caverns with compressed air
  • Using large banks of supercapacitors to store electricity
  • Spinning large flywheels

These techniques are certainly able to store energy and make it available on demand. Bringing them up to utility-scale (or even power-a-house scale) is a challenge, though. Pumping water and compressing air are both relatively inefficient and only work in certain geographical locations. Flywheels, compressed air, and supercapacitors have a safety issue, in that if Something Goes Wrong they can release a huge amount of energy uncontrollably fast (that is to say, they can explode). To my knowledge, none of these schemes has made it past small scale pilots, though they sound promising on paper.

Upconverting Excess Electricity to Fuel

One really intriguing approach is to find a chemical process which can be used to produce liquid fuel using electricity, and using the fuel produced to power vehicles or electric generators for times when the renewable power isn't available.

This is attractive for several reasons:

  • It turns excess renewable power into a valuable commodity
  • It allows renewable power for cars, trucks, and airplanes, where renewable power isn't really an option
  • Liquid fuels are easy to store and transport in large quantities, making it possible to use renewable power in times and places where it otherwise wouldn't be available
  • Power-to-fuel plants could be turned up or down as needed to absorb the excess electricity

If I had to guess, I would say that this is the approach most likely to win over the very long term (50+ years). There are a lot of people researching ideas in this space, but to my knowledge nobody has come up with something cheap enough at large scale. On the other hand, there are almost an infinite number of chemical possibilities, and the reward for cracking this puzzle will be immense.

Demand Shifting

The simplest and cheapest way to store power for later use is through demand shifting, adjusting when you use power to match when it's most readily available. One of the biggest consumers of power in a typical home is heating and cooling, including not just the home itself but also hot water, refrigerators, air conditioners, and so forth.

Heat (and cool) are fairly easy to store for up to a day or two. For example, thermal storage heaters (which have been available for decades) use off-peak electricity to heat up a pile of bricks, and then blow the heat into the room throughout the day as needed. Similarly, an off-peak hot water system can heat extra hot water when electricity is cheap for use at other time.

Along the same lines, freezers can get extra cold when there's cheap electricity available (so they don't have to run as much at other times), and an air conditioner could chill a pile of bricks or tank of water to make cool air available at other times.

Using tricks like this, it's probably possible to move 75% (or maybe more) of the electrical use of a typical American home to times when renewable power is available. Other appliances (clothes washers, phone chargers, etc.) can be programmed to mostly run when there's solar or wind.

The beauty of this approach is that it requires no new technology, and has the potential to dramatically increase the amount of our power consumption which could be met with solar or wind power. The downside is that it will require changes to almost any electrical device which can be demand-shifted, and a lot more intelligence in our power systems. But those changes can happen gradually.

It's not unreasonable to think that with aggressive demand-shifting and only a modest amount of battery storage (for lights, computers, and entertainment systems), a typical home could be built with solar power and be off-grid for close to the cost of grid power.