Mass balance analysis of algal biodiesel

Physorg.com reports on a recent paper in which the authors analyze the sustainability of algal biodiesel from a mass balance perspective. The paper, Bioresource Tech. 102, 1185, essentially highlights one of the tradeoffs with algal biodiesel. The low tech route of large containment ponds limits the total output of dry biomass per hectare, as evidenced by the author’s computation that even 11 square miles of algae ponds, at a growth rate of 50 g of bone-dry biomass per square meter per day, would only be sufficient to replace 0.1% of the US consumption of diesel.

Of course, there are many ways to increase the output per hectare. One of these are vertical tubes, or bioreactors, for algae growth. The issue with this approach is that it is capital intensive, requiring not only the tubes, but cooling systems to prevent algae death from overheating and requires higher overhead, since the tubes must be scrubbed occasionally to reduce fouling.

If I were to be looking at this area for technology breakthroughs, I’d be looking at people applying anti-fouling or other surface chemistry applications to reduce the maintenance costs, or clever engineers designing passive cooling systems for these reactors. I can imagine a system where the bioreactors were built to exchange heat with an HVAC system in cooler environments, or with their own ground-sourced heat pump in warmer times. The cost of the cooling is a major barrier and it would be a win to spread that cost around amongst several different systems.

Measuring shape

I’m breaking the long silence here to mention that amongst the other reasons I’ve been quiet, I am now working on a book with my friend and mentor, John Russ. The tentative title of the book is Measuring Shape, which describes its subject pretty accurately.  We’re intending this work to be a good handbook for people who are looking to measure and classify shapes in images. This is a subject in which I’ve done some work on and off for the past decade or so and I’m super-excited to finally be condensing my knowledge into something concise.  I’m also very excited to be working with John professionally for the first time in quite a few years. As we get deeper into this project, I’ll share more about where we’re going and hopefully get some feedback on topics that might be of interest.

Coincidences

After ordering a copy of Cox’s “The Elements” from ABE., I received a copy previously owned by Gene Bertin, a pioneer in the field of x-ray fluorescence spectroscopy, who passed away in 2008. The book is meticulously annotated, with elegant lettering. The graphs he annotated are better than as printed, not just different. In the plot of binding energy vs. stable nuclide, he carefully labelled the break between exothermic fusion and fission, then connected it to the adjacent graph that was a detail of the Z=10-30 region with careful “zoom-lines.”  The text is carefully underlined with a straightedge in key sections. No sloppy highlighting here.

I feel somehow privileged.

Dr. Bertin’s obituary can be found in Powder Diffr. 24, 59.

The book is a classic Oxford Science text: Short, concise, dense, and interesting. It covers the basics of nucleogenesis and the geochemistry of both the Earth and the solar system. I’m interested in understanding the distribution of phosphate-bearing minerals. (Also, rare-earth-bearing minerals, but that’s a different story.)

Panel on sustainability and innovation

I’ll be on a panel tonight at Asheville Green Drinks entitled “Does Social Innovation Support or Stifle Sustainability?” There are a host of really great people on the panel, including my buddy Ian Wilker, a social media expert of great insight.

Those of you with an eye towards precision will immediately ask “what does social innovation mean in this context.” I’ll go ahead and stick a stake in the ground on this question and say that social innovation is a lot more than “Facebook+Twitter.” Social innovation, by my definition, is when one or more different types of innovation (technological innovation, market innovation, cultural innovation, design innovation, etc.) is highly leveraged by the power of a social network.

Even though Metcalfe’s Law was first articulated in 1980 (or 1993, depending on how pedantic you want to be), we have only really brushed the surface of how pervasive it truly is. It is possible to frame technological development in terms of progress as a function of largest polity in existence – from the rise of hunter-gatherer tribes to the first cities, to the multi-city civilization of the Sumerians. As the number of people in the network grew, so did the capacity for innovation of all stripes.

Once the telegraph, then the telephone, air travel, and eventually the internet made the world to become smaller, or rather, grew our networks larger, our capacity for innovation increased commensurately. The innovations the proceeded from this, I argue, were necessary to understand the different facets of sustainability and to develop strategies for getting there. One example of this was the Viridian movement, from which ground grew Worldchanging.

My argument Friday night will be that social innovation is absolutely required if we are to develop a civilization that is sustainable in all facets.  I think this is the case is because I am increasingly of the opinion that a lot of the necessary innovation for sustainability lies in the realm of design and cultural innovation. These innovations happen most rapidly when you build a critical mass of passionate people with similar ideas, a task that I believe requires social innovation.

Limitless solar?

One of the things I have been almost continuously talking about in the realm of renewable energy is the need to diversify our sources of energy. Another is the need to beware of people who preach that there is One True Solution. It was thus with great interest that I read about an upcoming paper in the Proceedings of the IEEE.

In this paper, Derek Abbott of the University of Adelaide argues that solar, and in particular, solar thermal, is the Ultimate Answer to the world’s energy problems.  In fact, according to Physorg, he claims that solar thermal can last us for “the next billion years.”

Despite this claim, the quoted numbers in the article and the conclusions are actually pretty reasonable in general. Solar thermal is the most cost-efficient (although certainly not the most space efficient) renewable technology in terms of energy yield.  However, stating that solar thermal by itself is sufficient for the next “billion” years is rather unreasonable.

Either Abbott presumes that the rate of growth of energy usage on the planet will slow down to nearly nothing or that we will eventually fill near-Earth space with solar collectors and ship either hydrogen or microwaves back down to Earth. No other possibility can justify his statement. As I calculated some time back, at modest growth rates, there is a much-closer horizon of about 500 years before we start running up against the limits of solar power.

There are also other issues in the article that should be addressed. The first is the cost, both capital and variable, of transmission lines in his scenario. If, as he suggests, we convert 8% of the desert land in the world to energy production, we are faced with the challenge of either building transmission lines to the hinterlands, which are on average about 30% efficient, or according to his scenario, generating hydrogen, liquefying it, and shipping it. I don’t know the efficiencies of electrolysis of water, or of hydrogen liquefaction, but in any case, there are three lossy steps here, before that hydrogen is either burned or passed through a fuel cell to make electricity.

Don’t get me wrong: in large part I agree with Dr. Abbott. Both my numbers and his point to the same conclusion – that solar must be a part of any renewable future. My primary concern about this article and others like it is that they will serve to skew the funding and research environment in renewable energy the same way that the biofuel craze has. We have a good way to go before we can replace fossil fuels in their entirety and it seems clear to me that as we transition away from a fossil fuel energy monoculture, we would do well to avoid another one.

Notes from my Renewable Energy talk

As promised, you can click through here and get a list of resources that I used in putting together my talk and that you might find helpful in general. I appreciate the great audience that I had – everyone was really engaged in the subject and I’m glad that so many of you got a lot out of it.

There are a couple of points I want to reiterate. First is that I think that true wealth can only be measured in Joules, the unit of energy, and that access to energy is a key human rights issue. I also think that the current and coming energy crisis can be solved by breaking both design and technology constraints on our production and use of energy. Of these, I think that the design constraints are going to be hardest to solve.

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Renewable Energy 101

This Friday, I’m going to be speaking at Asheville Green Drinks about renewable energy. The event starts at 6 pm and I’ll start talking at around 6:30. The blurb about my talk is up on the AGD website already, but I wanted to write a little bit about why I’m giving this presentation.

Talking to lots of people has made me realize that it is easy to be overwhelmed by the quantity of information out there about renewable energy.   Energy production and consumption is a complex topic and it is made more complex by those who have the most financial interest in the field tossing out truths and truthiness, often out of context, in order to solidify their position. And without some kind of base level of knowledge, its impossible to think critically about the news and propaganda that’s flying around in the media.

What I want to do is to give a quick overview of the state of the art in renewable energy – pros, cons, myths, and challenges. In addition, I’m going to talk about the size and scope of the “energy problem” that the world is facing and why its of utmost importance that we solve it, rather than deferring it or succumbing to it. I’m going to talk about why energy is the only true measure of wealth and how access to energy is a human rights issue. And, I’m going to end up by giving my perspective on what the ultimate solution will look like.

Its shaping up to be an exciting presentation.