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.

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.

The two most useful resources that I found were the Sustainable Energy without the Hot Air ebook, by David MacKay, a professor of physics at Cambridge, and the Energy Information Administration website. Be sure to check out the EIA’s section on renewables. David MacKay’s book is worth a careful read, simply because he has a very quantitative approach to renewable energy. In general, I think he is a lot more pessimistic than is strictly warranted. For example, he assumes at one point that the British populace at large will simply reject certain renewables outright. I think that belies a certain cynicism. The book is well researched and footnoted, however, and while it is focused on the renewable resources and needs of Great Britain, there is a lot of relevant information for us Yanks as well.

The chart that showed the energy consumption in the US by sector was put together by the Energy and Environment Directorate at Lawrence Livermore National Laboratory. This is probably one of the most informative infographics I’ve ever seen.

I mentioned Amory Lovins and his concept of Negawatts. The book you want to read about this is called Winning the Oil Endgame. I also highly recommend his book, Natural Capitalism.

I’ll break the rest of the resources out by section.

Biomass

Robert Rapier, a well-regarded engineer and writer, often posts very careful and critical pieces about new biomass technologies on his blog, R-Squared. He is very savvy about the field and is currently working with a startup in biomass gasification. He has been very critical of new ethanol startups that have claimed to “break the mold” with some new process and has thus far been correct.

Many companies are trying hard to breed bugs to generate biofuels in larger quantities and without the need for expensive distillation or other separation steps. Two that I think are interesting are LS9 and Synthetic Genomics. Synthetic Genomics is a startup company run by J. Craig Venter, the guy who made history for being the first person to sequence the human genome. He gave a TED talk last year about his work at engineering bugs that will produce fuel, which I recommend watching. The TED conference is a very wonderful program, by the way, and we’ll be doing a TEDxAsheville conference at the end of August. Very few scientists are as polarizing and controversial as Venter is, but he is undeniably brilliant. I highly recommend both of his TED talks.

Blue Ridge Biofuels is a local producer of high-quality biodiesel. They run a waste oil collection service for the WNC area and produce their biodiesel from that waste oil. Their facility is located in the River Arts District in Asheville.

The company associated with the University of Georgia that is working on biochar is called Eprida.

Wind

The cute little vertical axis turbines I showed are made by Mariah Power.  Unbeknowst to me, Bob, our host at Green Drinks, works for Blue Sun Renewables. You can buy these wind turbines from him.

The big turbines I showed are made, in large part, by GE Wind Energy. Many of the nacelles for these large turbines are manufactured at their Greenville, SC facility. Most of my data about the large turbines came from a presentation given by a GE Wind technical manager.

Solar

CIGS (copper-indium-gallium-selenide) thin-films and nanoparticle systems are the chief technology to watch in solar photovoltaics right now. The company I mentioned at length is called Nanosolar, but there are other competitors in the market, including OptiSolar, Miasolé, and Oerlikon.  I also mentioned that several groups have broken the 40% efficiency mark on photovoltaics. The first of these was a company called Spectrolabs. Their work has been published in a peer-reviewed journal [Applied Physics Letters 90, 183516 (2007)] and there is a mainstream article about it here.

Solar thermal is a great way for the average homeowner to take advantage of solar energy. There are companies in the Asheville area that install solar thermal panels. If you have the proper siting and the space for the tank, I recommend this.

One note about solar. A lot of folks will claim that the sun provides enough energy to power our society indefinitely. Suspicious of those claims, I did a back-of-the-envelope calculation and found that nothing could be further from the truth. I estimate that if we were to rely solely on solar power, we would “run out” in just over 500 years. There are some calculations to back that up, along with the assumptions I made in the process, in an earlier blog post.

Geothermal

The best source for information about geothermal energy comes from two places. The first is the MIT report that I mentioned in my talk. You can find that report here.  There is also Geo-Heat Center in Oregon that publishes a lot of useful information. My numbers for cost per watt installed came from the Geo-Heat Centre Quarterly Bulletin (Klamath Falls, Oregon: Oregon Institute of Technology) 28 (3): pp. 8-19.

Hydro

A lot of you were interested in microhydropower. Western NC is a great place for microhydropower. Interested parties should check out Microhydropower.net, a web portal.

Finally, a few of the images I used in the presentation were Creative Commons licensed. I believe strongly in the Creative Commons model. Because of their license lack-of-restriction, I’d like fulfill my obligation by attributing the photos I used.

• The photo of the Hoover Dam is licensed under the CC-By-SA 3.0 license from Wikipedia user Stubbleboy
• The picture of the jatropha flowers is licensed under the GFDL.
• The picture of the terra preta earth is licensed under the GFDL.

Most of the rest of the images I used are in the public domain. A few of the images were used without permission for educational purposes.

If I promised to make a note of something here during my talk and then forgot it, please contact me via this website or leave me a comment and I’ll rectify my oversight.

Technorati Tags: electricity, energy, green, worldchanging

First, let me tackle the article. While no one will argue that corn ethanol is an extremely poor choice for a biofuel feedstock, it is also inarguable that the article focused on current biofuel technology. This implicitly assumes that all new biofuels will be roughly equally bad for the environment. Clearly, this is not the case, since algal-derived biodiesel and similar biomass-derived fuels will not contribute equally to global warming through the destruction of ecosystems. The article also assumed by implication that biofuels are the primary driver behind conversion of ecosystems to cropland. Past data would indicate that this is almost certainly not the case, since slash-and-burn was prevalent in the Amazon basin well before biofuels become a cause celebre. The issues around land use in the developing world would exist with or without biofuels contributing, since there is rarely an incentive for the governments who control these lands to preserve them. Rain forests do not yield significant economic benefit to those who live near them. All the biofuel boom has done is exacerbate the situation. Hopefully, this will bring attention to dealing with the root causes of the destruction of these ecosystems – namely, food security and poverty.

The media has been largely guilty of indulging in shrill hachet jobs on the nascent biofuel industry based on this article. I am certainly not implying that the authors of the Science report intended this; rather, I think that the natural tendency to want to take potshots at large targets is to blame here. Nevertheless, I think its important that people interested in short term energy development continue to work on capturing energy from biomass. With any luck, we’ll solve both the petroleum problem and the disappearing ecosystems problem at the same time.

After receiving my first electrical bill that included a full month of the heat pump, I realize I may have underestimated the savings. The amount had only increased by about $35. At first, I thought that this month might have been warmer than usual, and in fact there were some warm days in the month. There were also several nights of temperatures in the teens. The National Weather Service’s climate data page did not indicate that the highs and lows during the month were excessive in either way (average temperatures 3-5 degrees above normal in December and a roughly equal number of days above and below in January.) With that, I was reasonably satisfied that the bill represented a typical January bill. A quick check back through my financial records showed me that from Oct. 2006 to Oct. 2007, I’d spent $766 on heating oil.

Going back to my spreadsheet, I plugged those differences in. Still not trusting the $35 number, I assumed that over the 6 month “winter” period, I’d average $50 more a month, for a total of $300. This number I assume is the cost of heating with electricity. Plugging in the growth rates I mentioned earlier, I set about determining my time to payback over an oil furnace. It’s less than 5 years to save the $2300 difference between the two units. But this really isn’t a good comparison – the new oil furnace would be much more efficient than the ancient Lennox furnace we had. The oil furnace we were quoted on was 90% efficient. Though I don’t have the numbers for certain, I’m estimating that the old furnace was no more than 70% efficient. Using that to adjust the cost of fuel oil, I recomputed the time to payback and got 7 years. Still, not bad at all. Assuming the growth numbers hold, I’ll save around $9000 (in today’s dollars) over the lifetime of the heat pump. And this doesn’t even count the savings in the summer of the 16 SEER heat pump over the old 11 SEER air conditioning unit that came with the house.

Bottom line for us was that the heat pump is looking to be a very good investment. And if folks like Nanosolar make it ultra cost-effective to put photovoltaics on every roof, the heat pump will be an even better decision.

Technorati Tags: energy, heat pump, home, oilheat