Marty Bender, retread naturalist who trained initially in physics and chemistry, has died of cancer way before his time. [via Nature Noted]

Bender, who taught himself calculus in junior high school, was naturally made for science. But as a self-described city boy from Dayton, Ohio, he was not a born or bred naturalist. He graduated, cum laude, with a degree in physics and chemistry before developing the interest in biology that would take him to The Land Institute.

"I look back," Bender said at the institute's Prairie Festival in 2004, when a nature trail was named for him, "and find it hard to believe that during the first 25 years of my life, the only things I could actually name were robins, blue jays, cardinals, pigeons and nighthawks."

I've valued his work in quantifying agricultural energy flows. From the obit:

Bender's answers were both blunt and exacting, what institute board Chairman Conn Nugent called a "tough theology":

"Will biofuels one day power an expanding American economy? No way, says Marty: You could grow fuel crops on every square inch of North America, and still fall way short of the net energy provided by the contemporary supply of fossil fuels. Solar panels? Wind machines? Hybrid vehicles? Sure, Marty would say, those are good things. Just don't expect them to let you live in the style to which you've become accustomed."

His used his own farm to experiment and quantify on farm energy issues.

Some important consequences for farming result from some differences between fuel crops and solar technologies such as heat collectors, photovoltaics, wind turbines and hydroelectric. The annual energy efficiency of crop production by photosynthesis is less than 1 percent, far below the range of 10-25 percent for the conversion of sunlight into useful energy by solar technologies. Hence, to produce a given amount of useful energy, fuel crops require ten to 100 times more land area than solar technologies.5 Solar's smaller land requirement is why the Sunshine Farm uses a photovoltaic array as its primary source of electricity instead of a generator operated on a renewable fuel. Fuel crops' larger land requirement explains why the national production of ethanol from corn grain for use in gasohol raised a furious ethical debate over diverting substantial cropland from food to fuel production. Moreover, solar's smaller land requirement would make it more desirable than fuel crops for powering tractors on farms of about 100 acres or less in an all-solar future, but the technology will require further development.6

He had some interesting socio-economic insights related to farm energy.

The purpose of the renewable energy technologies in our project is to reduce our dependence on fossil fuels but not our dependence on local energy systems. Virtually all farms are part of the local community in many ways, energy being no exception. For example, from our exploration of biodiesel production, we have learned that biodiesel fuel with quality satisfactory to engine manufacturers can be produced by farmers' co-operatives but not by individual farms producing various, unregulated home-brews of biodiesel fuel. Also, although our photovoltaic array has a bank of batteries and could stand alone, it is connected to the electric grid of the local power company to sell excess electricity.

Just as important as the monetary income from the sale is the fact that the excess electricity is now on the grid for use by the local community. In other words, in an all-solar future, given certain limits of energy production by solar technologies compared to current conventional technologies (see below), it will likely be considered uncivic to own a personal electrical technology located near a grid but not connected to it. This would prevent the use of the technology's potential excess electricity by other people, and in effect, would be squandering some of the hard-won, solar-based energy embodied in the manufacture of that technology. Since any solar technology exposed to the weather will slowly deteriorate whether or not it is used, there would be little to be gained from the selfish idea of operating a personal solar technology only when the owner needs its energy. The obligation to sell excess electricity would be quite contrary to the current popular notion of achieving energy self-sufficiency in order to disconnect oneself from the grid. This notion is made possible by the present industrial economy with its abundance of fossil fuels and mineral resources.

My emphasis. It's a point worth expanding since it speaks to the general case: we are interdependent, the very idea of energy autarchy is not only uncivic, it is a fantasy that this could be done except by a small number of free-riders that take advantage of the world's systems without contributing their proper share. I think it scales up to the national level too. Those who argue for becoming energy hermits in effect argue for harming the world to achieve what in the last analysis is a spurious objective.

There's also a fairly long overview of various energy sources for their efficiency, the amount of energy yielded for the energy used to get that yield and concludes:

This brief review shows that industrial society has been powered by nonrenewable energy sources with energy ratios much greater than the values of 2.0 or less for mixed crop and livestock farms. With energy ratios this low, agriculture will not be a net source of renewable fuels or electricity. Simply, if outputs from mixed farms were converted into fuels or electricity, typically half of the energy in the outputs would be lost during the conversion processes.22 In conjunction with the energy ratios of 2.0 or less, this implies that for any mixed farm the potential output of marketed fuel or electricity would be less than the embodied energy required in the manufacture of the farm's purchased inputs. Hence, beyond the food and feed already marketed by mixed farms, there would be no net output available as energy for society. The same conclusion also applies to US agriculture for which the energy ratio is greater than 1 but probably less than 2, as elaborated above. The nation exports one-fourth of its grain production, and one might think that it could be converted into a lot of energy for society, but the resulting converted energy would provide less than one-half of the embodied energy in the farm inputs used by US agriculture.4,8

For mixed farms or US agriculture to have some net output available as energy for society, the energy ratios must be raised by reducing purchased inputs and increasing marketed outputs. Many farmers have been using less purchased fertilizers and pesticides, mainly to cut expenses. Farms could someday, like the Sunshine Farm, energetically supply their own fuels and electricity instead of purchasing them. Inputs can also be reduced by utilizing biological efficiencies in crops and animals, such as letting animals obtain their own feed through grazing and foraging which involve no embodied energy, in contrast to feeding them machine-harvested grain and hay.

As far as increasing the amount of marketed outputs from mixed farms, increased crop yields will not be an option under a regime of fewer commercial inputs in farming. It is envisioned that yields will be maintained not quite as high as current levels by diverse farming practices that will require more use of land, biological efficiencies, and human labor. Also, substitution of fuel crops in place of feed and food crops will have little effect since they have fairly similar yields under equivalent farming practices.

The uncertainty about current US efficiency is that the data hasn't been comprehensively collected for 30 years. It is better than it was then, but it isn't known how much better. Still, it's a good overview. There are parts that can be disputed or expanded, as ever, but it could be a fruitful discussion that begins with some fairly straightforward data collection and basic analysis. I too will miss Marty Bender.