Kevin Stearns/University Photography

Norm Scott

Norm Scott, professor of biological and environmental engineering (BEE), served as director of the Cornell Agricultural Experiment Station from 1984 to 1989 and as vice president for research and advanced studies from 1989 to 1998. He once studied biothermal engineering for plants, animals and humans, such as thermoregulation in poultry and biomechanics of machine milking of dairy cows. Since returning to the faculty in 1998, he has redirected his work toward sustainable development and co-teaches the courses Sustainable Development (BEE 299), Sustainable Energy Systems (BEE 487) and Seminar in Sustainable Development (BEE 673/NBA 573).

He sat down with the Cornell Chronicle to answer questions about sustainable agriculture and development.

Why the dramatic shift in interest?

I believe "sustainable development" is the dominant economic, environmental and social issue for this century. Meeting this challenge requires an entrepreneurship, which combines energy, environmental, industrial and agricultural knowledge and innovation to engineer new ecologically sustainable communities. Characteristics of a sustainable community will be based in biologically derived fuels, renewable energy, recycling, energy conservation, reduced transportation, managed ecosystems, advanced housing systems and sustainable agriculture.

Can you tell us about your cow power project?

We're looking at the technical feasibility of converting dairy manure-derived biogas from anaerobic digestion to electricity and heat on the dairy farm. Whereas present conversion technologies include the internal combustion engine, we're interested in assessing the feasibility of fuel cell technology for energy conversion of biogas. The potential success of fuel technology could increase farm profitability by well over 20 percent and reduce waste impacts on the environment by over 25 percent. Our analysis has determined that a commercially available stationary 250-kilowatt unit is an ideal size for 1,000 cows.

One of the issues with any energy converter, though, is you have to do gas cleanup. So another area we're working on, which is consistent with sustainability, is to use the compost that's produced on the farm to remove hydrogen sulfide, which is the most difficult contaminant in manure-derived biogas.

How does your work on GIS [geographic information systems] fit in?

We published a paper (Biomass and Bioenergy: 18, 2005) showing how GIS can be used to locate farms. We have developed an Internet-based tool where people can locate their farm and find nearby food processors that need to get rid of food waste, so this is an opportunity to co-digest. We now have another project that looks at mixing different food wastes with animal manure to determine the best proportion. So far, seven farms in New York have an anaerobic digester, and there will be several more by the end of the year. These help farmers handle manure in an environmentally friendly way and produce methane in the process, which can be converted to energy for heat and power.

We also published a paper recently (HortScience: 40(2), April 2005) that discusses connecting greenhouses with dairies, because greenhouses need heat and electricity, and farms can produce more of these than they need for the farm.

These are examples of the kinds of synergies that can be developed. You have to think of agriculture as more than food -- it is a driver of bioenergy and bioproducts.

Are there other uses for methane on the farm?

Actually, instead of putting methane in an energy converter for power or heat, we're also looking at the feasibility of producing hydrogen from the methane. Farmers could possibly make a greater profit on high purity hydrogen production versus electricity and heat generation. We're also looking at producing a liquid fuel -- dimethyl ether (DME) -- from the methane that could be used to run a diesel engine.

Isn't recycled oil also being used as a fuel?

Yes, and I'm working with a group of undergraduate students involved in Engineers for a Sustainable World who are trying to develop a system for utilizing used vegetable oil from restaurants in the area to replace diesel fuel for vehicles. They're looking at a number of ways to develop this concept, including constructing a solar settling tank to filter the cooking oil. But vehicles have to be modified to use vegetable oil because it's thicker than normal diesel fuel. So another student group is trying to develop an actual biodiesel product from the oil so that it or the vehicle doesn't have to be modified for use. This isn't a new technology, but it could provide impetus for a new venture for Ithaca.

Can you address the controversy about whether ethanol production from biomass is worth the energy it takes to produce it?

We could do a great service if we did a thorough analysis to figure out why researchers have come up with such widely different answers, and we're trying to do that. We have an analysis in progress to look at not just how much fossil fuel it takes to produce a gallon of ethanol, but the broader question of how much energy is required to produce a gallon of gasoline? We're trying to determine precisely these numbers and verify the approaches that have been taken to explain why such analyses vary so widely.

You know, where you draw the boundary on the system makes all the difference. It's absolutely key to what you obtain when you analyze the system. For example, electric cars are much more efficient than internal combustion engines, but if you look at the energy that has to be generated and transmitted to run both types of cars, they turn out to be approximately the same. So when you include the primary production point in a system, it changes your perception.

On the topic of systems, just what does a systems approach mean in the context of agriculture?

One of the most interesting ideas we have is integrating renewable energy systems to enhance the prosperity of rural agricultural communities. You can't expect one technology to solve all of our energy problems. Small communities could put together a suite of potentially renewable energy systems from wind, solar and biomass from animal manure, food waste, crop biomass, various crop and forest residues and even fast-growing forest plants, such as willows.

We're working with a village in China, for example, that has a digester, and we're helping them create a complete system to manage their needs for electricity and heat. By putting the energy-producing capacity within the community, you provide jobs, financial benefits and create an industrial ecology -- a community where waste from one industry becomes the input for another. We're also exploring the development of an extension initiative in Jiangsu Province with other land-grant universities.