Dr. Evan Mills - Controlled Environment Agriculture

Flanigan's Eco-Logic

Controlled Environment Agriculture (CEA) produces less than 1% of all food in America, and consumes more energy than all open-field agriculture in the country. According to Ted's guest Dr. Evan Mills, CEA could increase and consume some 7% of national energy use... more than data centers, all enclosed malls, air travel, cement making, or chemical production. These findings are the highlight's of Evan's recent research paper titled, "The Emergence of Indoor Agriculture as a Driver of Global Energy Demand." Cultivating crops in mechanized greenhouses and windowless plant factories is a big deal. The paper is a "meta-analysis" of 116 publications that document CEA practices involving 23 crops grown in 154 locations in 40 countries plus Antarctica.

Evan puts CEA in context: For the past 10,000 years, agriculture has been almost exclusively outdoors. Early experiences with growing food indoors dates back to the Roman Empire when the Emperor had his melons grown in greenhouses glazed with translucent stones. In the 1450s, Koreans grew some crops in heated greenhouses. But it wasn't until the 1960s that CEA took off in countries like Norway, Sweden, Russia, Japan, and Iceland... largely in cold climates where fresh vegetables are not available in the depths of winter. The research includes Inuit villages in Canada and other "extreme CEA" at the poles.

Evan discusses types of CEA facilities: Some are low-tech, open greenhouses. Others are closed, windowless structures. No soil, no rain, no wind, etc. They use energy for lighting, heating, cooling, dehumidification, snow melting, refrigeration, and soil streaming. This energy use allows year-round, multi-crop farming of crops including lettuce, tomatoes, herbs, leafy greens, cucumbers, and micro-greens. Of all CEA crops, Evan explains, cannabis is the most energy intensive... demanding 23,200 megajoules/kilogram of marketable weight. This compares with an average of 78 MJ/kG for other plant factories. Being the largest US cash crop, cannabis can afford the costs of that level of energy intensity. Its energy use results in CO2 emissions equivalent to 10 million cars.

The discussion digs into how to make CEA more efficient. Barriers are discussed -- cost, finance, lack of knowledge, skepticism, etc. -- as well as opportunities for increased efficiency including more efficient lighting, glazings, and heating practices... as well as decreasing the photoperiod and varying "fertigation" techniques. Root zone cooling has been experimented with in the United Arab Emirates. Later, Evan comments that trying to make CEA more efficient "is like optimizing the suboptimal."

Evan and Ted discuss claims that CEA is more sustainable that conventional agriculture: "It uses less land, it requires less transport of food crops, it is more resilient." Each are debunked. And major companies such as General Mills, Google, GE, GTE, and Sylvania all made attempts with CEA... and all backed out given the unattractive economics of the practice. Consider this, noted Evan: Growing enough protein for one adult for an entire year, if done with CEA, requires as much energy (16 MWh) as an all-electric home with two electric vehicles. That's a lot of power. The conversation ends with Ted asking Evan for his views on CEA. Is it ever appropriate? Yes, in certain applications and certain locations it is... if done efficiently, of course. Final point made by Evan: Conventional agriculture has tremendous opportunities for greater efficiency as well.

Dr. Evan Mills is a retired Senior Scientist at the Lawrence Berkeley National Laboratory and a Research Affiliate at the Energy and Resources Group at the University of California at Berkeley.