At EPRI Labs: Frank Sharp


Senior Technical Leader

PUF 2.0 - November 15, 2017

Electric Power Research Institute Senior Technical Leader Frank Sharp discusses research to examine opportunities and benefits of indoor agriculture.

PUF's Steve Mitnick: Can we really do some farming inside buildings, using electricity?

Frank Sharp: We can and here's why.

First, we'll probably need to. Currently, there are about seven billion people on Earth. By 2050 it'll be around 9.5 to 9.6 billion, by U.N. estimates.

Next, we're running out of farmable space to meet demand. About 80 percent of arable farmland in the world is already in use. We're also seeing more people become urban. Throughout the world, people are moving to cities and away from rural areas, which requires food to be transported. On average, a head of lettuce may travel several thousand miles from farm to table. 

Finally, we have an opportunity to reduce water use and emissions, while growing produce closer to home. It takes six gallons of water to grow a head of lettuce outdoors, and a gallon, or less, indoors. Furthermore, growing crops indoors, closer to consumers, reduces the need to transport them long distances, reducing vehicle emissions associated with that transport. This logistics improvement also expands shelf life and provides fresher vegetables to consumers.

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PUF's Steve Mitnick: How does indoor agriculture work?

Frank Sharp: I'm a lighting researcher here at EPRI. A few years ago, I began to look at agricultural lighting, the primary load source for indoor growing. We didn't know a lot about it and wanted to understand it. We wanted to understand agriculture lighting fixture performance (light output, energy, and so forth), the potential energy profile of the lighting load, the unique spectral nature of agricultural lighting, lighting manufacturers working in this space, and what lighting research was occurring.

Our research gave us some insight into this emerging industry, and we determined that agricultural lighting was, and is, different from commercial, or residential, or industrial lighting in many ways.

We started looking at the three primary forms of indoor agriculture: the converted warehouse or the custom building, the converted shipping container or pod, or an augmented greenhouse where we add heating and lighting to keep that greenhouse operating year-round.

What we found is that this industry still had a lot of unanswered questions, but had a lot of utility impact. Indoor food production has a large potential energy profile, but it may lend itself to demand response opportunities in some situations. It is an expanding, energy-intensive industry where efficiency takes a back seat to crop yield (though efficient farm operations are critical for business success). This focus on yield, combined with high energy use, could directly impact many utilities' goals for efficient electrification.

Indoor agriculture greatly reduces the amount of water usage to grow crops, so it may provide opportunities and benefits in water-restricted or water-sensitive areas. It is also an industry whose key technologies such as LED lighting, tunable spectrum LED's, and systems driving heating, cooling, pumping, insulation, glazing, building control systems, refrigeration are all in a state of change or evolution.

This combination of factors and forces made this an industry that is ripe for research about the industry, its loads, impacts, and technologies. We've launched a project to begin addressing these issues and are now preparing to launch several other indoor food production projects.

PUF's Steve Mitnick: Is indoor agriculture best for smaller crops and/or more specialized foods?

Frank Sharp: The simple answer is yes. Could you grow long shelf life row crops indoors, yes, but long shelf life or tall crops don't lend themselves to indoor production. What you want to grow are high-value or short shelf life crops that you can stack.

In pods and warehouses, you grow your plants vertically, either by vertical beds or stacking multiple, horizontal beds. You can also stack multiple pods vertically. For example, in a pod, you can grow a wall of lettuce, and it's a foot or two feet wide, in rows. Electric lighting is directly in front of each wall or row of lettuce. Think of a shipping container, and you walk down the row so your fields are on both sides of your shoulder. Another way to do this, in a pod or warehouse, is to build horizontal beds with lighting directly above each bed and then stack the beds vertically.

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You can grow herbs, lettuce. Literally, the restaurant could grow the food they're serving you in the salad, in the back of the building.

PUF's Steve Mitnick: Do we think by 2040 or so, that cities will use buildings for indoor farming? What's the potential?

Frank Sharp: The potential is good because of indoor farming's potential versatility. Maybe you could convert a space. A business moves out. Let's put a farm in it.

You could operate them for profit, like a farm or a community service, where a local group running the farm is feeding the local community. There are many opportunities around water usage, sustainability, food availability, and substantial, potential benefits associated with indoor agriculture.