Vertical Farming. Sustainable Solution or an Energy Burden?

“Sustainable” is a simple word but a very difficult concept. What is meant to be achieved and what are the system boundaries?

In simplistic terms growing plants requires 5 things, Water, Light, Nutrients, Warmth and CO2.

In a field these are all supplied, but not consistently, so growth is not maximized but generally proves to be sufficient.

In a greenhouse the temperature is generally higher, promoting growth, and the water and nutrients can be better controlled. The light is supplied by the sun and so varies with the seasons and weather. Greenhouses are usually heated by burning gas or oil which also increases the CO2 level and further promotes growth.

Using a greenhouse means you can grow more plants in a reduced space and time but at an additional cost. For higher value plants this probably makes sense.

How would the ‘sustainability’ be measured? What are the system boundaries? What value is put on the land area used? Is transport to the place of consumption considered? Is it better to grow something locally in a greenhouse or to transport it from a distant place with a more suitable climate? Over what timescale do you amortize the energy and resources used to build and operate a green house in comparison to open fields with transport, irrigation and fertilizers?

Vertical farming takes this to the next level. The growth of plants is certainly optimized for space and time. With artificial lighting 24hr growth is possible, however as Andy pointed out where does the electricity for the light come from. Solar PV and batteries is probably not a sensible option. As with greenhouses over what period are the energy and resources required to build the system amortized?

The suggestion is that vertical farming can be used to supply food directly in urban areas. How much space is really required to produce, for example, enough wheat for 50 000 people? Where is the wheat processed into flour, also locally in the urban area? Where is the nutrient mix produced and what is the energy consumption and waste produced.

What are the expected benefits of vertical farming? The main one I can see is a reduction in transport emissions but what is the payback against the increased emissions from vertical farming?

The same system based approach can be used for ‘sustainable’ electricity generation. What is the system? Is it just a wind turbine or solar PV system, this may well produce a payback. Does it include interconnecting cable systems from the North Sea or some remote part of Scotland, the payback is becoming less. Is it required to supply dispatchable electricity so storage or back up systems are required, there is probably no payback.

“Sustainable” is a simple word but a very difficult concept. What is meant to be achieved and what are the system boundaries?

In simplistic terms growing plants requires 5 things, Water, Light, Nutrients, Warmth and CO2.

In a field these are all supplied, but not consistently, so growth is not maximized but generally proves to be sufficient.

In a greenhouse the temperature is generally higher, promoting growth, and the water and nutrients can be better controlled. The light is supplied by the sun and so varies with the seasons and weather. Greenhouses are usually heated by burning gas or oil which also increases the CO2 level and further promotes growth.

Using a greenhouse means you can grow more plants in a reduced space and time but at an additional cost. For higher value plants this probably makes sense.

How would the ‘sustainability’ be measured? What are the system boundaries? What value is put on the land area used? Is transport to the place of consumption considered? Is it better to grow something locally in a greenhouse or to transport it from a distant place with a more suitable climate? Over what timescale do you amortize the energy and resources used to build and operate a green house in comparison to open fields with transport, irrigation and fertilizers?

Vertical farming takes this to the next level. The growth of plants is certainly optimized for space and time. With artificial lighting 24hr growth is possible, however as Andy pointed out where does the electricity for the light come from. Solar PV and batteries is probably not a sensible option. As with greenhouses over what period are the energy and resources required to build the system amortized?

The suggestion is that vertical farming can be used to supply food directly in urban areas. How much space is really required to produce, for example, enough wheat for 50 000 people? Where is the wheat processed into flour, also locally in the urban area? Where is the nutrient mix produced and what is the energy consumption and waste produced.

What are the expected benefits of vertical farming? The main one I can see is a reduction in transport emissions but what is the payback against the increased emissions from vertical farming?

The same system based approach can be used for ‘sustainable’ electricity generation. What is the system? Is it just a wind turbine or solar PV system, this may well produce a payback. Does it include interconnecting cable systems from the North Sea or some remote part of Scotland, the payback is becoming less. Is it required to supply dispatchable electricity so storage or back up systems are required, there is probably no payback.