Agro-Industrial Symbiosis and Alternative Heating Systems for Decreasing the Global Warming Potential of Greenhouse Production

Round 1

Reviewer 1 Report

The paper is very interesting and well written. It can be accepted in the present form.

Author Response

Thank you for your review!

Reviewer 2 Report

Comment to Authors

Manuscript No.: sustainability-1265573

Title: Agro-Industrial Symbiosis and Alternative Heating Systems for Decreasing the Global Warming Potential of Greenhouse Production

This paper assesses utilization of industrial waste heat and CO2 enrichment in greenhouses as an example to propose “agro-industrial symbiosis” (AIS), to refer to symbiotic cooperation between agricultural and industrial partners. The global warming potentials (GWPs) of greenhouse production using different heating systems are inadequately compared in literature, which is the research gap addressed herein. They found that utilizing industrial waste heat and CO2 resulted in a low GWP. The authors have presented an important and interesting topic in a crisp manner. The manuscript is applicable worldwide to guide political decision-making and clean energy production in the horticultural sector. English used in the text is reasonably good and authors are careful in using their words. However, there is still a chance of improvements in the manuscript. The manuscript may be accepted with a minor revision. I can list some of the issues as:

Comments

1. Line 96-100: Although, the authors have mentioned that several similar studies have been made in different climates and continents. But they have elaborated on them. I would suggest the authors discuss a bit more on their studies
2. Figure 3: It would be nice to discuss the negative CO2 production in the case of CHP natural gas boiler.

Author Response

Thank you for the review and good points!

1. An elaboration of the similar studies carried in the field added to the lines 99-109 to support the clarification of the research gap.
2. Improved wording and explanation on the negative CO2 production of the CHP natural gas boiler added for lines 334-340 and 372-380.

Reviewer 3 Report

This paper signifies the impacts of heat demand and the heating method on the GWP of greenhouse production. The GWP of Finnish greenhouse production can be minimized by switching to biomass and biogas boilers as heat sources or by establishing AIS with nearby industrial partners. More detailed analysis regarding the implementation and feasibility of heating system selections, especially industrial waste heat utilization. It is an important and interesting research topic for the future.

1. Using industrial waste heat to meet the requirements of greenhouse production, what is the economics of the proposal? Can it be estimated?
2. Will industrial waste gas affect the safety of fruits and vegetables?
3. Are there any limitations of using industrial waste heat for greenhouse production?

Author Response

Hello,

1. The economics of the proposal are discussed on lines 631-637. Following paper of the authors will examine this in more detail and aim to calculate the profitability of such a proposal.
2. The gas components must be measured in every case, since as all combustion gases (boiler or industrial) are different, no one rule applies to all. This issue is neither particularly discussed in recent publications. Extended discussion on the topic added to lines 655-665.
3. The limitations are centered around the availability and intermittency of the heat are discussed on lines 597-623. However, any regulative limitations have not been noted in the literature. 

Round 2

Reviewer 3 Report

Thank you for the revision. I think the paper is acceptable at present form.