Combined Heat and Power (Chp) as a Possible Method for Reduction of the Co2 Footprint of Organic Greenhouse Horticulture

Abstract

In recent years, the horticultural sector has been confronted with questions about the carbon footprint of its products. However, the global standards used to calculate the greenhouse gas (GHG) emissions have some gaps that do not address the sector-specific issues for horticulture, such as crop rotation, land use of soil organic matter and the use of combined heat and power (CHP). The need for a sector-specific standard which addresses these interpretation gaps was identified. In response to this need, the 'Carbon footprinting of horticulture products protocol' (DNCF2009) was developed by the Dutch horticultural sector. The protocol is intended to follow the guidelines of PAS 2050 for the life cycle analysis of horticultural products; a lot of situations in greenhouse horticulture have to be described in so-called "Best Practices". In greenhouse cultures, energy consumption is the main component of the CO 2 emission. To save energy, many Dutch greenhouse companies use CHP to heat their greenhouses. These growers may sell the superfluous electricity produced by the CHP to the national grid, thereby generating two products; the horticultural product, e.g., a tomato and the electricity. The CO 2 emission of the electricity production should be deducted from the total CO 2 production of the CHP, in order to calculate the CO 2 emission that should be assigned to the production of the crop. To investigate the carbon footprint of organic crop production, an organic crop production system and a conventional crop production system are compared, and the effect on carbon emissions of a CHP system is studied for both production methods. An example for organically grown tomatoes is worked out. It shows the specific organic input factors and their impact on the CO 2 footprint. The functional unit used is kg CO 2 per 1000 kg product, and the system boundary is from seedling production until the delivery of product at the distribution center of wholesalers or supermarkets. The CO 2 footprint of the organic tomato crop grown without cogeneration is 10% higher than that of the conventional crop grown without cogeneration and more than double that of the conventional crop grown with CHP. The higher footprint compared with the footprint of conventional growing without CHP can be mainly explained by the lower yield of the organic crops. With CHP, the organic and conventional tomato crops have an equal CO 2 footprint. The use of CHP is a way to reduce the CO 2 footprint for both organic and conventional tomato growers.

Carbon and Water Footprints and Energy Use of Greenhouse Tomato Production in Northern Italy

“…The topic of different energy provision setups is often the focus of greenhouse agriculture LCA literature, with a focus on cogeneration, which is a widespread practice in northern countries (e.g., Vermeulen and van der Lans ). However, to our knowledge, no publication has thus far compared the setups described in this article.…”

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

“…In Central Europe, the GWP of greenhouse tomato production using natural gas was 1760 kg CO 2 -eq. FU −1 in the Netherlands [5] and 2070 kg CO 2 -eq. FU −1 in France [9].…”

“…LCA is usually used to define the solutions and designed systems that come with the highest or lowest burdens for the environment. LCA has been used in numerous studies for assessing the environmental impacts of the European greenhouse production [5,7,10,23,32,33].…”

“…Organic farming is presented as a solution to secure sustainable food production. However, the low yields of organic farming have in some cases increased the environmental impact of greenhouses due to higher energy demand [4,5]. Bosona and Gebresenbet [6] have also recognized the need to examine sustainable greenhouse practices with solutions other than solely organic farming.…”

“…With increased curiosity toward clean energy sources, greenhouse horticulture has also experienced a rising trend in the utilization of heating solutions such as combined heat and power (CHP) systems [11]. Studies conducted in the Netherlands [5,15] have shown promising environmental and financial benefits associated with the use of CHP boilers compared with conventional natural gas boilers. Industrial waste heat can also be used for heating greenhouses because they can easily utilize such a steady source of low-temperature heat.…”