In order to be less dependent on other countries, Singapore wants to grow its own vegetables for food. The urban environment means that this has to be done in buildings. The large amounts of energy required result in a relatively large environmental impact by comparison with importing vegetables. This impact can be significantly reduced by adapting the type of crop, the yield per m2, and particularly by using other types of energy, making local cultivation more favourable than imports. It has been found that solar cells make a relatively large contribution to the environmental impact because of the materials needed for their production. Using other types of energy, such as wind or geothermal, would significantly reduce this impact.
Local production of vegetables
Singapore is a densely populated country which depends mainly on imports for its food supplies. A method has now been developed to grow vegetables in buildings for the local market. A Life Cycle Analysis (LCA) has been conducted to compare the impact with that of importing vegetables from Malaysia and Australia, the usual approach until now.
LCA for lettuce and kale
This study compared the environmental impact of importing two vegetables – lettuce and kale – over different distances to Singapore and growing them locally in a building. Local cultivation requires 16-20 hours of energy daily for lighting and the dehumidification of the atmosphere. Solar energy is used for this purpose. In addition, the study also included parameters such as water use, fertilisers, the lack of pesticides and the modifications required to the building.
Environmental impact dependent on type of energy
Growing vegetables locally requires a lot of energy. When solar energy is used for this purpose, it has a relatively high environmental impact because of the basic materials needed to make solar panels. This impact is often actually higher than that of importing vegetables. By growing vegetables that require less energy and by increasing the yield per m2, the impact of local cultivation can be reduced to the same level as imports or even lower. It is particularly advisable to look at using other forms of energy such as wind or geothermal.