Overview of the Use of Sustainable Energies in Agricultural Greenhouses

Global concern on environmental problems like climate changes has altered our energy patterns promoting non-polluting renewable energies instead of fossil fuels. Technological advances in sustainable energy technologies allow their increasing use in all sectors of everyday life. Agricultural greenhouses utilize energy for heating, cooling and operation of various electric devices. The highest amount of energy used in greenhouses is consumed in heating them. Controlling crops growth conditions including temperature results in higher productivity and in better economic results. Various sustainable energies including renewable energies and high efficiency and low carbon energy technologies have been used in commercial scale and the technical and economic viability of others has been investigated in experimental scale. Among renewable energies solar energy, biomass and geothermal energy can be used in order to cover part or all of the energy requirements for heating, cooling and power generation of greenhouses. Energy efficient and low carbon technologies like co-generation of heat and power, heat pumps, fuel cells but also waste heat can be used also for energy generation in them. Governmental energy incentives for the promotion of sustainable energies like feed-in tariffs or net-metering allow the use of the abovementioned energy technologies for electricity generation in greenhouses offering additional economic benefits to the farmers. Use of the sustainable energies which are mature, reliable and cost effective in greenhouses results in mitigation of climate changes, use of local renewable energy resources instead of fossil fuels and better profitability of the cultivated crop.