Articles
ECONOMIC ASPECTS OF GREENHOUSE HORTICULTURE; ENERGY EFFICIENCY AND CO2-EMISSION IN THE DUTCH GLASSHOUSE INDUSTRY
The environmental policy plan aims at an improvement of the energy efficiency by fifty percent over the period 1980–2000. Energy efficiency is defined as the direct energy consumption per unit of physical production.
A new environmental plan will probably aim at a reduction of the total CO2-emission.
The direct energy consumption consists mainly of natural gas.
The quantities of consumption changed in the eighties.
In the beginning the gas price increased strongly but later it decreased again.
The fuel consumption per m2 showed an opposite development.
The glasshouse industry showed an evident reaction to the gas price.
The physical production per m2 increased by 57% in the period 1980–1989, an average of 5.2% per year.
The energy efficiency improved by 35%. The total CO2-emission amounted to 6.5 million tons in 1989.
In future an increase of the gas price is to be expected.
This will cause a decrease of the fuel consumption per m2. The production per m2, however, will increase.
Consequently the energy efficiency will improve further and the objective of improving the energy efficiency by 50% in the year 2000 looks achievable.
Because of the lower fuel consumption the CO2-emission per m2 will decrease.
The total area under glass, however, will probably be extended, the decrease of the total CO2-emission therefore will be less than might be expected.
The fuel consumption and consequently the CO2-emission can be reduced further by the use of extra energy-saving measures and alternative energy sources.
The most important saving measures are condenser, heat storage and thermal and climate screens.
Economically the outlooks are good.
The results in the year 2000 will depend on the technical achievements and the gas price.
The alternative energy sources have the largest possibilities to save for fuel.
The simultaneous production of heat and power is the most important option.
This can be realized by using reject or abstract heat from power stations by the growers or by total energy units on the individual holdings.
The economic values of these options are not clear.