Article. Energy in fokus - from Kyoto to Copenhagen. - AgroTech

Article. Energy in fokus - from Kyoto to Copenhagen. - AgroTech

Silke Hemming, Wageningen UR Greenhouse Horticulture, The Netherlands,

Towards the semiclosed

The liberalisation of the energy market

has increased the awareness of

the energy consumption. This free market

implies that growers do not pay a fixed

price per unit of natural gas anymore, but

that prices are greatly determined by the

maximum supply capacity of the gas contract.

Therefore, it is important to reduce

peaks in energy use.

Improved energy efficiency

In view of the Kyoto protocol several

governments have set goals for energy use

and CO2 emission. In the Netherlands, the

horticultural sector and government have

agreed to improve the energy efficiency

(production per unit of energy) by 65% in

2010 compared to 1980 and to increase

the contribution of sustainable energy to

4%. Over the period 1980 - 2005, energy

efficiency in Dutch greenhouse industry

has more than doubled. However, total

energy use per square meter of greenhouse

hardly changed. Efficiency improvement

resulted from a more than doubling in

yield per m 2 caused by amongst others

improved greenhouse transmission, cultivars

and cultivation techniques.

The use of fossil energy can be reduced

by limiting the energy demand, higher

insulation and by intelligent control of climate,

by increasing the energy efficiency

and by using sustainable energy sources.

Energy saving of

greenhouse systems

Energy losses occur through the ventilation

but also greenhouse covering. Greenhouse

covers with higher insulating values and

energy screens highly limits the energy

loss. Increased insulation can be obtained

by modern greenhouse materials, where

new coatings (low emission and antireflection)

are applied. Energy saving of

25-30% seems to be possible with the

new materials without loss of light. If additional

CO2 is applied production will not

decrease, in spite of considerable energy


In current greenhouse horticulture, next to high production,

levels, quality and timeliness of production are important.


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