LED lighting for greenhouses is an investment that should pay for itself within a few years. LED Lights should improve yields and the quality of output even more in the next few years.
This is a complex topic with numerous subtleties. There is no shortage of arguments in favor of eating locally grown food because of the lower transport costs. Greenhouses allow for a wider variety of fruit and vegetable for a given climate. LEDs give farmers greater flexibility at a lower cost and a smaller environmental footprint.
LEDs can be adjusted to emit light in very specific parts of the spectrum.
Plant physiologists have long known that chlorophyll absorbs mainly in the blue, green and red parts of the spectrum but absorbs a little in the orange and yellow. So it makes sense to produce light only in these parts of the spectrum. That’s easy with LEDs, of course, but impossible with sodium lamps
Light energy is an important factor for plant growth. In regions where the natural light source (solar radiation) is not sufficient for growth optimization, additional light sources are being used. Traditional light sources such as high pressure sodium lamps and other metal halide lamps are not very efficient and generate high radiant heat. Therefore, new sustainable solutions should be developed for energy efficient greenhouse lighting. Recent developments in the field of light source technologies have opened up new perspectives for sustainable and highly efficient light sources in the form of LEDs (light-emitting diodes) for greenhouse lighting. This review focuses on the potential of LEDs to replace traditional light sources in the greenhouse. In a comparative economic analysis of traditional vs. LED lighting, we show that the introduction of LEDs allows reduction of the production cost of vegetables in the long-run (several years), due to the LEDs’ high energy efficiency, low maintenance cost and longevity. In order to evaluate LEDs as a true alternative to current lighting sources, species specific plant response to different wavelengths is discussed in a comparative study. However, more detailed scientific studies are necessary to understand the effect of different spectra (using LEDs) on plants physiology. Technical innovations are required to design and realize an energy efficient light source with a spectrum tailored for optimal plant growth in specific plant species.
Large Scale Greenhouse use and making a more robust civilization
Greenhouses can boost yield by 6-12 times for regular greenhouses and 20-30 times for “advanced greenhouses”
It is believed the first practical greenhouse was built by French botanist, Jules Charles, in 1599 in Leiden, Holland. Ancient greenhouses might have existed in Pompeii.
Greenhouse management is well understood.
A survey disclosed that construction costs to establish a complete economic unit [greenhouse], to include required equipment, varied from $5,500 by a Louisiana grower, to over $70,000 for a completely automated unit in Canada. Turn key construction costs by competent greenhouse construction contractors were substantially higher than construction costs by an owner/operator who supervised construction and used subcontractors. The average construction costs varied from $1.90 to over $30/ft2 ($20.90-$323/M2). These expenses did not include the cost of land. The average cost was $5 per square foot in the US or Canada.
Penn state has a greenhouse design for Africa that is 5.5 meters by 6 meters (over 300 square feet) and is one-fourth the cost of other greenhouses in Kenya. The Penn State greenhouse costs approximately $600, compared to a standard greenhouse, which goes for about $2,300.
“They can purchase it and pay it off within three growing seasons,” Eckard said. “It’s about empowering others. That’s why I’m involved.” With a greenhouse, a farmer can extend a growing season to three crop cycles and they can keep insects away from the crops.
About $65 million for greenhouses that cover a square kilometer for the average deployed systems.
The lower cost Pennstate system would be about $20 million to cover a square kilometer.
So let us say $65 trillion for 1 million square kilometers. This would be nearly double the agricultural yield. Over years it would be less than 2% of GDP. If volume production and economies of scale could lower the cost the more “advanced greenhouses” were scaled that can achieve 20-30 times the yield of regular land then either the yield could be increased or less land could be used. This is before considering vertical farming to apply skyscraper technology to boost the amount of land. Similar simple approaches can be used to boost water and energy levels.
Spain has over 50,000 hecatres of greenhouses in Almeria Inveranderos.