Our directory of things of interest

University Directory

Floating Deep Farms to feed a growing population

  • Written by  Saffa Riffat
  • Published in Opinions
An example of a coastal Floating Deep Farm [Image: Prof. Saffa Riffat/WSSET] An example of a coastal Floating Deep Farm [Image: Prof. Saffa Riffat/WSSET]
23 Apr
2019
Professor Saffa Riffat explains the potential of Floating Deep Farms to feed the world’s ever-increasing population 

Feeding the projected 2050 world population of approximately nine billion will require global food production to be increased by some 70 per cent between now and then, but current land-based systems for food production cannot meet this extra demand. This problem is exacerbated by rising sea levels caused by climate change as land area reduction due to inundation and coastal erosion will have a major impact on the availability of agriculture land for food production.

To use less land, farms could be spread vertically rather than horizontally. This ‘Vertical Farms’ approach uses multi-layer greenhouses or skyscraper towers to intensify food production. With a controlled climate involving LED lighting and a closely monitored water/nutrient supply, these farms can produce multiple crops and high yields. But there is another option: aquaculture.

fdf6Model of a Deep Farm beneath an accommodation tower [Image: Prof. Saffa Riffat/WSSET]

Some countries have been practicing aquaculture for many years. In the UK, salmon from fish farms is already a staple of our diet. Bren Smith, a former fisherman turned sustainable shellfish and seaweed farmer, has developed a vertical ocean farm in New York’s Long Island which uses a water column to grow a variety of species such as sugar kelp, oysters, mussels and scallops. In fact, aquaculture recently surpassed wild fishing as the primary source of protein from the ocean. However, these type of inland farms are not suitable for large-scale crop production, and so instead we may need to turn to the seas for a solution. Floating Deep Farms use large vertical shafts submerged in sea water near coastal areas. The shaft is sealed at the bottom end and is covered by a dome. A variety of crops can be grown using hydroponic planters (plant roots fed with nutrient-rich water) or aeroponics (growing plants in an air or mist environment). LED units providing illumination at appropriate wavelengths to maximise photosynthesis with minimum power input replacing sunlight. A major benefit is that crop production is largely unaffected by climatic or seasonal factors – one of the greatest limitations of conventional farming methods. Furthermore, enclosed Floating Deep Farms allow plant diseases and pests to be readily controlled with little or no application of chemical biocides.

The engineering knowhow to build marine vertical shafts is already available from the off-shore oil/gas and wind energy industries. Indeed, Floating Deep Farms could be integrated with wind turbines to power the LED lighting and other systems necessary for crop production. Such installations would not be subject to seasonal light variation, continuing with production throughout the year.

About 70 per cent of the Earth is covered with seawater. The fresh water required by the Floating Deep Farm can be created through a simple seawater evaporation desalination unit driven by a combination of solar energy and waste heat from LED lights. It is anticipated that much of the fresh water will be recycled, so, after initial charging, only a limited quantity of ‘make-up’ water will be required. The quantity of water required will be reduced by 80 per cent compared to conventional land-based agriculture.

Unlike conventional greenhouses, which rely heavily on heating and cooling systems, the submersion into seawater offers a stable temperature throughout the year. The diurnal fluctuations in solar radiation and temperature that limits the productivity of many plants will be eliminated by the farms’ closed environments.

The Floating Deep Farm can also be designed to incorporate an aquaculture for fish and other species (scallops and mussels, for example). This will allow oxygen generated by the plants to be fed directly into the fish sections of the farms. Structures would need to withstand extreme weather, but offshore wind turbine technology has already addressed these problems.

fdf3The Floating Deep Farm concept [Image: Prof. Saffa Riffat/WSSET]

Eighteen of the word’s megacities which are located along the coastal areas could use Floating Deep Farms to supply fresh crops instead of using frozen food transported by refrigerated trailers. This will help to reduce expensive carbon miles caused by mass food importation and therefore minimise the world’s overall carbon footprint. This would address food shortage in developing and third world countries with coastal areas.

Floating Deep Farms could allow crop production all year-round. Up to ten crop cycles per year can be achieved compared to just one to two cycles for conventional agriculture. One small Deep Farm can produce around 80 tonnes of food per annum and crops can be ready for harvesting within three to four weeks of propagation. They will also have lower energy requirements than traditional vertical farms. A single Deep Farm will have about the same consumption as three UK homes using innovative LED illumination and controls combined with natural lighting using light rods or optical fibres. The carbon dioxide demand of photosynthesising plants can be captured from ambient air using materials such as activated carbon.

We have to come up with solutions such as this to address food production in countries which are vulnerable to sea level rise caused by climate change.

Professor Saffa Riffat is President of the World Society of Sustainable Energy Technologies and teaches in the University of Nottingham’s Department of Architecture and Built Environment

This was published in the April 2019 edition of Geographical magazine

geo line break v3

Free eBooks - Geographical Newsletter

Get the best of Geographical delivered straight to your inbox by signing up to our weekly newsletter and get a free collection of eBooks!

geo line break v3

Related items

Julysub 2020

geo line break v3

Free eBooks - Geographical Newsletter

geo line break v3

EDUCATION PARTNERS

DurhamBath Spa600x200 Greenwich Aberystwythherts

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in OPINIONS...

Opinions

Science and technology are making incremental steps to a cleaner…

Opinions

An uncertain future makes predicting it big business says Marco Magrini

Opinions

The only way forward is to reject coal, says Marco…

Opinions

A proposed development at Toondah Harbour, in the Moreton Bay…

Opinions

Many of the crises we are currently experiencing trace their…

Opinions

The Covid-19 pandemic has profoundly shocked energy markets, but it’s…

Opinions

Graham Loomes, professor of behavioural science at Warwick Business School shares…

Opinions

The coronavirus pandemic and subsequent shifts in working practices have…

Opinions

A message for A-Level geographers from Danny Dorling, Halford Mackinder…

Opinions

Helen Sharman CMG OBE, the first British astronaut and now…

Opinions

‘Regeneration’ more often than not means ‘gentrification’, says Jade MacRury

Opinions

It is imperative that governments support the farming and agriculture…

Opinions

The effects of climate change are disproportionately unforgiving, with those…

Opinions

By revaluing food we can revalue nature to build more liveable,…