In blogs over the last couple of weeks I’ve looked briefly at the unsustainability of current systems of farming. As the global population continues to rise there are many predictions of further food shortages and yet more ecological damage. I remain convinced that we could feed 9 billion or more people and simultaneously restore biodiversity. To do so will require changes to systems of grants, subsidies and economic justice, which I’ll cover in a future blog. Greenhouses, and other systems of protected cropping, seem to me to be the most important technological change.
I grow a huge range of fruit and vegetables in my two small unheated greenhouses and little polytunnel, all in an urban back garden. We have plenty of organic fresh green salad crops to feed family, friends and neighbours every day of the year. For six months of the year we have an abundance of tomatoes. However it is at the bigger scale that the real possibilities open out.
Thanet Earth is the largest greenhouse complex in the UK. Inside each of their five huge greenhouses is a gas combined heat and power plant, utilizing the heat and Co2 within the greenhouses and selling electricity to the grid at times of peak demand. In Australia Nectar Farms have recently built a 40 hectare greenhouse project, linked to a local wind farm and battery storage system, to provide heat and light for greater year round cropping. Sundrop Farms Port Augusta project uses concentrating solar power to provide desalinated water as well as heat and electricity for their innovative desert based farming system. They, like Thanet Earth, Nectar Farms and many modern greenhouses can control temperatures very precisely, so ideal growing conditions can be maintained year round. They grow hydroponically, and use light, as well as heating and cooling, to maintain year round cropping. Yields per acre are huge.
Plenty Farms in California are expanding rapidly as Silicon Valley billionaires are pouring money into this new start up, which is organically growing leafy green vegetables under a system of vertical hydroponics and relying just on LEDs for light. Around the world others too are growing crops in old shipping containers, factories and warehouses, often in inner city areas, close to where the people are.
I’ve blogged before about solar desalination and mentioned pioneering projects in Australia, Jordan and Qatar. The team at Seawater Greenhouse have just completed construction of their project in Somaliland, which uses cheap shade netting and evaporative walls to create cool moist conditions in the hot dry desert. This is a tiny project yet it shows one possible way to rapidly and sustainably increase food production. It could be hugely significant in the future. Christopher Rothera’s blog and photos really give a good sense of this project.
Another system that I’m passionate about is aquaponics; I blogged about this in 2011 (here and here). Kate Humble and her team, together with Aquaponics UK have built a great system near Monmouth. Again it is a tiny project that could well be a prototype for much larger systems. They’ve some great videos on their website.
In this blog I’ve mentioned some very diverse types of greenhouses and related technologies. The one thing they all have in common is that they produce a lot of food in a limited area and do it in ways that are energy efficient and, to varying degrees, ecologically sustainable: just what we need to feed nine billion people.