Water shortages could follow Chinese and Indian plans to use sugarcane to make biofuels, according to a report from the International Water Management Institute (IWMI) , carried on Planet Ark this morning.
The report, Biofuels and implications for agricultural water use:
blue impacts of green energy says
“Domestic production of biofuels derived from crops will put greater stress on these countries’ water supplies, seriously undermining their ability to meet future food and feed demands,” it added.
The report says that it took 2,400 litres of irrigation water to produce one litre of ethanol from maize in China. For the same amount of ethanol from Indian sugarcane, 3,500 litres of water was needed.In the US, where mainly rainfed maize is used, only 3% of all irrigation withdrawals are devoted to biofuel crop production, corresponding to 400 liters of irrigation water withdrawals per liter of ethanol.
By contrast, it took just 90 litres of irrigation water to produce a litre of ethanol in Brazil from mainly rain-fed sugarcane.
The IMWI says:
In the shorter term, nations could also exploit dry land rain-fed crops such as sweet sorghum, Jatropha or Pongamia. That could help small-scale farmers and curb rural poverty.
I’ve not come across Pongamia before (there’ll be a post about it in a while). What is interesting is just how much more efficient sugar cane is than corn when it comes to making ethanol, according to IWMI.
In Brazil, the biggest bioethanol producer, 2.5 million ha (5% of the cropped land) is used for biofuel production, with a production rate of 6200 liters of ethanol per hectare, mostly from sugarcane. The USA, the second biggest ethanol producer, allots nearly 4 million hectares to biofuel crops (4% of the total cropped area), with yields of roughly 3300 liters per hectare, mostly from maize.
The group estimates that the global avearage is going to be around 3500 litres/hectare and says
In Europe, where biodiesel is the main product made from rapeseed, one million hectare is used, yielding on average 1700 liters of biodiesel per hectare.
There is much more than I can go into in this post. It is well worth reading the rest of the report.