Using eco-brick technology in our school building project in Nepal
In the run-up to the COP-26 climate conference in Glasgow this November, against the backdrop of a spike in climate change-induced natural disasters, there is greater interest than ever on new "green" technology. Much is said about eye-catching approaches such as electric vehicles and biofuels, but it is easy to ignore the elephant in the room. The largest contributor to global emissions isn't flatulent cattle - it is actually the construction sector. Globally, in 2018 this sector accounted for 36% of final energy use and 39% of energy and process-related CO2 emissions, 11% of which resulted from manufacturing building materials and products such as steel, cement and glass.
From a regional perspective, Nepal shares its northern border with the world's worst greenhouse gas emitter, China, and its southern border with the third worst, India. These are two of the fastest growing global economies with burgeoning construction industries linked to population growth and increasing urbanisation. These industries require vast quantities of raw materials while generating a huge amount of pollution, including greenhouse gasses. India's brick kilns are estimated to be the source of 9% of the country's CO2 emissions.
There are an estimated 1,100 brick kilns operational in Nepal, 200 of these being in Kathmandu valley and most of the remainder on the Terai (southern plains). The Kathmandu valley kilns are a prime source of air pollution (an estimated 40% in the winter months), with the topography of the valley contributing to pollutants not being blown away by the wind. Seventy percent of the fuel used by brick kilns is coal, 24% is sawdust and the remaining 6 % is wood. This use of wood is a contributor towards deforestation and soot is a factor in Himalayan glacial melting.
The construction industry is also the source of one other major negative environmental factor; the illegal mining of sand as material costs rise. River sand is being excavated in Nepal by so-called "sand mafia", dangerous people whose greed is destroying river systems, the ecological impact including a drop in water tables and an increase in flash floods.
There are alternative ways ahead in construction. In Nepal, "Compressed Stabilised Earth Brick" (CSEB) technology is growing in popularity. The technique involves combining 10-12% of cement as a binding agent with low-quality damp sand and soil and cold-compressing the mixture in a machine that results in high density bricks without the need to burn any wood or coal. The bricks are also interlocking, which makes walls more resistant to shear and buildings better able to withstand earthquakes. Mud-brick buildings dissolved in the 2015 earthquakes. These benefits come with an estimated 30% reduction in building costs and well insulated, cooler, buildings.
We are currently building up a stock of these bio-bricks for our next major capital project. This is the construction of a computer room at the school for forest children at Bhatighadi that is being funded by Guy's Trust in the UK. In doing so we are also setting an example to others as to the essential greener alternatives that we must now adopt. Urgently.
To read more about "Compressed Stabilised Earth Brick" (CSEB) technology and impact, see this link from the Nepali Times.