Straw – When old becomes new – The revival of a sustainable crop
Background: Straw usage
Efforts to reduce the effects of harmful human activities must be greatly increased. The EU has emphasized that innovation is not always about new Materials, but also finding different approaches to “old” materials. Can you imagine straw, one of the least used residue from agriculture, is about to take a leading role in energy generation and construction? As a result, global greenhouse gas emissions could decrease by 20% by 2050, and thus the Risk of further environmental degradation could be reduced. The trend towards innovative and sustainable use of straw could be part of the long-awaited development.
Our ecosystem provides abundant natural biomass from forests, wood and agricultural products. The composting of this biomass transforms it from waste into valuable soil enriching materials, with which the quality of the soil can be controlled by stabilizing the organic matter. Composting has extremely positive effects on agriculture, by enhancing growth of the crops and destroying weed-seeds, as well as enabling plant and human pathogens.
Straw is a complex carbon made up of cellulose, hemicellulose, and lignin. These components are resistant to decay and are generally found in plants. They give them stability and durability. When local regulations require erosion or soil quality control concessions, farmers generally enrich the soil with 1 to 2% chopped straw, which will help reduce erosion (Brewer et al, 2013).
Currently, there is a huge supply of unused straw waste available around the world. China, India and the US are the largest producers of straw and rice straw waste (Mantanis et al, 2000). China currently produces more than 620 billion tons of straw a year. The use of straw in energy production improves both environmental protection and the sustainable development of an ever-growing economy (Zeng & Ma, 2005).
There are farmers who see the production of straw as a risk, as the stalks can break in storms or strong winds. Species with shorter stalks were developed to facilitate harvest with big machines and at the same time to reduce the wind break considerably. Long straw that has been exposed to hail tends to break in strong winds and is more prone to diseases (Paulsen, 1997). Therefore, farmers prefer shorter-stemmed varieties. As a result, the biomass that comes from long-stemmed straw is constantly decreasing, which in turn has a negative effect on its beneficial use in the environment.
Straw is known to all of us as a by-product from agriculture: the dry stalks that remain on the farm or field after threshing. These dry stalks make up about half of the total mass when growing grain, such as oats, rye, barley, etc. They are collected and pressed into bales of straw. It may seem like a surprise that this by-product, usually not given great value, can be used for a wide variety of purposes, and increasingly in the emerging new uses in the future energy mix and the construction industry.
Innovation: New sustainable straw applications
The historical and modern use of straw may come as a surprise. We know straw as animal feed, as roughage in the diet of cattle and horses. It comes to use as a raw material for the production of beehives, laundry baskets and as litter for cattle. Straw mattresses, so-called palliasses, are still made in many parts of the world. The positive effect that straw has on health, is due to the silicate contained in many types of straw, e.g. in rye and rice.
Silicate, in its form as silicon carbide (SiC,) is used in dozens of industrial applications, electronics and jewelry. Straw itself is used for erosion control at construction sites, for hat making, for cucumber houses, in the cultivation of mushrooms, in soil loosening mixtures, for ropes, shoes, in particular for the Korean jipsin sandals, for manufacture of biodegradable packaging and paper making.
Today, straw is also used around the world in the development of safe, energy efficient and sustainable construction techniques. The material is available locally and can easily be used for production of more comfortable, safer, more sustainable and more aesthetic alternatives to costly and environmentally unfriendly construction variants. Currently, in China it is very trendy to build houses and public buildings from rice straw waste. In 2005 there were already 600 of these houses and they had amazing advantages, especially concerning environmental friendliness. They drastically reduce coal consumption and CO2 emissions, reduce the risk of respiratory infections, are very earthquake-resistant, and much more.
In Lithuania, the Ecococon straw panel is a good example of the successful use of straw in the construction industry. The panels are made of straw that is pressed into a wooden frame, with which houses are built on wooden foundations, placed on a waterproof layer and finally treated in the same way as conventional constructions. The houses are suitable for use over decades, even centuries. The construction does not require concrete or heavy construction machinery. Will the house no longer needed, it can simply be removed and the building materials recycled. This avoids the environmental pollution that goes hand in hand with demolishing brick houses and contributes to a healthier environment.
In the English city of Bradford, an entire straw business park has been built. The Inspire Bradford Business Park consists of two buildings with a total area of 2,800m2, it includes common rooms, workshops, offices and a café. This makes the park currently Europe’s largest straw complex. It was built in accordance with sustainable principles and corresponds to the energy efficiency values of the Building Research Establishment Environmental Assessment Method.
The potential of straw is obviously so significant that the EU is supporting the EUROCELL project with 1.6 million € from its Competitiveness and Innovation Program (CIP). The project is aimed on the elaboration of a certification of the straw panel construction, as a basis for the market development and the public acceptance of the model. It is important to highlight that Modcell as a partner
is involved in this project. Modcell is one of the first products to commercialize carbon-negative building on a significant scale. It makes use of its amazing thermal insulating properties of straw ball and hemp construction to produce prefabricated panels. This makes the construction a super-insulated, high-performance, low-energy houses with renewable, carbon-sequestering and locally available sustainable building materials.
Potential: The trend is expanding
Most ecologically oriented development agencies in the world are currently experimenting with straw as an option for the future energy mix. In Germany, the research results of the TLL (Thuringian State Research Center for Agriculture), the DBFZ (German Biomass Research Center) and the UFZ (Helmholtz Center for Environmental Research) are very promising.
The results of this experiment, which assumes a total of 30 million tons of grain straw that is produced annually, show that between 8 and 13 million tons of straw could be used for the production of sustainable energy or fuel production. This undoubtedly underscores the role that straw could play as a source of renewable energy. Was found that 1.7 to 2.8 million households could be supplied with electricity or 2.8 to 4.5 million households could be heated with straw as a basis.
So here is a potential energy- and environmentally healthy alternative to unsustainable energy production. With the increasing demand for electricity, which is expected to grow 2.7 times higher than in 2015 by 2025, straw could become the pacemaker for providing energy sources that could satisfy the world’s energy needs, without harming the health of the environment. Hence, there is hope of being able to produce over 90% of the energy in such a way, that coal and natural gas power plants can be converted. Does this seem like a Sisyphus project?
The properties of straw are so diverse that it must seem very urgent to stop the short-straw trend. The many scientists who developing species that are winterproof, wind, storm and hail resistant (Limagrain Cereal Seeds, 2010), hopefully direct their attention to stronger stalks instead. Wheat is constantly developed for new varieties that are being tested in the United States by the NVT (National Variety Trials Project) and the DAFWA (Department of Agriculture and Food) (Shackley et al, 2014). The development of varieties with longer stalks and greater resistance and hardiness is desirable. In combination with traditional cultivation methods, the straw supply would have to be guaranteed in the long term. The innovative and environmentally friendly use of straw, to boost the global energy mix and to absorb the effects of harmful practices and the environmental degradation associated with the construction industry, represents a new phase in eco-invention. The use of straw is reliable, sustainable, easy in all areas transportable, inexpensive, comfortable, possible in stock, and flexible. Therefore, it represents a fantastic option on a global scale to meet the need for clean energy. Is seems, straw is becoming the leader in the eco-innovations of the future.
This could also be interesting for you: Forest dieback 2.0.
Brewer, L., Andrews, N., Sullivan, D., & Gehr, W. (June 2013). Agricultural
composting and water quality (EM 9053). Oregon State University Extension Service.
Paulsen, G. (May1997). Growth and development. Wheat production handbook.
Kansas State University Agricultural Experimental Station and Cooperative Extension
Service. Verfügbar unter:
Mantanis, G., Nakos, P., Berns, J., & Rigal, L. (2000). Turning agricultural straw
residues into value-added composite products: a new environmentally friendly
technology. Verfügbar unter: http://users.teilar.gr/~mantanis/research.files/G1.pdf
Shackley, B., Zaicou-Kunesch,C., Dhammu, H., Shankar, M., Amjad, M., Young, K.
(2014). Wheat variety guide for WA. Grains Research & Development Corporation.