Biomass - A Storehouse of Clean Energy

Gargi Malik* 

Agriculture continues to be the main source of livelihood for a large part of   population in the country. Biomass, thus, is readily   available widely across the country, thereby, overcoming regional limitations. Biomass, which implies biological material from living or recently living organisms, can be used as an important source of energy. It is a renewable and carbon natural source of energy. 

Biomass resources in India are estimated to be about 565 million tonnes per year. It includes agriculture residues and forest residues. Agriculture residues result from crop harvesting and processing. They include rice husk, bagasse, sugar cane tops and leaves, groundnut shells, cotton stalks and mustard stalks. Forest residues result from logging and wood processing. They include small trees, branches, tops and un-merchantable wood left in the forest. 

The surplus biomass resources available for power generation annually are about 189 million tonnes, which could support roughly 25 GW of installed capacity. Further, co-generation plants provide both heat energy, used in the mill, and electricity, which is typically sold to the grid. It is estimated that about 15 GW of electricity generating capacity could be achieved through adding cogeneration capabilities in various industries including sugar mills, breweries, textile mills, distilleries, fertilizer plants, pulp and paper mills, and rice mills. In addition, there exists a potential of setting up 12 million family type biogas plants.

Types of Biomass                                                                                                      

Biomass includes three distinct categories:

·         Solid Biomass, which includes tree, crop residues like rice husk, bagasse, coconut shells, jute waste, etc. and animal and human waste.

·         Biogas which is obtained by anaerobically digesting organic material to produce combustible gas methane.

·         Liquid biofuels which are obtained by subjecting organic materials to one of various chemical or physical processes to produce usable combustible liquid fuels.

 Biomass Conversion To Useful Energy                                                                              

A number of technological options are available to make use of a wide variety of biomass types as a renewable energy source. Conversion may release energy directly in the form of heat/electricity or, may convert it into another form such as liquid biofuels or combustible biogas. There are basically three types of conversions:

·         Thermal Conversion- A process in which heat is used to convert biomass into another chemical form.

·         Chemical Conversion - A range of chemical processes may be used to convert   biomass into other forms so that fuel may be used more conveniently, transported or stored.

·         Biochemical Conversion- It involves anaerobic digestion fermentation and composting.

Benefits Of Using Biomass

·         It reduces air pollution as biomass emits less Sulphur dioxide and Nitrogen Oxide than fossil fuels. Further, biomass fuels recycle atmospheric carbon, minimizing global warming impacts since zero net Carbon dioxide is emitted during biomass growth phase. Amount of carbon dioxide emitted is equal to the amount of carbon dioxide absorbed from atmosphere during growth phase of biomass.

·         Using biomass decreases animal and municipal waste. Through anaerobic digestion process biomass in the form of waste is converted into useful energy.

·         Using biomass  as  fuel  reduces  the  landfill  space  required  to  dump  the    woody biomass, lumber  mill waste, etc.

·         It helps in creating local jobs in a rural areas. 

            Presently, biomass contributes to around 30% of the total primary energy supply in the country. The major source of energy for cooking for 85% of households in rural India includes firewood, chips, dung cake, etc.  Moreover 20% of urban households still rely primarily on traditional fuels to meet their cooking needs. The Ministry of New and Renewable Energy (MNRE) has initiated various  schemes  and  also  promoted  various  NGOs to  work  in  the field of energy from biomass. The initiatives can broadly be classified into two categories:

·         Rural  Areas  Initiatives: National  Biomass  Cookstove  Initiative(NBCI); Family  Type  Biogas  Plant; Biomass  Gasification  System.

·         Urban  Areas  Initiatives: Programme  for  Energy  Recovery  from  Urban  Waste; Biomass  Gasifiers  and  Biomass  Cogeneration (Non-Bagasse) Projects.

Rural Areas Initiatives

            National   Biomass  Cookstove  Initiative(NBCI): In  rural  areas  a  large  percentage  of  population  continues  to  depend  on  biomass. Clean  and  efficient  energy  is  provided  for  energy  deficient  section  of  population  through  smokeless  chulha, where  different  types  of  fixed and  portable  cookstoves  are  made  available  to  rural  household. In a  case  study  on  various  Dhabas  and  roadside hotels  in  Andhra Pradesh,  it  was  observed  that  fuel  efficient  stoves  installed  were able  to  conserve  about  50-60%  of  fuel  as  compared  to  traditional stoves.   There  was  reduction  of  smoke  and  thus  increase  in  productivity  with  a  positive  impact  on  environment.

Click here to see Photo: Smokeless Chulha

Family  Type  Biogas  Plant: In family type biogas plants  cattle  and  other  organic  wastes  are  used  to  produce  energy  and  manure. India  supports  the  largest  cattle  wealth  and  this  scheme  helps  to  answer  the  growing  energy  crisis.  In this technology,  anaerobic fermentation  of  biodegradable  materials  such  as  biomass ,  sewage,  green  waste, etc.  is  done  to  produce  biogas  which  mainly  comprises  of methane  and  carbon dioxide.  This biogas is used for cooking purposes in the households.

The National Programme on biogas development has multiple benefits. It helps to save tonnes of fuel wood every year. Biogas technology provides energy in a clean and unpolluted form and makes available enriched organic manure as a by-product for supplementing and optimizing the use of chemical fertilizers. Now-a-days institutional and night-soil-based biogas plants are being deployed increasingly. Toilet linked biogas plants are coming up in places like bus stands and educational institutions.

Biomass  Gasification  System: In  the  scheme  various  biomass  gasification  systems  are  set  up  in  rural  areas  to  provide  electricity supply  in  villages  as  well  as  develop  the  industries  there.  Various  gasifiers  fed  on  rice  husk,  wheat  husk , maze , etc  are  set  up  in  the area  depending  on  the  sustainable  source  of  supply available  from  agriculture  or  plantation.  In gasification process  organic  material  is converted  into  methane,  carbon  monoxide, hydrogen, carbon dioxide . It  is  obtained  by  reacting  the material  at  high  temperature (>700⁰C) without  combustion  with  a controlled  amount  of  oxygen / steam  and  the  resulting  gas  mixture  is  called  Syngas  or  Producer Gas  which itself  is  a fuel.

       

India is known as an acknowledged leader in conversion of solid biomass into clean gaseous fuel.   Small-scale biomass gasifiers of upto 500-600 KW capacity are eminently suited for off-grid electricity supply in our rural areas. A number of projects have already been initiated with private sector participation for supply of 6-8 hrs electricity daily through gasification for domestic lighting and 6-8 hrs for other commercial activities like water pumping for irrigation purposes and to micro enterprises and telecom towers.  Projects are  being  carried  out  in  Araria  and  Purnea   districts  of Bihar where Daincha/Ipomoea,  maize  residues  and  hardwood  ensure  perennial  supply  of  feedstock.

Rice Husk based power generating units in the villages of West Champaran district in Bihar have been lighting up around 500-700 households spread over 20 villages in the district, and changing the profile of cluster altogether. The west Champaran experiment is supported by the Ministry and implemented by Husk Power System(HPS), an NGO. The technology employed is simple: It uses the Husk based gasifier technology to provide electricity using 32kWe ‘mini power plants’ that deliver power on a ‘pay-for-use’ basis to households in rice producing belt of India. The price paid to procure electricity generated by these mini power plants is very low, Rs 2 per day per household, located within a radius of 1.5 km. It results in a reduction of consumption of kerosene by as much as two thirds. Power is supplied from 5 pm till midnight each day. Success of this initiative has led to further planning for  installation of such plants  in Samastipur and Lakhisarai. The Ministry of New and Renewable Energy has now plans to take up the rice husk based electricity systems on a ‘Mission Mode’. It has enormous potential and even some of the larger rice mills can feed power to grid as well as distribute locally. More than 5000 to 10,000 industries can be benefitted in the next 2-3 years. These systems can lead to saving diesel to the tune of 200-250 million litres annually.

                                             

                                                                                                                       

Click here to see Photo: A Biogas Plant  and the Design                              

Urban Areas Initiatives         

Biomass  In Urban  Areas  and  Commercial  Applications: Crop  residues  and  agro  industrial  wastes  are  used  through  biomass gasification  technique  for  both  electrical  and  thermal  energy. Several industries like sugar, paper and pulp, fertilizers, food processing, etc. Require   electrical as well as thermal energy for their operations.  These  requirements  can  be  met   through  different  energy  sources  or  a  single source.  The  simultaneous  production  of  power and  thermal  energy  from  a  single  source  is  termed  as  Cogeneration. The Government  is providing  assistance  for  setting  up of  Biomass  Gasification  and Biomass  Cogeneration (Non-Bagasse)  Projects.

Programme For  Energy  Recovery From  Urban Waste: According  to  a  recent  estimate,  about  42  million  tons  of  solid  waste and 6000  million  cubic  meters  of  liquid  waste  are  generated   every  year  by  our  urban  population.  A  total  of  8  projects  for  energy  recovery from  urban  waste  i.e.  an  aggregate  capacity  of  19.05 MWeq  have  already  been  set up.

Biofuels

Biofuels  are a  type  of  fuel  whose  energy  is  derived  from  biological  carbon  fixation. It  includes  fuels  derived  from  biomass conversion as  well as solid  biomass, liquid  fuels  and  various  bagasses.  Biodiesel and bio-ethanol  can  be  used  as  diesel  additive  and  gasoline  additive  respectively.

              Biofuel   development  in  India  mainly  centres  around  the  cultivation  and  processing  of  JATROPHA  plant  seeds  which  are  very rich  in  oil (40%). Jatropha  oil  can be  used  directly  in  diesel  generators  and engines.

While a target of 20% blending of biofuels in diesel and petrol by the year 2017 has been indicated in the National policy on Biofuels announced in December 2009, a mandatory target of 5% blending of ethanol with petrol and recommendatory target of 5% blending of bio-diesel with diesel is in force since October 2009. Indian  Railways  has  already  started  using  Jatropha  oil mixed  with  diesel  for  meeting  the  fuel requirements.

The potential of biomass energy is yet to be exploited fully for India. Considering the nature and current growth of economy and the future trajectory of growth, optimal exploitation of biomass energy will offer a great respite to India at energy front. (PIB Feature).       *****

*Assistant Director (Media & Communication).