Agribusiness continues to play critical function in Pakistan ‘s economic system. Bing the 2nd largest sector of the state, it contributes 21 % toward the Gross Domestic Product ( GDP ) and involves 45 % of labour wholly. Livestock is the largest depositor to the agribusiness. It parts about 53.2 % to the agribusiness value-added, later 11 % to the GDP [ 1 ] . Energy is the major restricting factor and accountable for the reverse in developing economic systems [ 2 ] . As a effect of energy shortage, development in harvest sector is hampered and growing rate of -2 % has been recorded in Pakistan for 2009-10 [ 1 ] . In Pakistan about 20 % of the foreign exchange is spent on import of fossil fuels [ 3 ] . Approximately 7 US $ billion on imports of conventional energy resources were exhausted equivalent to 40 % of entire imports by Pakistan [ 4 ] . Careful estimates show that by 2050 Pakistan ‘s energy demands are expected to increase three times while, the supplies are non really animating [ 5 ] . It is imperative that surrogate and renewable resources for energy must be explored [ 6 ] . Among all renewable resources biomass energy i.e. biogas, is alone as its handiness is de-centralized [ 7 ] . Almost all small town families have animate beings and agro wastes to bring forth bioenergy. Biomass bonds about 15 % energy ingestions worldwide later sharing 38 % in developing states [ 8 ] . In Pakistan, a family devouring biomass as exclusive energy beginning uses 2325 kilogram of firewood or 1480 kilogram of droppings or 1160 kilogram of harvest residues per annum about [ 9 ] . Expenses on these resources can be easy exchanged with a better and efficient beginning of renewable energy i.e. biogas. Current paper purposes at overviewing the energy supply state of affairs and possible, history, recent state of affairs, impact, theoretical accounts, bounds and chance of biogas in Pakistan.
Energy Supply and Demand Situation
Pakistan is anticipated to move as energy corridor for the part as it holds of import strategic location by surrounding with Arabian Sea, India, China, Iran and Afghanistan. To keep-up this place Pakistan will hold to endeavor for the energy autonomy [ 10 ] . The energy supplies are much less and unable to run into the demand. Increased dependance on oil, liquefied crude oil gas ( LPG ) and imported electricity has been reported and the one-year cumulative growing rate of oil, gas, LPG, coal, hydral electricity, atomic electricity and imported electricity found to be 5.7 % , 3.7 % , 14.3 % , 7.5 % , 0.6 % , -1.7 % and 25.5 % , severally [ 11 ] . Similar consequences have been confirmed by Pakistan economic study 2009-10 [ 1 ] . Table-1 shows that change in supply of energy for twelvemonth 2009-10 was -0.64 % and per capita handiness of energy in dozenss of oil equivalent ( TOE ) reduced up to -3.09 % . With current resources and gait Pakistan will hold to confront 29.06 % of its energy shortage in 2021-22. The Figure-01 gives a clear prognosis about energy supply and demand over the following decennary [ 12 ] .
European Union ( EU ) has legislated that each member state should be bring forthing at least 22.1 % of their electricity from renewable resources in order to lodge to the committedness of bring forthing energy from best alternate energy beginnings [ 13 ] . Pakistan, by following same codification of behavior may carry through its energy demands and fulfill the function of being an environment friendly state.
Potential for biogas and fertiliser
Bing an agro-livestock based economic system ; Pakistan has immense resources of biomass that are available in the signifier of harvest residues, droppings and fecal matters, domestic fowl litter, sugar cane bagasse and wood [ 5 ] . Electricity coevals utilizing biomass is one of the most convenient options, about 9 Giga Watts of electricity is generated from biomass worldwide. Pakistan is universe ‘s 5th largest sugar cane manufacturer with an mean one-year production of 50 million dozenss cane and 10 million dozenss of bagasse. Harmonizing to an estimation there are about 80 sugar Millss holding possible to bring forth about 3000 megawatt ( MW ) energy through biogas coevals but they are presently runing at 700 MW [ 12 ] .
Livestock sector is turning at the rate of 4 % yearly [ 1 ] . There are about 159 million animate beings and their manure can be used for coevals of biogas in rural countries. Energy production by utilizing carnal fecal matters is extremely sustainable as it is economically feasible, socially acceptable besides being environment friendly [ 14 ] . There are about 65.2 million cowss and American bison ( Table-2 ) [ 1 ] presuming that an mean animate being can bring forth 10 kilogram of manure day-to-day would account for about 652 million kilogram of droppings. If 50 % of produced fecal matters is collected and used for biogas production, it will be 326 million kilogram. Harmonizing to an estimation about 20 kilograms wet mass of manure can bring forth 1 three-dimensional metre ( M3 ) biogas [ 6 ] hence bring forthing about 16.3 million M3 biogas daily. Almost 112 million people in Pakistan are rural occupants and biogas can run into their cookery and other energy demands in a good manner. Pakistan can besides research biogas potency of citrous fruit mush, paper industry, slaughter house and street waste every bit good. Poultry waste is ideal substrate to bring forth biogas [ 15 ] .
Rice straw, when used for biogas production in comparing with other resources like cotton gin etc. was found best for methane production but when cotton gin assorted with farm animal droppings was fermented ; it produced more gas in lesser clip [ 16 ] . This clearly states that rice straw and cotton wastes can be used for electricity coevals as good [ 15 ] . Apart from gas coevals Pakistan has potential to bring forth 21 million dozenss of bio fertiliser per twelvemonth [ 9 ] . A survey shows that manure collected from cow farms has phosphorus value runing between 4100- 18300 mg/kg of dry affair [ 17 ] . Another research showed that 57 % of entire manure produced was collectible and after sing all the losingss 19 % of the fresh manure N, 37 % of P and 29 % of K were available to workss and they could counterbalance about 20 % of N and 66 % of P required in the Fieldss [ 18 ] . Manure application can certainly cut down the costs of chemical fertilisers and heighten the productiveness of dirt while moving as indirect energy beginning for the state.
History and Current Situation of Biogas in Pakistan
Biogas industry is good developed in China and India. In China entirely there were about 6.8 million family digesters and 1000 medium and large size digesters till 2007 with an estimated production of 02 million M3, bring forthing 5 % of entire gas energy in China [ 19 ] . In Tibet, residential biogas theoretical account ( RBM ) was introduced to reap the potency of cattle wastes and it has impacted positively on the socio-economic conditions of the country [ 27 ] . Individual efforts were made to develop biogas units in Pakistan ; first of all time documented biogas works running with farmyard manure was built in 1959 in Sindh [ 20 ] . Domestic biogas workss gained Pakistani authorities ‘s attending as alternate energy beginning in 1974 [ 4 ] . Pakistan Council for Appropriate Technology ( PCAT ) developed 21 biogas workss based on fixed dome Chinese type engineering. These workss failed to execute due to gas escape from hair line clefts in their construction. Subsequently on Indian design was followed and 10 demo units were installed in Azad Jammu & A ; Kashmir ( AJK ) . These units worked good, therefore ; were adopted for mass extension [ 21 ] . Meanwhile, Directorate General of New and Renewable Energy Resources ( DGNRER ) launched a undertaking to set up 4000 biogas workss by 1986. This three tier plan included 100 presentation units sponsored by authorities, 2nd stage was on 50 % subsidy and in 3rd stage subsidy ended with a go oning proficient support to the willing people [ 4 ] [ 21 ] . However, plan failed due to backdown of authorities subsidy, high costs of engineering, deficiency of proper preparation of the community members, deficient presentation and really low degree motive [ 9 ] . Biogas Support Program ( BSP ) was started in 2000 with the support of authorities of Pakistan to put in 1200 family biogas units, the plan has achieved its initial authorization and it is expected to put in another 10,000 biogas workss in coming 5 old ages ; it is expected to accomplish 27 % of entire biogas potency of Pakistan [ 23 ] . Presently Pakistan Dairy Development Company ( PDDC ) has started biogas units ‘ installing in its Horizon-3 enterprise with an purpose to supply surrogate renewable energy at really low cost to rural groups [ 24 ] . Up to May 13, 2009 about 450 biogas workss were installed. However due to overpowering response this figure jumped to 556 executions shortly after July, 2009 [ 25 ] . The disbursals per biogas unit are reported between 35000-40000 PKR and manure of 4-6 American bisons and /or cattles is adequate to run each of these domestic units. PDDC is supplying 50 % subsidy to the client husbandmans every bit good [ 24 ] .
Another plan started by Rural Support Programs Network ( RSPN ) in 2009 to build biogas across the state ; So far it has installed 70 biogas units in first twelvemonth. Peoples have pick to choose from assortment of unit sizes harmonizing to convenience and capacity ; moreover a subsidy of RKR 7500 is besides given to the clients [ 26 ] . Domestic Biogas Program is following Nepali design of fixed dome GGC 2047 [ 26 ] . This engineering has been promoted in Pakistan by cusps, broachers, Television and Radio plans, farmer meetings and manuals [ 23 ] . Alternate energy development board is reexamining policies and working actively with all stakeholders to bring forth renewable energy from biomass [ 28 ] . Pakistan Council for Renewable Energy Technologies ( PCRET ) have reportedly installed about 1500 family sized biogas units, 03 community size workss and 01 large thermophillic unit, but these units failed to work for a longer clip and it would be wise to develop large sized biogas workss by following Nipponese technique [ 10 ] .
Economic benefits of utilizing biogas over conventional fuels
Harmonizing to an estimation disbursals on conventional biofuels like LPG, fuel wood, droppings bars, chemical fertiliser history for app. 3550 PKR while wellness care costs account for 1000 PKR. Bio slurry can replace chemical fertiliser to an sum of 600 PKR monthly [ 29 ] . Whereas in Community Organizations ( COs ) of Punjab have reported that biogas workss produced plenty gas for their day-to-day usage and they found it far better than conventional biomass energy beginnings [ 30 ] . This clearly depicts the economic viability of biogas units as maintaining in all above appraisals ; a biogas unit can salvage up to 5150 PKR monthly. Another beginning confirmed that a biogas digester of 10 M3 showed economy of 7672 PKR monthly and 92062 PKR as one-year salvaging tantamount [ 31 ] . The entire cost of 5m3 is 35000 PKR hence per three-dimensional metre cost of gas production is merely 7000 PKR. [ 21 ] . It is established fact that cost on the capital cost of biogas works can non be reduced other than by utilizing the biogas works and the generated gas in an efficient manner. A survey on the “ Optimal biogas works size day-to-day biogas ingestion form and conventional fuel economy ” , It indicated that whole measure of droppings collected from paces is non fed to the biogas digester, harmonizing to an estimation merely 4.77 kilograms of droppings /cubic metre of digester was being fed in Nepal, while the recommended measures are reported to be 6 and 1.5 kilogram in hills and terai parts [ 32 ] . Among indirect benefits, considerable decrease in diseases was found, a survey on such history was done in Nepal and showed ample bead in complaints shown in graph -1 [ 33 ] .
A survey on residential biogas theoretical accounts in Panam, Tibet and China resulted that adult females ‘s chance cost with conventional fuels was 47.09 % to household income. With debut of biogas units, household income increased later impacting positively on chance cost contributed by adult females [ 27 ] .
Biogas theoretical accounts
Plants with movable gasholder, constitutional fixed dome gasholder and Low cost bag / balloon type are the 3 most common designs of biogas units working in Pakistan [ 21 ] . Movable drifting drum type workss consist of a dome shaped gasholder made of some metal ( Figure-02 ) . These units are easy to keep and supply really steady gas force per unit area [ 34 ] . As fixed dome units work belowground ( Figure-03 ) ; they are infinite efficient, need less care but their building needs particular accomplishments and gas force per unit area can be hard to keep. Bag balloon type units are non normally used in the Country. PCRET, after long research and development has recommended two biogas unit sizes ( 5m3 and 3m3 ) sized for efficient biogas production at rural degree [ 21 ] . Oversizing or the under eating of droppings and H2O to the digester are chief causes of inefficiency. So traveling to smaller sizes non merely reduces the capital investing but besides increase the efficiency [ 32 ] .
There has been no clear policy from the authorities over renewable energy resources. Technical, physical, or information coordination and cooperation in stakeholders are losing. While High capital cost coupled with smaller capacity and less efficient theoretical accounts of biogas workss make them less acceptable. And Participation is restricted due to fewer presentation units, really low motive and less promotional activities [ 35 ] . Research surveies showed that efficiency of biogas workss are being underutilized many of the husbandmans do n’t follow the recommended patterns. A survey shows that in Nepal 67.5 % of workss observed standard optimal water-feces ratio while 5 % workss were being fed with lesser measures of H2O and 27.5 % units were fed with more than prescribed H2O measures. This clearly reveals the fact that sufficient preparation is missing on history of running such units [ 32 ] . Similar is the instance with other developing states i.e. an Indian survey has indicated that there is potency of about 25700 MW electricity coevals from biomass but the existent production boulder clay 2007 was merely 1227 MW that is merely 4.47 % of entire possible [ 15 ] . Apart from these, care services are less common and non easy accessible ; gas escape and low force per unit area are besides factors responsible. Assortments of grounds make renewable energy resources less competitory as compared to conventional fossil fuels. So the authorities support is needed to do the alternate energy beginnings popular [ 35 ] .
With rapid addition in population and industry, energy demands are on rise. Almost 7 million M3 wood is used for commercial and domestic intent yearly in Pakistan [ 22 ] Biogas energy coevals systems are in demand and their figure is increasing steadily. They are cheaper and can be run with really low operating cost. This bio energy corridor can work as a good replacement for about 70 % of Country ‘s population residing in rural countries. Installation of workss to bottle the biogas can be another option. This will deconcentrate the beginning of energy and guarantee uninterrupted power supply to the small towns in Pakistan [ 23 ] . At present many bureaus like PDDC, PCRET and RSPN are working to circulate this renewable energy engineering. But the demand of a National policy is imperative to convey this engineering at husbandman ‘s doorsill and hike its success rate.