Jatropha is a feedstock for biofuels. It can be grown in very poor soils actually generating top soil as it goes, is drought and pest resilient, and it has seeds with up to 40% oil content.
Here are some facts and figures about Jatropha relating to its growth as an oil product:
- Jatropha grows well on low fertility soils however increased yields can be obtained using a fertilizer containing small amounts of magnesium, sulphur, and calcium.
- Jatropha can be intercropped with many cash crops such as coffee, sugar, fruits and vegetables with the Jatropha offering both fertilizer and protection against livestock.
- Jatropha needs at least 600mm of rain annually to thrive however it can survive three years of drought by dropping its leaves.
- Jatropha is excellent at preventing soil erosion, and the leaves it drops act as a wonderful soil enriching mulch.
- Jatropha prefers alkaline soils.
Correct pruning is vital to achieve high yields. Ideally, stems are pruned just above the ground to achieve bush-like plants with many branches. A good plant should have bunches of Jatropha fruits at every end of a branch. In the first years, patience is needed: Jatropha bushes need about 4 to 5 years until full production capacity is reached. Achievable yields then can reach 4 to 5 tons per ha per year.
When planted in a plantation, 1,300 plants can be found in 1 ha (2.5 meters between the planys, 3 meters between the rows). Then, 3.8 kg seeds/year/plant should be reached in theory. Yet, single bushes cannot be compared to bushes in plantations that easily (e.g. lower access to minerals, etc.), so the yield per tree will probably be a bit lower.
When starting a jatropha plantation with the aim to produce oil for electricity generation, potential land use conflicts with food cropping must be avoided.
Jatropha oil is a plant oil with some similar physical and chemical properties to diesel, which is why it is possible to run diesel engines on jatropha oil after some adaptations. The oil content of jatropha seeds is around 30-35%, so around 3 kg of seeds deliver one liter of oil.
- calorific content: Jatropha oil has a 7% lower calorific content than diesel. A greater quantity of Jatropha oil is needed when switching from diesel to jatropha oil.
- viscosity: Jatropha has a higher viscosity than fossil-fuel based diesel. Hence, at lower temperatures (in ares with colder climates) this can cause problems when running a diesel engines, especially during the start-up phase when both the engine and the fuel are relativly cool. More stress is put on the fuel pump, the filter and injectors. By installing heating coils around the fuel lines, this problem can be mitigated.
Jatropha Oil Extraction:
Before extraction, the seeds are is usually dried and cleaned. Cleaning the seed is to eliminate foreign material that may damage the oil extraction machine, while heating the seeds by leaving them in the sun or by roasting them gently for ten minutes, improving oil extraction efficiency of the hand expellers. Oil extraction can be done by both hand and machine. Traditional oil extraction methods are highly labour intensive, requiring some 12 hours to produce one litre of oil. The process requires roasting the seed kernels, pounding them to a paste, adding water and boiling, and then separating the oil by skimming and filtering.
Being rich in nitrogen, the seed cake of the oil extraction process is good excellent source of nutrients and can be applied as an organic fertilizer.
Also, the seed cake is a good feeding material for biogas plants.
Jatropha is also used to grow mushrooms and to produce soap.
Power Generation and Rural Electrification Based on Jatropha Oil
Oil from Jatropha seeds can be used to fuel diesel generators adapted to be operted with vegetable oils. The oil is usually filtered through a cloth before poured into the generator.
In rural electrification projects, which are (partly) based on jatropha oil, different models of jatropha supply (or a mix of the below) exist:
- large privately (e.g. by a company) planations ==> easy to administer, danger of plant deseases
- large or scattered community owned plantations ==> very difficult to organize and maintain, challenge of logitics but easier control over growing techniques
- scattered small holder plantations ==> challenge of logistics maintenance and growing
- small holder/household intercropping and fencing ==> lower yields, sometime contradictory goals (large bushes for fencing, lower yields, more difficult to collect seeds).
Experiences from Cambodia
Due to very high diesel prices (more than 1.25 USD per liter), rural electrification with jatropha, which is already used in Cambodia, seemed an interesting option to try.
In the rural community of Poy Char around 1,300 people (360 households) benefit from a mini-grid operated by a Rural Electricity Enterprisse (REE), where affordable electricity is partly generated through locally planted and processed jatropha oil (currently 20%, will be increased to up to 30% next year). Thus, the population of Poy Char has – for the first time – access to grid electricity (5-6hrs/day, this will be extended if demand is sufficient). The population benefits from improved lighting (CFL instead of kerosene lamps) and the usage of other electrical appliances (e.g. b/w t.v.), which improve their living condition. Thanks to the jatropha share, which will be increased further, electricity costs are lower in Poy Char than in communities nearby where power is generated by 100% diesel. Also, farmers have an additional income opportunity by planting jatropha. First signs of productive use of electricity have been registered, for example usage of light for additional income generating activities in the evening (tailoring, repairing, teaching, etc.).
To increase the share of jatropha, farmer contracts have recently been signed between the operator of the REE and farmers growing jatropha in order to increase planning reliability on both sides. Through this, additional 20 ha of jatropha could be planted and the harvesting of existing fields was intensified. Technical assistance with regards to jatropha growing, pruning and harvesting methods as well as with regards to the generator and the business management of the REE (marketing, book keeping, etc.) have been provided. A jatropha focal person was named, who supports farmers with information on growing jatropha, facilitates jatropha trading and builds awareness within the community.
Jatropha oil for diesel generator to power the small village grid had already been used before GIZ was involved. The operator had experimented himself before and had collected jatropha from existing bushes in the village. When the first village got grid connected, the opertor trnsferred his enetrprise to a new village and started from scatch. The generator was damaged as a consequence of jatropha oil usage which is why only diesel was used again. Then, the generator was modified with GIZ support to be suitable for Jatropha use and transferred to new location without access to the grid (the former village had been connected to the grid in the meantime) – PPP (for generator adaptation/ expertise).
Local jatropha planting, harvesting and processing has promoted in the village, with support of the monk, the school teacher and plantation owners, planting trainings have been held and villagers were trained in the handling of the plants. The operator and new focal point for jatropha are the main driving forces for jatropha activities in Paoy Char.
- Electricity is provided to around 500 households (2,500 people) of 1.000 in all scattered parts of the village
- Electricity is slightly cheaper than in the neighboring community ( AEC tariff Jun. 2011)
- Currently there is no grid connection fee so connections are increasing
- Up to 20% of fuel demand is covered by jatropha oil (very little, due to increasing connections and low jatropha yields)
- Operator buys Jatropha from local and from neighboring community (not enough supply in Paoy Char itself)
- The seedcake is sold as fertilizer (1300kg sold in 2011 to farmers for fruit crops plantation)
- 2700 KWh (6rs/day - 2hrs morning (30kW), 4hrs evening (70 kW)
- Jatropha was planted before the flood 2010 (0.5-1.5 years old), many plants suffered/died during the flooding
- The potential land for jatropha growing is far from being reached
- This year, many farmers planted cassava/ changed to cassava due to high market demand, loss in jatropha plantation
- To promote new plantation, 15 ha new trees were planted, and 10 ha old trees will be pruned and fertilizing. Most plants private and community land, 1.5 ha in the temple, 3 ha schools, 4 ha private owned plantation (total plantation: 33 ha)
- the yields are still very low as th eplant are still young, cultivation has not been well and deseases and floods have negativley affected the plants (250 kg/month or 490 l/month - no fruits in fall 2011 because of the flooding
- likely connection to the grid to come - question of PPA for operator or shift to a new location
- So far, economic activity created through the availability of electricity has been marginal (evening tailor shop/teaching/repairing)
Challenges and Lessons Learnt
- A lot of time needed for community involvement as many small farmers are involved, a mixture of plantations and existing bushes
- A large area which was supposedly available for planting jatropha turned out to be protected area of a bird sanctuary, thus reducing the envisaged possible jatropha planting area significantly
- Flooding during the first year after jatropha planting resulted in great damage to the young plants
- Updated national policy on electricity extension plan and produce appropriate business plan using the facts and figures from feasibility.
- Promote community framework (promoters/collectors, social representatives and farmers) by providing skills and knowledge accordingly.
- Relevant stakeholders at community level aware of common problems and help to solve them with participatory approach.
- Farmers need appropriate skills on jatropha plantation and cultivation techniques – motivating farmers for jatropha cultivation has proven to be very challenging, motivating farmers to collect seeds as well - Farmers were not sure what the seeds were worth and if th eoperator would buy them, hence, they didn't collect them. Through purchasing agreements, this issue was tackled.
- REE needs proper skills and knowledge e.g. expelling techniques and machinery, filtering systems and suitable generator for jatropha oil.
- Marketing information and planning for all stakeholders involved
- Establishing a better framework condition to stakeholders including; investors, development partners, social institutions local authorities
- Thorough cooperation between the REE and the community is needed in order to guarantee sustainability – a long-term oriented prizing scheme is being developed through a consultation process between the REE and the community. Moreover, the usage fee for the village grid, which can be used by the REE for free for the first 5 years in order to support business development, has to be decided upon together.
- Involve the public sector – that all national (safety) standards and license procedures have to be respected is common sense and doesn’t need to be further elaborated here. However, it is also important that the public sector on commune level (commune chief) shows ownership and is involved in the whole process from the beginning. Moreover, on national level, the relevant Ministries and Authorities (in Cambodia’s case e.g. ‘Electric Authority of Cambodia (EAC)’) have to be informed and planned activities need to be coordinated. In Cambodia’s for example, there exists a national development plan for rural electrification which can provide orientation for interested private companies as investment in local rural electricity grids only makes sense when the commune or area in question will not be connected to the national grid shortly.
- Ensure ownership and sustainability – especially when dealing with electricity, a long-term perspective needs to be adopted, i.e. that ownership and sustainability have to be ensured as economic benefits will only show after some time. Not only the commune – both the private (future) users of the service, but also the public side – has to be involved; but more important, engage the private sector! A private company will only invest if it sees benefits in the project; hence engaging it in a public-private partnership makes sense to guarantee future involvement, even after the project’s end
- Provide trainings – it’s a new service, a new technology, which requires training for the villagers not only about the technical aspects, but also about safety measures. At the same time, possibilities of how electricity can be used for economic activities beyond TV and karaoke should be introduced– e.g. providing training to sewers on how to increase their productivity with electric sewing machines. This will ensure that the new local electricity grid will contribute to the creation of jobs and the generation of income; hence, to economic development and eventually poverty alleviation.
- very time and resource intensive
- lower yields and ha of plantations that planned leading to a small renewable energy share
- supply of jatropha very unstable, shaky and fragile (e.g. floods, etc.)
- little productive use
- increase comfort of living conidtions through light, fans and t.v.
- project situation only achievable because of highly dedicated, motivated and enthusiastic REE operator who stared the project on his own initially. Large scale replication not feasible as strong individuals are needed who take such an approach forward.
- For further information see Electricity Generation from Vegetable Oils.
- www.jatropha-alliance.org and its Jatropha Handbook
- Fact Foundation Jatropha Handbook
- Jatropha: Wunderpflanze, Sackgasse oder Neuanfang? (*German)
- Stove by BSH (protos)