In May 2018, the University of Jaén (UJA) and Bioland Energy signed a contract to carry out an analysis of the feasibility and viability of a biomass gasification plant using olive by-products, with the aim of obtaining electricity and thermal energy of renewable origin, thus enabling energy self-sufficiency.
What makes this site special?
Bioland Energy is a subsidiary of Oleícola Jaén, a family business founded in 1982 whose main activity is the production of olive oil. Oleícola Jaén is a leading factory in the olive oil sector in the province of Jaén, with the largest olive tree grove in the world.
In 2018, Bioland Energy contracted the University of Jaén (UJA) to assess the feasibility and viability of a biomass gasification plant that would use the company’s by-products to produce on-site electrical and thermal energy. The aim was to increase their energy self-sufficiency while valorizing the residual biomass generated on site, which otherwise often ends up discarded and burnt, or sold at very low prices.
In late 2018, the plant became the first biomass plant used for self-consumption in Spain. It is located in a wet and greasy olive pomace drying industry, which generates its own biomass. The electricity produced is self-consumed for the production process of the plant, and the surplus is injected to the grid [In Spain it is currently not possible to receive compensation for the injection of surplus energy into the grid, ed.]. The thermal energy generated is used to dry or reduce the humidity of the bone (mill) or pomace (extractor).
The project, which required an investment of EUR 3.3 M, has perceived an incentive from the Andalusian Energy Agency of EUR 1.3 M, almost 40% of the total investment. The expected payback is around 6 years. It is also an innovative project as it is based on gasification.
Gasification: turning organic residues into syngas
Gasification is a process that transforms a carbonaceous material into carbon monoxide, hydrogen and carbon dioxide by means of a set of chemical reactions at a certain temperature and in the presence of a gasifying agent, usually air, under low-oxygen conditions.
For this purpose, and depending on the type of gasification technology used, the biomass and the gasifying agent are introduced into the gasifier, so the biomass undergoes the following processes: drying, pyrolysis, oxidation and reduction.
The syngas obtained consists of a mixture of gases: CO (35-40%), CO2 (25-35%), H2 (20-40%), CH4 (0-15%), hydrocarbons and H2O. It can be used in a gas boiler or in a turbine or a CHP (Combined Heat and Power engine). The process is depicted in the illustration below.
The plant has a nominal capacity of 1 MW of electric power and almost 3 MW of thermal power and it burns 19,000 ton of pomace for energy generation. The output supplies over 100% of the wet and greasy olive pomace drying plant electric energy needs, and 25% of its thermal energy needs. Furthermore, by means of utilizing the energy generated, 1,4 tCO2 are saved annually.
The main benefits the plant has generated are:
- Generating an added value for the industry’s by-product, which creates economic stability for the company in the long run
- Self-production and self-consumption of electric and thermal energy which generate independency as well as savings
- Emission reduction which gets them in line with their sustainability targets and helps them meet legislative requirements
“The plant was created with two objectives in mind: on the one hand, to give value to the biomass generated by the sector and, on the other, to produce renewable energy to supply the industry. This motivated the creation of BIOLIZA as a spin off from the University of Jaén, where the solution for the plant was developed”
José Antonio La Cal, President of Bioliza
The advantages of gasification
Gasification is a more versatile technology than combustion. In general, it requires less space, needs less biomass, administrative procedures are not as complex, and, more importantly, its overall energy efficiency is around 70%, compared to 25-30% of combustion cycles. This is because combustion cycles do not exploit the generated heat and the focus is electricity generation.
One of the many advantages of this technology is that it can be implemented in a wide variety of industries that generate biomass and use thermal and electrical energy, regardless of their specific characteristics (size, production volume, amount of biomass available, energy consumption etc.). This is due to its modularity, that is, the possibility of building a biomass gasification plant with engines ranging from 150 kWe to 5 MWe.
Furthermore, the required investments and operating costs are lower than in combustion cycles, and the joint use of energy for self-production can lead to savings and/or income taking payback times below 6 years, not considering possible incentives.
On the other hand, the operation of gasification plants is more complex than that of combustion plants. It also requires pre-treating the biomass for its conversion into energy and combustion cycles are still preferred over gasification for large-scale applications. Lastly, the technology used in gasification plants is newer and hence less proven and reliable and investment costs are still quite high.
Text: CREARA (Madrid) download pdf