POME is rich in organic matter and, when it decomposes without oxygen, it releases greenhouse gases like methane, which is approximately 27 times more potent than carbon dioxide in terms of global warming over a 100-year period. However, effectively capturing and utilizing methane from POME can mitigate environmental harm while contributing to Malaysia's energy sustainability.
Recognizing its environmental impact, Malaysia has started actions to enhance methane capture. Initially, there was a requirement for all palm oil mills to have methane capture systems by 2020. However, this mandate was changed due to operational difficulties.
Now, under the current rules, new oil mills constructed after 2014 must have methane capture systems in place, whereas existing mills with lower production capacities are exempted from this requirements. Currently, around 30% of Malaysia's palm oil mills have adopted methane capture technologies, showing progress but still highlighting the need for further growth.
While some methane capture systems are solely used for flaring without further utilization, most are designed to harness methane for diverse applications.
1. Electricity Generation and Grid Integration
Methane can be used to produce electricity that can be fed into the national grid under the Feed-in Tariff (FiT) system. The FiT mechanism offers a guaranteed price for renewable energy fed into the grid, aiming to incentivize investments in methane capture plants. However, the current FiT rates might not be appealing enough for widespread adoption. The Sustainable Energy Development Authority (SEDA) needs to review the current quotas and FiT rates to enhance the financial viability of methane capture initiatives.
While capturing methane from POME qualifies for carbon credits, renewable electricity produced from methane is not recognized as such by the Integrity Council for the Voluntary Carbon Market. This exclusion is being debated, especially in the context of Malaysia, where many methane-to-electricity projects would not proceed without the financial incentive of carbon credits.
With Malaysia’s renewable energy representation being limited—less than 20% of electricity comes from renewables, with a large share still depending on coal and natural gas—it is essential to explore special provisions for methane projects in the country. Thus, a project involving both methane capture and electricity generation should qualify for dual benefits in carbon credit assessments—one for methane capture and another for renewable energy generation.
2. On-Site Power Generation
Instead of integrating electricity into the national grid, methane-generated power is sometimes used to supply energy to nearby processing facilities, such as refineries or palm kernel crushing plants.
These facilities are highly energy-intensive. Without renewable electricity from methane, they would rely on power from the national grid, which is not only costly but also increases their carbon footprint due to dependence on non-renewable energy sources. By utilizing methane-generated electricity for internal consumption, these plants can significantly reduce both operational costs and, more importantly, their overall carbon footprint.
Products produced in facilities powered by renewable electricity should be considered for premium offerings. Could sustainability certification bodies such as the Malaysian Sustainable Palm Oil recognises this as an added sustainability criterion?
3. Reducing Reliance on Diesel Generators
Palm oil mills are energy self-sufficient, using steam boilers fuelled by biomass for power generation. Typically, boilers operate when milling activities are ongoing, with diesel generators stepping in during non-processing hours.
In some cases, methane is used internally and supplied to steam boilers. Incorporating methane into boiler systems enables extended operation beyond milling periods, thereby reducing dependence on diesel generators.
This approach decreases fossil fuel consumption and significantly reduces carbon emissions. Additionally, repurposing methane in boilers allows mills to allocate biomass residues, such as palm kernel shells, for alternative uses or revenue generation.
4. Bio-CNG Production and Utilization
Methane can be upgraded to bio-compressed natural gas (bio-CNG), providing a viable alternative to liquefied petroleum gas (LPG). However, widespread adoption remains hindered by high capital expenditure for upgrading facilities and uncompetitive selling prices to gas companies.
To fix these problems, changes in pricing are needed. Gas companies such as Gas Malaysia Berhad, should consider revising bio-CNG pricing structures to improve investment attractiveness. Competitive pricing can incentivize industry participation and support national decarbonization efforts.
Also, for mills that are far from gas pipelines, using bio-CNG on-site is a useful option. This can power heavy trucks, like crude palm oil tankers, which cuts down operational costs and emissions. A successful bio-CNG plant in Sabah has proven both the viability and economic benefits of this technology.
Exploring Co-Digestion with Other Biomass
Co-digestion of POME with other biomass waste like empty fruit bunches (EFB) can boost methane production. Historically, the complex lignocellulosic structure of EFB posed challenges for anaerobic digestion. However, advancements in biotechnological solutions, such as specialized enzymes, now allow for the hydrolysis of these complex components into simpler forms, facilitating more efficient digestion.
Mixing EFB into the digestion process can greatly raise methane production, making methane plants more economically viable and supporting better waste management. It is, therefore, time to revisit the concept of co-digestion.
Malaysia's journey in transforming methane from POME from an environmental liability into a renewable energy resource shows its dedication to sustainable progress. While some advancements have happened, continued efforts are essential to expand methane capture across all mills, optimize utilization strategies, and implement supportive policies, especially from authorities. By doing so, Malaysia can harness the full potential of POME-derived methane, contributing to environmental conservation and energy sustainability.
Eur Ing Hong Wai Onn, a chartered engineer and chartered environmentalist, is a Fellow of the Institution of Chemical Engineers, the Royal Society of Chemistry, and the Malaysian Institute of Management.
** The views and opinions expressed in this article are those of the author(s) and do not necessarily reflect the position of Astro AWANI.
