Environmental effects of traditional fuels are contributors to global warming, and the world is looking at other forms of sustainable energy generation, such as biomass as a source of energy.
From rice husks to manure, biomass comes in many forms depending on what it will be used for. When left in the open, such organic waste emits methane, a greenhouse gas that is approximately 20 times more potent than carbon dioxide, into the atmosphere. The World Bank estimated that agricultural methane emissions accounted for about 44 percent of the world’s total methane emissions.
Breaking It Down
Anaerobic co-digestion, which breaks down organic waste without requiring oxygen, forms biogas in the form of methane, which can then be ignited to drive turbines to generate electricity, resulting in a clean energy source. Leftover material from the process is called digestate, and can be sold as fertiliser, for which the entire energy cycle can start again.
Germany is arguably the biogas capital of the European Union. According to the German Biogas Association, 8,005 of 17,240 biogas plants across Europe were built in Germany, primarily in the agricultural sector. This adds up to about 4,000 MW of biogas capacity installed, or around five percent of Germany’s power capacity.
Other countries in Europe are not losing out either. Denmark’s largest biogas plant, Sønderjysk Biogas, located in southern Jutland, recently started operations. About 540,000 tonnes of livestock manure, straw and other organic residue will be converted into biogas by the plant. This would reduce Denmark’s annual CO2 footprint by 51,000 tonnes, producing about 21 million cubic metres of methane that will be injected directly into the nationwide gas grid, or the equivalent to the energy consumption of 15,000 homes.
Finding A Use For Waste
With a myriad of sources including liquid organic material, or solid organic material such as manure, slurry/sludge, food and diary waste, agricultural by-products or wastewater, the value of biomass lies in its flexibility to create a clean energy source from such varied types of organic waste. Asian industries that have high amounts of organic waste by-products (such as diary and food processing) are thus finding a new value for waste in the energy supply chain.
This is due to the fact that the region has lots of potential for biomass energy, with woody biomass (limbs, tops, needles, leaves, and other parts) production at an estimated annual 563.4 million tonnes.
Another important benefit is that biogas plants do not necessarily need to be connected to the central power grid, allowing for decentralisation of energy solutions in rural areas. This can serve to avoid energy blackouts and high costs of importing fossil fuels.
Palm oil producer Asian Agri plans to develop 20 biogas-fired power plants worth a total of US$90 million within the next few years to produce electricity for its own needs and for the people around the company’s plantations in Indonesia. These power plants are fired by biogas produced from palm oil mill effluent, the waste water discharge from processes of palm oil. The company estimates that 30 percent of the 2 MW of electricity generated per plant is sufficient to support plant operations, and the remaining will be distributed to meet public need.
India is also gearing up for the biomass market as well. According to Anirudh Tewari, principal secretary for industries, commerce, and renewable energy in the Punjab government in India, biomass is set to play an increasingly important role in the northern Indian state’s energy market. He said that the state recently developed biomass projects that generated around 150 MW, but has the potential to generate a total of 2,000 MW.
Biomass In Waste Management
Government efforts in Asia to incorporate biomass on a national scale are encouraging. Tenders have been called for Singapore’s co-located Deep Tunnel Sewerage System (DTSS) and NEA’s Integrated Waste Management Facility (IWMF), and the two projects are estimated to cost $9.5billion (US$6.95 billion).
The DTSS includes the Tuas Water Reclamation Plant (TWRP), which will be the world’s largest membrane bioreactor, with a total treatment capacity of 800,000 cubic metres per day. The IWMF will process various waste streams, including food waste and dewatered sludge from the TWRP.
The co-location of PUB’s TWRP with NEA’s IWMF is one of the country’s first initiatives to integrate used water and solid waste treatment processes. One such means of process integration is the co-digestion of food waste with used water sludge at for an increased yield of biogas production.
The biogas will be utilised at IWMF to improve steam quality and a higher overall plant thermal efficiency. Along with an incineration capacity of 5,800 tonnes per day, the IWMF will be able to export more energy to the grid while allowing both facilities to be energy self-sufficient.
Far From Running On Fumes
Prospects for biomass and waste-to-energy in Southeast Asia are encouraging, with the sector expected to grow to around US$1.5 billion in 2019 compared to US$1.12 billion in 2014, according to Frost & Sullivan.
While not the cheapest form of sustainable energy when compared to lowering prices for wind and solar energy, biomass still provides a wide spectrum of benefits, such as finding use for previously worthless waste, generating power in decentralised locations, and being a closed-loop energy system that enhances sustainability by providing energy reductions.
Ongoing government efforts to support and integrate biogas to complement existing waste management techniques show that the full potential of biomass is still not yet realised, and there are sure to be more innovative ways to utilise biomass as a form of clean energy in the future.