Waste generation is an ever-increasing global problem with high environmental and resource depletion impacts. If not managed properly, it can result in severe health and economic implications. According to the World Bank, the global average municipal solid waste (MSW) generation rate is 1.2 kg per capita per day (this ranges widely from 0.2 kg in low-income countries to over 4kg per capita in high-income countries). If the waste is not treated, it ends up in a landfill.
The use of waste-to-energy technologies is an energy-efficient and sustainable solution to this global problem. These technologies do not only address the volumetric and emission issues of greenhouse gases (GHGs) attributed to untreated landfilled waste but also contribute to the circular economy, primarily in the form of electricity and heat and secondary reusable products such as compost (digestate) and stabilized bottom ash.
The circular economy is gaining traction as a viable alternative to the traditional linear economy worldwide. Malta has recently been making efforts to close the loop by proposing and is in the process of implementing several waste-to-energy plans and solutions for waste management.
Malta is a small European island nation which forms part of the EU Bloc and is located in the Mediterranean Sea. Like many other countries, Malta faces significant challenges in managing its waste. With limited land area and a growing population, the government has identified waste-to-energy as a key instrument as part of its solution to address these challenges, with efforts in waste reduction, reuse, and recycling taking precedence.
Amongst the commitment of half a billion Euro by the government for several waste treatment projects to be managed by Wasteserv Ltd., one finds the construction of a WTE facility dubbed as 'ECOHIVE energy', which is the flagship facility of the ECOHIVE complex which uses incineration technology based on moving grate technology to convert non-recyclable waste to electricity. Following this, amongst the existing infrastructure is the organic processing plant, named the 'ECOHIVE organic' which uses dry anaerobic digestion technology to convert organic waste into energy and compost.
"Once the ECOHIVE is set up, Malta will be reducing its dependency on fossil fuels for its electricity demand by some 7 percent, bolstering its green energy generation"
Currently, the ECOHIVE complex consists of landfills, a mechanical-biological treatment plant (MBT), and a material recovery facility (MRF). From the current setup at the complex, approximately 4,000MWh are generated annually from a mix of landfill gas capture and the existing anaerobic digestion plant. With only a portion of the existing engineered landfill being tapped for biogas extraction, upon closure, it is expected that the electricity generation from these plants will reach circa 7,000MWh in the coming years.
The ECOHIVE energy, which will be based on moving grate technology, and an expected processing capacity of 192,000 tonnes per annum diverted from landfills, is expected to generate 126,000MWh to the grid annually. The process involves a complex system of boilers, turbines, and generators to produce electricity from the heat produced by the incineration process. This technology is particularly useful for non-recyclable waste that cannot be reprocessed or reused, and considering Malta's geographic conditions, this technology is the most sustainable way to handle non-recyclable and non-reusable waste.
The ECOHIVE organics will be expected to process up to 70,000 tonnes of organic and green waste derived from municipalities and the commercial sector. Using dry anaerobic digestion (fermentation in the absence of oxygen), biogas and digestate are generated. Biogas is a mixture of methane and carbon dioxide that can be used as a fuel to produce heat and electricity. Digestate is a nutrient-rich fertilizer that can be used in agriculture. The ECOHIVE organics plant will generate up to 21,000MWh of electric energy whilst the heat will be used for the pasteurization of circa 16,000T of compost (digestate) to render it safe for reuse as per EU legislation. This compost will be used for agricultural purposes. Thus, reinforcing the circular economy concept.
Based on the latest data available from the national statistics office (NSO), for 2021 data, the total electricity generated on the Maltese Islands was 2,215,055 MWh, of which, power plants generated 88 percent, and the remaining 12 percent was generated by renewable energy resources, predominantly photovoltaic materials (PVs).
Once the ECOHIVE is set up, Malta will be reducing its dependency on fossil fuels for its electricity demand by some 7 percent, bolstering its green energy generation. Therefore, Malta’s approach to implementing waste-to-energy proposals is the most sustainable option considering Malta’s geographical limitations and economies of scale. Such waste-to-energy facilities and waste management infrastructure will be beneficial from both environmental and socio-economical perspectives, with significant contributions to the country’s circular economy.
