Credits for energy use aimed at conservation
The average Abu Dhabi resident generates 730kg of waste a year. Disposing of it in a cost-effective manner is a challenge not only in Abu Dhabi, but all over the world.
Even the simplest option – landfilling – requires processing and comes at a cost. It is estimated that Abu Dhabi spends Dh1.5 billion to process its waste each year. And while cost is one concern, the overall environmental impact is another.
Dumping waste in a landfill, especially a non-sanitary one, can damage water tables, expose animals to hazards like plastic ingestion, and if nothing else, tie up potentially useful land for decades. Around 200 hectares – and rising – of Abu Dhabi land is turned into landfill every year.
But landfilling is not the only way to deal with waste. Mankind’s cast-offs of paper, food, plastic, metal and fabric have value in another form.
Through a range of processes, that waste can be employed as a source of energy.
With Abu Dhabi’s target of getting 7 per cent of its power from renewable sources by 2020, this seems like an obvious win. It would return some of the cost spent in waste collection and processing to the government, reduce carbon emissions, and be friendlier towards the environment.
Mixed municipal solid waste can be used to create energy in three ways. It can be burnt as a fuel with minimal processing. It can be turned into biogas fuel by anaerobic digestion, where microorganisms break down biodegradable material in the absence of oxygen. Lastly, it can be gasified using pyrolysis or thermal gasification techniques, where the organic material of waste undergoes thermochemical decomposition at high temperatures in the absence of oxygen.
Waste presents Abu Dhabi with a wonderful opportunity.
The challenge is that not all kinds of waste are suitable for all kinds of processes and each process comes with its own environmental impacts. So scientists at the Masdar Institute are working to find out which process is the most environmentally friendly, given the type and amount of waste produced by the emirate.
We are currently using life cycle analysis to examine each potential technology. This analysis looks at the process from its inception at initial design, all the way to the end of its useful life.
It accounts for inflow and outflow of energy and emissions. By using this tool – incorporated into specialised software – an informed decision can be made on which process to use.
Our first case study will be Masdar City, but eventually we hope to include Abu Dhabi city and hopefully the whole country.
We hope also to be in discussion with Abu Dhabi to develop a sound waste management strategy beyond waste-to-energy, which could be the first stage of a national strategy of waste management – allowing the country to rid itself of all its waste in an environmentally and scientifically sound manner.
As a national project, it makes good economic sense – especially given that Abu Dhabi has already begun to impose waste collection fees on commercial establishments and is likely eventually to do so for residents, too.
That decision is likely to prove a tipping point.
There are many sectors involved in solid waste management, including municipalities, scientific agencies and semi-independent parties such as Masdar City, and others such as power companies that can also be involved.
In order for a strategy to succeed, the various stakeholders have to be brought together to work as a team – a major challenge of cooperation and transparency.
But with Abu Dhabi’s commitment to tackling the waste challenge, seen through its establishment of the Centre for Waste Management in 2008, and its goals for harvesting renewable energy, we are confident Masdar Institute’s research focus will yield viable solutions for the emirate’s waste management future.
Dr. Sgouris Sgouridis is an associate professor of engineering systems and management at the Masdar Institute of Science and Technology.