There are two elephants in the room when it comes to the development of a sustainable or ‘smart’ city – population growth and increased demand. The two go hand-in-hand.

According to Urban world: Cities and the rise of the consuming class, a report by McKinsey & Company, from 2010 to 2025, the GDP of the City 600, the top 600 cities by their contribution to global GDP growth, will rise by over $30trn, nearly 65% of global growth.

More interesting is that the emerging 440 cities – the emerging market cities in the City 600 – will contribute $23trn of this, or 47% of global growth to 2025.

Speaking to edie, The Centre for Process Innovation’s (CPI) director of strategies, Graham Hillier also explains that over $10trn in additional annual investments is needed in cities by 2025 and emerging market cities will see 1 billion new consumers by the same year.

No small feat, says Hillier. Achieving the smart city vision will involve a number of technologies and measures that generate efficient properties, transport, power generation, agriculture, waste management and industry.

These technologies will need major investment from the private sector as well as Government and a clear uptake in resource efficiency from all sized businesses and society.

This uptake and the development of a combination of robust processes will help cities achieve a much higher level of sustainability but, according to Hillier, “every element of the loop must function effectively”.

“Although in principle the loop to create a smart city looks effective it must work as a fully functioning machine and the elements within the loop must be integrated together in very different ways so that you’re becoming more resource efficient as the process improves.

“This builds on the current way of thinking, which basically relies on a finite supply of energy. However, there are several issues associated with the development of the smart city such as the development of the technology and the implementation of the technology” he added.

Hillier pointed out that although this was a major issue, difficulty in the application of the technology throughout the city created a wider community issue.

“It’s a focus of becoming resource efficient and using these systems and linking them in cycles like the real world does,” added Hillier.

According to Hillier the smart city will need to mimic natural cycles and develop these cycles industrially. This will filter down to how to use less fossil fuel while supplying the same or increased demand volumes.

“You apply the thinking of a chemical engineer or process engineer to the way you go about building a town or community. The fundamental challenge is integrating the technologies and processes such as AD and waste management”.

The CPI says converting waste into a valuable resource, such as energy and water, is key to establishing the fundamentals of a smart city and efforts will be made to convert wastes into these essential outputs.

It is likely that anaerobic digestion will increase in use and gasification may be more widely used to convert wastes into power and fuels as well as treating water.

Future treatment systems are likely to integrate water treatment with energy production through the application of anaerobic digestion and gasification technologies that may be based on combined heat and power (CHP) principles.

“It is likely that more facilities will seek to create additional value for water companies and manufacturing sites by integrating locally arising wastes in system approaches that use wastes to generate heat and power as well as clean water,” the company says.

Using waste streams to their full potential will also provide the power industry with enough renewable energy to meet the demands of a growing city. More power stations will be built to supply to local residential and industrial users as well as major national facilities.

“By integrating heat and power with locally arising wastes in system approaches, heat will be used more efficiently, waste production will be reduced and overall feed to heat and power efficiency will significantly increase in CHP production”.

According to Hillier, gasification technologies will be widely used to convert wastes into power and fuels whilst there will be increased use of anaerobic digestion to process organic wastes, biomass and industrial by-products into methane gas for heat and power. These may be in local facilities that combine water treatment, energy production and waste treatment in community scale integrated systems.

In order to achieve this ideal vision, the community and governments must overcome current challenges revolving around balancing yield with capital and operating costs. Feedstock flexibility is paramount to economics in power stations of the future, says Hillier.

Leigh Stringer is the energy and sustainability editor for edie

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