How a Chinese City Might Transition to a Low Carbon Future
How can an industrial city transition to a low carbon future? This has been the subject of an intense investigation for the case of Wuxi, an industrial city located on the shores of Lake Taihu in eastern China, near the Yangtze estuary and Shanghai.
The investigation compared a business as usual track with the application of an advanced mix of different approaches. It was found that only with a complex interaction of integrated tools could the considerable complexities and uncertainties that are inherent in urban systems and their development be dealt with.
Such considerations, the authors of the report say, go beyond the short and medium term horizon of common urban planning practices and provide an example for many industrial cities around the world, not just in China.
Wuxi: an industrial city providing goods to the world
The overall economy of Wuxi has increased substantially in recent years with an average annual growth rate of 14% and, typical with many Chinese cities, attendant negative environmental effects such as air pollution and greenhouse gas emissions.
The city is also subject to extreme temperatures and the risk of flooding.
The city is responsible for 1.9% of China's crude steel production, as well as producing cement, fertilisers, paper, caustic soda and so on, plus hard drives and other technology.
The study found that statistical data on emissions was inadequate, and the first task was to account for the significant incompatibilities found between different data sets, gaps of as much as 1.4 billion tonnes of carbon dioxide emissions.
Then a quantitative energy and greenhouse gas emission simulation model was used, adapted from one developed by the Wuppertal Institute in Germany. This database is linked to sub-models of industry, commerce, households, transport and energy supply. It's a bottom-up model that allows for the evaluation of individual technologies, and was suitable for modelling the production capacity and the age of the manufacturing plants found in Wuxi City.
The models were projected into the future up to 2050 and assumed that production levels in that year will be lower than today, although the city's share of China's production would increase.
A business as usual model was compared to a low impact model, which had the following features:
- replacing old production stock with best available technologies from 2020 onwards;
- a shift from coal to natural gas and the phasing out of ammonia production;
- carbon capture and storage from 2037;
- other industrial process improvements;
- expansion of gas-fired combined heat and power plants;
- moratorium on more coal-fired power plants;
- the share of renewable energies to increase up to 73 GW hours in 2050;
- highly energy efficient appliances to be purchased from 2020 with replacement of inefficient air conditioners;
- increasing the share of ultra-low energy and positive energy residential buildings for 2020 after 100% of new construction in 2050;
- electric vehicles comprising 60% of new cars in 2050.
The authors of the report characterises as an exploitive scenario rather than a target-driven one. Looking at the impact on greenhouse gas emissions, these stem mainly from three different sectors: energy, industry and transport. Electricity and heat production represent more than 50%, so the carbon is in these areas would have a significant impact.
The results can be seen in the graphs below which compare the primary energy consumption in the Current Policy Scenario (CPS) with the Extra Low Carbon Scenario (ELCS) (2010-2050):
And the final energy use in the Current Policy Scenario (CPS) with the Extra Low Carbon Scenario (ELCS) (2010-2050):
Finally, direct and indirect CO2 emissions:
The overall conclusion is that it would take enormous effort on different levels to drive this city, and, by extrapolation, all industrial cities and sites, towards a low carbon path in the future.
The city has already set emission reduction targets and developed a low carbon plan, but this was seen to be not up to the challenge. If the low carbon pathway was adopted emissions would be reduced by half the current levels, but this level is still very high despite the existing support of policies and the inclusion of additional significant technology improvements, some of which are costly and yet to be developed, like CCS.
The authors note that the first step is the production of accurate and comparable data across-the-board, then setting in place measures to monitor the decarbonization process. This is crucial to any sort of success at all.
As urban growth is expected to be the highest in medium-sized cities and not in the metropolises, which are frequently analyzed, this study can also be an example for other industrial cities. It will become necessary to create comparative tools at city level for this type of regular accounting across the world.
Another discovery arising from the investigation is that it is difficult to initiate and implement a carbon neutral strategy at local level in isolation, because the city answers global demands for its products; its dominant energy and emission source is coal; and one city alone cannot easily reduce or even step out of its use.
Such a challenge demands a global response.
The investigation was part of the "Low Carbon Future Cities"-project (LCFC), which analyses three important problem dimensions of urbanisation and climate change:
- current and future GHG emissions and their mitigation (up to 2050);
- resource use and material flows;
- and vulnerability to climate change.