Week 1 - Getting the Research Project Started


Codebooks and Datasets


Selecting the Variables


As I am interested in pursuing a career in renewable energy and sustainability, one of my main areas of interest was carbon dioxide (CO2) emissions. From  my studies, I know that some fuels used in the generation of electricity produce these emissions and therefore, I chose the following two variables from the Gapminder codebook:
  1. co2emissions - the cumulative metric tons of co2 produced from 1751 to 2006
  2. relectricperperson - the residential electricity consumption per person during 2008 in kWh
Additionally, increased urbanisation implies increased human activity which means increased amounts of carbon dioxide emission. Thus a third variable was selected from the dataset:
     3. urbanrate - percentage of total population living in urban areas in 2008

Research Question 

Are CO2 emissions associated with the levels of residential electricity consumption and urbanisation?

Hypothesis

Countries with higher residential electricity consumption and higher urban rates contribute more to CO2 emissions.

Literature Review

Residential electricity consumption

Electricity consumed by end-users first must be generated, usually through the combustion of some fuel - a process which produces CO2 as a by-product. In the United States (US), combustion of fossil fuels (petroleum, natural gas and coal) for electric power contributes to 35%  of CO2 emissions (Ramseur 2019). Additionally, residential electricity consumption made up 13% of the CO2 emissions in the electricity sector.  This study also showed that CO2 emissions and electricity generation increased together from 1975 to 2010, after which the amount of generation steadied while CO2 emissions reduced. This was attributed to an economic downturn which resulted in less electricity consumption and therefore less CO2 emitted from generation processes. Introduction of new technologies to the electricity market such as nuclear, hydro (water) and renewable energies (solar, wind) also contributed to the decrease in emissions. Another study showed  that from 1950-2009, CO2 emissions associated with household electricity generation increased twelve-fold as the consumption increased 19-fold (EIA 2011). In 2009, residential electricity was responsible for over 70% of energy-related residential CO2 emissions.

Another analysis suggested that in the US in 2016, 18% of the reduction in CO2 emissions was as a result of reduced electricity usage. In the residential sector, this reduction in use was due to the implementation of energy efficient methods (Hausfather 2017). Energy efficient measures refers to activities such as using LED bulbs and other equipment which would use less electricity in their operation. Energy efficient measures were also stated as a possible reason for a similar reduction in electricity use in the United Kingdom (UK) in 2017 (Hausfather 2019). In this country, the largest contributor to the reduction in CO2 emissions was a cleaner electricity mix, meaning that the fuels used to produced electricity produced less CO2 emissions than were previously used. This cleaner mix accounted for 36% of the reduction in overall CO2 emissions, while  lower electricity use accounted for a 31% decrease in the industrial and residential sectors.

Finally, in Turkey, 24% share of the total electricity consumption came from the residential sector while the highest CO2 emissions came from electricity generation by fossil fuels (Kus, Akan, et al. 2017).Similarly in Nigeria in 2012, 75% of greenhouse gas emissions was made up of CO2, of which 80% was generated by the energy sector. A study showed that increased electricity consumption in this region was responsible for increases in CO2 emissions due to a higher use of individual generators rather than use of the grid (Akpan and Akpan 2012).

From the literature reviewed, it can be stated that there appears to be a positive relationship between CO2 emissions and residential electricity use in that each factor increases or decreases as the other does.

Urbanisation

Approximately 75% of CO2 in originates from urban areas (cited in The Role of Urbanization in the Global Carbon Cycle, Churkina 2016). This CO2 is released be activities including human and plant respiration, decomposition of waste and burning of fossil fuels. In tropical regions, urban expansion contributes to approximately 5% of CO2 emissions through deforestation and changes in land use.  A report by the World Bank stated that the world's 50 largest cities (i.e. cities with over 500 million people) produce a total of 2.6 billion tonnes of CO2 equivalent (CO2e) in emissions annually (World Bank 2010). CO2e refers to the combined atmospheric effect that all of the different greenhouse gases would have if they were all just CO2. The report also stated that emissions due to energy use in cities is driven by how electricity is produced and used in buildings as well as in transport. Additionally, it was observed that dense city centres tended to produce less CO2e emissions than suburban areas which are generally spread over a larger area. 

This last observation was similar to one noted in a 2019 study of Asian countries (Yazdi and Dariani 2019), in which it was suggested that less distance between cities implied less CO2 emissions due to a lower need for energy (for transport, presumably). This study also showed that of the countries observed, the one with the highest growth in CO2 emissions was the one with the highest growth in urbanisation. This would imply that CO2 emissions increase with urban rate. This was also observed in a study performed in Beijing (Wang and Zeng 2019) where it was deduced that commuting in urban regions was a major source of growth in transport-related CO2 emissions. In Beijing, it was seen that this accounted for 75-80% of the emissions. 

Thus, as with residential electricity consumption, there also appears to be a positive relationship between CO2 emissions and urbanisation.

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