Mapping the Spatial Diffusion of Hybrid Electric Vehicles across the UK

The introduction of Hybrid Electric Vehicles (HEVs i.e. the Toyota Prius) to the mainstream automotive market represents a significant moment in terms of the shift towards low carbon propulsion technologies in cars. Available since the start of the millennium, HEVs have established themselves as a large market niche, with over 184,000 currently registered for use of UK roads. 

Locating the registrations of HEVs across the local authorities of the UK, it is clear from the map below that these vehicles have seen relatively high demand in the South East of England, with areas around the South West of England, Wales and in the North of the UK having observed more muted levels of registrations. Interesting, a correlation analysis between the current level of HEVs registrations and the current level of Electric Vehicle registrations returns a coefficient of 0.469 (significant at the 0.01 p-value). This result indicates that Electric Vehicle registrations tend to be occurring in the areas which have already witnessed a relatively high level of HEV adoption. This may imply that Electric Vehicle registrations are shadowing those of HEVs. A question which may come from this observation is will the spatial registration rates of Hydrogen Fuel Cell Vehicles mirror those of Electric Vehicles when they are introduced to the market?

 

The Average Carbon Dioxide Emitted per Kilometre of the Car Stock Registered Across the Local Authorities of the UK

Whilst promoting the adoption of Ultra Low Emission Vehicles such as Electric Vehicles is part of the long-term strategy to attain a zero carbon car fleet by 2050, there is no getting away from the fact that the vast majority of the current car stock is comprised on Internal Combustion Engine Vehicles (ICEVs) propelled by fossil fuels. Indeed, ICEVs will likely remain the most popular variety of new car for the next decade. With this in mind, understanding the relative carbon dioxide intensity of local car fleets and how this metric is changing over time represents an important issue.

 All cars which have been sold in the European Union since 2001 have had to undergo a test procedure referred to as the New European Driving Cycling (NEDC). The NEDC measures the grams of carbon dioxide the car emits per kilometre travelled under test conditions (gCO2/km). The map inserted below charts the average gCO2/km for the cars registered across the local authorities of the UK in 2014. A significant range is present concerning this metric, with the London Borough of Kensington and Chelsea displaying the highest value with the cars registered in this area emitting on average 188.77 gCO2/km whilst the local authority of Slough has the lowest value with the cars registered in this area emitting on average 134.99 gCO2/km. Ultimately, what this map shows us is that the car stock of the UK is much cleaner and dirtier in places (with regards to gCO2/km). Understanding the spatial variation which is present can be useful in considering what local conditions are causing it and how to respond to it.

Electric Vehicle Registrations in 2014

If the United Kingdom is to achieve the ambitious targets set for reductions in the emission of greenhouse gases, which requires an 80% reduction in territorial emissions by 2050, the transport sector will likely need to undergo a complete decarbonisation process. If we assume that a mass modal shift to public and active transport is unlikely to occur, then a transition to zero emission vehicles to replace the current stock of cars represents a fundamental requirement to realising this objective.

This transition is currently being framed in terms of the mass adoption of Electric Vehicles (EVs), which are expected to diffuse through the car fleet over the next 20 years. Currently, we are at the beginning of this diffusion process, with the number of EVs which are currently registered for use of UK roads being low in comparison to the overall size of the fleet. However, charting the early stage of the diffusion process might offer insights regarding what areas tend to be early adopters of clean technology and the degree to which the diffusion of EVs follows that of past advanced propulsion system technologies (such as Hybrid Electric Vehicles). This final issue could be of use when considering the likely indicators of the diffusion of future propulsion systems (such as Hydrogen Fuel Cell Vehicles).

 The map below charts the rate of EV uptake across all of the local authorities of the UK. It notes the current level of EV registrations per 10,000 cars and clearly shows that certain areas are more advanced in their EV adoption than others.

    

Local Authority Car Fleet Overview 2014

The Department for Transport produces on an annual basis a series of statistical outputs from their Vehicle Licensing Statistics Databases. These outputs are useful in demonstrating how the car fleet is changing over time and note such issues as the number of new car registrations, the average emissions levels of new vehicles and the number of advanced propulsion system vehicles (such as Electric Vehicles) registered. However, the outputs omit an important dimension which involves how the fleet is changing across space. Considering this spatial dimension can be quite important, through its ability to illustrate how the car fleet varies across different areas of the UK and allowing for areas which appear to be distinct in their local car fleet profiles to be identified.

The interactive map illustrated below describes some of the key performance indicators of the car fleets registered across the local authorities of the United Kingdom at the end of 2014. These indicators cover such issues as Electric Vehicle registrations, average fleet emissions levels and the average age of the registered cars. This map represents the first stage in the development of a spatial tool-kit which aims to bring to light previously unknown issues surrounding how the UK car fleet varies across the different parts of the United Kingdom. In subsequent posts, some of these key performance indicators will be investigated in more detail to demonstrate their spatial variation.