Posts Tagged 'transport'

Your car is probably less than 1% efficient

The processes which deliver energy from an energy source to the wheels of a vehicle can be broadly summarised by the ‘well to wheels’ energy flow. Obviously, this term has been developed with the crude oil supply chain in mind. A more generalised summary can be developed to include a wide range of fuel types, as indicated below.

Fuel cycle energy flow of a vehicle

As can be seen, any thorough energy analysis of a vehicle’s operation should start at the energy source and end with the desired forward motion of the vehicle. This ‘well to wheels’ efficiency is described here as ‘source to wheels’ and in addition to accounting for a vehicle’s drive cycle, it accounts for the entire fuel cycle.

Going one step further than a combined fuel and drive cycle analysis is the concept of a complete life cycle assessment. Energy and material costs do not reflect their entire social costs, and as a result, the process of life-cycle assessment is an attempt to look beyond the current prices of materials and fuels. In addition to accounting for processes during vehicle operation, it also includes vehicle manufacture, service, disposal and re-use.

A simplified life cycle analysis of a road vehicle

To overcome the complexities of a complete assessment, a limited life cycle assessment can be conducted by considering only energy inputs and outputs. A complete energy assessment allows for the comparison of existing and emerging vehicle technologies whilst still accounting for the important issues of embodied energy, operation and maintenance, and waste management.

The concept of life cycle assessment is destined to become increasingly important as externalities gain significance to all stakeholders, and the component of resources used during vehicle operation diminishes. A Massachusetts Institute of Technology study titled On the road in 2020 notes that the embodied energy of present vehicles accounts for about 7% of life-cycle energy, whereas the same parameter for emerging vehicle technologies will account for up to 18%. This is based on the widely accepted notion that vehicles will become lighter in weight, and that vehicle power trains will become more efficient.

Load cycle efficiency is yet another way of examining vehicle energy use. The load cycle uncovers the efficiency of carrying out the intended task of transportation; that of getting something or someone from origin to destination. During a typical test cycle about 17% of the energy in fuel reaches the wheels of a vehicle (decreasing further if accessories are being operated), and considering 95% of that energy is used to propel the vehicle not the driver, the efficiency of actually transporting the driver is less than 1%.

This is an edited excerpt from Opportunities for Vehicle Integrated Photovoltaics.

The influence of transportation

Transportation is most succinctly defined as a catalyst for progress. The opposite is also true, as lack of transportation is regarded as a major cause of poverty in many isolated areas around the world. This basic fact infers that increased access to safe and economic means of transportation will, inevitably, lead to a more equitable and prosperous global community.

As described in The Geography of Transport Systems, transport represents one of the most important human activities in the world. It is multidimensional and its importance is historical, social, political, environmental and economic. In summary,

  • transport has aided the development and defence of many civilisations;
  • transport supports and shapes social structures;
  • through government, transport is invested in and regulated;
  • transport pollutes;
  • transport both shapes and is shaped by economic activity.

Interestingly, a wide range of evidence points to the fact that transportation’s influence is not simply significant, but increasing. As both developed and developing nations advance, their demand for transportation is increasing. This demand is further compounded by economies of scale and gains in efficiency which have led, at the same time, to a significant reduction in transport costs over the last several decades. Finally, transportation infrastructure continues to gain significance across all industries, which is resulting in increased government and private sector investment.

The European Union’s white paper titled European transport policy for 2010: time to decide attempts to address this increasing influence of transportation. The document, similar to those being produced by governments all around the world, acknowledges the wide ranging implications of the transport sector:

Total expenditure runs to some EUR1,000 billion, which is more than 10% of gross domestic product. The sector employs more than 10 million people. (European Commission 2001)

In other words, policy decisions surrounding the transportation sector should not be taken lightly; their influence is set to be wide ranging and long lasting.

Linked to this enormous influence on global economics is transportation’s dependence on a continuous supply of energy. In Australia, the transportation sector accounts for 39% of final energy use (or, in real terms, a staggering 1,308PJ of energy). Road transport is by far the most significant energy consumer in the sector (see below). Within this category, the majority of energy use is taken up by passenger vehicles and light commercial vehicles (see below).

Australian transport energy use (ABARE 2005)

Road vehicle transport energy use (ABARE 2005)

Despite the monumental influence of transportation, in many instances the various transportation systems being used around the world are far from ideal. For example, when considering the objective of transportation to move something or someone from origin to destination, a typical passenger vehicle has an energy efficiency of about 1%. This represents enormous scope for improvement which, if achieved, will foster progress not simply in the transportation sector, but in nearly every aspect of our lives.

This is an edited excerpt from Opportunities for Vehicle Integrated Photovoltaics.

Opportunities for Vehicle Integrated Photovoltaics

In 2006 I completed an undergraduate thesis at the University of New South Wales as part of a bachelor of engineering at the University’s School of Photovoltaic and Renewable Energy Engineering. I have included the summary and full report below. Plenty has changed since 2006, but the key points and findings in this report still ring true…

Vehicle integrated photovoltaics (VIPV) is a fuel delivery system like no other. It has the potential to re-shape the world’s transportation systems, from centralised and dependant, to distributed and autonomous. Despite this, the concept remains poorly understood and seldom researched.

This report reveals that VIPV is no longer a design curiosity. Its benefits are wide ranging and its implementation is both technically and economically feasible in many instances. Trends in vehicle design, photovoltaics, vehicle use, government policy and consumer behaviour all point to the potential for widespread implementation in the near future.

This report was written to bring all these potential benefits together, to assess the current state of research and propose a number of opportunities for further investigation. This has been conducted with the many engineering, economic, legal and social constraints of vehicle design firmly in mind. Additionally, the current state of transportation fuels and technology have also been reviewed, to identify the synergies and shortcomings of the concept of VIPV. It is within this broad context that well over 40 distinct benefits, opportunities for application, and key trends, have been identified.

Download the full report (3.3MB PDF): Opportunities for Vehicle Integrated Photovoltaics

Reproduction of this document or its content is prohibited without prior consent from the author.


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