Tag Archives: GHG

Where we are and what we have

Pie chart showing green house gas emissions by sectorIn his closing statement at COP26 in Glasgow earlier this month, António Guterres, the Secretary-General of the UN stated that ‘Science tells us that the absolute priority must be rapid, deep and sustained emissions reductions in this decade. Specifically – a 45% cut by 2030 compared to 2010 levels.’   About three-quarters of global green house gas emissions are carbon dioxide (30.4 billions tons in 2010 according to the IEA). A reduction in carbon emissions of 45% by 2030 would reduce this to 16.7 billion tons or an average of about 2 tons per person per year (tCO2/person/yr) allowing for the predicted 9% growth in the global population to 8.5 billion people by 2030. This requires the average resident of Asia, Europe and North America to reduce their carbon emissions to about a half, a quarter and a tenth respectively of their current levels (3.8, 7.6 & 17.6 tCO2/person/yr respectively, see the graphic below and ‘Two Earths‘ on August 13th, 2012).  These are massive reductions to achieve in a very short timescale, less than a decade.  Lots of people are talking about global and national targets; however, very few people have any idea at all about how to achieve the massive reductions in emissions being talked about at COP26 and elsewhere.  The graphic above shows global greenhouse gas emissions by sector with almost three-quarters arising from our use of energy to make stuff (energy use in industry: 24%), to move stuff and us (transport: 16%), and to use stuff and keep us comfortable (energy use in building: 17.5%).  Hence, to achieve the target reductions in emissions and prevent the temperature of the planet rising more than 1.5 degrees compared to pre-industrial levels, we need to stop making, buying, moving and consuming stuff.  We need to learn to live with our local climate because cooling and heating buildings consumes energy and heats the planet.  And, we need to use public transport, a bicycle or walk.  By the way, for stuff read all matter, materials, articles, i.e., everything!  We will need to be satisfied with where we are and what we have, to learn to love old but serviceable belongings [see ‘Loving the daily current of existence‘ on August 11th, 2021 and ‘Old is beautiful‘ on May 1st, 2013].

Infographic showing CO2 emission by region and wealth

Press button for an exciting ride

Painting by Katy Gibson

Artist: Katy Gibson

Someone has suggested that I should write more about what engineers do.  So here is the first in a series of posts in that vein.

A few weeks ago, I went to the ‘Future Powertrains Conference‘ held at the National Motorcycle Museum near Birmingham, UK.  A ‘powertrain’ is the system that creates and delivers power to the wheels of vehicles.  It is at the heart of a motorcycle but they were not discussed at the conference and instead the discussion was about cars and commercial vehicles.  There was a big focus on achieving the EU commitment under the Kyoto Protocol to reduce greenhouse gas emissions (GHG) to below 18% of 1990 levels.

Electric powertrains figured strongly and would certainly improve the air quality in our urban environment but they shift the GHG emissions problem to our powerstations [see my post on ‘Energy Blending‘ on May 22nd, 2013 and on ‘Small is beautiful and affordable in nuclear powerstations‘ on January 14th, 2015]. Even so, the high energy density of fossil fuels means that they remain a very attractive option.  The question that engineers are trying to answer is whether their GHG emissions can be reduced to below 18% of their 1990 levels.

CO2 emissions vs mass of light commercial vehicles (see source below)

CO2 emissions vs mass of light commercial vehicles

When you plot CO2 emissions as a function of kerb weight for all passenger cars the graph reveals that the best in class achieve about 0.1 grams CO2 emitted per kilogram of kerb weight.  Kerb weight is the term used for the weight of a car without passengers or luggage but with a full fuel tank.  Of course, this means the simple answer is that we should all drive lighter cars!

The EU has assumed that most of us will not opt for lighter cars and has introduced legislation which is forcing manufacturers towards 0.02 grams CO2 per kg, which is a huge challenge that is being tackled at the moment by engineers, such as Paul Freeman at Mahle Powertrain Ltd who spoke at the conference.  To help meet this challenge, the UK Automotive Council has produced a series of technology roadmaps such as the one shown below and discussed by Dr Martin Davy from Oxford University during the conference.

As an alternative, we could move more quickly towards driverless cars which would both use the powertrain more efficiently and reduce the risk of accidents to almost zero.  A very small risk of accidents would allow lighter cars to be designed without a heavy crash-resistant cage.  But, as one conference delegate commented on ‘driving’ a driverless car “where would be the fun in that!”  Perhaps that shows a lack of imagination. After all, we can create exciting and safe fairground rides in which you have no control over the ‘vehicle’ into which you are strapped.  So why shouldn’t there be an ‘extra excitement’ button in a driverless car in just the same way that some modern cars have a ‘sport’ button.



Top graphic: http://ec.europa.eu/clima/events/docs/0019/final_report_lcv_co2_250209_en.pdf

Bottom graphic: http://www.automotivecouncil.co.uk/wp-content/uploads/2013/09/Automotive-Council-Roadmaps.pdf