Tag Archives: electricity

Inconvenient data about electricity generation

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Decorative infographicI like a good infographic and this one showing annual energy flows for a country  is one of my favourites [see ‘Energy blending’ on May 22nd 2013].  Some governments produce them annually.  The image shows the latest one for the UK [2021]. It makes interesting but perhaps depressing reading.  Transportation using fossil fuels accounts for 31% (41.6/134.1 million tonnes oil equivalent) of the UK energy consumption while electricity output accounts for only 21% (28.6/134.1 million tonnes oil equivalent).  This implies that if all vehicles were powered by electricity then the output of our power stations would need to increase to 70.2 million tonnes oil equivalent or between two- and three-fold (excluding conversion & transmission losses).  You can perform a similar analysis for the USA [see 2021 Energy flow chart from LLNL].  Fossil-fuelled transportation accounted for 25%  (24.3/97.3 Quads) and electricity output 13% (12.9/97.3 Quads) so converting all transportation to be electrically powered requires a three-fold increase in electrical output from power stations. It is more difficult to find equivalent data for Japan; however, in 2014 [see Energy flow chart from I2CNER Kyushu University] fossil-fuelled transportation accounted for 32% (3.03/9.52 EJ) and electricity output 38% (3.66/9.52 EJ) so converting all transportation to be electrically powered requires a two-fold increase in electrical output from power stations.  None of the above takes account of space heating mainly via fossil fuel or that many existing power stations are fossil-fuelled and need to be replaced in order to achieve net zero carbon emissions.  Hence, the required scale of construction of power stations using renewable sources, including nuclear, solar and wind, is enormous and in most countries it is barely discussed let alone planned or started; leading to the conclusion that there is little chance of achieving net zero carbon emissions by 2050 as called for by the Paris agreement.

Difficult or inconvenient data about electric vehicles

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photograph of a MDI Airpod 2.0The embodied carbon (i.e. the greenhouse gas emissions produced by its manufacture and assembly) of a typical small (compact) battery electric vehicle (BEV) is about 14 tonnes CO2 compared to about 7 tonnes CO2 in a compact internal combustion engine vehicle (ICEV) [see brusselblog.co.uk for overview of estimates from several sources].  This is mainly a result of the embodied carbon in the batteries.  My compact ICEV does about 50 mpg and we drive about 8,000 per year so we burn 160 gallons per year and one gallon generates about 9 kg CO2; thus, the carbon emissions from my ICEV are about 1.4 tonnes CO2/year. Hence, with our driving habits, building and using a compact ICEV car for five years is equivalent, in carbon emissions (= 7 + (1.4 x 5)), to just building a small electric car.  This does not account for the carbon footprint of electricity generation for the electric car which will not be zero and be dependent on how the electricity is generated; nor is recycling of your old vehicle included.  If you already have a ICEV car then your additional emissions resulting from its continued use will take about a decade to be more than buying a new electric car though by buying an electric vehicle you will move the pollution away from where you live and work.  If you buy an electric SUV, as about 45% of new car purchasers do worldwide [see IEA data], then many more years will be required to acheive a net reduction in carbon emission because the embodied carbon in an electric SUV can be five to ten times more than a compact ICEV.  The challenge for engineers is to develop vehicles that have both zero emissions in use and also zero embodied carbon.  Meanwhile, the bottom line is to use public transport whenever possible but if you need a car then have a small one and keep an electric one for much longer than an internal combustion engine vehicle – neither helps achieve net zero.

Image: the MDI Airpod that runs on compressed air [see ‘Hot air is good for balloons but cold air is better for cars‘ on May 19th , 2021.

Slow progress replacing 150 year old infrastructure

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Photograph of salvaged section of original gas mainThe Liverpool Gas Light Company was formed in 1816, just as the amount of carbon dioxide in the atmosphere started to rise above the pre-industrial revolution level of 278 ppm. A rival Oil Gas Company was formed in 1823 and became the Liverpool New Gas and Coke Company in 1834. The two rival companies merged in 1848. Last year a piece of cast iron gas main from around this period was salvaged while replacing a gas main on the Dock Road in Liverpool. It was date-stamped 1853. For the last month, works have been underway to replace the original gas main in our street which appears to be of a similar age. The concept of gas-fired central heating using pressurised hot water was developed in the 1830s by Angier March Perkins [1838 US patent], amongst others; but did not become fashionable until the 1850s which coincides approximately with laying of the original gas main in the road outside our house. There is a cavernous coal hole under the pavement (sidewalk) in front of our house which would have been used to store coal that was burned in fireplaces in every room. So, we can deduce that the house, which was built in the early 1830s, did not initially have gas-fired central heating but that it could have been installed sometime in the second half of the 19th century, just as the level of carbon dioxide in the atmosphere started its exponential increase towards today’s level of 412 ppm [monthly average at Mauna Loa Global Monitoring Laboratory for August 2020].  Carbon dioxide represents about 80% of greenhouse gas emissions, according to the US EPA, and heating of commercial and residential properties accounts for 12% of these emissions in the US and for 32% in the UK.  Hence, before our house is two hundred years old, it is likely that we will have converted it to electrical heating in order to reduce its carbon footprint.  We have made a start on the process but it is pointless until our power supply is carbon neutral and progress towards carbon neutrality for electricity generation is painfully slow in the UK and elsewhere [see ‘Inconvenient facts‘ on December 18th, 2019].

You can check live carbon dioxide emissions from electricity generation and consumption using the ElectricityMap.

Reinforcement ensures long-term structural integrity

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Last month when I was in Taiwan [see ‘Ancient Standards‘ on January 29th, 2020] , I visited Kuosheng Nuclear Power Plant which has a pair of boiling water reactors that each generate 986 MWe, or between them about 7% of Taiwan’s electricity.  The power station is approaching the end of its licensed life in around 2023 after being constructed in 1978 and delivering electricity commercially for about 40 years, since the early 1980’s.  There is an excellent exhibition centre at the power station that includes the life-size mock-up of the reinforcement rods in the concrete of the reactors shown in the photograph.  I am used to seeing reinforcing bar, or rebar as it is known, between 6 to 12mm in diameter on building site, but I had never seen any of this diameter (about 40 to 50mm diameter) or in such a dense grid.  On the other hand, we are not building any nuclear power stations in the UK at the moment so there aren’t many opportunities to see closeup the scale of structure required.