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In 2005 I calculated that in Australia, due to our use of coal to generate electricity, electric cars had a higher carbon footprint than conventional cars. 

There's been a lot of water under the bridge since then and now (April 2019) many are promoting electric cars as environmentally friendly, so I thought it was worth a revisit. 

The biggest improvement has been in batteries. These are more efficient, lower cost and safer. And since 2005 we have more renewables, so the carbon footprint of electric cars has shrunk a bit.

Another change is that electricity prices have been driven up, by around 70%, by changes in the energy mix and due to consequent changes to the grid.  Yet this higher price has not been a disincentive to electric cars, as the energy cost is still a lot less than petrol, that attracts a hefty road tax.

My earlier calculations were based on engine and power generation and delivery efficiency.  This time I've taken a simpler path, comparing actual published consumptions, as electric vehicle technology has matured and been tested.  I've chosen three technologies:

  • the new Tesla Series 3 (long range - 523 km), all electric, consumes just 16 kWh/100km
    (claimed - yet the independently measured combined City/highway rate is 29 kWh/100km); 
  • the Toyota Prius, hybrid, that consumes 33 kWh/100km (3.4 litres of petrol/100km*); and
  • the fuel efficient yet conventional Audi A1 that consumes 42.7 kWh/100km (4.4 L/100km*). 

*petrol yields 9.7 kWh/litre.

Conventional petrol driven cars lose a lot of the energy as heat.  While newer cars have more efficient engines, energy is also lost to air resistance, to the tyres and when braking.

Electric vehicles, including hybrids, achieve their low overall energy consumption per kilometre by regenerative braking that recharges the batteries when slowing or stopping: recovering kinetic energy that was invested during acceleration. 

Whereas fully electric cars get their energy entirely from the grid, hybrids use a petrol engine to keep the battery charged and to provide supplemental mechanical power.

But to find out which has the lowest carbon footprint we need to consider where the energy comes from and how it gets to the wheels. Petrol is more energy intensive and produces less carbon dioxide (CO2) per unit of energy (kWh) than coal (2.3 kg of CO2/L petrol). 

Coal produces over a third more more CO2 than petrol for the same quantum of energy. According to the Australian Department of the Environment and Energy (National Greenhouse Accounts) black coal produces 90 kg of CO2 per GJ (0.324 kg/kwh) while petrol produces 67.4 kg of CO2 per GJ (0.242 kg/kWh).

But this assumes the conversion from coal to electricity across the grid to the battery then to actually driving the wheels, is 100% efficient whereas most older coal burning power stations fall well short of total efficiency.  

For example according to the published statistics, Bayswater power station in NSW produces 14,148,670 tonnes CO2-e / 15,944,580 MWh annually (0.89 kg/kWh) or around 38% efficient and this is among the most efficient of the 20th century stock.  Meanwhile, published grid losses have fallen, so maybe some of the recent investment in the grid is paying off.  Back in 2005 7.5% of the electricity generated was lost during transmission. Now just 4.5% is lost.

Batteries too are less than 100% efficient and need to be charged with direct current (DC). This has to be converted from the grid's alternating current (AC) by an 'inverter'.  These too have improved. Newer inverters are said to lose less than 6% and lithium-ion batteries lose between 10% and 20% in the charge discharge cycle (fast charge loses more). In addition they lose about 8% of their charge per month. Cumulatively, we can estimate that in excess of 25% of the electrical energy, generated at the power-station, is lost prior to its consumption in an electric vehicle.

As the following table from the Department's latest report indicates, in Australia most of the energy electric cars consume from the grid comes from CO2 generating sources, predominantly coal.

 

Australian electricity generation by fuel type - 2016-17
(source:  Department of the Environment and Energy website)
     
  GWh Percentage
Non-renewable fuels
  Black coal 118264 45%
  Brown coal 43633.79 17%
  Natural gas 51257.09 20%
  Oil products 6288.439 2%
Total non-renewable 219443.3 84%
     
Renewable fuels  
  Biomass 3625.085 1%
  Wind 12482.78 5%
  Hydro 16531.25 6%
  Large-scale solar PV 672.397 0%
  Small-scale solar PV 7399.259 3%
  Geothermal 0.502 0%
Total renewable 40711.28 16%
     
Total 260154.6 100%

 

Obviously natural gas also produces CO2 but at a lower rate per unit of electrical output than coal: typically around 0.55 kg/kWh (US average). Thus we can estimate that the CO2  released by Australian electricity generators exceeds 0.67 kg/kWh. While this carbon footprint has fallen since 2005 it has not been sufficient to justify the present greenwashing of electric cars.

Those of you who like back-of-envelope maths can quickly use the above numbers to calculate that to travel 100 km:

  • the hybrid Toyota Prius produces around 8 kg of CO2;
  • the conventional petrol driven Audi A1 produces about 10 kg of CO2; while
  • the fully rechargeable electric Tesla series 3 produces between 13 kg and 24 kg of CO2  (after allowing an additional 25% for transmission, inverter and battery losses).

Obviously the Audi A1 is a smaller car than the Tesla or the Prius and the Tesla is a sports-car, with performance that might be more fairly compared to a Mercedes-Benz E-Class or perhaps the hybrid Lexus RX450h.  The petrol driven E Class produces about 17 kg of CO2 per 100km (7.4L/100km) while the comparable Lexus hybrid produces about 13 kg of CO2 per 100km.

So if you are concerned about your carbon footprint there is presently little advantage in buying an all-electric car in most of Australia. Your best option remains a hybrid.  Alternatively a small advanced conventional petrol driven car like the Audi remains an environmentally friendly solution.

Hybrids presently have the additional advantage over all electric cars in that they are not as distance or location constrained (you can get petrol almost anywhere); do not require any charging time; and replacement batteries (when the time comes) are smaller and thus considerably cheaper.

So if someone gave me a Tesla series 3 or the new plug-in Jaguar I-Pace I would probably keep it for showing off around town, with a relatively clear environmental, if not egalitarian, conscience. Both have brilliant performance statistics and are very cool. Unfortunately this performance is difficult to realise when our maximum speed limit is 110 km/hr, and given present charging restrictions, I'd prefer a more conventional car for trips into the country or to drive to Melbourne or Brisbane.

The main incentive, should the purchase price fall to match that of a typical family car, is the relatively low cost of electricity compared to fuels purchased at a petrol station that attract a road tax. Thus, at present, plug-in vehicles travel on roads that the owners are not paying for while the average family currently pays just over a thousand dollars a year in fuel excise. While this can be tolerated for a short time, while numbers are small, it will need to be corrected as numbers grow. Perhaps all-electric vehicles will need to be levied a thousand dollar registration premium to compensate? Might this cause those who make such a purchase without being informed of this likelihood to get upset?

At the moment the main beneficiaries of this tax avoidance are cruising around in up-market luxury sports-sedans. Do they really need government subsidised charging stations as well, when hybrids do it better?  It seems to me that the Sir Humphreys, advising their politicians, might have suggested that such a policy was: 'courageous'.

In Australia, if we want to match European attainment and make fully electric cars environmentally worthwhile, we need to find a new low-carbon base-load electricity technology to replace coal. Yet there remain some significant constraints to achieving this.

We have have a highly centralised urban society with very long loss-making grid lines between centres. Unlike Europe it's a dry continent with insufficient hydro resources to make a big difference and while there is ample wind and solar in remote areas there are few well-placed wind prospects within a practical distance of Sydney or Brisbane.

South Australia and Tasmania have many excellent wind prospects but South Australia, like Denmark, is now effectively saturated with wind, generating much more electricity than the State can consume at times while falling short at others. 

As I have explained elsewhere, the cost of wind-power is entirely due to the capital and maintenance cost of the equipment and associated grid. So in practical terms adding more wind turbines, or batteries, to make up for times of shortfall, adds significantly to electricity costs.  As a result South Australia, that has prematurely retired its thermal base-load generation, and is too remote to share excess generation with NSW or Queensland, has close to the highest electricity prices in the world. 

Fortunately, compared to the Australian electricity market overall, South Australia, like Tasmania, is a small component.

While subsidised PV Solar is an option for domestic electricity, it's even more variable than wind and requires a large battery if the household is to be removed, even partially, from dependence on the grid.  At least the wind still blows just as much in winter; at night; or when it's cloudy. 

The present solar subsidy is funded by a small increase in electricity price, levied on everyone else.  As the table above shows domestic PV solar is presently a small contributor.  But if it were to become more significant the present subsidies would become increasingly unsustainable, perhaps limiting it's potential.  The subsidies are already criticised for discriminating against those who rent; or don't own a suitable dwelling; or who lack the capital to invest.

So - it's back on my hobbyhorse - we need to replace those filthy and unhealthy coal burning behemoths and their increasingly catastrophic ash-dams with nice clean nuclear stations. If we do it in-situ, the existing grid and cooling infrastructure could be upgraded and the workforce and local residents would enjoy the improved environment.   

Just ask the French who get 72.3% of their electricity from nuclear reactors and export inexpensive electricity to most of their neighbours.  

 

 

 

 


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Travel

The United Kingdom

 

 

 

On the surface London seems quite like Australia.  Walking about the streets; buying meals; travelling on public transport; staying in hotels; watching TV; going to a play; visiting friends; shopping; going to the movies in London seems mundane compared to travel to most other countries.  Signs are in English; most people speak a version of our language, depending on their region of origin. Electricity is the same and we drive on the same side or the street.  

But look as you might, nowhere in Australia is really like London.

Read more ...

Fiction, Recollections & News

The McKie Family

 

 

 

Introduction

 

 

This is the story of the McKie family down a path through the gardens of the past that led to where I'm standing.  Other paths converged and merged as the McKies met and wed and bred.  Where possible I've glimpsed backwards up those paths as far as records would allow. 

The setting is Newcastle upon Tyne in northeast England and my path winds through a time when the gardens there flowered with exotic blooms and their seeds and nectar changed the entire world.  This was the blossoming of the late industrial and early scientific revolution and it flowered most brilliantly in Newcastle.

I've been to trace a couple of lines of ancestry back six generations to around the turn of the 19th century. Six generations ago, around the turn of the century, lived sixty-four individuals who each contributed a little less 1.6% of their genome to me, half of them on my mother's side and half on my father's.  Yet I can't name half a dozen of them.  But I do know one was called McKie.  So this is about his descendents; and the path they took; and some things a few of them contributed to Newcastle's fortunes; and who they met on the way.

In six generations, unless there is duplication due to copulating cousins, we all have 126 ancestors.  Over half of mine remain obscure to me but I know the majority had one thing in common, they lived in or around Newcastle upon Tyne.  Thus they contributed to the prosperity, fertility and skill of that blossoming town during the century and a half when the garden there was at its most fecund. So it's also a tale of one city.

My mother's family is the subject of a separate article on this website. 

 

Read more ...

Opinions and Philosophy

The Chemistry of Life

 

 

What everyone should know

Most of us already know that an atom is the smallest division of matter that can take part in a chemical reaction; that a molecule is a structure of two or more atoms; and that life on Earth is based on organic molecules: defined as those molecules that contain carbon, often in combination with hydrogen, oxygen and nitrogen as well as other elements like sodium, calcium, phosphorous and iron.  

Organic molecules can be very large indeed and come in all shapes and sizes. Like pieces in a jigsaw puzzle molecular shape is often important to an organic molecule's ability to bond to another to form elaborate and sometimes unique molecular structures.

All living things on Earth are comprised of cells and all cells are comprised of numerous molecular structures.

Unlike the 'ancients', most 'moderns' also know that each of us, like almost all animals and all mamals, originated from a single unique cell, an ova, that was contributed by our mother.  This was fertilised by a single unique sperm from our father.

This 'fertilisation' triggered the first cell division. These two cells divided; and divided again and again; through gestation and on to birth childhood. So that by the time we are adults we've become a huge colony of approximately thirty seven thousand billion, variously specialised, cells of which between sixty and a hundred billion die and are replaced every day. Thus the principal function of a cell, over and above its other specialised purposes, is replication. 

As a result, the mass of cells we lose each year, through normal cell division and death, is close to our entire body weight. Some cells last much longer than a year but few last longer than twenty years. So each of us is like a corporation in which every employee and even the general manager has changed, yet the institution goes on largely as before, thanks to a comprehensive list of job descriptions carried by every cell - our genome.

Cell replication is what we call 'life'.  The replicating DNA molecule can therefore be regarded as the 'engine of life' or the 'life force' on Earth.  So it is quite a good thing to understand. 

 


What makes us human?

Different animals and plants have different numbers of genes and chromosomes that together make up their genome.  Many are far more complex than humans.  The 32 thousand  human genes are organised into 23 pairs of chromosomes within each of our cells.  But the protein-coding genes, that differentiate us, form only a fraction (about 1.5%) of the instruction and memory data that is stored in DNA. The remainder, coding for other aspects of cell chemistry, seems to be administrative overhead.

When human girls are born, they have about a million eggs in each of their two ovaries, nestled in fluid-filled cavities called follicles. But this number declines quite rapidly so that it is depleted by the time of menopause (usually before 50 years of age). Unless fertility treatment is in use, just one or sometimes two of these (apparently randomly selected) ova descends from the ovaries each menstrual period - down the woman's fallopian tubes where it (or they) may become fertilised if the woman has recently engaged in coitus (had 'sex').

As in vitro fertilization (IVF) demonstrates every day; we now understand that a unique version of your father's genome was injected into your mother's egg by just one of his millions of spermatozoa. So that when the two genomes merged a doubly unique cell, that became you, was the result.

Our genes, that are encoded in their DNA, come in equal proportion from both parents.  Unless we have an identical twin, resulting from division of the zygote (see below) after fertilisation, each of us is genetically unique; our genetic identity determined by that successful fertilisation. 

 

 


Human Reproduction - Click here to Expand

 

Within our species we are said to be of Caucasian or Asian or African appearance, to have dark or fair complexion and so on, and possibly to bear a ‘family resemblance’.  These traits are due to the particular gene variants we have inherited from our parents.

These have been passed down to us, with regular variations, from parent to child, and through many ancestor species, since life began on the planet. And all plants and animals on Earth belong to a single family because we all inherit the same system of reproduction from one original replicating cell, our last universal common ancestor (LUCA) 3.5 to 3.8 billion years ago.

 


Replication

The DNA molecular structure resembles a zip fastener, where each tooth can be any of four molecular bases.  The bases G-C and A-T are each small organic molecules that at one point are covalently bound to a triphosphate (containing three phosphorous atoms) and a sugar group that binds them in a ribbon.  At their free end Guanine is attracted to Cytosine, with triple hydrogen bonds, and Adenine is attracted to Thymine, with double hydrogen bonds. 

In the following notation: black = Carbon;  blue = Nitrogen;  red = Oxygen; white = Hydrogen.   Bars joining them indicate a covalent bond, an electron shared between the atoms.  A double bar indicates two shared electrons.   

 

  Cytosine (C4H5N3O) has a shape that attracts (fits)   Guanine (C5H5N5O) 


but not  Thymine (C5H6N2O2)  or   Adenine (C5H5N5), that attract (fit) each other.

 

Each of these bases is bound to a ribbon of  sugar molecules and at its other end lightly bonds to a matching base on the other half of the 'zipper' such that when it is 'unzipped' each attracts its opposite number (like magnets attracting the opposite pole) thus recreating a new matching half in the same sequence.

 


DNA replication. 

 

This unzipping and reforming is called self-replication. It is going on continuously in all living things as new cells are created to replace those that die. In an adult human around three quarters of a million of our cells divide every second.  This cell division is the process we call organic life and may continue (usually briefly) after we are legally (brain) dead.

Other chemical mechanisms within the cell translate the genetic information stored in the DNA sequence to manufacture the proteins from which new cells are built and differentiate themselves, organising to become our various organs and to thus arrange themselves to form a human; and not a gorilla or a crocodile or a kola or a rose or a cabbage. The human genome project had now identified 32,185 human genes.

Accurate reproduction is very important to the viability of an organism.  Just as: 'WOLF' does not have the same meaning as 'FOWL' the location and order of sequence G-A-T-C within a particular DNA string (chromosome) will result in a different outcome to the sequence C-A-G-T .   And this difference will influence cell structure and purpose:   'The wolf eats the fowl' has a totally different meaning to: 'The fowl eats the wolf'.

This method of storing and reproducing instructions and data is twice as efficient as the binary method we presently use in electronic devices.  For example the binary processor in your computer or reading device requires each character in in each word in this sentence to be encoded in two bytes (each of 8 characters or bits).  In other words 16 ones and zeros are required for every character on this page (eg 'a' = 0000000001100001) and a similar number for each pixel in a simple colour image.  But DNA can encode the same information (sufficient for every unique character and symbol in every language in the world) in just eight characters.

There are a fraction over 3 billion characters in the human genome (3,079,843,747 base pairs).  In computer terms this is equivalent to about three quarters of a gigabyte of information storage. The same data is stored in the nucleus of each of our cells.  This is in nuclear DNA, before taking into account separate, but smaller, storage in each of the mitochondria (see below). 

A 'gig' isn't much you might say (less than $1's worth) but the actual data storage density is in excess of anything offered by our present electronic technology.  Cells are a lot smaller than the chip in a memory stick - there around a billion cells per cubic centimetre in hard tissue.

This also points to another reality.  Had not this replication chemistry been available, and the conditions for the reactions been just right, life could not have occurred in its earthly form. 

Life relying on another replication method that was say binary would be at a disadvantage and would have to use different replication mechanisms.  If there was a chemistry, at different temperatures and chemical concentrations, allowing say six base pairs it would be different again.  We and our cousins (the other animals, plants and other organisms) that are all descended from the original replicating cell (LUCA - see above) are here because the conditions on Earth were and are just right for our kind of life to prosper.

Elsewhere in the universe it may be different.

 


Gene Mapping

Genes are just patterns of chemical molecules that are held within the replicating DNA mechanism.  The way they are encoded onto DNA can be likened to any other mechanism for copying and recording data: a DVD or even a vinyl record or the memory in this computer.  As a result they can be altered or damaged from time to time and some of these variations are successfully copied into subsequent offspring.  If they are particularly advantageous to survival and reproduction these changes, or mutations, rapidly spread throughout the species, so that over tens of thousands of years, individuals successful in one environmental niche are so different from those successful in another that a new species has formed (followed by a new genus, family, order, and so on). 

This process of periodic differentiation has been likened to the branching of a tree but because of the activity of bacteria and viruses and residual DNA that may be reactivated as well as limited cross-species reproduction  (for example later Humans and Neanderthal) it is no longer believed to be quite that simple.

DNA encodes the instructions for creating each cellular colony, defining each species, and each individual within a species. DNA changes over time in such away that each change is a development on previous generations. So it is possible to trace DNA ancestry back through generations of a particular species over time.  For example, DNA studies are increasingly shedding light on the questions around human origins. 

Most animals, including humans, carry two types of DNA.  Our main genome is carried by the chromosomes in the nucleus of each of our cells. This comes from both our parents. The secondary genome, mtDNA, is carried by bacteria-like organelles within each of our cells, that convert sugars for cell energy, called mitochondria. These are all cloned (reproduced by asexual division) from the mitochondria that were within the original egg cell provided by our mother.

Cells may contain from one mitochondrion to several thousand mitochondria depending on species and cell differentiation.  As a result this is the predominant DNA found in a cellular sample.

So our mtDNA comes only from our mother; in turn from her mother; and so on and mtDNA allows us to map the female ancestral line.  This original egg cell was fertilised by a sperm from our father (sperm do not contribute their mitochondria). Once fertilised, the egg cell then divided repeatedly, differentiating in accordance with the coding instructions in our DNA, into the many cells that form the cellular colony that became 'us'.

Males are differentiated from females by a Y chromosome in place of one X. So sons can only inherit this from their father (like their family name in our culture) and periodic mutations in the DNA of the Y chromosome allow the (actual) male ancestral line to be traced back.

As a result of this work we now know that humans on the planet are all descended from a single group that left Africa less than 70 thousand years ago. 

Recent DNA analysis shows that early humans sometimes interbred with the Neanderthal; a separate hominid subspecies that left Africa much earlier and settled in the Middle East and Europe over quarter of a million years ago.

It's amazing to think that we have only understood it within my lifetime. Now the ancient view that people grow from a seed, provided by their father, and gain the spark of life at 'conception' from a god is totally debunked. So throw away all those ancient texts.

 


Viruses

Viruses have been around since life began but they are 'of life', they are not technically 'alive' because they cannot themselves reproduce. They are extremely small - about 70 microns in diametre - and until the invention of electron microscopes in the 1930's their existance had only been inferred. 

To create copies of themselves they need a host cell with the necessary reproductive mechanisms. Over the millennia viruses have evolved the necessary mechanisms to penetrate cells, much like spermatozoa, and inject their DNA or RNA and capture the host's replication mechanisms so that the infected cell begins manufacturing thousands of virion (virus particle) clones of the invader. These then capture other nearby cells in the host animal or plant; or in similar bacteria.  Huge numbers of infected cells are usually destroyed in the process, sometimes killing the plant or animal.

 

Coronavirus particles (yellow) on the surface of a dying cell (that produced them)
Niaid/National Institutes of Health/Science Photo Library (from 
https://www.newscientist.com)

 

But animals plants and bacteria have become familiar with this threat and have in turn evolved means of dealing with or living with viruses to the extent that some are exploited for the benefit of the host.

In turn viruses evolve new strategies to perpetuate their reproduction. Thus new viruses arise from time to time, sometimes jumping from one species to another when an opportunity arises.

Many animals, including humans, have an immune system that has a memory of harmful viruses and means of neutralising them. Thus, once the animal has been infected and survived, the chances of reinfection are reduced.  Vaccines work by presenting our immune system with a harmless sample that allows it to recognise a particular harmful virus.

Since I first wrote this article the World has suffered a new viral pandemic.  It is a novel corona virus for which we have no established immunity and there is no vaccine.  At the end of June 2020 the Covi-19 virus has already killed half a million people.

It is estimated that this virus will no longer find sufficient vulnerable hosts to spread further after infecting around 70% of the populations in which it is spreading.  It has a case fatality rate of just under 1%, that is, of those who catch it just under one in a hundred die.  

Quarantine restrictions are in place in many countries to protect relatively uninfected areas, with local measures to eliminate 'hot spots'.  But the majority of the world's population, in excess of five billion, are in countries in which it is presently spreading.

Unless a vaccine is available soon it seems inevitable that many millions more will be killed.  The economic consequences are also dire.

 

 

 

 


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