By David Archibald
The people on Australia’s east coast have volunteered to conduct a big experiment. The experiment is to close the Liddell power station in NSW and see what happens.
Liddell’s operator, AGL, has applied to the NSW Government to blow up the power station rather than leave it in a form that can be restarted.
This is the military equivalent of burning your bridges behind you – the expedition succeeds or you die.
The grid operator on the east coast, Australian Energy Market Operator, is likely to gain valuable experience in cold starting a grid with violently fluctuating power inputs.
The restart process may take weeks at a time. During the weeks of darkness, those who voted for the experiment will have plenty of time to contemplate whether global warming is real or is it just an ideology concocted to justify killing off a chunk of the world’s population via covid.
As petrol stations run on power from the grid, to obtain fuel you might have to take your generator down to the station and offer to power them while you are there. That presupposes you have a generator.
The closure of Liddell has coincided with the release of the public version of the Defence Strategic Review which the Government received on 14th February.
As with the closure of Liddell, Australian governments of both persuasions spent the last 20 years effectively blowing up most of Australia’s refining capacity.
When China attacks Taiwan we will be in the invidious position of importing most of our petrol, diesel and jet fuel from the war zone.
The results of that experiment are predictable – a lot of dead Australians. The Defence Strategic Review pays obsequence to global warming and recommends setting up a Fuel Council.
One benefit from the current interest in renewables and hydrogen is that it has quantified the cost of using electrolysis at scale.
Wind isn’t suitable for powering the grid of a modern economy but the physics and chemistry of converting wind power to diesel is more forgiving.
Wind has a capacity factor of 42% under ideal conditions. That means that a wind farm rated at 100 MW might produce 42 MW on average at best.
The energy return on energy invested (EROEI) for wind is near 20 times which is half-reasonable. This means that a wind farm will produce an amount of energy that is 20 times the energy it took to make it.
Solar has an EROEI of six which is out of the question. It is also just once-through and off to the rubbish dump.
It is not renewable if the major component, the photovoltaic panels, are not recyclable. Solar’s capacity factor is 29% under ideal conditions which is no clouds during the day.
The problem with wind is that it needs firming to be useable. This means pumped storage of water up into dams which doubles the capital cost and halves the EROEI to a level which will allow civilisation to tread water at best. There is also a 20% to 30% power loss on the round trip through the storage dam.
When the fossils fuels do run out, and they will run out, our energy system may be plutonium breeder reactors powering electric vehicles.
There will be segments of the economy which will be hard to electrify such as tractors in agriculture and long-distance haulage.
That means producing hydrocarbons using electricity. So what will be the cost of converting the electric power produced by nuclear reactors to diesel? I guess we will find out when push comes to shove.
In the meantime it looks like converting wind power to diesel will be commercial.
The optimum route to that is the Bergius process which was invented in 1913. In this process coal is combined with hydrogen at 400°C and 150 atmospheres of pressure.
In brown coal the yield is 810 litres of liquid fuels per tonne of coal, an extraordinarily high rate of yield.
Hydrogen consumption is 50 kg per tonne of coal. The following diagram is from a lecture by Friedrich Bergius on his acceptance of the Nobel Prize in Chemistry in 1931:
Just about all the products are in the diesel and jet fuel range. Wood is about half oxygen as the formula for cellulose is C6H10O5.
Bergius found that heating wood in the presence of water at 300°C produced a lot of carbon dioxide and left behind a substance with the formula C10H8O, very similar to coal.
So biomass is eminently suitable for hydrogenation to liquid fuels.
So what are the economics involved? The two parameters which rule the process are the fact that power at $0.05/kWh will produce hydrogen at $7.00 per kg and that coal liquefaction will take 50 kg of hydrogen per tonne of coal to produce 810 kg of liquid product.
In short, we pay $350 for the hydrogen and get 1,000 litres of diesel worth about $1,900 at the pump.
The hydrogen can be produced by steam reforming of an internal process stream supplemented by hydrogen produced by electrolysis. Running the process with excess hydrogen produces a lighter product suite.
There are difficulties involved but wind is far better suited to coal or biomass liquefaction than trying to inflict it on the power grid due to its intermittent nature.
The process starts with the hydrogen electrolysers which can be turned down to 25% of rated capacity.
This suits the inherent variability of wind and has a big benefit in how much wind capacity needs to be installed.
A plant using 1,000 tonnes of coal per day as feedstock will need power at 292 MW to produce the requisite 7,000 kWh per tonne of coal.
To produce that power at a wind availability factor of 42% will require installed capacity of 972 MW.
At wind’s capital cost of $1.4 million per MW this would cost $972 million for our 1,000 tonne per day of coal plant.
Hydrogen is a valuable substance at its production cost of $7,000 per tonne so the solution is to over-size the hydrogen plant to suit the wind conditions of the plant site and store excess production in a gasometer to even out the supply.
This will be cheaper than building the pumped storage necessary for wind’s utilisation in the power grid.
The losses in storage will be next to zero. Hydrogen is insoluble in water so gasometers with a floating roof can be used.
So what are the economics? Assuming a capital cost of $200,000 per daily barrel of capacity, a 1,000 tonne per day coal plant has a capital cost of $1.1 billion with the following results:
The process needs US$120 per barrel to provide an adequate return, about 50% above the current price. Prices at that level are coming:
The chart of world oil production above shows that production outside of North America peaked in 2015.
The US tight oil boom supplied demand growth up to 2019 which is now the all-time peak in world oil production.
What is coming is similar to what happened to England in the 19th century. Coal gasification was so useful in making a lighting and heating fuel that just about every town over 3,000 people had a gasifier.
Coal liquefaction will start with brown coal deposits with the highest hydrogen content.
Surat Basin coals are particularly suitable for the Bergius process. When the coal runs out production will shift to areas with enough rainfall to support fast-growing eucalypt species and also cities.
For example Perth produces annually 360,000 tonnes of organic garden waste and 203,000 tonnes of paper waste.
This is enough feedstock for 2,500 barrels per day of diesel which would fuel 72,000 cars each doing 20,000 km per annum.
There is another way of looking at it. A car driving 20,000 km per annum at 10 km per litre is using 5.5 litres per day.
The capital cost of providing that fuel supply via the Bergius process is $6,900 and that coal liquefaction plant will last far longer than the vehicle.
Most people spending$50,000, for example, on a vehicle would happily stump up another $6,900 to provide the fuel for it. We should give people the opportunity to do that, for everyone’s sake.
Under optimum growing conditions in Brazil, eucalypt plantations produce 40 cubic metres/hectare per annum which becomes 20 tonnes of dried wood.
This in turn converts to 10 tonnes of lignin which would yield 10,000 litres of liquid fuel.
Assuming in Australian conditions that the yield per hectare is 25 cubic metres, one square kilometre would produce 3,900 barrels per annum of diesel or 10.7 barrels per day.
To supply Australia’s requirement of one million barrels per day would require close to 100,000 square kilometres of plantation forests – about 1.3% of Australia’s land area.
In energy content terms, if the cost of power from wind is $0.05 per kWh in turn producing hydrogen at $7/kg that is equivalent to diesel at a price of $2/litre.
In those areas where the capacity factor of wind is at least 40%, electrolysis is likely to be used for generating hydrogen for the Bergius process plants.
Where the capacity factor is below 40%, steam reforming of the methane portion of the process stream is likely to be the source of process hydrogen.
As to whether or not petrol and diesel vehicles will be replaced by electric vehicles, the International Energy Agency has a website which allows you to compare operating costs at different petrol and power prices.
The operating costs are much the same. Unfortunately, the capital cost of an electric vehicle is twice the price of a petrol or diesel one.
A telling indicator is that some 70% of people who bought an electric vehicle buy a petrol or diesel one as their next purchase.
We will run out of oil but there are still plenty of forests left. The two thousand litres per annum of diesel for a car doing 20,000 km per annum at 10 km/litre would be produced from four tonnes of wood produced on an area of about half an acre.
Wind is a suboptimal solution for a high level civilisation. The optimum source of energy for power generation is plutonium breeder reactors.
The current dominant technology in nuclear power generation, U235-burning light water reactors, is quite wasteful of our uranium endowment. Uranium is 0.7% U235 in the ground, the balance is U238. The U235 is enriched to 3.5% for consumption in light water reactors. The balance of the 99.3% is sent to storage. The US Department of Energy has 750,000 tonnes of depleted uranium in storage, with the energy equivalent of 11.5 trillion barrels of oil. As a civilisation we could obtain at least 141 times the energy out of each tonne of uranium by adopting the plutonium breeder reactor route instead of the U235 burning light water reactor route.
Beyond that there are the safety concerns. For the light water reactors these are considerable and the high level nuclear waste concerns are monumental.
The first commercial breeder reactor was commissioned in the Soviet Union in 1973 at 350 MW.
The Russians brought an 800 MW breeder reactor online in 2016. France had the 1,242 MW Superphenix breeder reactor operating until 1996 when it was closed in a political deal with the Greens.
If those countries can operate a breeder reactor, Australia can too. The particular design we should adopt is the GE-Hitachi Prism reactor which uses pyrometallurgy to separate out the small volume of high level waste.
Diesel is the first pillar of civilisation; the other three are plastics, cement and steel.
Plastics are currently made commercially from hydro-carbons such as oil and gas. When fossil fuels run out, plastics will be produced from the carbon and hydrogen in wood. Some four per cent of world oil production goes into making plastics. Assuming the same ratio holds in the post-fossil fuel world, this will be supplied by wood equivalent to four per cent of the wood used in making diesel. So for Australia this will be produced by an extra 4,000 sq km of plantation forest.
With respect to cement, Australia consumes nine million tonnes per annum. The making of a tonne of cement consumes 200 kg of coal.
In the post-fossil fuel world energy for cement making will be made from charcoal produced from plantation eucalypts.
The yield from wood to charcoal is 35% so nine million tonnes of cement will be made using charcoal from 5.4 million tonnes of wood produced from 2,160 sq km of plantation eucalypts.
Smelting of iron ore to liquid iron takes about ten times as much energy as melting scrap steel in an electric arc furnace.
Steel production may be two thirds from iron ore and one third from steel scrap to produce lower grades such as reinforcing bar.
As such, energy consumption in the latter route is negligible. Australia consumes some 300 kg per capita of steel so let’s assume that includes 200 kg per capita from the blast furnace route.
Coke consumption in a blast furnace is 500 kg per tonne of steel produced. To replace that with charcoal produced from wood would require 1.5 tonnes of wood from 0.06 hectares of plantation forestry.
At the national level this will require 15,000 square kilometres of plantation forestry.
The blast furnace route is unlikely to work, however, due to the fact that charcoal doesn’t have much compressive strength and so can’t support the weight of a big column of iron ore.
Production may shrink to small pig iron furnaces with this iron remelted in an electric arc furnace.
Alternatively, smelting could be conducted in an electric arc furnace with charcoal used as the reductant but with the energy to drive the smelting provided by electric current.
The current coking coal price of US$350 per tonne equates to a power price of US$0.04 per kWh, suggesting that the age of using power from nuclear reactors to smelt iron ore isn’t that far off.
Thanks to Bergius’ 1931 paper we know that brown coal will yield 5.1 barrels of diesel per tonne of coal dry weight.
So the 65 billion tonnes of brown coal in the Yallourn Valley of Victoria would yield 166 billion barrels of diesel on conversion.
This is equivalent to 450 years at Australia’s present consumption level. Any fuel shortage that Australia experiences from here will be self-inflicted.
The current ideologically driven push to renewable energy will end in tears.
The good news is that we now know what to replace that with.
Australia’s optimal energy path will require an army of welders and pipe fitters.
David Archibald is the author of The Anticancer Garden in Australia
