Energy to waste – fossil fuels’ dirty secret
· 13 min read
The fossil fuel lobby is overlooking its own enormous material footprint and waste problem.
Detractors of renewables like to wring their hands about the waste involved in solar panels, EV batteries and even wind turbine blades. But they never talk about the enormous waste streams associated with fossil fuels. Or just how little renewable infrastructure would be needed to power all our energy needs in comparison.
Fossil fuels (coal, oil and methane gas) represent a massive 15% of the roughly 100 billion tonnes of materials produced each year globally (including all the concrete, steel, aluminium, plastic, timber, food and everything else we currently depend on).[1]
There’s a massive amount of infrastructure associated with extracting, processing, transporting and burning that 15 billion tonnes fossil fuels, around half of which is coal.
And all fossil fuels, when burnt, produce waste. Methane gas and oil produce little solid waste, but all, including coal, produce greenhouse gases, pollutants that are rapidly heating the planet. Here’s an interesting fact: burning a tonne of coal actually produces over 2 tonnes of carbon dioxide emissions. That’s because the carbon atoms in the coal react with oxygen in the air to form carbon dioxide – over 70% of the weight of a carbon dioxide molecule is the two oxygen atoms.[2]
What else is left over from burning a tonne of coal? There’s about 150 kg of coal ash, and 6kg of assorted gas and solid nasties including sulfur dioxide, nitrogen oxides, uranium, thorium, mercury and other nasties. That’s over 1.1 billion tonnes of solid waste per annum, which typically accumulates in vast slurry ponds along with spent water. Leaks into local waterways are common.[3]
And that’s just at the burning stage. How about the mining stage, where landscapes are converted to dystopian moonscapes? Did you know that coal mining is one of the most fresh-water intensive industrial activities? [4] Coal needs to be washed to remove impurities, a process that produces vast amounts of polluted water, much of which returns to local waterways and aquifers. Extracting the coal also upsets the local water table and buries streams. [5]
In fact, it has been estimated that to produce and burn each tonne of coal requires about 230 -310 tonnes of fresh water (i.e. 230,000 to 310,000 litres). [6]
Plus, mining coal often releases significant quantities of methane trapped in the coal seams – a potent greenhouse gas that is over 80 times more powerful at trapping heat in the atmosphere than an equivalent mass of carbon dioxide. [7]
Meanwhile, in addition to their greenhouse gas contribution (which also includes methane releases from well heads, gas pipes, industrial plant and domestic appliances), the consumption of gas and oil is “the largest industrial source of emissions of volatile organic compounds… that contribute to the formation of ground-level ozone (smog). Exposure to ozone is linked to a wide range of health effects, including aggravated asthma, increased emergency room visits and hospital admissions, and premature death.” [8] In fact, human exposure to fossil-fuel air pollution is estimated to account for the deaths of at least 8 million people globally per annum – nearly one in five deaths from all causes. [9]
In summary for fossil fuels:
That’s one side of the ledger. Onto renewables.
A solar panel weighs about 20 kg [11]; a typical 2-3MW wind turbine around 200 tonnes including its concrete footing. [12] Equating that to 15 billion tonnes of fossil fuels, you could install about 75 million wind turbines or 750 billion solar panels for the same material mass.
Globally, primary energy consumption for all uses (electricity, industry, transport, etc.) from all sources (fossil fuels, biofuels and renewables) was about 420 Exajoules in 2019, over 116,000,000,000,000 kWh hours (116,000 TWh). [13]
A standard solar panel produces about 300 Watts, around 20% of the time over the course of the year (i.e. it doesn’t produce at night and produces less during winter and cloudy conditions). [14] That’s about 525 kWh per panel per year [15]. Therefore, it would take a bit over 221 billion solar panels to generate all the energy the world currently uses in a year, weighing about 4.4 billion tonnes. Typically, solar panels work, with minimal maintenance, for at least 25 years. [16]
Meanwhile, a well-located onshore wind farm can achieve capacity factors exceeding 30% and a service life of 20-25 years or longer [17]. Offshore wind, which is more consistent, has produced capacity factors as high as 57% over 12 months of operation. [18] The typical turbine size installed in the US in 2020 was 2.75MWh. [19] Taking a conservative 30%, that equates to 7.2 GWh of energy per turbine per annum, requiring about 16.1 million turbines to provide all the world’s energy, weighing about 3.2 billion tonnes.
Let’s reflect on that. For just 29% of the fossil fuel weight used every year – in other words about 15 weeks’ worth – we could produce enough solar panels to power all of the world’s energy needs for 25 years [20]. Or, for 21.5% - 11 weeks’ worth – we could build enough wind turbines to power the world!
Yes, there is supporting infrastructure required including transmission and storage. But it’s hard to see how the total footprint of a completely renewable energy system could go beyond the combined weight of about 6 months of fossil fuel consumption.
“Ah,” you might be thinking, “but what about electrifying vehicles, buildings and industry? What about all the used batteries, etc?” Well, the news there is still pretty good: there are about 1.5 billion cars in the world, [21] weighing on average about 2 tonnes each. [22] Typically, the batteries are warranted for at least 8 years / 160,000km [23] (after which they can still be used for stationary storage applications for many more years). [24]
But here’s the thing, an EV only weighs perhaps 150-300kg more than an equivalently sized and featured petrol/diesel car because you replace a bulky internal combustion engine, starter motor, radiator, gear box, etc. with a compact electric motor and large battery. [25] From a materiality perspective, it’s just the increased weight that needs to be considered. Over 25 years, using a generous 3 battery changes and a 300kg differential, that’s a mere 1.35 billion tonnes of extra materials. That’s 9% or just over a month’s worth of fossil fuels.
Here's the other neat thing about EVs – assuming 15,000km driven per annum and a 10 year life, they save about 15,000 litres of petrol weighing 11 tonnes, or more than 5 times the weight of the vehicle. [26]
It's beyond the scope of this article to examine the materiality of building and industrial electrification / decarbonisation in depth, except to say that, as with transport, the changes will involve marginal differences to various machines. These will be rolled out over the next few decades, most often when the fossil-fuel version reaches the end of its service life and would need to be replaced anyway.
However, it’s worth noting that displacing fossil fuels will mean we won’t need to keep repairing and replacing (as they reach their service lives) the approximately:
As energy expert Dr Saul Griffith has noted, an electrified world is also a lot more energy efficient. Based on extensive analysis he calculated that the US could use a whopping 58% less energy overall given the superior efficiency of machines such as heat pumps, and the fact that we would no longer be using vast amounts of energy to extract, process and transport fossil fuels. [32] We now find we may need less than half the number of solar panels or wind turbines that we talked about earlier.
And none of the foregoing is to say it is necessary or desirable to replace our current world on a like-for-like basis. For example, we would be doing ourselves a great disservice to simply replace the current global vehicle fleet with zero emissions vehicles. Instead, we should be redesigning cities to prioritise active and public transport, encouraging car sharing, and reversing the large SUV and pickup truck trend to encourage more compact vehicles (where individual ownership is still warranted). There are hundreds of ways we could make our civilisation far more efficient, including by distributing and democratising renewable energy supply.
There is no waste mountain associated with the transition to clean energy. Far from it, the changes, phased in globally over the next few decades, will greatly reduce the need for materials and produce a fraction of the waste currently generated by fossil fuels.
Back to the hand wringing, and we find recycling plants for solar panels, wind turbine blades [33] and batteries [34] are popping up all round the world, including in Australia. [35] Not that this is yet a material problem, given where we are in the renewables adoption curve, so there is time to put appropriate mechanisms in place to maximise recycling rates.
Bearing in mind many of the materials in a renewably powered, electrified world have considerable value, including copper, silver, steel, rare earths and so on, there is likely to be no shortage of companies seeking to monetise those waste streams.
While we’re at it, if detractors insist on putting out gloomy articles about bird deaths from wind turbines and the like, then it is incumbent on editors to ensure that these are put into perspective by a) comparing like-for-like bird deaths (in terms of equivalent generation capacity) from fossil fuel mining, supply chain and power generation; and b) comparing both with other far more significant causes such as window strikes or domestic cats. [36] And let’s ensure they include the solutions, like avoiding known migratory flight paths, and painting a stripe on one of the blades.[37]
There is one more claim that needs to be unpacked. Some commentators believe that all the extra copper, nickel, lithium, cobalt and a dozen or more other metals and rare earths associated with the transition will lead to an environmental disaster from all the extra mining needed to obtain them.
Clearly we will be, to an extent, swapping coal mining and gas/oil drilling for other forms of mining. And some of the materials involved are far less abundant than a coal seam, and require significant amounts of dirt and rock to be shifted to extract relatively small quantities, often also disturbing flora and fauna at the surface and affecting natural watercourses.
The thing is, we’ll be mining these materials to make machines, not fuel for machines. Fuel can be burnt once. In machines, however, mined materials are used for 10-50 years. Further, these materials can often be recycled many times (particularly with the right incentives in place such as supplier take back schemes as seen in the European Union [38]). And many of the existing machines that may run on fossil fuel infrastructure right now use at least some of the same materials.
The World Bank, for example, has estimated the increase in key materials necessary to transition to clean energy in line with Paris targets (covering generation and storage). [39] Their analysis, using a 2 degree scenario, indicates significant increases for some minerals. However, it doesn’t consider how much might be able to be recycled from existing machines.
Take copper. According to the US Geological Survey, 700 million tonnes have been produced globally to date. [40] The World Bank’s estimated additional cumulative demand to 2050 between business-as-usual and a Paris-aligned roll out of renewables and storage: about 12.5 million tonnes. Surely we can extract a fair percentage of that from old machines, starting with the turbine coils in retiring coal power stations.
Or silver, for which total production to date totals about 1.74 million tonnes. [41] The cumulative additional requirement for renewables and storage over business-as-usual demand to 2050 is about 0.25 million tonnes.[42]
Faced with potential resource constraints, renewable innovators are not standing still either. For example, a flurry of recent announcements suggests new battery chemistries based on more accessible minerals such as iron and sodium could displace some applications of current lithium ion technologies. [43]
This is not to diminish the urgent need to improve the environmental performance of mining operations, its own emissions footprint, and the industry’s dubious record of social injustices. [44] Or the need to retool our economy around circular principles, to reduce waste, and wasteful consumption.
However, perspective is critical: if we continue anthropogenic emissions, cross natural tipping points [45] and let the climate genie completely out of the bottle, then the environmental damage from non-fossil mining operations will be the least of our worries. [46] It’s a classic case where we can’t let perfect be the enemy of the good.
Let’s face it, recycling qualms about renewables are simply another diversion, another red herring, used by fossil fuel firms and their allies to deflect attention from the truly mammoth and horrific environmental, health, and materials costs of their products.
And did I mention renewables are cheaper?
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1. https://drive.google.com/file/d/1NMAUtZcoSLwmHt_r5TLWwB28QJDghi6Q/view
2. https://www.freeingenergy.com/how-much-co2-and-other-pollutants-come-from-burning-coal/
3. https://www.ucsusa.org/resources/water-coal
4. https://www.wri.org/insights/identifying-global-coal-industrys-water-risks
5. ibid
6. US estimates adapted from https://www.circleofblue.org/2010/world/a-desperate-clinch-coal-production-confronts-water-scarcity/ based on standard metric conversions.
9. https://www.seas.harvard.edu/news/2021/02/deaths-fossil-fuel-emissions-higher-previously-thought
10. https://www.uq.edu.au/news/article/2018/04/gas-stoves-and-damp-houses-increase-aussie-asthma-rates
11. https://gosolargroup.com/modules/typical-size-and-weight-of-solar-panels/
12. Estimated from various sources including, for example, Vestas product literature: https://www.vestas.com/en/products/2-mw-platform/V100-2-0-MW
13. https://prod.iea.org/reports/key-world-energy-statistics-2021/final-consumption
14. https://www.e3s-conferences.org/articles/e3sconf/pdf/2020/41/e3sconf_icsree2020_02004.pdf
15. Figures used are conservative. Solar capacity factor varies greatly based on the latitude, local cloud cover, and installation approach including use of tracking mounts that rotate the panels to follow the arc of the sun over the course of the day. Well designed installations in suitable locations report capacity factors above 30%. Contemporary high quality panels are rated at 400 Watts or more based on the same physical panel size.
16. https://www.solarreviews.com/blog/how-long-do-solar-panels-last
17. https://www.twi-global.com/technical-knowledge/faqs/how-long-do-wind-turbines-last
18. https://energynumbers.info/uk-offshore-wind-capacity-factors
19. https://www.energy.gov/eere/articles/wind-turbines-bigger-better
20. For those interested, the footprint of all those panels (if installed in a contiguous block) would be about 375,000 square kilometres excluding service accesses – similar in size to Norway or Japan and around the size of Australia’s largest desert (the Great Victoria). The Sahara Desert is 9.2 million square kilometres. On the other hand, it’s also an area similar to the combined land size of just 75 of the world’s largest cities – rooftop and road-side solar can minimise the environmental impact of renewables.
21. https://hedgescompany.com/blog/2021/06/how-many-cars-are-there-in-the-world/
22. The rise of Sports Utility Vehicles (SUVs) has steadily been increasing average vehicle weight, wiping out much of the gains of engine fuel efficiency. (https://www.forbes.com/sites/scottcarpenter/2021/01/22/growing-popularity-of-suvs-complicates-efforts-to-reign-in-auto-emissions/?sh=21e6c0b73531)
23. https://www.evconnect.com/blog/how-long-does-an-electric-car-battery-last
24. Sure, many people replace their car at shorter intervals, but the second hand market means vehicles are typically used for 10-15 years before winding up at the wrecker’s yard.
25. For example, the kerb weight of a Nissan Leaf (fully electric) vs a Toyota Corolla Hatchback (petrol) is about 200kg heavier (source: cars-data.com).
26. Assuming typical petrol fuel efficiency for a mid-sized vehicle of 10 litres per 100km. A litre of petrol weighs 0.737kg.
27. https://globalenergymonitor.org/projects/global-coal-plant-tracker/
28. https://globalenergymonitor.org/projects/global-gas-plant-tracker/
29. https://globalenergymonitor.org/projects/global-coal-mine-tracker/
30. https://globalenergymonitor.org/projects/global-oil-gas-extraction-tracker/
31. https://hrcak.srce.hr/file/65010
32. Griffith, Saul (2020), Rewiring America - A Field Manual for the Climate Fight
33. https://news.yahoo.com/fact-check-wind-turbine-blades-235853274.html Wind turbine blades can be recycled though the economics compared to landfill are not yet compelling. This could change with sensible regulation. For example, GE recently announced the largest fully recyclable wind turbine blade: https://www.world-energy.org/article/23859.html
34. https://www.weforum.org/agenda/2021/05/electric-vehicle-battery-recycling-circular-economy/
35. https://reneweconomy.com.au/australias-first-solar-panel-recycling-plant-swings-into-action/; https://thedriven.io/2022/03/15/mercedes-benz-to-build-battery-recycling-plant-with-australias-neometals/
36. https://factcheck.afp.com/bird-deaths-misleading-numbers-conceal-biggest-culprits
37. https://www.bbc.com/news/science-environment-53909825
38. https://ec.europa.eu/environment/topics/waste-and-recycling/end-life-vehicles_en
40. https://www.usgs.gov/faqs/how-much-copper-has-been-found-world
41. Ibid.
43. https://www.science.org.au/curious/technology-future/batteries-future
44. https://www.responsibleminingfoundation.org/app/uploads/EN_Research-Insight_Human-Rights_Feb2021.pdf
45. https://www.climaterealityproject.org/blog/what-are-climate-change-tipping-points
46. Refer to https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_SummaryForPolicymakers.pdf for a summary of projected impacts at different levels of warming.
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