Energy and the scale of the decarbonisation challenge

I have recently given a few talks on the scale of the decarbonisation challenge and why much of it is about or heavily linked to energy, as well as the massive benefits highly available and storable energy sources have brought to humanity. The following are a few of the main points, in my view, from those talks:

·??????CO2 concentration has increased from 280ppm to ~420ppm since the start of the industrial revolution. It continues to rise at 2ppm per year.

·??????Global temperature rise is currently estimated to be 1.15C above 1850 average.

·??????To limit to 1.5C by 2050 estimated requirement of 45% reduction in emissions by 2030 and net zero by 2050.

·??????Since the industrial revolution global primary energy consumption has gone rapidly in one direction – up.

·??????Some regions have ‘plateaued’ in consumption but have high per capita energy consumption, some regions are increasing energy consumption use as people move out of energy poverty and manufacturing increases (frequently displaced from the plateaued regions).

·??????Share of fossil fuel as primary energy has reduced from 87% in 2000 to 84% in 2019.

·??????In 2021 the world used approximately 600 Exajoules of energy – 1 Exajoule is approximately 300TWh – which is about equal to the annual UK electricity consumption. Therefore, the UK’s electricity consumption is less than 0.2% of global primary energy.

·??????Side note – burning hydrocarbons for energy tends produce a lot of waste heat – so by avoiding wasteful combustion processes primary energy need could be reduced, E.g., by directly using low carbon electricity from non-combustion sources. However, demand is likely to go up too with increasing electrification and hopefully through continuing to eradicate energy poverty.

·??????Humanity produces approx. 50 billion tons of greenhouse gases a year.

·??????Of this approximately 73% come from energy sources and conversions - ~36.5 billion tons.

·??????Since 1810 average life expectancy and income has increased markedly – this can be directly related to abundant use of energy dense fuel sources to create chemicals and products, efficiency and free time for innovation, education, health etc. Some regions are still to benefit as much as others in this regard.

·??????Humanity uses massive amounts of stuff – alongside our primary needs for water, food, energy and shelter we use per annum 4.5 billion tons of cement, 1.8 billion tons of steel, 350 million tons of plastics and 180 million tons of ammonia. This is not likely to go down soon.

·??????Whilst energy efficiency and being selective about what we use energy for (i.e. not wasting it) is incredibly important to reducing emissions it does not mean energy systems will get smaller. Recycling and re-use of materials in any proposed circular economy is also likely to require energy to process and a huge change in markets and behavious.

·??????Almost all future forecasting of energy systems (varies by region but the principles are consistent) show significantly larger (by GW capacity) electricity systems producing a proportionately lower ratio of TWh output to GW installed (due to increased levels of intermittency).

·??????These future systems are incredibly more complex and diverse and require massively more infrastructure such as transmission systems and energy storage to sustain operability.

·??????Future system scenarios often depend on technologies yet to be proven or deployed at scale. They may also introduce energy inefficiencies driven primarily by system balancing and multiple energy conversions (e.g. making transport fuels from low carbon electricity).

·??????We need to be very clear on how we want to use manufactured fuels/feedstock such as hydrogen. Hydrogen is not an energy source, it is a carrier and needs to be made, stored and used all of which introduces inefficiencies. We already use over 90 million tons of hydrogen per annum which has a high carbon emission associated with it. Decarbonisation of our current use is a herculean challenge - my thesaurus doesn't have a word for the scale of the challenge to add lots of other uses in at the same time.

·??????Multiple regions are pursuing similar strategies. Hence competition for materials and skills will increase. Reliance on interconnection between countries with similar strategies may be flawed (e.g. shared weather patterns). Reliance on single technologies or fuel sources comes with increased risk (e.g. gas). Diversity for security of supply and resilience is practical.

·??????Forecasting future costs of raw materials and technologies is a tricky business – inflation, competition, rapidly increasing demand, and supply chain issues can drive rapid cost swings.

·??????Building a diverse energy mix with a clear understanding of local resources is a fairly obvious thing to do – i.e. markets may or may not pick the right technologies for system needs, some countries get a lot less sun than others, firm and reliable power should be valued appropriately etc.

·??????The energy trilemma is a demanding thing – balancing energy security of supply (fuel and resilience), affordability with sustainability is hard and needs policy hand in hand with a clear in-depth scientific and engineering understanding.

·??????We are paying the price for historic levels of low investment and construction in robust energy generation – relying on past assets well past design lives.

·??????UK power system targets require hitherto unachieved levels of build rate of generating assets as well as the transmission system capable of connecting it all up. The UK has not achieved this build rate in the past - but other countries have - so it is possible.

·??????Holistic system design of energy generation, transmission and storage with demand is pretty fundamental for such a complex thing to work efficiently and reliably – an energy system architect is a sensible thing to deploy.

·??????Levelised cost of electricity is not a great comparison metric for system cost and cost to the consumer / user.

·??????System balancing is getting harder and more expensive on the UK electricity system and for other countries and capacity margins are reducing to low levels.

·??????We need a mind-blowing amount of new materials to make the forecast systems a reality – one estimate is that we will require more mined material in the next 30 years than has been mined in our history and the materials processing required to go with that will be on a hitherto unseen scale. The potential for environmental damage is high and concerning if this is not done well.

·??????Keeping things simple: electrify everything you can, create or grow synthetic fuels / for energy storage and when you can’t economically electrify, and carbon capture and sequestration for anything left.

·??????Civilisation is energy intensive, electricity will be the foundation of a low carbon society, the faster we can build a reliable low carbon electricity generation system the better, all technologies have a potential role to play, sustained policy and sustained build is required at pace to bring down costs and time.

·??????Above all though have a fact-based approach and a questioning attitude – understanding the energy market, different technologies and a huge variety in perspectives is not straightforward.

With thanks to BP statistical review, our world in data, Vaclav Smil, Hans Rosling, Dieter Helm , Michael Liebreich , James Lovelock, the late Sir David MacKay and many others for providing highly informative source material and interesting perspectives. Interested readers can also see our reports on Engineering Net Zero here.