Possible is a nuts and bolts guide to the technologies that could help the world reach net zero emissions by 2050.
Researched and written by veteran energy specialist Chris Goodall of Carbon Commentary, Possible surveys the state of the art across all the main areas for decarbonisation. The scope of the energy transition is so vast that there’s not many people who can stay on top of the detail in every area, so a wide-ranging study like this is a welcome addition to any sustainability shelf.
The first and longest section considers electricity generation – a relatively easy part of the puzzle, at least as far as technology is concerned. Goodall is confident that renewables, supported by hydrogen as an energy storage medium, can do do the job.
He does note that nuclear can be used where necessary and economic, but is sceptical about costs and timescales. The detailed models I’ve seen from other organisations do generally find that a significant share of nuclear is required for an optimised energy mix, but a lot depends on assumptions about energy storage to mitigate the limitations of variable renewables.
H is for hope
Goodall puts a high priority on green hydrogen, created by electrolysis using renewable electricity, as an energy store. This cycle inevitably loses at least half the initial energy, but can still make economic sense. In some cases, it could be cheaper to produce hydrogen to pipe over large distances than to build and operate grid connections.
Hydrogen also has a large potential role in decarbonising industries such as steel, cement and chemicals. Goodall also digs into the challenges of plastics, food and clothing, before diving into transport. Aviation remains one of the most challenging sectors to decarbonise, and makes up an ever-growing share of global emissions.
For me, perhaps the most interesting chapters were on carbon removal techniques. These include carbon capture at source for some industries (it’s unlikely to ever make economic sense for fossil-powered electricity generation), emerging technologies for direct air capture, and nature-based solutions. These will play an increasing role as direct emissions reduce.
Even if we reach net zero emissions by 2050, atmospheric concentrations of greenhouse gases are likely to be much too high for comfort. The costs of a permanently hotter world mean that pulling CO2 back out of the air could be a major industry of the late 21st century.
Goodall closes with a brief consideration of some of the political and social factors around the energy transition. Perhaps the most effective step would be the introduction of a global carbon tax – the obvious thing to do economically, but one of the hardest politically.
State of the art
In many ways, Possible serves as an updated version of the late David MacKay’s classic Sustainable Energy – without the hot air, which I reviewed for another blog way back in 2009. It’s not as engaging a read, though.
It’s clear that Goodall has interviewed countless people working to bring these technologies to market, but the reader is often given little sense of the scale or nature of the many projects discussed. A more journalistic approach could have brought these projects to life.
The text is extensively referenced, although you will have to read with a device in hand as the references aren’t included in the book. Instead, they can be found on Goodall’s website. That makes it a lot easier to dive into the online references, but can be frustrating when you just want to look one thing up quickly. It’s also likely to limit the book’s value to any future historians of the energy transition.
There’s also an annoying number of typos and errors – most eyebrow-raisingly, the accidental claim that one solar farm will boast “840 gigawatts of PV” (should be 840MW). That’s maybe a consequence of rushing such a timely book through production.
As a review of the state of the art in energy and climate technology, Possible will inevitably date quickly. It was published in early 2024, and a few parts are already out of date – frustratingly so, in the many US projects which were set to benefit from government support from Biden-era programmes which have since been demolished by the reality-denying Trumpists.
Still, as the book sets out in detail, net zero is still within our reach. We just need will, action and the readiness to reap the rewards.