A new book that outlines a pathway to meet the 1.5°C goal of the Paris Agreement has been released for open access online , but is also available in hard copy from March 7th on Amazon. The work has been conducted by various academic institutions and is largely sponsored by the Leonardo DiCaprio Foundation. The route chosen is to meet all energy needs with renewables such as wind, solar and hydroelectric with the consequent phase-out of fossil fuel use for all energy needs by 2050. Carbon capture and storage (CCS) is not considered as an option, but natural sinks play an important role through large scale land restoration and reforestation. So rapid is the proposed transition that emissions fall sharply from next year (2020) and fossil fuel consumption is reduced by 60% in just a decade. An important additional component is an overall reduction in energy demand through a very strong efficiency drive.
There are six major components to the transition, with the first five relating to objective of 100% renewables for all energy use;
- Increased capacity to generate electricity mostly through solar and wind power, enabling the electrification of all energy uses including power, heating, transportation, and even industrial uses.
- Increased storage capacity in the form of battery arrays and pumped hydroelectric (which uses excess generation to pump water up to a reservoir releasing the energy when needed).
- Improved energy efficiency – decreasing overall energy consumption, especially in the developed world, by making buildings, cities, and vehicles more efficient.
- Re-purposing the existing gas pipeline and storage infrastructure to deliver hydrogen produced by renewable sources.
- A gradual retraining of the energy workforce to participate in the burgeoning green economy.
- Land restoration and reforestation to meet negative emissions requirements.
Following the IPCC 1.5° Special Report last October (SR15), it is clear that the lowest risk pathway in terms of climate impact is one that sees emissions fall rapidly, with minimal temperature overshoot before the end of the century. The book effectively follows the pathway P1 (no CCS, rapid fall in fossil fuel use) set out in SR15, although they make more extensive use of land sinks than P1.
The IPCC P1-P4 archetype pathways can be categorized in terms of final energy demand and their use of sinks (both natural and artificial, e.g. bio-energy with CCS or BECCS), which also allows a comparison with the Shell Sky Scenario that featured in SR15.
Sky is akin to the SR15 P4 pathway, in that the additional energy demand they both foresee leads to extensive use of sinks to balance overall emissions and deliver a 1.5°C outcome. Within the Sky scenario efficiency plays a major role in curbing demand, but final energy demand still rises throughout the century (see chart below), albeit coming close to a plateau from 2080. This is driven primarily by the demands of some 2-3 billion people moving from modest income to middle income. In addition, there are a further 2-3 billion people moving from little income to modest or even middle income. Even with a major efficiency push, energy demand just doesn’t fall that easily, unless of course consumers hold back in their demand for energy services, e.g. travelling by air.
Sky, like P4, doesn’t see emissions falling until about 2030 in that this is the minimum time the scenario requires to build the necessary political and technical capacity to introduce carbon prices, ramp up production of various technologies and at least begin developing further out technologies such as hydrogen use for metallurgical smelting.
But the new pathway proposed in the publication seemingly allows no time for such change. As noted, under that pathway emissions fall sharply from 2020, yet we are currently in a period of sharply rising emissions (according to an analysis by the Global Carbon Project, 2018 emissions are estimated to have risen by 2.7% compared to 2017). While such a fall would be an ideal outcome and for a better than 50% chance of being below 1.5° is probably required, the difficult question that must nevertheless be answered is by what process this happens? In the Sky Scenario it was proposed that rapid ratcheting of NDCs throughout the 2020s could lead to emissions beginning to fall by 2030.
A further challenge is the decision by the authors not to employ any form of CCS and also phase out all fossil fuel use by the 2050s. For sectors such as aviation, the likely energy source in 2050 will still be hydrocarbon liquids, even if new engine technologies have begun to appear. Some planes that will be flying in 2050 are being built now and there is no line of sight to an alternative technology, so presumably the current generation of planes will continue to be built for several decades.
With no CCS, it means that the fuels must be synthetically produced, either from biomass or by chemical conversion of hydrogen (generated by electrolysis of water using solar energy) and carbon dioxide (extracted from the air), such that they have a net-zero impact on atmospheric carbon dioxide. But these synthesis technologies hardly exist today, although parts of the possible process do (the Shell synthetic fuel plant in Qatar which uses natural gas as the starting point). Just meeting aviation and marine needs with synthetic fuel plants in 2050 would require some 100 large scale facilities, starting from a current position of zero (or perhaps two, if the synthesis reactors in the handful of existing facilities were re-purposed).
A 100% renewable energy world will still require an energy carrier that isn’t electricity, for example for intense heat in certain combustion applications. Hydrogen could be such a carrier and could also be used for energy storage as well as having a role in liquid fuel synthesis. But the scale of a global hydrogen industry to support the renewable energy world would far exceed the global Liquefied Natural Gas (LNG) industry we have today. The LNG industry includes around 300 million tonnes per annum of liquefaction capacity and some 400 LNG tankers. That amounts to about 15 EJ of final energy compared to the current global primary energy demand of 500 EJ. In a completely new energy system in 2050, a role for hydrogen as an energy carrier that reached 50 EJ would imply an industry that was four times the size of the current LNG system. The current LNG system has emerged over a period of 60 years; building a system four times the size in 30 years seems unlikely.
There is no doubt that the 1.5°C Paris pathway outlined in the book is an incredibly ambitious one, but it may even be beyond the bounds of the possible. It will take some time to review the full publication, so I hope to report back in the coming weeks on various aspects of the story presented.
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