Malcolm Wilkinson and members of the Sustainability Special Interest Group discuss the technologies available for decarbonisation
ICHEME’s Sustainability Special Interest Group (SSIG) has prepared a series of thought pieces on achieving zero-carbon, a challenge and an opportunity for the engineering community in general, and chemical engineers in particular. Chemical engineers will play a crucial role in the design of pathways for the decarbonisation process in specific energy-intensive sectors, notably power, heavy industry and transport and to a lesser extent in buildings and agriculture. This is the second thought piece, the first entitled The Future of the Oil & Gas Industry1. This piece focuses on the power sector and the technologies available to decarbonise electricity. Two further pieces will cover the decarbonisation of end uses and materials efficiency.
Electricity is key to the low carbon transition. In the last 10 years electricity generation has increased by 33% – around two thirds faster than total final energy consumption – and 83% of this growth has come from non-OECD countries2. In addition, as of 2017, 840m people, living mainly in Africa, still lacked access to electricity, down from 1.2bn in 2010, and strategies will be needed to address this issue.
Whilst many national and international policies are strongly oriented towards the electrification of energy systems, electrification must proceed in parallel with decarbonisation. A strongly integrated approach across sectors and energy pathways is essential to address the adverse consequences of climate change. A holistic perspective on the entire life cycle of technological solutions is needed with consideration of potential secondary effects to avoid unintended consequences (see later) arising from today’s technology choices. The necessary systems approach requires input from all stakeholders in the supply chain and hence strong government leadership.
As far as primary fuel sources for electricity generation are concerned, coal use is already in decline and must be phased out completely, oil demand is considered to be now at peak and whilst natural gas will contribute during the transition it will also need to be decarbonised or phased out to reach the zero-carbon emissions target. The future lies with renewable energy sources.
In 2019 renewables, solar PV and wind accounted for 10% of global electricity generation, equating to 41% of the growth in energy demand, and were growing at 14% year on year2. In addition, hydroelectricity and nuclear power accounted for a further 26% of electricity generation. The motor of change rests in emerging markets, which is where all the growth in energy demand lies. Emerging markets have higher population density, more pollution, and rising energy demand. They have less fossil fuel legacy infrastructure, rising energy dependency, and are likely to seize the opportunities of the renewables age where rapid growth and technology-driven learning curves have resulted in a fall of around 20% in costs for each doubling in capacity.
The International Energy Agency (IEA) reports that solar, wind and hydropower projects are rolling out at their fastest rate for four years. Its latest report3 predicts that by 2024 a new dawn for cheap solar power could see the world’s solar capacity grow by 600 GW, almost double the installed total electricity capacity of Japan. Overall, renewable electricity is expected to grow from 1,226 GW in 2019 by 1,200 GW in the next five years, the equivalent of the total electricity capacity of the US.
Whilst solar power is growing at an appropriate rate, wind and hydropower growth rates are slightly behind the IEA’s projections to meet its Sustainable Development Scenario (SDS), which is Paris compliant though only reaching zero-carbon in 2070. Onshore wind capacity additions began to grow again after stagnating during 2016-18 and in 2019 onshore wind electricity generation increased by an estimated 12%. A more rapid capacity increase is needed through to 2030 to get back on track with the SDS. Compared with record 32% growth in 2017, offshore wind electricity generation increased only 20% in 2018. Given its relatively small global base, offshore wind growth must accelerate even further to reach the generation levels anticipated in the SDS. The cost reductions, technology improvements through larger turbines and more recently floating structures, and the rapid deployment achieved in the UK and Europe need to be extended to other regions. Hydropower generation is estimated to have increased by over 2% in 2019 but capacity additions overall declined for the fifth consecutive year, putting this technology off track with the SDS, which requires continuous growth in newly-built capacity to maintain an average generation increase of 3% per year through to 2030.
Under the auspices of the United Nations (UN), world governments agreed at COP21 in Paris in 2015 to limit the global temperature increase to well below 2°C above pre-industrial levels and to pursue efforts to limit the rise to 1.5°C to avoid potentially catastrophic impacts on human existence. More recently the 1.5°C target has gained increasing focus. The Intergovernmental Panel on Climate Change (IPCC) emissions pathways to limit warming to below 2°C require net zero CO2 emissions by around 2050 from a peak in the 2020–2030 period4.
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