Our world has witnessed an unprecedented time in the last twelve months, with many activities coming to a standstill because of the COVID-19 pandemic. In all walks of life, the world will not be the same as it struggles for normality at present, with many sectors shut for extended periods of time and some businesses shutdown for good. Yet, with all this upheaval, there are still challenges ahead that can make the last 12 months seem insignificant, with the potential of becoming an existential crisis for the human race. This is none other than Climate Change. Ironically, the last 12 months have given time for the Earth to recover marginally from the ever-present pollution and smog, the release of large amounts of greenhouse gases into the environment, as a result of the unrelenting need for energy. Despite warnings as far back as 1997 from Kyoto at the Conference of Parties 3 (COP3), and then replayed with much evidence in December 2015 in Paris at COP21, the world continues to be heavily reliant on fossil fuels for energy to power the human-desired technologies for a higher quality of life. Historically, whatever the reason was for opting into a fossil fuel-based technology, at present, there is no excuse to do so, not monetary, not environmental, not societal. Therefore, with no reason to continue our dependence on fossil fuels based on sustainability, how do the energy materials community help achieve the Sustainable Development Goals (SDGs) (Figure 1) identified by the United Nations[1] in a non-fossil future? Over the last century, humanity has been hooked on cheap energy generation by burning coal, oil, and gas to produce energy, that has sustained industry, domestic heating, and electricity. Despite the efforts over the last two decades to wean our energy supply from fossil fuels, the world at large uses nearly 80% of fossil fuels in its energy mix,[2] as shown in Figure 2. This is partly historic and has been embedded into society until recently due to the significantly cheaper price of fossil fuel-based electricity conversion in comparison to renewable energy sources. Yet, this equation has now changed. Over the last 2–5 years, the cost of electricity generation using solar farms and wind generation has plummeted to values cheaper than fossil fuels even in northern climates such as the UK, far from the equatorial sweet spots with maximum insolation, as shown in Figure 3a. Furthermore, with the ability to tailor solar cells to absorb more in the infrared, diffused solar irradiation will enable better use of the optical spectrum to continue to deliver energy even in indirect conditions, such as indoor lighting. This will lessen the burden of running the ever-increasing IoT infrastructure on scavenged “solar” energy. Closer to the equator, solar price auctions as low as US$10 per MWhr[3] have been sold in large 600 MW farms, and these prices reflected typically in a range of US$15-40 per MWhr at large auctions in India, Brazil, Chile, Mexico, Middle East, and China. With energy this cheap one could envisage a world in which electrolysis of water with solar technologies kick-starting the hydrogen economy with green hydrogen production. In Germany, solar and wind costs in the range of US$35-55 per MWhr have been sourced at auctions in 2020-21.[4] The variation of average levelized cost for electricity is illustrated in Figure 3a based on major energy source conversion to versatile and ubiquitous electricity from 2000 to 2050. Even the UK Government announced in its recent BEIS report that solar and wind provided the cheapest large-scale energy provisions at present in the country.[5] For the last two decades, most professional bodies projecting the levelized cost of energy (LCOE) of solar PV have significantly underestimated the reduction in costs observed due to the reduced emphasis on deployment studies and as a result have not been able to accurately predict its competitiveness. Therefore, we estimate the projected deployment of both solar PV and wind in Figure 3b. Many experts have compared the deployment of solar PV to the enlargement of automobile sector starting with the Model T or Moore’s Law for IC circuits, to estimate price reductions. Based on historic data, it is possible to show that the logarithm of solar deployment follows an inverse relationship, when plotted against LCOE price. Approximately, the LCOE price premium for solar PV halves with every decade rise of global installed capacity. Due to the squared nature of the price reduction, it is also possible to get an approximate straight line between the log-log plot of LCOE price for solar PV and cumulative solar deployment in MW. Using this simple rule of thumb, with the projected deployment of 5TW of solar by 2035, it is possible to foresee the price reduction from the current LCOE average of US$37 per MWh to US$9.5 per MWh, rather than the EIA estimate of US$30 per MWh. The recent IEA Report[6] highlighted that for the world to maintain its ambitions of meeting the 1.5°C rise in temperature from the pre-industrial values, we need to get to carbon net zero by 2050. For this to happen, the IPCC noted that we need to decrease our methane emissions from fossil fuels by 75% over the next 10 years, while sustaining a world economic growth of 40%. Furthermore, we need an additional 1000 GW of wind and solar energy by 2030, although the total increased capacity in the whole of the decade between 2010 and 2020 was only 200 GW, that is, from 2020 to 2030 a highly ambitious target of 100 GW per annum is required in the ratio of 60:40 solar to wind (Figure 3b). For the energy storage based upon these intermittent energy sources, the prediction is the need for major innovation in advanced batteries. Furthermore, the decarbonization of the transportation sector would require a 15-fold rise in electric vehicles (EV) sales to 145 million for 2030 from the 10 million in 2020. All these are heavily dependent on technology advancement in battery storage technology. The size, scale, and distribution of the innovations required in solar energy harvesting and energy storage are unprecedented. We can wait and allow the current technologies to take the strain of what is required from an energy materials perspective for the next ten years, but it will not be viable beyond that. We need new solar materials that are much cheaper, more easily deployed, with shorter payback times, and increased stability, maintaining the 20–30% efficiencies currently available with the incumbent silicon solar technology. There are a number of thin-film technologies, new polymer, and small molecular materials, particularly when modified by third party inorganic/organic hybrids that are giving fourth-generation solar technologies with advanced photon spectrum capture, coupled with enhanced transport and much thinner, cheaper build of materials coming to the market.[7, 8] Novel halide perovskite thin films initially as active materials in tandem configurations on silicon are also highly likely to feature in solar energy harvesting over the next decade.[7, 8] In the case of energy storage, there are many new technologies pushing hard against the existing mature systems (e.g., lead-acid battery, flow battery, and Li-ion battery), waiting to improve their Technology Readiness Level (TRL) to allow for its exploitation on a national scale. It is important for such technologies to go through all the necessary safety tests, with a rewinding toward the dendritic growth shorting of batteries that caused major fires confined largely to history. But, one cannot but speculate that with the need for higher levels of energy storage, the risks associated with the storing of potential energy in the form of electricity do bring its own risks. We have progressed hugely since the Hindenburg Zeppelin disaster in 1937, and the over-charging induced battery combustion of some mobile phones as well as electric vehicles in the last decade, which periodically remind us as to the capacity to ignite being present with energy storage devices, particularly at high density. In considering potential mitigation on the types of future batteries, maybe non-flammable electrode and electrolyte would be best placed to reduce the risk of fires.[9] The need for novel green energy harvesting and storage materials, with a proven record for scaling and manufacture, is real and present today. National governments will find it very difficult to justify to its people the use of fossil fuels for future energy, when the cost associated with the energy materials is decreasing rapidly, as illustrated in Figures 3 and 4. With the pressure of avoiding a catastrophic climate change scenario, it is expected that close to US$100Billion will be invested in the next decade on clean energy materials for harvesting and storage. We concede that it is not possible to terminate the progress of current large-scale programs, but what we can do is to replace where possible, all infrastructure and buildings with more sustainable alternatives, to save our society and humanity. In doing so, energy materials are going to be at the center of these requirements moving forward. The need for very large-scale institutes that take high-quality research to high TRL levels, suitable for exploitation by industry, will become increasingly crucial. Within these scenarios, Energy Materials will be the “King” with the precious task of looking after the Environment as its symbiotic “Queen,” the Yin and Yang of future humanity. The stakes are high, but my confidence in the research community of energy materials to deliver is higher. Let us keep a close watch on the research and future work in this highly important field.
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S. Ravi P. Silva (2021) studied this question.
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