## 1 Introduction
Additionally, if the car user is dependent on the power grid and adopts \"smart load management,\" this will inevitably be a short-term policy. Increased vehicle charging will rapidly offset any current lower charge period, as the demand will grow per vehicle sold, which will rapidly exceed sustainable power generation. Ensuring that batteries are made using renewable energy is also a challenge, as rare earth metals are extracted in countries not readily amenable to moving from fossil fuel energy production to sustainable solutions. In short, the Fraunhofer report [6] can support longer-term change to electric vehicles, which contributes to the needed balance between pro and con arguments and the adoption of electric vehicles only where optimal. The question of variable production from solar and wind power also remains, which urgently demands advances in electricity storage and an understanding of the implications for deciding the future transport power source. The cracking of water to release hydrogen is one of the most efficient options to provide such storage. Thus, it may be simpler to adopt hydrogen alone as the prime distributed fuel for industrial and transport needs. In such a case, the need for fuel cell technology can be removed. [PERSON] et al. describe how the rotary Wankel engine, with its extended combustion volume and ignition timing and its separation of cooler and high temperature regions to prevent premature ignition, is extremely suitable for direct hydrogen combustion [8]. Given the desire to opt for the minimal carbon emissions pathway to navigate the evolving regulatory environment aimed at promoting sustainably favourable energy sourcing and motive power, these findings indicate that ICE transition from petrol to diesel and then to hydrogen provides the greatest relief to the climate change and global resourcing threat. Even if these scientific findings are ignored and political expediency alone prevails in the field of transport, the use of hydrogen for energy storage and for industrial energy processes cannot be ignored on economic grounds. In 2019, the technology for water separation into hydrogen and oxygen took such a great a leap forward that hydrogen production efficiencies of up to 98.7% may be achievable, which could lead to a cost reduction of 50%. The technology is based on decoupling the electrolysis into two reaction steps in which the first is an electrochemical step that reduces water at the cathode while oxidising the anode. The process is then followed by a chemical step driven spontaneously at raised temperature, which reduces the anode back to its initial state by re-oxidizing water. The authors, [PERSON] et al., claim to be able to split water at average cell voltages of as little as 1.44 V to 1.60 V using current densities of as low as 10,200 mA\(\cdot\)cm\({}^{-2}\) in a two-electrode cell without needing a membrane [9]. This means that point-of-use combustion will remain and move from carbon burning to hydrogen burning. Burning, by definition, means oxidation, which is most efficient at high temperature and pressure. These are the conditions under which oxidation derived from air, which is a mix of oxygen and nitrogen, inevitably leads to the formation of oxides of nitrogen (NO\({}_{x}\)). The unavoidable consequence is that NO\({}_{x}\) pollution at ground level will remain a hazard to human health even if society becomes carbon neutral or abandons carbon altogether. It is imperative to find a way to mitigate this threat without creating further negative effects, such as ammonia release. Ammonia release can lead to particulate formation in the air when using NO\({}_{x}\) inhibitors as additives directly in the combustion environment.