Electrification is probably humanity’s biggest energy shift since the industrial revolution. With a world expected to gulp down 610 quadrillion (610,000,000,000,000,000) Btu, this transition is going to take many decades. But why is this happening and why does it make sense in terms of sustainability?
To explain it, we need to look at some basic physical principles. It has to do with how much useful work can theoretically be extracted from a type of energy source, described as the quality of the energy. Heat is usually a low quality energy compared to kinetic energy (i.e. movement) or electricity. A low graded energy form cannot be fully converted into higher quality form. This concept is one of the principle of thermodynamic. A list of the form of energy and their quality is described by Otha’s ranking.
The maximum amount of energy that can be transformed into higher quality is named exergy and does not depend on the machine used, it is dictated by the laws of thermodynamic. The goal of this writing is to have a purely theoretical approach and consider the machines are without losses. This method can indicate how much room your R&D has for improvement of the existing process.
A good example is the internal combustion engine versus the electric motor. A gasoline vehicle reaches an efficiency of around 35% even though great engineers have been working on improving the system for more than a century. The thermal engine efficiency is limited by the Carnot cycle and breaking this limit would break the laws of physics. Electric cars, on the other hand, easily reaches efficiency above 90% resulting in a dramatic reduction of the energy transported by the vehicle (A Tesla Model S 100D contains the equivalent of 10 litres of gasoline for a range of 600 km). Understanding this explains simply why automakers are switching to hybrid vehicles to comply with strict emission standards.
Going back to the electrification of our economy actually, it is a replacement of thermal energy to improve overall energy efficiencies. Renewable energy generation is great for this as the energy quality of photon, wind, hydro are of better quality than heat (i.e. coal & gas). Once the economies of scale are sufficient, thermal energy generation will be so inefficient compared to clean energy there will be no economical reason to burn fossil fuel for energy (considering the subsidies are removed).
However, the current main challenge of those high quality energy types is the storage. Electromagnetic, mechanical, photon cannot be stored for long period of time. This is the fundamental reason why electric cars disappear for a hundred year. They were popular in the early 20th century and lost the battle because battery could not store as much energy as gasoline. Having a power grid full of wind and solar cannot work if there is no massive storage systems. But, again, looking at first principle, those technologies are feasible and are diverse. It is only a matter of time for the engineers to develop the right systems.
Understanding this first principle about energy quality is important when making strategic decision on what technology to invest in. Developing key performance indicators is an essential metric but if they are not defined properly, such as the energy efficiency for vehicle, the resources may not be exploited in the most useful manner.
Peter Asmus. (2019). A Growing Role for Energy Storage, Energy Storage Enhances the Economics of Microgrids and VPPs. Distributed Energy, The Journal of Energy Efficiency & Reliability
Dr. Linda Capuano. (2018). International Energy Outlook 2018 (IEO2018). US Energy Information Administration