A HOLISTIC VIEW ON ELECTRIFICATION
Electricity is a unique and valuable form of energy. It is very versatile and user friendly on the demand side, but equally awkward and inefficient on the supply side. The latter is dominant in the overall impact of large scale electrification of heating, mobility and industry. Increasing electrification of society therefore appears unable to substantially reduce CO2 emissions on a global scale, and is not the way to go in an energy transition.
Electricity is one of the various carriers of energy in our daily life and work, next to e.g. natural gas, gasoline and district heating. It presently (2020) represents some 20% of our total worldwide energy consumption, powering our lighting, computers, fridges, trains and many production machines. Our largest energy users however are presently not driven by electricity, such as most cars, heating systems, trucks, airplanes and industrial processes. There is a very fundamental reason why economy and technology in the 20th century have developed this way: Electricity is intrinsically difficult and inefficient to produce, transport and store on a large scale.
The demand side of electricity
Electricity from any power socket is usually reliably available at any time of the day or night. Electrical devices are generally easy to operate, and relatively efficient, quiet and clean. Electricity can power a larger variety of appliances than any other carrier of energy, from flashlights to heat pumps. Many appliances even can only be powered by electricity, such as smartphones, computers, TVs and in fact all electronic devices. Increasing electrification of society therefore seems an attractive strategy.
The supply side of electricity
The whole chain that supplies electricity to the power socket in our home and workplace can be divided into three segments: Production, distribution and storage. Let us review each of these three segments:
We have a variety of technologies at our disposal to generate electricity: Fossil fuel plants, biomass, nuclear power, hydropower, wind turbines, solar panels, and tidal and geothermal energy. Fossil fuel, biomass and nuclear plants primarily produce heat followed by gas expansion, and are therefore subject to the thermodynamic Carnot cycle. This limits their efficiency in practice to roughly 50%. Hydropower, tidal and geothermal energy are very dependent on specific geographic circumstances, and can therefore not be applied in most places on earth. Wind turbines and solar panels on the other hand operate everywhere, but are very variable and/or unpredictable on a daily basis, and require vast amounts of space.
Long distance electricity transportation comes with substantial losses, which can be limited by transformation to very high tension, up to e.g. 380,000 volt. Subsequent local distribution again requires transformation, down to e.g. 10,000 volt, and then further down to 230 volt in your home and work place. Each transformation step up or down also comes with losses. The total energy loss in a regional or national transformation and distribution grid is typically in the range of 5-10%.
Storage of electricity is by far the most difficult and expensive step. The most common way at present is battery storage, being relatively fast and efficient. Batteries are very bulky, heavy, polluting and expensive per stored kilowatt-hour, but work fine for low power applications such as smartphones, laptops and even vacuum cleaners. For cars, batteries become more cumbersome, for buses and trucks increasingly difficult, and for trains and airplanes practically impossible. The penalty of battery size, weight and cost for such large energy users is progressively prohibitive, reason why battery driven trains and airplanes for mass mobility will be literally and figuratively unable to lift off. Large scale battery storage for public grids is very limited at best, on technical as well as economical grounds.
A more novel way of electricity storage is through some chemical substance, such as hydrogen gas, metal or synthetic fuel. The electrical energy thus stored can be kept and transported relatively easily, and be used at any convenient time and place (much like fossil fuels). The big downside of chemical electricity storage is the high cost and low overall efficiency, typically less than 50%. The latter is a thermodynamical given, like the Carnot cycle for heat and gas expansion. So every kilowatt-hour of electrical energy stored in hydrogen gas, metal or synthetic fuel is expensive and yields less than 0.5 kilowatt-hour later on. This implies that for full scale storage capacity of our present electricity consumption, we would roughly have to double our total electricity production. If on top of this we double our electricity consumption by large scale electrification of heating, mobility and industry, that would again require doubling the total electricity production – to four times as high as today.
Reliable sustainable electricity supply
Classical large scale electricity generation with fossil fuels, biomass and nuclear power has the prominent advantage of high stability, high reliability and effective tunability for supply-demand balancing. This eliminates the need of large scale electricity storage. These options are however widely considered non-sustainable.
Hydropower and tidal / geothermal energy are also stable, reliable and tunable, but are too dependent on specific geographic circumstances to become a major global option. Other electricity generation options, in particular wind turbines and solar panels, are so variable and/or unpredictable that future expansion will necessitate large scale electricity storage. This strategic theme is presently addressed with a lot of good research. There is as yet, however, no viable technology available, and any possible future storage technology will be intrinsically inefficient and costly. The more electricity we need, the more prohibitive the downsides of electricity storage will become. Also, the more electricity we store the more we lose, and the more we have to generate and transport. This requires more grid capacity and brings increased grid losses.
Replacing classical power plants with wind turbines and solar panels will necessitate vast amounts of space, much more electricity production, much more grid capacity and large scale electricity storage. We presently do not have feasible large scale storage solutions, and it is uncertain when these will become available. Large scale electricity storage will in any case be intrinsically inefficient and expensive. Therefore, large scale electrification of heating, mobility and industry appears unsuitable for a global energy transition and realization of the climate targets.
Large scale electrification of energy consumption and production requires increasing quantities of rare elements such as lithium, manganese, cobalt, nickel, copper, silver, cadmium, indium and neodymium. These elements are essential for efficient wind turbines, solar panels, batteries and electric engines. This already leads to an international run on these strategic resources, and a fast growth of invasive mining in vulnerable natural locations and politically unstable regions with poor human rights control.