Band 3, Heft 2 - Energy Transition – Energiewende (Part 2 of 2)

In the next few decades there is expected to be a global shift in power generation from fossil fuels and nuclear fission to various forms of renewable energy. This process will be accompanied, however, by a strong demand for non-fuel raw materials required for the generation, storage, transmission and utilisation of these energy forms. Some of the raw materials are potentially exhaustible; some are already regarded, rightly or wrongly, as geochemically “scarce”. Many of them have been characterised by steep price increases in recent years. Examples are neodymium, praseodymium and dysprosium for rare earth-based permanent magnets in wind turbines; indium, gallium, selenium and tellurium for thin film solar cells; helium. The supply situation with regard to such elements is often described as “critical”. A possible geochemical scarcity is, however, not the only factor contributing to this designation; the supply situation is influenced by various other parameters. We discuss the use of the terms “critical” and “criticality” in this context, pointing out the confusion which arises because of a different meaning of the terms in the physical sciences. In examining the elements mentioned above – both with respect to the supply situation and to their specific energy-oriented applications – we look at the issues of potential geochemical scarcity, substitutability and extraction as by-product. Together with the recycling potential these are three important indicators, or constraint parameters, in so-called criticality analyses. Geochemical scarcity already seems to play a role in the case of helium and could also soon become apparent for tellurium, indium and possibly dysprosium. We conclude that geochemical scarcity may pertain as a consequence of mineral depletion when average grades of ore are falling, but at the same time inflation-corrected mineral prices are rising. The use of rare metals for the production of renewable energy – like nearly all resource-consuming systems in our society – does not satisfy “strong” sustainability criteria.

Heat storage for high temperature applications can be performed by several heat storage techniques. Very promising heat storage methods are based on thermochemical gas solid reactions. Most known systems are metal oxide/steam (metal hydroxides), carbon dioxide (metal carbonates), and metal/hydrogen (metal hydrides) systems. These heat storage materials posses high gravimetric and volumetric heat storage densities and because of separation of the reaction products and their storage in different locations heat losses can be avoided. The reported volumetric heat storage densities are 615, 1340 and 1513 [kWh m −3 ] for calcium hydroxide Ca(OH) 2 , calcium carbonate CaCO 3 and magnesium iron hydride Mg 2 FeH 6 respectively. Additional demands for gas storage decrease the heat storage density, but metal hydride systems can use available hydrogen storage possibilities for example caverns, pipelines and chemical plants.

To date, none of the predictions that have been made about the emerging BIPV industry have really hit the target. The anticipated boom has so far stalled and despite developing and promoting a number of excellent systems and products, many producers around the world have been forced to quit on purely economic grounds. The authors believe that after this painful cleansing of the market, a massive counter trend will follow, enlivened and carried forward by more advanced PV technologies and ever-stricter climate policies designed to achieve energy neutrality in a cost-effective way. As a result, the need for BIPV products for use in construction will undergo first a gradual and then a massive increase. The planning of buildings with multifunctional, integrated roof and façade elements capable of fulfilling the technical and legal demands will become an essential, accepted part of the architectonic mainstream and will also contribute to an aesthetic valorisation. Until then, various barriers need to be overcome in order to facilitate and accelerate BIPV. Besides issues related to mere cost-efficiency ratio, psychological and social factors also play an evident role. The goal of energy change linked to greater use of renewables can be successfully achieved only when all aspects are taken into account and when visual appeal and energy efficiency thus no longer appear to be an oxymoron.

Finland has set up several programs and platforms to be well prepared for the electric mobility development. The goal is to establish an international community focusing on the creation of new business around electric vehicles and related machinery and systems.

One of the biggest challenges of rural electrification through renewables is getting people to see the bigger picture: we are not only helping African children who still do their homework by candlelight, there is also a growing market out there yet to be fully tapped by the private sector. It is the proverbial win-win situation. If private companies are willing to take a chance and invest on the extraordinary potential of these countries, there is no telling the proportions that the market might take. In the next few years, renewable energy can become both a formidable boost to Africa's economic development and the answer to the problem of energy access.