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All-electric world?
The latest trend is for houses that are operated solely with electricity. This particularly applies to zero-energy houses & Co. They do not require oil, gas, heating networks or biomass. However, does electricity really provide a convincing alternative in the heating market in ecological and economic terms? Are we heading towards an “all-electric world”? The illustrious panel sought to find answers to these questions. The discussion veered between fierce controversy and consensus. Then finally a player was identified who must play a facilitating and steering role in supplying energy to buildings and settlements…
The experimental homes in the Solar Decathlon Europe competition require very little energy, since they can be supplied with electricity and heat using just the sun. Electricity is entirely relied on here as the sole means for exchanging energy between buildings – fossil fuels and heating networks are no longer needed. However, do these “electricity-only buildings” offer a model for our cities? This was an issue that the discussion panel sought to clarify: Chaired by Johannes Lang (BINE Informationsdienst), the panellists included Professor Manfred Hegger (HHS, TU Darmstadt), Professor Dirk Müller (E.ON Energy Research Center), Professor Jürgen Schmid (Fraunhofer IWES), Klaus Preiser (Badenova) and Dr. Knut Kübler (German Federal Ministry of Economics and Technology).
Professor Hegger would like to see durable, simple and robust technical solutions for the building services technology. Ideally, they would be as durable as the building itself and just as easy to use. For him, purely electrically operated buildings are just one of several options.
Professor Müller believes that there will ultimately be two types of energy concepts for buildings: firstly the “electricity building”, which in particular uses heat pumps to supply heat and cooling; secondly, there will be co-generation buildings that utilise different types of combined heat and power generation – all electricity-led and with electrical efficiencies of more than 40%.
Klaus Preiser views heat pumps as key components in electricity-only buildings. However, he considers this technology to be ecologically questionable because – given the widespread, preferential rates offered by the electricity suppliers – it ultimately consolidates the current power plant structure with centralised coal-fired and nuclear power stations. Moreover, he believes that in most cases heat pumps make neither commercial nor economic sense.
According to Professor Schmid, electrically operated heating systems should only be deployed in highly energy efficient buildings such as passive houses. He also sees this as the preferred application area for heat pumps. For the existing building stock, there is considerable potential for co-generation, whereby the fuels should come from renewable sources, in particular from biomass.
For Dr. Knut Kübler, there is much to be said for an energy future that comprises an “all-electric world”. He believes that this trend can already be seen in the building sector. However, he advises against putting all the eggs in one basket. Other possible energy worlds must also be explored through “sustainability research”.
During the course of the discussion it became clear that not all developers can go their own way. This is because the heating and gas networks – including the networks that can be expected in future with 100 per cent renewable energies – can only be economically operated if a specific energy requirement density is reached. For this purpose, regional energy concepts must be developed and agreed upon in order to develop optimum building concepts and energy supply systems in accordance with the local conditions and settlement structure. Here the local authorities must play a much more active role in future than they have done in the past. This was one aspect that, despite their differences, all the panellists agreed upon.
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