The great electric manufacturers dream of it: they describe a luminous future world where everything will be more electric than today. Will the Smart Cities fit in with this trend? Does this vision make sense for the cities? Or is it only an incantation launched by the industry leaders sowing trouble in the market that is nostalgic of the growth of past years?
Buildings represent a very high proportion (about 45%) of urban energy consumption; in buildings, except those built according to the latest standards, the most energy consuming uses are the thermal ones (heating, air conditioning, hot water) (70% to 75% of buildings’ energy consumption). Given the time and money required to make the majority of existing buildings thermally efficient, that is to say conform to the latest standards, the predominance of thermal applications in the energy consumption of buildings is a lasting one.
For these thermal applications, solutions avoiding the conversion of primary energy into electricity (such as heat networks, well suited to certain urban configurations) often have a better yield and a lower cost. It is also interesting to consider heat pumps whose performance is superior to 100% electrical solutions; these heat pumps have of course less use of electricity. Similarly, shared solutions between multiple dwellings or multiple buildings are often more efficient. The trend is therefore to the recession of 100% electrical solutions in the countries that have favoured them in the past. In no country, 100% electric thermal solutions are destined for a very strong development.
Heat networks can benefit more easily from certain sources of virtuous energy (geothermal energy, combustion of waste, use of the unavoidable heat of certain industries etc …) and find in this characteristic an additional legitimacy to the cities.
In parallel, new uses of electricity can emerge: the most emblematic is the electric car. Perhaps they will induce a surplus of electricity in some countries but they are unlikely to be able to compensate for the effects of the consumption recession mentioned above in thermal uses in countries that have relied heavily on electricity for these uses in the past.
The vision of an all-electric world probably does not correspond to the vision of an energetically efficient world, especially in cities. It was, and still is, a vision more attached to the wishes of industry leaders, anxious to promote and develop their productions. To their shareholders to be vigilant about the real growth of their market!