A micro-grid, a district heating network, are before any local initiatives, that are at the heart of the energy concerns of a Smart City. They allow defining an energy mix that is optimized for a limited perimeter, that presents a major, inaccessible interest on the national level: the creation of links, bridges between elements of the energy system.
As an example, a district heating network, that is the perfect example of a local piece of an energy system, is more and more often fed by multiple sources of heat:
– Waste incineration plants
– Geothermal or seawater heat pumps
– Biogas cogeneration or trigeneration units (as to Udine in Italy), the biogas being of agricultural origin or coming from the methanisation of waste.
– Biomass power plants
– Industrial waste heat recovery (as in Sweden, particularly at Luleå)
– Wastewater heat pumps
This list is not exhaustive; it already shows that these accessible and rarely exploited sources are local. Some are as much source of heat as raw material in the generation of electricity. It is impossible to plan their use in the national level, even less to implement the necessary synergies.
Each of the examples above highlights the importance of a link, naturally non-existent, between local actors up to here independents:
– The operators of heat networks or the utilities and the waste management companies.
– The operators of heat networks or the utilities and the agricultural cooperatives
– The operators of heat networks or the utilities and the big local industries
– The operators of heat networks or the utilities and the operators of water distribution networks and water treatment plants.
The existence of regional or national actors is not a deterrent to create such links but their organization has to leave a sufficient level of autonomy to the local level. Too much centralized organizations can quickly forbid the exploitation of these synergies between local systems.
On the technical plan, a micro-grid can favour the deployment of very energy-efficient technologies.
On the governance plan, a micro-grid requires the implementation of one local energy meta-operator favouring the achievement of the optimal global performance.
But, in theory, for the long term, a question remains: “do the local systems have to answer shadow zones left by the global energy systems? ” or ” Must the global energy systems be conceived as the complement necessary for the local systems to guarantee the levels of energy independence, price, capacity and reactivity wanted?”
Favouring the second option, I measure the way to go for the big actors established on the current market.