Four visions to plan the future interoperability grids.

Emanuel Bué (RTE – France)

Interoperability between grids means interconnections between power generation and grids but also have an idea about how these interconnections could evolve. This is the support of the Working Group Economic Studies and Scenarios (WG ESS) to the Technical Committee “International exchanges of electricity” inside the Mediterranean projects targets. We discuss with Emanuel Bué RTE – France, Convener of the WE ESS about targets, method and vision that the workshop will show us in Alger next 24th 25th October.

Why is it necessary in the Mediterranean Project to develop for a long time some visions about the dynamics of the electric system?

The long term scenarios that we establish within Med-TSO bring to the horizon 2030. If this may seem far for electricity consumers or for professionals who wish to connect production facilities as quickly as possible, the energy sector is first and foremost an industry that requires very important and long-lived investments. For example, a gas-fired combined-cycle power plant commissioned this year is intended to operate at least 40 years. For lines and substations this time is still much longer.

The evolution of electricity consumption and production is permanent, driven by economic growth and new needs. The power grid, whose role is to safely guide energy from the power plants to the consumer, must therefore also progressively adapt with the reinforcement or the development of new substations and lines. However, short-term development would lead to a multiplication of saturated investments at the end of a few years, that would then have to be further strengthened. It would be an economic mistake and also because the citizens would not understand the fact that we are constantly building new lines in their environment.

It is for these reasons that the companies in charge of the development of electrical networks must above all build a long-term vision of future network needs, which will enable them to propose long-lasting solutions.

But the exercise is complicated, because no one can exactly predict the evolution of the evolution of consumption. An error of plus or minus 1% per year represents about 15% difference in 2030. For the production also, uncertainty is strong to predict the development of such or such generation technology. To this is added the unknown of the location of the future power plants. That is why one does not build one but several scenarios, four for Med-TSO, which will try to represent a set of possible futures, without any of them being more or less likely.

Within Med-TSO, we have built these scenarios so that they may be coherent across all countries. For example, a highly sustainable economic growth should benefit all. The same applies to technological progress in renewable energies. This coherence is essential to take into account the exchange of electricity between countries, which have a growing role to play with the development of renewable energies.

Which parameters and definitions have been considered and which principal variables have been taken in consideration?

The long-term scenarios developed by Med-TSO are built starting by six technical and economic drivers. The first concerns the level of economic and demographic growth, of which we know that they are directly linked to the evolution of electricity consumption. Naturally, this level of growth cannot be similar among all the Mediterranean countries, from North to South and from East to West. That is why we do not try to hold back common values, but to propose three contrasting levels, ranging from weak to strong. It is then the context specific to each country which leads to the determination of the values of each.

The second determining driver is the development of production from renewable energy. The difficulty here is to propose development trajectories that may be in breach with the past, because of the acceleration of knowledge of currently renewable energies following the engagement of nations in the Paris Agreement (COP 21) and the sharp decline in production prices.

Depending on the country, national policies to reduce or combat the increase in CO2 emissions of electricity production can also rely on the use of nuclear plants or the transfer of coal and fuel oil to natural gas.

The technological evolution also concerns more innovative fields, such as storage, management consumption and Smart Grids.

Other applications that consume electricity are also likely to develop a more or less sustained rhythm. Within the Mediterranean region, these new uses are for the most part electric public transport (train or tram), electric cars and desalination of water.

The last driver taken into account in the scenarios of Med-TSO concerns a not very visible dimension of particular consumers of electricity: this is the level of integration of electricity markets. This scale of integration has three levels: national, regional or global market.

Has a decisive role of the renewable power emerged?

The answer is yes, with no doubt. Today the development of renewable energies at very significant levels is a common feature of energy policies shared around the world. Certain countries have played a leading role, such as Germany or Spain, while others are experiencing a later conversion.

The terrestrial wind and the solar photovoltaic are technologies called mature, that is to say that after having had about fifteen years of continuous and spectacular progress, they are now perfectly controlled. The luck of most Mediterranean countries is to have exceptional resources in terms of sun and wind. Each country can take advantage of the special features of its climate in order to reach extremely competitive production prices. From Morocco to Jordan, in Tunisia or very recently in Turkey, the competition of global investors has seen offers in the range 30-35 €/MWh, that makes it the most competitive energy in the region.

The evidence that these developments are sustainable is that investors accompany their offers with modalities of technology transfer, less for cyclical causes, but because the governments that put out tenders take a long-term view, where these renewable energies are an essential part of energy policies.

How central is the interoperability among the grids to define a general scenery of the system of energetic provisioning?

By nature, the small networks are made to be connected in order to form larger and stronger networks, to tend towards a single and completely connected network, that integrates Europe, Mediterranean countries and their neighbours. The first reason is mutual aid, which benefits the power supply of each. The second reason is economic, since the network can help to call for priority to the production plants with the lowest cost of production wherever they are located.

But on the contrary, it is not desired that a fault occurring on the network of a country spreads to its neighbours and causes a very large accident. All these technical reasons have been studied by network operators since many years and common rules have been defined to ensure network interoperability.

However, the massive development of renewable energies complicates the problem for several reasons: no rotating machine to synchronize networks, a more difficult production to control, given its dependence on climatic conditions and very decentralized installations.

In order to ensure that the massive development of renewable energies does not take place at the cost of a degradation of the safety of networks, the operators have established new technical requirements that are called Grid Code. In particular, ENTSO-E, the association of European network operators, has established the technical rules that must accompany the European ambitions about renewable energies. With the adoption of these rules, it is often seen in Spain that the wind and photovoltaic production exceeds 50% of the consumption, without the security of the network being degraded.

With the development of renewable energies there is also an exchange of electricity between neighbouring countries, the variation of which from one hour to the next is increasingly strong. It is a consequence of the fluctuation of production according to weather. In Europe, it is found that the network operators implement market and trade mechanisms that are increasingly complex in order to always improve the fluidity of exchanges.

We see it with these two questions, the interoperability between networks takes part of the most essential issues, so that network operators meet the energy transition and the massive development of renewable energies.