Reconciling Energies: Mission Impossible? With @GaspardG

Daily life, encompassing heating, lighting, and appliances, requires substantial electrical energy. The average consumption is estimated at 6,180 kilowatt-hours of electricity daily. This figure excludes the substantial indirect electricity usage supplied by public networks to power elements such as tramways, street lighting, signaling systems, and industrial operations. Meeting this constant demand necessitates drawing energy from diverse sources that transform primary resources into usable electrical power.

The concept central to balancing this demand is the energy mix. This term designates the specific combination of different energy types utilized across national production and overall consumption profiles. While the focus remains primarily on electricity, the challenge involves skillfully juggling these varied production options to match the ever-increasing energy needs of modern society. The expert accompanying this discussion will illuminate the practical realities of this mix on the ground.

The energy mix is formally defined as the combination of various energy types integrated into a region's energy production and consumption structure. Currently, the primary concern driving discussions around this mix is the urgent necessity to significantly improve the proportion represented by renewable energies within the total global production. It is crucial to recognize that energy is not created from nothing; rather, it is captured from a source in one form and then transformed to render it easily transportable and readily usable, typically as electrical energy.

Examining a coal-fired power plant provides a concrete example of energy transformation. Coal, extracted from the earth, holds chemical energy that is released as heat during combustion. This heat then generates steam, which drives a generator to produce electricity. However, this process is inherently detrimental, as the burning coal emits carbon dioxide and harmful fine particles affecting public health. Furthermore, coal reserves are finite, and their extraction carries significant ecological and political consequences.

A concrete example involves examining the operation of a coal power plant. The chemical energy stored within the extracted coal is liberated as heat when the fuel burns. This heat is subsequently used to convert water into steam, which then powers a generator responsible for producing electrical current. Unfortunately, this established process yields undesirable secondary products. When combusted, coal releases carbon dioxide and fine particles detrimental to human health.

The transition shifts focus toward energies classified as renewable, derived from sources that are fundamentally inexhaustible, such as solar radiation, the movement of air or water, or even waste materials via processes like methanization. This approach eliminates the need to extract combustible fuels from specific locations, thereby avoiding the associated ecological and political implications of resource dependency. While materials are needed to construct the necessary installations, the operational phase of these technologies is entirely clean.

To summarize, giving more room to renewable energies helps slow down climate change, develop territories, and also gain energy independence. Nothing but good!

In essence, prioritizing renewable energy sources contributes positively to mitigating climate change effects, fosters regional development, and enhances national energy independence. However, maximizing the benefits and encouraging widespread adoption requires implementing refined and intelligent management strategies for these intermittent sources.

The operational reality of managing these energies is demonstrated at a control center, such as the one located in Châlons-en-Champagne. Here, a team of 15 people supervises 1,000 wind turbines and 130 solar power plants. Collectively, these facilities produce the equivalent annual electrical consumption of 3 million people, operating continuously, 24 hours a day, 7 days a week. Screens display real-time electricity production from all installations, allowing remote monitoring and verification of proper functioning.

The necessity for such sophisticated monitoring stems from the fact that, on a large scale, electricity cannot be stored effectively. Once generated, it must immediately enter the grid from various sites to be conveyed and utilized directly. This national-scale equilibrium requires constantly adjusting the output from different installations to precisely match the fluctuating demand. For instance, on March 24, 2022, at noon, nuclear power accounted for 60% of production.

To complement this fine management, one of the most effective strategies involves multiplying the sources and installations based on the specific characteristics of each territory. This practice, known as foisonnement, helps smooth out production fluctuations. Currently, renewable energies constitute only 19% of electrical production in France, a figure notably below scientific recommendations and national objectives. Despite this, hydraulic power remains the largest contributor, while wind energy shows the most significant rate of progression.

Wind energy production fundamentally relies on converting kinetic energy—derived from the mass and speed of moving air—into electrical energy. This is achieved by rotating a magnet within a conductor coil, or vice versa, which is the principle behind all generators. The primary goal of a wind turbine is to optimally capture this kinetic energy, transforming it first into mechanical energy via the rotation of its blades, which then drives the generator to induce electricity.

Typically, turbines feature three blades profiled like airplane wings to maximize rotation efficiency under wind pressure. The entire assembly rotates an axle connected to the generator. This system is mounted atop a tall mast to ensure optimal exposure to the wind, as the energy deployed by an air mass heavily depends on its speed. Generally, wind speeds increase significantly with altitude, making elevated placement crucial for effective energy capture.

When establishing a wind farm, developers seek locations with sufficient and consistent wind, such as the Thivolet forest park, which supplies the electrical consumption for nearly 14,000 individuals. Nationally, the strategy involves multiplying these implantation zones across areas subjected to different wind regimes. This geographical scattering ensures that at any given moment, a portion of the overall wind park infrastructure contributes reliably to the energy supply.

An area offering abundant space and consistent wind resources is the sea, leading to the development of offshore wind power. These sea-based parks are expanding globally as the technology becomes increasingly competitive. While the impact on marine biodiversity is closely monitored to ensure continuous reduction, these installations possess the advantage of transforming large quantities of wind energy into electricity.

While terrestrial turbines generally peak between 1.8 and 3 MW, offshore units easily reach 6 to 8 MW, with future projects targeting around 15 MW. Some offshore farms already rival nuclear power stations, particularly in northern seas like the North Sea, because the wind offshore is both more powerful and more regular than on land. These large-scale offshore projects are deemed indispensable for achieving the necessary global shift in electricity production methods.

Solutions exist that perform exceptionally well for both large and small-scale projects, perfectly suited to the environment: photovoltaic panels. These panels harness energy that is just as limitless and abundant as wind: the radiation provided by the Sun. Understanding their function requires grasping two fundamental concepts related to the silicon material that constitutes these panels: the existence of atoms composed of a nucleus surrounded by orbiting electrons, and the fact that electrical current is precisely the circulation of these electrons.

To achieve electron circulation between the two silicon layers composing a panel, a surplus of electrons must be created on one side and a deficit on the other. The upper layer is doped with phosphorus atoms, which possess an electron surplus, thus carrying a negative charge. Conversely, the lower layer contains boron atoms, which have an electron deficit, resulting in a positive charge. When exposed to sunlight, the electrons are excited by this energy input and become ready to circulate from the negative to the positive layer.

According to a 2019 study, covering European rooftops with solar panels could potentially satisfy a quarter of the continent's electricity needs. Beyond residential applications, ambitious projects exist, such as the solar park in Luxey, Southwest France, covering 25 hectares with nearly 40,000 panels, generating 12 megawatts—enough for 7,400 people. An added benefit is the ability to combine activities, such as hosting sheep grazing beneath the panels.

It is essential to remember that these energy installations have finite lifespans; for example, a solar panel typically lasts about 30 years before needing replacement. This raises concerns about the entire life cycle, starting with production, which requires significant energy and raw materials like silicon. The extraction and refining of silicon, particularly in China, carry notable environmental and social impacts, although European and French producers are succeeding in considerably limiting these effects.

It is not perfect yet, but it must be kept in mind that despite this, these installations ultimately emit dozens of times less CO2 per kilowatt-hour produced than fossil fuels.

Regarding end-of-life management, solar panels are recyclable at rates between 95% and 99%, and the recycling industry expands as the volume of decommissioned panels increases. For wind turbines, over 90% of the weight is recyclable. While the blades present a challenge post-dismantling, energy recovery methods exist, and fully recyclable, eco-designed blades are beginning to emerge, reinforcing the overall low-carbon advantage of these technologies.

While wind and solar are highly emblematic sectors, it is crucial not to overlook other renewable energy avenues available for exploration and development. Hydroelectricity stands out as one of the world's oldest forms of renewable energy. Other significant sources include biogas, often produced from agricultural waste, and geothermal energy, which utilizes the heat stored beneath the earth's surface and is actively used in France.

The overarching strategy involves diversifying energy portfolios rather than concentrating efforts on a single solution—this is the true meaning of the energy mix. Furthermore, resolving the issue of energy storage is paramount to encouraging the growth of variable sources; this allows for maximal production when possible and storage of the surplus for later utilization. Ultimately, the cleanest energy available is the one that is never consumed, making energy sobriety a necessary consideration at both the large scale and the individual level.

The discussion concludes with a lighthearted request regarding the return of a bicycle, implying a long walk home. The final positive note suggests that the lack of a bicycle removes the need for an anti-theft device. This wraps up the exploration into reconciling various energy sources to meet modern demands.