The Challenges of Renewable Energy, and why we haven’t fully converted yet
Renewable energy sources have been around for quite a while. They exist in many forms: solar PVs, wind turbines, hydroelectric dams, biomass, tidal, geothermal, etc, and we know exactly how they work. However, only 24% of our global electricity consumption comes from renewables, which means that we are still dramatically dependent on fossil fuels and nuclear energy. Since we know how much reliance to fossil fuels is toxic to our planet (and our geopolitics), why haven’t we made the big leap towards renewables yet?
First of all: they are expensive. The construction of any power plant (renewable or not) is rather on the expensive side. It is generally in the order of tens of millions therefore they require an important financial investment, which raises the question of profitability.
Let us take the example of a geothermal power plant. A geothermal system extracts heat from the depth of the earth and uses it to operate steam turbines (and therefore create electricity). Although a sustainable and cost effective resource, the drilling and exploration for high temperatures is very expensive. When we know that a typical geothermal plant delivers a power of 300 megawatts, and a fossil fuel power station produces ten times that, it raises a very simple question: do we really want to build ten plants and dig ten holes several kilometers deep into the ground, when we can enjoy the same amount of power from one existing unit? Probably not.
Second reason: they are land-consuming. They require acres and acres of land, simply because their primary raw material is nature. If we were to depend fully on wind turbines to produce electricity for the whole planet, we would need a wind farm the size of Turkey. If we were to depend on biomass, we would need the equivalent of the South American continent.
Of course these are foolish requirements and they can never be satisfied, but in all seriousness: even if we split the renewable energy sources in many smaller groups, it will be extremely difficult to find the appropriate locations without competing with food crops, national parks, industrial zones, protected areas, etc. And if we do find such locations to settle them on, their presence will deeply affect the flora and fauna, which, in the end, is not very eco-friendly.
Last but not least, most renewable energy sources are intermittent, which means that they are subject to environmental changes, thus unstable. Wind turbines cannot work without wind, photovoltaics cannot work without sun. With a massive electricity consumption such as ours, we simply cannot rely on the weather and pray everyday for the sun and wind to let us turn the lights on. Geothermal and biomass are examples of stable resources that could serve as base loads, but the reasons previously stated make them poor candidates for that.
Although it could be very tempting to follow the hype and jump all-in with “green” energy, we are still highly dependent on big old “brown energy”. Making a full conversion would require us to re-think our lifestyle and change our consumption patterns. Researchers are currently looking for ways to trigger the so-called “demand-response” which aims to adapt electricity demand to production and not the other way around. Only when we reach this kind of flexibility will we be ready for a full transition.