What is the TerraWater scenario?

Myrto Tripathi, President & Founder of The Voices of Nuclear

The TerraWater scenario was initially an attempt to assess the feasibility of a net zero transition in an highly developed country, freed from as many technical, geopolitical, industrial deployment and societal uncertainties as possible. It was published in November 2022 and is now one of the main scenarios used by government and energy stakeholders to debate France’s plan to transition to net zero.

The main points of attention to be secured technologically were as follows:
• Most scenarios rely on non-mature technologies or overly optimistic technical hypothesis for critical roles of the electric system. Some bet on a complex and interconnected hydrogen system (production, storage, transport and distribution). Others are unreasonably optimistic over the grid scale maturity of frequency stabilisation technologies within a full renewable system, or over the deployment of industrial capacities constrained by raw material availabilities such as wind turbine rotors or batteries, or even over the time required for new technologies to reach industrial maturity, including sometimes nuclear, in order to meet ambitious targets and replace current designs.
• Nearly all scenarios make excessive use of biomass resources in their energy mix. Biomass is a limited resource, requiring more land than any other energy source, with a high risk of promoting deforestation. Furthermore, biomass is very polluting when combusted directly (especially wood for space heating, which is largely promoted in a lot of scenarios).
• Some technologies have been largely ignored, or their contribution minimized: nuclear energy, obviously, in all 100% renewable scenarios, but pumped hydro as well, even if it is currently the only very large-scale electricity storage system available industrially.
• There is an excessive dependence on interconnexions or demand management in order to achieve furniture reliability.
TerraWater sports a simple system based on mature technologies with the goal of providing the maximum robustness to the grid. Using this principle as an input led to a model based on the dramatic electrification of the economy (nearly 80% in 2050 and beyond). This increase in electrification is made necessary by, for example, the need to reduce biomass usage to as little as is reasonably possible and dedicate its use to synthetic fuel production (for farming equipment, military use, maritime and air transport, and residual heating needs which cannot be met by any other source). Our search for simplicity also led to the internalisation of hydrogen production within the industrial installations of hydrogen-intensive processes – the role of the grid being to provide stable, clean, and affordable electricity to every industrial user
To satisfy that demand (nearly 800 TWh gross per annum in 2050), the scenario focuses on:
• Extending the French nuclear fleet to 70 years in order to maintain a solid baseload.
• Installing large renewable capacities to follow the short and medium-term demand increase.
• Creating huge new pumped hydro capacities to get rid of gas from the electricity mix and provide the low-carbon peak production needed during cold winter spells.
• Rejuvenating the nuclear industry to be able to build new, large reactors one after the other from the 2040’s onwards.
• Building reserve capacities fuelled with strategic biofuel stockpiles for last resort situations.

Why would other countries have an interest in the TerraWater scenario approach and conclusions?

Even if TerraWater is an energy scenario based on France, we believe it embeds interesting notions and conclusions of relevance to other European countries.
Indeed, the issues it aims to address aren’t specific to France but are essentially common to every country. TerraWater’s approach of technical rationality is also quite new and is aimed at guaranteeing the success of the transition for future generations by resorting to demonstrated, existing, low tech, and robust solutions. For example, for a long time, nuclear and renewables were played against each other, while this scenario tries to bring them together by using every technology to its best advantage and where it is most suited. It also demonstrates that the European Union (EU) targets may be achieved without coming at a price to the economy and industry and can minimise the efforts required from citizens in terms of behavioural change and sobriety efforts. The approach proposed by TerraWater could be a source of inspiration for other countries that still are open to discussing their own energy transition.

The EU could also have a strong interest in the successful realization of a scenario like TerraWater in France for several reasons.

Due to its position and its size, the French electricity system will de facto remain an important piece of the European grid. Offering a robust mix diversified from that of its neighbours, this scenario can increase the resilience of the entire interconnected area. Moreover, as not all countries will have the same possibility to development very large pumped-hydro facilities (for instance, Germany, Belgium, the UK, or the Netherlands have very little potential compared to France or Austria), it is in the common interest of the continent that countries like France invest largely in this area to share this ability to efficiently store huge amount of clean electricity. More generally, in the interest of tackling the global climate crisis, all countries capable of deploying nuclear and hydroelectricity capacities should do so, in order to support wind and solar capacity and reduce the production rate of fossil plants wherever they remain.
It can also be seen as a failsafe for the European grid. Indeed, if some key technologies which are needed to run a grid with a very high share of variable renewables don’t work according to plans (whether it be large scale hydrogen storage or frequency stability keeping), having a central country with a massive and efficient electricity storage capacity at its disposal and which still relies on large synchronous generation units to stabilize the grid is a big plus.

Moreover, France is the only European country to host a fully integrated nuclear industry capable of managing all activities from uranium mining to spent fuel reprocessing, as well as reactor design and construction. It is important that France keeps capitalizing on its nuclear industry because it offers any European country that desires it an independent and local access to the technology, without having to rely on US, Korean, Chinese, or Russian nuclear industries. And the more France keeps investing in nuclear, the more capable it will be of providing nuclear technologies to its neighbours, whether it be to support current Russian-made nuclear plants in eastern-Europe, or to help countries that want to develop a national nuclear industry.

Myrto Tripathi & Benjamin Larédo