As more people are finally recognizing, LCOE is wholly unrelated to systems costs of large scale decarbonized systems. It assumes you have a free and giant fossil based grid hanging around to back you up when you hit a calm month.
I do not get where you think that need of a fossil grid comes from? Seems like a hyperbole based on preconceived notions? Research has consistently shown that a 100% renewable grid is feasible and economically sound.
> Much of the resistance towards 100% Renewable Energy (RE) systems in the literature seems to come from the a-priori assumption that an energy system based on solar and wind is impossible since these energy sources are variable. Critics of 100% RE systems like to contrast solar and wind with ’firm’ energy sources like nuclear and fossil fuels (often combined with CCS) that bring their own storage. This is the key point made in some already mentioned reactions, such as those by Clack et al. [225], Trainer [226], Heard et al. [227] Jenkins et al. [228], and Caldeira et al. [275], [276].
> However, while it is true that keeping a system with variable sources stable is more complex, a range of strategies can be employed that are often ignored or underutilized in critical studies: oversizing solar and wind capacities; strengthening interconnections [68], [82], [132], [143], [277], [278]; demand response [279], [172], e.g. smart electric vehicles charging using delayed charging or delivering energy back to the electricity grid via vehicle-to-grid [181], [280]–[282]; storage (battery, compressed air, pumped hydro)[40]–[43], [46], [83], [140], [142], such as stationary batteries; sector coupling [16], [39], [90]–[92], [97], [132], [216], e.g. optimizing the interaction between electricity, heat, transport, and industry; power-to-X [39], [106], [134], [176], e.g. producing hydrogen at moments when there is abundant energy; et cetera. Using all these strategies effectively to mitigate variability is where much of the cutting-edge development of 100% RE scenarios takes place.
> With every iteration in the research and with every technological breakthrough in these areas, 100% RE systems become increasingly viable. Even former critics must admit that adding e-fuels through PtX makes 100% RE possible at costs similar to fossil fuels. These critics are still questioning whether 100% RE is the cheapest solution but no longer claim it would be unfeasible or prohibitively expensive. Variability, especially short term, has many mitigation options, and energy system studies are increasingly capturing these in their 100% RE scenarios.
Or we can take a look at Wikipedia for an even broader view
> 100% renewable energy means getting all energy from renewable resources. The endeavor to use 100% renewable energy for electricity, heating, cooling and transport is motivated by climate change, pollution and other environmental issues, as well as economic and energy security concerns.
> Research into this topic is fairly new, with very few studies published before 2009, but has gained increasing attention in recent years. The majority of studies show that a global transition to 100% renewable energy across all sectors – power, heat, transport and desalination – is feasible and economically viable.[5][6][7][8] A cross-sectoral, holistic approach is seen as an important feature of 100% renewable energy systems and is based on the assumption "that the best solutions can be found only if one focuses on the synergies between the sectors" of the energy system such as electricity, heat, transport or industry.[9]
> I do not get where you think that need of a fossil grid comes from?
This comes from the assumptions made when computing LCOE. For example in Germany last month they ran on almost all fossil for a whole month. Paying for the ability to not do that is not included at all in Lazard LCOE numbers.
Who cares if 100% renewable is possible. Of course it is. Things are either forbidden by the laws of physics, or possible. Things that are possible are not necessarily desirable or logical. For example, "renewable" is a meaningless term. Biofuel is included in renewable, though it leads to a high ("but stabilized!") atmospheric concentration of CO₂ and deadly particulate emissions.
Sustainable and low-carbon are much more specific, well-defined, and important characteristics for a future world energy system. If you go for 100% sustainable and low-carbon, nuclear is in and biofuel is out.
The main people publishing 100% renewables papers are hardcore anti-nuclear leaders like MJZ. For every 100% renewable publication, there are many others showing that a judicious mix of 24/7 nuclear plus renewables is a far more flexible, resilient, robust, and cheap mix.
I don't understand why people want to fight nuclear so much. With so much fossil and biofuel in operation, there's way more than enough room to build everything that's low carbon, sustainable, and safe.