20,000 Volts Under the Sea
“A religion that takes no account of practical affairs and does not help to solve them is no religion.” – Mahatma Gandhi
Today’s media is filled with claims of breakthrough technologies poised to revolutionize our relationship with energy. The reporting follows a predictable pattern: sophomoric barbs launched at oil and gas (now, aimed at Putin’s oil and gas, specifically) couched in breathless excitement over the latest promising solution. However, these features do a disservice in that they are almost always heavy on the possibilities and comically light on the constraints. How can constraints be addressed if we ignore them?
Believe it or not, Doomberg isn’t anti-renewable. This publication believes solar can and should play an important role in our collective energy future and we are regularly analyzing newly touted programs in the field. Recently, a Doomberg Pro subscriber sent us a piece of commentary in The Telegraph titled (emphasis ours) “Sahara solar could soon rescue Britain’s broken energy system: A new energy order based on cheap desert solar will undercut and replace Opec and Russia’s oil hegemony.” Written by Ambrose Evans-Pritchard, the piece describes an audacious plan from Xlinks to build a huge renewable energy project in Morocco and transmit the electricity directly back to Britain. While Evans-Pritchard litters his article with unscientific platitudes and a lazy attack on nuclear energy, drilling down into the project itself does offer an excellent opportunity to assess the current prospects for renewable energy, what is really holding the industry back, and where research dollars should ultimately be focused. Interestingly, this project is one of the better concepts we’ve reviewed, and it still falls short of likely.
Xlinks is a private company proposing to build the world's largest solar and wind generation facility. It hopes to construct 10.5 gigawatts of generation capacity in Morocco’s Sahara Desert (7.0 gigawatts of solar and 3.5 gigawatts of wind), augment the facility with 20 gigawatt-hours of lithium-ion batteries, and use a pair 3,800 kilometer long high-voltage direct current (HDVC) cables laid underwater to deliver an estimated 3.6 gigawatts of baseload power to Britain – the equivalent of two nuclear power plants. The project seems almost preposterous at first blush, but in reality, it would use no new or unproven technologies. It would merely link together a suite of existing innovations on an enormous scale. The project is slated to cost £16 billion, or roughly $21 billion.
Baseload Power from a Distance
What makes the Xlinks project compelling is the commitment to deliver consistent baseload, rather than intermittent, power. Intermittency is the Achilles’ heel that hinders the implementation of renewables at scale, and the significance of solving this challenge cannot be understated. Xlinks proposes to do so via the reliably high daily average radiation experienced in the Sahara and the powerful, steady trade winds off the Moroccan coast. The company claims a capacity factor in excess of 50% for the project’s wind turbines (vs. 35% industry average). The icing on this cake is a huge 20 gigawatt-hour battery pack that would further smooth weather-induced variability, resulting in a predictable electricity production profile. In other words, at long last, a profile suitable for baseload supply.
It is one thing to generate the power and another to transmit it. Although the underwater HDVC cable proposed by Xlinks might seem like the most improbable aspect of this project, the only novelty here is in the length. The technology is a well-known and efficient way to transmit electricity across long distances and relies on extremely high voltages to minimize transmission losses. The longest subsea HDVC cable in operation today is the North Sea Link, which connects the British and Norwegian power grids (emphasis added throughout):
“North Sea Link (NSL), a joint venture with Norwegian system operator Statnett, is our latest interconnector to come into operation. Stretching 720 kilometres under the North Sea, at depths of up to 700 metres, NSL is capable of sharing up to 1400 megawatts [or 1.4 gigawatts] of electricity – enough to power around 1.4 million UK homes.
NSL is our fifth interconnector. We already have links connecting the UK to the energy systems of Belgium, France and the Netherlands. By 2024, National Grid will operate enough interconnector capacity to power around 8 million UK homes.”
While we were aware of the potential for HVDC technology and knew about projects like the North Sea Link, Xlinks claims transmission losses will only be approximately 10-12%, a surprisingly low number (at least to us). This is especially interesting when you consider the distance being contemplated here is 5.3x the NSL project, or roughly the distance from New York to San Francisco. A similar project under development to connect Australia to Singapore would use an even longer cable. As thought-provoking as it may be to contemplate a world with huge electricity production plants in remote areas feeding a globally interconnected power grid, it is yet another solution that relies on counterparties beyond domestic borders.
The Constraints
While upgrading renewable energy reliability from intermittent to baseload is interesting and essential, how Xlinks seeks to achieve this milestone is a classic example of an exception that proves the rule. That a project such as this needs high and consistent solar incidence, unusually strong and steady nighttime winds, and a massive battery for storage to deliver baseload power lays bare the weakness of most other renewable power projects. It exposes the fallacy of using levelized cost of electricity (LCOE) measurements for projects that produce intermittent power. The real costs of ensuring grid stability that arise as a direct result of intermittency are specifically and knowingly excluded from such calculations, which only serves to obfuscate the real cost/benefit analyses needed to make informed energy policy decisions. No similar game of Three-card Monty needs to be played by the Xlinks team in its baseload modeling.
Fundamentally, we question the use of lithium-ion batteries for the storage aspect of this project. The choice relies on materials in which the world is structurally short and for which higher priority use cases exist.
Because of the high energy density of lithium-ion technology, such batteries are currently the industry standard for electrified vehicles where the weight of the battery is a critical constraint on range and overall practicality. A full battery electric vehicle (BEV) typically has an 80 kilowatt-hour battery pack, whereas a plug-in hybrid vehicle (PHEV) might have a 20 kilowatt-hour pack. The proposed Xlinks battery is slated to be 20 gigawatt-hours – the equivalent battery capacity for 250,000 full BEVs, or 1,000,000 PHEVs. Space nor weight are problematic in the desert and therefore energy density need not be an important parameter.
Even if Xlinks is willing and able to pay the price, there are simply not enough “green” metals – cobalt, lithium, and nickel (the key ingredients needed to make lithium-ion batteries) – to facilitate a meaningful transition away from legacy internal combustion engine vehicles as it is, and the Xlinks project would be competing for supply with the powerful OEMs under pressure from heavy-handed emissions targets. The price of Lithium Carbonate over the last year makes clear the magnitude of this challenge.
Quite frankly, solving for grid storage in a manner that relies on cheaper and more widely available materials is the critical technical challenge facing the renewable energy industry. This is not a simple problem, and the size of the battery pack needed for the Xlinks project – despite the near-perfect solar and wind profiles – is a sobering reminder of the profound impediments constraining wider deployment. Physics will not be denied.
But Wait, There’s More!
There remains the question of HVDC cable supply, which the CEO of Xlinks admits is sold out for the next 4-6 years. Here, the issue is not the lack of materials needed to construct such cables, but rather the capacity and know-how to do so in the face of exponentially rising demand. Buried in the company’s FAQ page is this worrying confession, which should make one wonder about the viability of the entire effort:
“To manufacture the required HVDC interconnector cable, Xlinks will create an export-led cable manufacturing industry in Britain, via a dedicated cable supply system company called XLCC, who will provide approximately 1,350 new, permanent regional jobs by 2024. Agreements for factories to be located in Hunterston and Port Talbot have been signed with planning permission applications underway. Discussions are also taking place for a third factory in the North East.”
On the same page, and in response to a question about whether Xlinks will require subsidies for the project to be successful, we further discover that the project does not yet have funding lined up: “To enable us to raise the private financing we need, Xlinks just needs the security a UK policy commitment to a predictable price that a CfD would provide.”
Final Thoughts
The Xlinks project is a pretty good concept, and yet…it needs access to materials already claimed by many others at prices increasing by the day, it needs to build an entire HVDC industry in Britain from the ground up, and it needs money, lots of it.
Replace OPEC and Russia’s oil hegemony? Sorry, Evans-Pritchard, not in this wartime.
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I am an Energy Engineer with Siemens in the area of demand side energy and renewable energy sources. Your article is spot-on.
I have often thought the real solution for solar and energy storage is to use solar to generate hydrogen by electrolysis at the shoreline using seawater, store the hydrogen for night use in a fuel cell array. Making these total units small and placing them near the energy end users would solve the transmission line issue. If I saw this perfected, we would have a base loading capability from solar and wind.
What a ridiculous scheme. Perhaps connecting north Africa with Spain would make some sense. Or using the electricity locally to produced some power-hungry product like clean hydrogen. But trying to integrate the power grids of Morocco and Britain is beyond crazy. As if our supply chains were not complicated enough already, lets introduce more tight coupling and bottlenecks, and opportunities for failure.