Here comes the sun
Wind power has been getting most of the attention in the renewables field, but pretty much all the energy on Earth is provided by the sun. The trick to making solar power projects work is joined‑up thinking, Richard Young discovers.
What energy crisis? A back-of-an‑envelope calculation spells it out: 173,000 terawatts of solar energy hits the Earth around the clock. That’s about 10,000 times more than the world’s current energy use. Net zero feels a lot more achievable if we could access this power more directly through solar photovoltaic (PV) generation projects. And progress is good.
Researchers from Imperial College London recently reported that wind, solar, biomass and hydropower accounted for 40% of the UK’s electricity in 2022 – up from 35% in 2021. Solar PV could be critical in increasing that proportion. The installed base increased from just 22 megawatts (MW) in 2008 – less than 0.01% of UK electricity consumption – to around 14,000MW (14 gigawatts, GW) last year. That’s well above 4% of total capacity. Solar PV generating costs have fallen 89% in 12 years (far faster than wind generation), and plummeting battery costs are helping make it an increasingly compelling option for investment.
But the critics of renewables have a point. If you predicate your power needs on wind and solar, what happens when it’s a still and/or cloudy day? Base load provision remains the issue even net zero advocates struggle with (see box). And the UK just isn’t that sunny. The solution? Get your solar power from places where sunshine is reliable; somewhere like Africa.
Linking up
That’s why British company Xlinks is proposing a project in Morocco to develop a 10.5GW solar farm, a 20GWh battery storage system and a 3.6GW high‑voltage direct current interconnector to carry electricity to the UK (and a massive windfarm, to boot). The scale of the Xlinks project is overwhelming – and could, if completed to plan plan (political barriers notwithstanding), provide nearly 10% of UK electricity needs, far more than Hinkley Point C’s projected output of 3.2GW. The full £18bn proposal would take up 1,500 sq km of desert (including the 200 sq km solar array) in the Guelmim‑Oued Noun region. That’s about the size of Greater London.
According to project founder Simon Morrish, it’s the fall in solar costs that makes Xlinks a more compelling proposition than earlier Sahara solar projects such as Desertec. “At our site now, with advances in technology, our cost of generation is around about £10 per MW hour,” he told Trade Finance last summer. “One of the biggest differences here is timing. But there’s also more of an impetus around renewables and sustainable power. This is much cheaper than fossil fuels as well. It stands up on its own two feet rather than previously when it was required to have enormous subsidies to make it work.”
Cable vision
Empty desert, reliable sun and wind, technological and cost advances, a UK market desperate for additional low‑carbon power… and a price tag several billion pounds less than Hinkley Point C, with none of the controversy. Sounds great. There’s one small problem. It’s 3,800km from source to market. To get the power home, Xlinks needs four high‑voltage direct current (HVDC) undersea cables running along the continental shelf, landing in Devon. (Direct current results in relatively low loss during transmission – unlike the alternating current on the National Grid.) European manufacturing capacity for that spec of cable is around 2,000km a year, which creates a massive supply bottleneck for the project. The solution? Make your own, via sister company XLCC.
Alan Mathers, Project Director for the XLCC start‑up, says: “The great thing about Xlinks and XLCC is that there’s really nothing new about the project. It’s just that no one has ever done it at this scale before [see box, page 41]. Our mission is to introduce as few variables as possible so that backers are comfortable.” So, while the scale of the factories being planned – at Hunterston in Scotland and Port Talbot in Wales, both near deep‑water ports that the specially commissioned cable‑laying vessel will need – is massive, the technologies are all well proven.
The XLCC factories’ fortunes could also be boosted by the need for new HVDC links within the UK to balance supply and consumption as renewable generation ramps up in windier parts of the country while demand stays put. According to RenewableUK’s onshore wind EnergyPulse report, the amount of wind capacity under construction or consented in the UK in Q3 last year had increased by 1.1GW to 6.8GW. But nearly 80% of the new projects in the UK are located in Scotland. It seems counter‑intuitive that onshore wind should boost demand for undersea cabling. But the most promising plan to increase the bandwidth for transmission of power south of the border is HVDC links down east and west coastal waters (starting, conveniently for XLCC, in Hunterston). And that’s just in the UK.
Joined-up thinking
The Xlinks project shows that renewables – and energy projects more generally – have to be weighed up, developed and run as part of a wider approach. It’s not just how you generate, but where, and in concert with which other sources of capacity. That could be power infrastructure – balancing different generation types with different inputs. Or how we design any project around energy efficiency. Because solar PV – unlike wind, hydro or biomass – can be integrated into almost any infrastructure or construction project with minimal fuss.
“The cost of the consenting process is a major hurdle for many big solar projects,” explains Matthew Clayton, Managing Director at Thrive Renewables – set up 28 years ago by Triodos Bank to arrange investments in low‑carbon power projects. “For a solar farm, there’s planning permission for the land, even if you’re able to lease it; the grid connection; and a range of environmental considerations.” Thrive specialises in connecting project managers with landowners and investors for wind, solar and hydroelectric schemes. “Project managers need to consider the complexities – ground, grid, irradiance, shading, ecology – and work through the financials,” Clayton says. A typical solar panel has a 25‑ to 30‑year life, and the best large‑scale sites pay back their investment within eight years. But some of the most interesting projects are rooftop solar, which faces fewer of those hurdles.
“The ‘private wire’ model is ideal for large consumers of electricity,” he says. “With a large roof area – on a factory or warehouse, say – a project can get going without any of those barriers. And because you’re not connecting to grid, you reduce capex and planning times, you don’t face any tolling charges from the network, and there’s no transmission loss.” These integrated power projects are particularly interesting because, unlike carbon offsetting or signing solar power purchase agreements from ‘green’ providers, they’re incredibly efficient – both in energy terms and for the project manager. “We also find that employees of businesses that undertake this kind of solar project get more interested in renewables,” Clayton continues. “We know companies that have won business on the back of being lower carbon emitters, especially if they supply industries with tough targets on carbon emissions, such as automotive.”
Wiping away the sunblock
While the on‑roof solar that most project professionals might factor into projects tend to be uncontroversial, Mathers admits that planning consents are a huge factor for Xlinks. He’s confident that the XLCC factory projects – using brownfield sites and creating thousands of jobs – should achieve planning permission despite their scale. And the proposed site of the huge Xlinks array in Morocco is rocky desert where there’s no one to object. But there’s more to it than that. “Even laying the cables under the seabed is complex – we’ll be crossing 68 other cables along the way,” he says. “And then once it comes back to the beach, it’s got to go 15km inland to the conversion site. So that will need planning too.”
Consulting with local residents is now key – as onshore wind project managers are learning now that central government has warmed to the concept. For example, Xlinks needs a 50‑acre site near the south coast at Gammaton to build a converter station to feed the electricity from Morocco into the grid. In January it agreed to extend its consultation with local residents after an intervention by local MP Geoffrey Cox.
It’s a reminder that even the biggest and best‑planned projects – with transformative outcomes – have critical dependencies that must be managed in concert. Which brings us back to the idea of diversified approaches. Solar is low‑profile, efficient and scales well. But the sector needs a mix of household, industrial and domestic solar farm projects – plus the associated infrastructure – to sit alongside high‑availability, at‑scale solutions like the Moroccan solar megaproject, with all its engineering and political challenges, if it is to live up to its potential as a driver of net zero.
Project opportunities in the UK energy mix
Energy is hard. UK electricity generation fluctuates during the day, during the week and over the year as people sleep, use heating or cooling, open or close factories, and spend longer in the dark. The low end of UK consumption is around 26GW; generation peaks closer to 50GW. But it’s not just variability of demand. Solar energy clearly doesn’t deliver at night (UK consumption drifts down from the daily peak during the evening, happily); the wind doesn’t always blow; at the end of the summer hydroelectric power is reduced as reservoirs get lower. All this affects pricing, too. In the spring thaws, for example, meltwater drives massive increases in output from Scandinavian hydro power – driving down cost.
That’s why ‘base load’ generation projects are considered so important. Nuclear plants deliver a consistent output – it’s actually costly to power them down – and gas-fired power stations can be cycled on and off very quickly, making them ideal to handle daily fluctuations in demand. Making the journey to net zero requires us to find projects that can offer both this ultra-reliable base and an extremely flexible variable supply, without adding to CO2. And that means variety in renewables – not just how they’re generated, but where.
Cable manners
The XLCC project to manufacture the undersea cable Xlinks needs is itself a massive undertaking with complex timelines, dependencies and risks. Project Director Alan Mathers explains why it will take at least three years just to get going. “To meet Xlinks’ needs, we need to construct two factories for HVDC cable manufacture – one with six lines and one with three. Assembly requires cable to run through the factory building layers on the aluminium core, through to the outer insulation layer. But that coating takes three hours to harden, and to avoid it collecting on the underside of the cable, we have to run it vertically for that period. So we need a tower 180m high – it will be Scotland’s tallest building.
“The tower alone will take a year to build. It will take another year to build and fit out the rest of the plant – which will end up being 800m long and 375m wide. Then the cable we make needs to be tested – which means putting a section under incredible stresses of heat and cold for a year, at 180% capacity. So we’ll build the first line to manufacture that, then build out the rest ready for full production at the end of that year.
“The biggest cable‑laying vessel in the world, Prysmian’s Leonardo da Vinci, can handle two spools of 10,000 tons and 7,000 tons, but we’re going to need a bigger vessel capable of carrying two 13,000‑ton spools. So that has to be commissioned – a three-year project on its own. The vessel will be 200m long, 35m wide and include 110 bedrooms and a canteen. We also need to be able to join the cable, which is manufactured in 20km sections, into the 160km spools for the vessel. That’s a skilled job, so we need 60 joiners on the team – twice as many as Prysmian has. It takes three years to fully train and certify them. We’ve already been working with academic institutions to recruit engineering graduates to join a programme.” But the dividends – from jobs and educational opportunities, to the project itself – should make the effort worthwhile.
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This is an amazing project and will change energy in the UK beyond belief. It will be interesting to see if this comes off laying HV cables from Morocco to the UK. Really pushing to boundaries of technology.