UK to Belgium HVDC Interconnector "Nemo" enters final testing stage. - Sensationalist Headlines

A £600m cable connecting the UK and Belgium’s energy systems is about to be switched on, becoming the first of a new generation of interconnectors that will deepen the UK’s ties to mainland Europe just as it prepares to leave the EU. The Nemo link is in the final stages of testing and from early 2019 is expected to transmit power over an 80-mile route along the seabed between Richborough in Kent and Zeebrugge, becoming the first new electricity interconnector to the continent since 2011 and the first to Belgium. Although built with the expectation of the UK mostly importing electricity, in the short-term, Nemo will provide a boost to Belgium. Six of the country’s seven nuclear plants are offline this winter because of repairs and safety checks, raising fears of blackouts. That means UK power stations will initially be largely exporting via Nemo when it becomes fully operational in early 2019. ... The government expects imports via interconnectors to increase from 6% now to 20% by 2025. Unlike new nuclear plants such as Hinkley Point C, which is expected to take around decade to complete, they can be built relatively quickly: work started on Nemo in 2015. The project was on time and on budget, despite encountering more than 1,000 objects on the seabed during the laying of the interconnector, including an 18th century cannon, unexploded bombs and parts of British, German and US second world war planes. “It was a difficult job offshore,” said Tim Schyvens, Nemo’s chief engineer. This year the cable was pulled onshore in Belgium, buried beneath a beach and run a few miles underground to a station that converts electricity from direct current (DC) to alternating current (AC) so the Belgian electricity grid can use it. Inside the station, Schyvens points out where the interconnector emerges from the ground, an unremarkable-looking 14cm-diameter black cable that can transmit enough power for a million homes. https://www.theguardian.com/business/2018/dec/05/funding-nemo-600m-power-cable-connects-uk-and-belgium

Article's title was much better

I'm still not sure what the benefits are of a HVDC system over traditional AC. You need more complex (read: expensive) circuitry for voltage conversion, you have more line losses, and most larger electronics use AC anyway. I only did a short stint in the utility industry so I'm not the most well versed on the topic.

You need less material for the cable, as you don't have to support three phases. The losses are significantly lower than AC when you start doing long distances as well.

I feel like we're not the country to be rescuing Belgium this winter. In March, mind you when the days were 3 months worth of brightening longer than in December, the entire NG - both electric and gas - was extremely close to the edge. Add to that rescuing Belgium's grid during one of these storms and you start to raise the question of which country do you want to plunge into darkness.

But won't it have to be cut when Brexit cuts ties with Bruxelles? Waste of money imho.

from what I understand if you get the voltage high enough your losses drop because the cable just acts as a directional transmission, and it also lets you transmit between different AC grids, avoiding having to synchronize the current at either end of the cable, you just convert the dc current to your grid standard

They'll just unplug it and stick it in the cupboard under the stairs along with all the other space extension cables.

These are valid reasons, but don't get to the core of the issue. You don't build a submarine power cable just to transmit a bit of power, you do it to move shitloads of it. The inner and outer conductors of a submarine cable form a massive capacitor, and you can't really get rid of the outer shielding because you need it to protect against the elements. So now we have a massive capacitor on our high-power AC line, which fucks up our power factor, which increases our apparent power, which means we need larger conductors to carry that apparent power, which increases the cost of the cable, which makes it cost more and by the way, it makes our capacitor larger. HVDC doesn't suffer from that issue, and as long as you can do efficient conversion at both ends, it's a good choice, since you can increase the voltage to get more power (P=U*I). This problem with apparent power isn't exclusive to submarine cables, large industrial installations get charged for apparent power instead of true power, in order to incentivize them to fix their power factor issues. It's a big enough problem that the EU requires "commercial solid-state-lighting luminaires" (LED lighting not used at home) to have a power factor of 0.9 or better.

You realise that Brexit doesn't literally mean the UK is drifting out into the Pacific Ocean, right?

i'd be shocked if it drifted out into the pacific since britain is in the atlanic

That's why I said drifted out into the Pacific, as it's already in the Atlantic, lol.

Pretty sure it does. What, you haven't heard the talk of the UK getting closer to New Zealand and Australia as a result?