There are two interlinked stories when it comes to decarbonising the UK power sector. One is about generating our power from cleaner sources – renewables are the hero here. The other is about reducing the amount of power we need in the first place and sees energy efficiency take the starring role. But that second story is missing something: the UK currently loses approximately 26TWh, or 7.4 per cent of the power it generates annually during transmission and distribution. Those are big numbers, and by closing that gap we stand to save a lot of money and carbon.
Quantifying losses
Think about those figures: we are currently generating 26TWh of electricity which we don’t even get to use. To put that in perspective, in 2016 the UK generated roughly 31TWh from coal (a number that is falling): we lose almost enough power to account for our remaining coal generation.
That’s more than £1 billion spent annually on lost power. If you take the UK’s 2016 average carbon intensity for power generation of 254 tonnes of carbon emitted per GWh produced, that could mean 6,604,000 tonnes of carbon released into the atmosphere, without powering a solitary lightbulb.
From a financial or environmental perspective, can we afford that?
Why the silence?
These are significant figures and they merit inclusion in the decarbonisation debate. So why have they been largely absent?
In all likelihood, it’s because there hasn’t really been an alternative. If you transmit power long distances via cables, a certain amount will be lost. There are limited ways to minimise these losses and there hasn’t been new technology to provide a better option.
Opportunity knocks
However, there soon might be. Innovative companies like Enertechnos are working with new long linear cable technology, dubbed the capacitive transfer system (CTS). Capable of delivering up to 20 per cent more power than current cable technology, the technology can also reduce capital expenditure by reducing need for AC booster transformers or HVDC converter stations.
What would this mean in practice? For a start, big savings measured in both pounds and tonnes of carbon. We wouldn’t be paying for as much power generation simply to cover network losses, and it could also help to ease pressure on capacity margins. If we could cut even 10 per cent of those emissions caused by network losses, that’s more than 600,000 tonnes of carbon per year.
And there are other benefits too. Think, for example, of the UK’s big achievements and big ambitions in offshore wind. Once generated, the power has to be transported long distances back to shore. Cutting transmission losses here could make a big impact on the economic viability of projects, helping more wind farms come online and boosting efforts towards completely subsidy-free renewable power. In doing so, cutting transmission losses facilitates a second layer of economic and environmental benefit.
Low loss, high cost?
However, a major infrastructure upgrade programme would be impractically expensive, right? Not necessarily. As mentioned, more efficient transmission cables could reduce costs associated with booster transformers, as well as reducing redundant generation. Less equipment also means lower maintenance costs.
Then you have the fact that roughly 75 per cent of the UK’s transmission and distribution cabling is more than 25 years old. With a natural lifespan of between 25 and 40 years, much of this infrastructure will soon be due for renewal anyway.
Some might argue that decentralisation and the rise of distributed generation might lessen the need for high voltage, long-distance transmission. However, even if that were true, the transmission network accounts for roughly 28 per cent of losses, with 72 per cent coming from distribution. Proliferating distributed generation sources will only increase the amount of cabling needed at this level, making the investment case for low-loss cable even more compelling.
And finally, consider that electricity demand is only set to go one way in the UK. Electric cars are hovering on the cusp of mass adoption, there are proposals to electrify much of our heating and the economy is growing. Even apparently small changes, like the modern expectation for heating, air-conditioning and Wifi on trains, can add to overall demand. As it does so, that seven or eight per cent lost in transmission represents a growing financial and environmental hazard.
So, maybe we haven’t been talking about transmission losses because, in the absence of better options, there wasn’t much point. Better to spend time on renewable generation and energy efficiency measures that are already making a difference. However, that’s changing and it’s time we had a serious conversation about what tomorrow’s transmission and distribution infrastructure will be built with. Tomorrow’s cables might just be the surprise factor that makes a big difference to the UK’s decarbonisation hopes.