The reaction to Britain’s blackout this past Friday has been particularly withering. The dual-shutdown of a Bedford gas plant and a Humber offshore wind-farm left 1m UK homes without power, while travel chaos reigned as traffic lights and rail networks failed.
Despite National Grid’s protestations that this was an ‘unusual’ incident and its fail-safes worked as planned, energy watchdog Ofgem and MPs have been lining up to demand the electricity company explain exactly what went wrong.
Today, news also emerged that National Grid had seen three blackout ‘near-misses’ before Friday’s incident.
It has led to questions over the UK’s ability to transition to more prevalent use of renewable energy and how that would increase the risk of future blackouts. But where does our electricity come from in the first place? How much do we rely on renewable energy? And how does this impact the risk of future power outages?
For example, did you know that this past Sunday lunchtime our ‘carbon intensity’ - or the amount of carbon dioxide emitted for each unit of electricity generated - was a relatively green 122g?
Desktop and mobile users can navigate the Electricity Map below to track real-time global energy usage
Up to 82pc of the country’s energy use was low-carbon, including nuclear power, while 55pc came from renewable sources such as wind and solar.
According to National Grid, from January to May of this year, there was more electricity produced from zero carbon sources than fossil fuels, with 47.9pc from wind, solar, nuclear and hydro power compared to 46.6pc from coal and gas. (The remaining percentage is taken up by other energy sources such as biomass, which is neither zero carbon nor fossil fuel).
But come the energy-hungry maw of Monday morning our carbon intensity, fuelled largely by gas, was more than doubled at 290g. Less than half was low-carbon, while only a quarter of our energy use was renewable.
This is according to French-Danish developer Tomorrow’s Electricity Map, which tracks energy usage, carbon emissions and which energy source is being used in real-time from across the globe.
How does that compare? The UK shares a similar energy mix with many European countries, such as Spain and Germany, with the countries introducing more renewable energy from wind, solar and hydro to its traditional coal and gas plants.
France’s embrace of nuclear power, often providing over 70pc of the country’s power, means its carbon density is consistently low. Norway, meanwhile, is one of the greenest countries in the world, with the majority of its energy output provided by renewable hydro and nuclear power at a carbon intensity of 42g at most.
The highest in Europe? Poland’s reliance on coal produces an intensity of over 700g. Data on Russia and China is conspicuous by its absence.
These fluctuations between countries (and even within them) shows the task ahead for more widespread adoption of renewable energy. As part of a groundswell of global support for combating climate change, the UK government has pledged to reduce its carbon emissions to net zero by 2050.
The challenge of renewables
While there is no doubt that action needs to be taken worldwide to reduce carbon intensity, introducing more renewable to existing infrastructures has its own challenges. Friday’s blackout was a ‘rare event’ that would be ‘difficult to protect against’, according to Tom Edwards from energy analyst firm Cornwall Insights, and is unlikely to be tied to the increased role of renewables.
But critics of renewable energy often point to ‘intermittency’ as a drawback, meaning that when the wind doesn’t blow or the sun doesn’t shine, turbines and solar panels are not able to produce predictable levels of energy. The issue being that clean energy such as wind is less effective at dealing with shifts in demand.
“Increasing penetration of renewables makes it more challenging to balance supply and demand ,” says Edwards. “We can do more to integrate renewables, such as using the power available from wind farms and investing more in the network capability to absorb rapid changes in demand.”
One method of balancing the peaks and troughs of electricity demand is the use of ‘interconnecters’ between different networks.
At the time of writing, for instance, 6pc of the UK’s electricity is coming from France at a carbon density of 39g. Three per cent is coming from Holland and 2pc from Belgium.
While the density of the latter countries’ exports are rather less clean, interconnecters are set to play a ‘crucial role’ in decarbonisation according to a report by environmental think thank E3G.
Dr Iain Staffell, Lecturer in Sustainable Energy at the Imperial College of London agrees that imports are becoming increasingly important to the energy mix.
“Britain has never imported a greater share of its electricity than it does at the moment, with more than a tenth coming from France, Belgium and the Netherlands,” he says. “These links can bring stability as they let us import power at times of greatest need.”
Despite Friday’s blackout, Britain does have one of the most reliable power systems in the world with Australia and America suffering twice as many blackouts.
However, island nations such as Britain can be more prone to blackouts as they cannot rely on imports to pick up any slack in the system. It is for that reason that Switzerland ‘arguably has the most reliable electricity system in the world’, as it can import more readily from its neighbours.
'Countries relying on one energy source are most vulnerable to blackouts'
A slew of new interconnecters are planned between the UK and Norway, France, Belgium, Denmark, Germany and Ireland in the decade.
A government report in 2017 said that it expects imports to make up 25pc of Britain’s electricity by 2025. However, the looming possibility of a no-deal Brexit may make interconnecters ‘less useful’, according to Staffell.
“The UK would likely leave the single market for electricity, which falls under the jurisdiction of the ECJ,” he says.
“At the moment, electricity flows between countries are worked out automatically, but if we leave, then power flows will be bought and sold by energy traders.”
Unsurprisingly, the strength of a country’s electricity systems depends on its wealth.
“Most G7 countries have near-perfect reliability, while Nigeria and India suffer several blackouts every month,” says Staffell. “South Africa has seen rolling blackouts for years as the country struggled to generate enough electricity.”
For all the righteous fury over Friday’s blackout, then, it seems the disruption was so severe because it was such an unusual occurrence in the UK.
There is no particular energy mix that is more susceptible than another, but any that is over reliant on one source is the most vulnerable.
Brazil, for example, can face energy shortages in a dry year as a high percentage of its energy comes from hydropower (64pc in central Brazil at the time of writing).
As for the UK? Currently the country has a melting pot of energy sources that helps keeps the lights on. As more clean energy is introduced, that balance will need to be maintained to avoid more blackouts.
There are also new technologies coming to our homes that will better control our own demand for energy as these changes roll out.
“Having nothing but wind and solar power would be very unreliable as we cannot control the weather, so having these as part of a mix with flexible sources of power is essential,” says Staffell.
“More flexible generation, energy storage and demand-side response (such as smart-charging electric vehicles or smart fridges in homes and supermarkets) will be critical to minimising system costs in future.”