Zero-carbon energy sources are poised to overtake fossil fuels as the UK’s largest electricity source over a full calendar year.

This year will be the first that fossil fuels make up less than half of the electricity generated, according to National Grid, following a dramatic decline in coal-fired power and rising renewable and low-carbon energy.

Instead, UK homes and businesses will rely more on “cleaner” electricity generated by wind farms, solar panels, hydro power and nuclear power reactors.

A decade ago, coal plants generated almost a third of the UK’s electricity, but in the first half of this year they have provided only 3%.

In the same period renewable energy has climbed from supplying just 2% of the UK’s power to a fifth of all electricity produced.

The “landmark tipping point” is an “historic achievement” in the UK’s journey towards becoming a net-zero carbon economy by 2050, said National Grid.

John Pettigrew, the UK power system operator’s chief executive, said: “The incredible progress that Britain has made in the past 10 years means we can now say 2019 will be the year zero-carbon power beats fossil fuel-fired generation for the first time.”

“We wouldn’t have said it if we weren’t confident that this will be the year.”

National Grid is able to confidently predict the 2019 record only six months into the year following the UK’s greenest ever winter, and the huge number of coal-free days recorded since then.

The UK reached a record stretch of consecutive 18 coal-free days earlier this year, which ended on 4 June.

The electricity system reached a second record this week after racking up 1,838 coal-free hours for this year, breaking a record set across the whole of 2018 in a little over six months.

The coal-free days have effectively prevented 5m tonnes of carbon dioxide from entering the atmosphere, or the equivalent of over 12bn miles driven in a car.

Chris Skidmore MP, the interim energy minister, said coal is “fast becoming the fossil of our energy system and it will soon be consigned to the history books”.

He added: “We’ve set in stone our commitment to end our contribution to climate change entirely by 2050 and this is yet another step on the path to becoming a net zero emissions economy.”

By the end of the winter the UK will be left with only five remaining coal fired power plants, after SSE said last week it plans to shut its Fiddler’s Ferry plant near Warrington, Cheshire, next March. SSE revealed the closure after EDF Energy said it would shut its Cottam coal plant in September.

The government plans to phase out all coal-fired power generation by 2025.

National Grid is spending around £1.3bn a year to adapt the grid to run on renewable energy, and believes that it will be ready to manage a completely zero-carbon electricity grid within six years.

“Do I expect that this will be a reality? No,” Pettigrew said. “But we won’t be a constraint in a low carbon world. We will be prepared to play our role.”

Doug Parr, Greenpeace UK’s chief scientist, said the “watershed moment” is a sign that the UK is “broadly heading in the right direction”.

“The question is, are we moving fast enough?” he said.

Research undertaken by National Grid alongside its record forecast has found that “climate anxiety” is rising because people believe there is a lack of urgency in tackling the climate crisis.

Nearly seven out of 10 people surveyed by National Grid are concerned about climate change and believe it is not being addressed urgently enough.

More than a third of young people said their concerns about climate change would drive them to join a protest. Almost a fifth of 18- to 24-year-olds said they are prepared to skip school or work to do this, possibly inspired by student activist Greta Thurnberg who visited the UK earlier this summer.

“As the climate emergency hits home right across the globe from Greenland’s melting ice to India’s scorching heatwave, the clock is ticking on our chances to avoid climate breakdown and public anxiety rightly remains high about the speed of change,” Parr said.

“This is no time for ministers to pat themselves on the back and uncork the bubbly,” he said.

• This article was amended on 24 June 2019 to clarify in the text that nuclear is not a renewable energy source, and to change the description of the non-fossil fuels that are growing in use to “cleaner”, as they are referred to by National Grid.