Renewables generated very nearly as much electricity as nuclear sources during 2015, prompting the continued fall in power supply from coal-fired power stations.

Renewables generated very nearly as much electricity as nuclear sources during 2015, prompting the continued fall in power supply from coal-fired power stations.

This is one of the topline features of the latest GB Electrical Market Summary report by industry specialists EnAppSys*.

The EnAppSys report shows that the significant growth in renewables seen in recent years continued during 2015 with the generation of 65.4TWh (7.5GW) or 21% of total electricity, only marginally below the contribution from nuclear plants which provided 21.1% of the total.

Within the renewables sector, wind was responsible for just under half of the total contribution with the generation of 32.4TWh (3.7GW) of power, fuelled largely by an increased contribution from offshore wind farms.

Over the 12 month period, biomass also saw significant growth to 19.0TWh (2.2GW), with the ongoing conversion of some Drax units to biomass from coal.

The rush to meet subsidy deadlines saw solar PV also increase its contribution significantly to 7.1TWh (0.8GW), with solar providing more electricity than hydro plants (6.84TWh) for the first time.

Overall, during 2015 Britains fuel mix was provided by CCGT (gas) plants at 27.2%, coal (24%), nuclear (21.1%), renewables (21.0%) and interconnectors (6.7%).

Despite a fourth quarter increase in coal-fired power generation as a number of coal units returned to service following maintenance outages, coals contribution to GBs electricity generation fell to its lowest level since 1951 - a period when overall power generation was much lower.

During 2015, the total generation from coal fired-power stations fell to 74.5TWh (8.5GW) during the year, representing 24% of total generation (down from 31% in 2014).

As a result of this fall, coal was displaced as the primary source of electricity by gas-fired power stations (CCGT), which contributed 84.4TWh (9.6GW) of electricity.

With the rise of renewables, and the contribution of interconnector supplies from outside the UK, the overall level of fossil fuel power generation has now fallen by 39% over the past five years, from 259.8TWh to 158.8TWh.

This represents an share of total power generated from fossil fuels of just over 51% during 2015 and has led to an estimated fall in the countrys carbon emissions (excluding interconnector supplies) from electricity generation to around 88.7Mt, compared to an estimated 106Mt in 2014.

Paul Verrill, director of EnAppSys, said: ""Renewable sources now provide almost as much electricity as nuclear plants and are expected to overtake them during 2016 as the Wylfa nuclear plant closes and as new wind and solar projects come on stream.

"The ongoing closure of coal stations and the Governments stance against them perhaps marks the end of an era for coal stations which have dominated the GB power market since its inception, with coal-fired generation at its lowest level since 1951.

"Since 1948, coal fired power stations have provided over half of the countrys electricity generation, but this picture is now changing rapidly with the growing emergence of wind, solar and biomass.

"These changes in generation have also had an impact on supply margins and prices. Although the greater reliance on renewables has caused occasional tight supply and demand margins, leading to some rare but spectacular balancing price spikes, the overall impact on the grid has been manageable.

"GB network transmission restrictions have meant that in 2015 the UK missed opportunities to further reduce carbon emissions as renewable generation has been curtailed particularly through December, but 2016 sees increased transmission capacity in the North of Scotland and construction ongoing on the Western link between the South of Scotland and England.

"With the UKs carbon floor price causing profit margins at coal plants to decline despite low coal fuel costs, the GB electricity fuel mix looks set to continue with high levels of renewable generation and declining gas and nuclear; with gas and imports from the continent helping balance any differences between supply and demand."

Against this changing fuel mix picture, overall power generation levels continued to fall - largely as a result of energy efficiency measures, contraction by large industrial users and the increasing use of local distribution that does not rely on power transmission through the GB network.

In fact, the total of 310.58 TWh of electricity generated during 2015 (representing an average daily demand of 34 GW) represents a near 9% fall over the last five years from 340.3 TWh (37.25GW) in 2010.