‘Greenest’ winter ever, says National Grid winter report


THE ‘greenest’ winter ever is to be expected due to shift towards gas and renewables, National Grid states in their recently published Winter Outlook Report for 2019/20.

“Last year was the lowest carbon intensity winter on record in terms of electricity generation”, Fintan Slye, Director and UK systems operator at National Grid, said.

“If weather conditions are similar this winter, we expect this positive trend to continue and anticipate more records being broken in terms of increasing renewable generation and coal-free running.”



Regards to electricity, the nation Transmission System peak demand this year is expected to reach 46,4GW, lower than last year.

Rising levels of generation, especially renewable, mean there is a surplus capacity on electricity of 7,8 gigawatts. This surplus – known as the de-rated margin – determines how much reserve is in the system; this is 0,7GW higher than 2018/19.

This drop in expected demand peak and increase in available capacity both give assurance that the system should be reliable and therefore daily prices should remain within expected norms, although electricity forward prices are expected to be higher than in Europe. This may result in it being economic to import rather than trigger domestic capacity.


Triad forecasting

Forecasting Triad peaks has become increasingly difficult in recent years as major consumers become more sophisticated at demand management.

Operational Surplus of Power is expected to be higher than last year with the average cold spell demand to be met under base in all weeks.

Last year, frequency deviations occurred within settlement periods before a predicted Triad peak for the first time.

This is thought to be due to battery storage coming online in response to suppliers and consultants sending out Triad warnings. Such behaviour makes balancing harder due to abrupt changes in the system and therefore Triad peaks are harder to predict.

National Grid expect this challenge to persist throughout the 2019/20 winter period. The predicted maximum Triad avoidance this year is set at 2,6GW, an increase from last year’s 2GW.



The total winter gas demand is expected to be slightly higher than last year at 52,3 billion cubic meters. This is driven largely as a result of more gas fired thermal generation plant coming online, particularly to provide winter baseload as coal-fired power stations are being decommissioned.

A change in methodology after ‘Beast from the East’ means more gas balancing notifications may be issued but actual storage levels are considered to be comfortable.



The intended departure from the European Union is expected to have no impact on the operability of the national gas or electricity grid networks.

However, the analysis of forward electricity prices suggests that there will be net imports of electricity from continental Europe to Great Britain at peak times during winter 2019/20. Great Britain is expected to be a net exporter of power to Ireland in peak periods.


Grid carbon mix

The continued rise in renewable capacity and reduction in coal generation means that National Grid is expecting winter generation mix to remain relatively green, continuing the trend after last year had the lower carbon intensity on record.