The rise in UK renewable power generation

01 Nov 2017

October 2017 reaches a major milestone for weather dependent renewable electrical generation


October 2017 is the month that the combination of wind + solar + hydro generation produced more electricity than Nuclear for the first time. It may even be possible that wind and solar alone produced more than Nuclear, but this blog post explains why it is not possible to say this with greater certainty.

There is understandable excitement associated with the new records being set by electrical generation technologies over recent years. This is newsworthy for the mere fact that it alerts a wider audience to the low-carbon transition that is well underway.

Data capture from large installations

Several visualisation websites have grown in popularity over the years, with pioneering the visualisation of the electrical generation system. The usual source of data for these websites is from National Grid, Elexon or BMReports who ultimately use metered data from National Grid. The differences can be found in areas such as the type of aggregated data and whether the data is subsequently updated with potentially more accurate values at a later time.

Larger generation plant that is connected directly to the high voltage network (the large pylons that traverse the country - the transmission network) have metered output that is shared with National Grid on an operational basis e.g. real-time or near real-time. As with any metered data, this can contain errors from time to time or even drop out with a meter fault.

Data from small installations

Some wind farms are connected at this transmission level (and metered) - but solar generation and other wind generation are connected within the lower voltage electrical distribution network (local networks), which is termed embedded or distributed generation.

Due to the sheer volume of smaller installations, it is impossible to measure all of these on an operational basis, so the generation from solar and embedded wind is estimated by National Grid using a number of different models. One of these is from Sheffield Solar (, who provide a data feed for embedded solar generation.

The certainty of assumptions

The data behind the chart in this blog, and therefore behind the statement that wind + solar + hydro was greater than nuclear output in October, is a combination of the Elexon generation by fuel type data (for transmission connected) and National Grid data (for distribution connected). Even with potential errors in the estimation of solar and embedded wind, the difference in generation between wind + solar + hydro and nuclear is of such a level (about 2.5 days of average nuclear output) - that it seems safe to state that weather dependent renewables generated more than nuclear in October.

However, knowing that wind actually produced over 5000 GWh during the month is harder to say with certainty, but stating that it smashed its previous record set in December 2015 of 4200 GWh will be accurate.

In short, although the data may be subject to errors around the margins, the trends and overall levels are likely to be accurate.

Wind + solar + hydro generates close to 6000 GWh in October

Therefore, to end this blog post as it started - the month of October 2017 is a major milestone in the transition of Great Britain to a low-carbon electrical system - a transition that is clearly well underway.

Weather dependent renewable generation has significant challenges in terms of integration and intermittency, but the thought that they are unable to produce more than a 'fraction' of electricity should be able to be laid to rest once and for all. Wind+solar+hydro have generated over 4000 GWh for each month throughout 2017, and in October they generated somewhere in the region of 6000 GWh.

2017 is on track to be a record year for renewable generation

This puts 2017 firmly on track to be another record year; weather dependent renewables may generate close to 55,000 GWh. This would be somewhere in the region of 18% of the generated output using these data sources, in comparison the same values in 2016 were 43,500 GWh or 14.5% of generated output.

If Nuclear is rightly seen as providing a substantive amount of electricity over a timeframe as long as a month, then surely the month of October 2017 proves that weather dependent renewables are able to do the same.

Grant Wilson is a Teaching and Research Fellow in the Environmental and Energy Engineering Group at the University of Sheffield. To access graphs used in this blog post, and archives from 2015, visit