In October 2020 the UK Prime Minister pledged that “Wind farms could power every home by 2030”, as reported by the BBC. While I am certain that the Prime Minister had been well advised before making such a statement, I wondered nevertheless if the numbers stack up, whether this pledge is feasible, or overly ambitious, or simply an “inverted pyramid of piffle”. The objective of this story to get a grasp of the order of magnitude in annual wind energy generation needed in order to realise the pledge; hence this story provides a simple energy analysis based on annual statistics.
The starting point has to be some statistics of energy generation and consumption over the past few years. Fortunately, there is quite a wealth of information available on the UK government statistics website and its associated government agencies such as the Balancing Mechanism Reporting Service (BMRS). For this analysis only aggregated datasets were needed.
Domestic Energy Consumption
While there are quite a few sources on domestic energy consumption, Energy consumption in the UK, offers a spreadsheet with all data needed. Focusing on electricity and gas only, the domestic consumption over the years shows:
The past few years exhibit an annual domestic energy consumption of about 300 TWh in natural gas and 100 TWh in electricity with a falling trend since the mid naughties where the domestic energy consumption peaked at about 400TWh for gas and 125TWh for electricity.
Wind Energy Generation
Even though the government does publish some data on wind energy generation on Energy Trends: UK renewables and related pages, Wind power in the United Kingdom includes data for a longer period, starting with 2008. So far I haven’t found a good source that goes further back in history.
The year 2019 in the above plot shows an annual energy generation of about 64 TWh with an annual increase of about 8TW per annum in the preceding years. The Annual addition of 8TWh is approximately equivalent to 1GW continuous electrical power added every year. The installed power capability is certainly much higher given the intermittent nature of wind.
In this story the objective is to only focus on the annual domestic energy consumption versus the annual wind energy generation. There are two interpretations of the PM’s announcement.
Domestic Electricity Only
Possibly, the PM was thinking about producing all domestic electrical energy by 2030. Well, that could work out well:
- given the current trend in domestic energy consumption it is perhaps safe to assume that the annual domestic electricity consumption in 2030 will be around 100TWh/annum, leaving a shortfall of about 36TWh with wind energy generation of 64TWh from a 2019 perspective.
- if the current trend of adding wind power generation at 8TWh/annum can be sustained, it would only take 4.5 years to accumulate the 36TWh needed and to reach the target annual energy generation of 100TWh.
That being said, the objective of generating the annual domestic electricity through wind farms should be achieved at the latest in 2025.
Total Domestic Energy
The statement “Wind farms could power every home by 2030” could also be seen in a different way: all domestic energy consumption is replaced with energy generated by wind farms which has important implications. Barring a hydrogen infrastructure for generating, storing and consumption as well as not taking into account additional electrical power needed to charge Electric Vehicles, it would mean homes can only consume energy in the form of electrical energy, so no consumption of natural gas at all.
As it stands, homes consume some natural gas for cooking, but most is burnt for space heating and domestic hot water using gas boiler. This energy sink would have to be replaced. If the UK follows the recommendation of the International Energy Agency’s “Net Zero by 2050”, however, then the sale of new gas boilers should be phased out by 2025. It is conceivable that by 2030 the majority of gas boilers could indeed be replaced by air heat pumps for both space heating and domestic hot water preparation (the economic feasibility of that transition is matter for another investigation). At an average efficiency of 300%, i.e. every unit of electrical energy is converted into 3 units of thermal energy, the projected domestic consumption of 300TWh in natural gas could be met with about additional 100TWh electrical energy. The grand total on the domestic electricity consumption would be about 200TWh/annum for the year 2030.
Where does that leave the PM pledge? Well, starting at 64TWh in 2019 and with the current trend with of additional wind energy of 8TWh/annum, it would take 17 years to get to 200TWh/annum; this would lead us to the year 2036. Conversely, if the shortfall of 136TWh/annum was to be met in 2030, then an average addition of about 12TWh/annum is needed which is about 50% more than the current annual addition. It is even conceivable to ramp up the current 8TWh/annum to about 16TWh/annum by 2030 to arrive at the same number in 2030. That does not sound too far off the charts?
The simple energy analysis carried out here works on accumulated energy consumption and generation, grossly neglecting the dynamic characteristics of both; whereas the domestic electricity consumption is somewhat predictable and regular within bounds, wind energy generation is very intermittent. A further, dynamic analysis focusing on power consumption and generation over time should reveal that the devil is in the details (that can get in the way of a good story, unfortunately) and talk about how it can be made work using demand response, forms of energy storage and shifting some storage to homes (electrical and thermal):