Potatoes and Photovoltaic Performance

Spring 2020 (March-April-May) was the sunniest since records began in 1929 according to the Met Office. This immediately followed the wettest February since rainfall records began in 1862 and it is very likely to be the driest May in England since 1896 (it is 30th May as I write this). And let’s not forget that in Hereford we had 2 frost days in May (12th and 14th) which was a new experience for me in this part of the world.

Although these unusual weather patterns cannot be directly attributed to climate change, our understanding is that we can expect more of these weather extremes as the planet warms.

The Potato Patch

Weather extremes do present challenges to the gardener. My potato patch certainly suffered some frost damage (Figure 1) although the plants in potato bags seemed to escape (Figure 2). My Davis weather station recorded a temperature of 0 °C (measured six foot above ground) on both frost days so at ground level the temperature was probably just below freezing.

Figure 1

Figure 2

Currently, the main issue in the garden is lack of rainfall. Our rainbutts (2000 litres) have run dry and we are having to use our metered water supply.

Photovoltaic Panels

The number of ‘clear blue sky’ days during Spring 2020 has been amazing. Has this been due, in part, to reduced air traffic during the Covid-19 lockdown? The record-breaking sunshine, as noted by the Met Office, has also delivered record-breaking electricity production from my PV roof panels (Table 1).

Table 1: PV Generation (kWh) for Spring 2020

YEAR/MONTH	MARCH	APRIL	MAY	SPRING (MAM)
2012	374	383	515	1272
2013	299	477	512	1288
2014	344	443	510	1297
2015	351	563	654	1568
2016	343	497	573	1413
2017	366	483	496	1345
2018	303	409	550	1262
2019	384	509	582	1475
2020	439	582	700 *	1721

* Provisional value calculated from current value (519) on 30/5/20 and projected weather forecast up to 8/6/20. Note: monthly PV generation data reported from 9th of the month to 8th of following month (e.g. March data is from 9th March to 8th April inclusive).

2020 set records for highest ever PV generation for March, April and May. Spring (MAM) 2020 PV output was 10% more than the previous highest (2015) and 26% higher than the mean for the previous 8 years. In fact, the differences should be slightly larger because I estimate PV performance has, for example, dropped about 4% since 2015.