By DB Watson, Retired chartered electrical engineer

THE UK Parliament’s climate change committee in May this year opined that Net Zero CO2 emissions is possible by 2050 “with known technologies alongside changes in people’s behaviour”. Our politicians then made Net Zero by 2050 legally binding.

Net zero anticipates a continuing increase in wind-based generation. The limit of turbine wind energy capture from Betz Law is a maximum of 59 per cent, with today’s turbines achieving much less. Much of the unconverted energy is lost to warming surrounding air.

In a recent study of 411 onshore windfarms Harvard University calculate that to theoretically meet existing US electricity demand with 100 per cent wind would warm average surface temperatures by 0.24C and at night by up to 1.5C . Professor David Keith concludes the contribution from operating turbines is instantaneous whilst the reduction in CO2 due to the reduced fossil fuel generation will take almost 100 years to cool the atmosphere by the same amount and therefore windfarms contribute to global warming over that time frame and “if your perspective is the next 10 years, wind power actually has – in some respects – more climate impact than coal or gas”

Net zero also anticipates prohibition of gas boilers in new homes with heating replaced by hydrogen or electricity. Each atom of hydrogen has to be manufactured. It is therefore not an energy source, only a poor energy carrier requiring, via predominant methane conversion, around 50 per cent more energy to manufacture than it delivers.

Since April 2018 new domestic gas boilers must be a minimum of 92 per cent efficient per the Governmen t Clean Energy Growth legislation. Using gas turbine -riven electricity generating stations instead drops efficiency to 60-65 per cent. This 50 per cent increase in CO2 output will have to be captured in new carbon capture usage and storage plants at power stations which technology is not yet developed.

National Grid with self- doubting overtones in its recent Future Energy Scenarios 2019 report considers the implications of net zero and speculate a range of future scenarios requiring it to “flex” its assumptions in areas of “speculative technologies” to theoretically achieve it, including assuming we will be heating 13.9m homes by hydrogen by 2050. It consequently concludes that “peak electricity demand is forecast as 115GW, almost twice today’s level”: this achieved by dependency upon more European interconnectors – increasingly via highly-polluting lignite from Germany – as our life-expired nuclear stations shut.

FES 2019 credits our now-compulsory future use of electric vehicles, estimating 35 million, but we need to address car and energy storage battery provision and here the situation is also seriously worrying. The Institution of Engineering and Technology has just published its investigative report Lithium at any Price? on the huge ecological problems extant within Chile, which produce around 38 per cent of the world’s lithium for batteries.

Most is extracted by evaporation typically from the Atacama salt flats. Fresh water levels in nearby National Reserve lakes are consequentially and unsustainably falling, threatening flamingo habitats and micro-organisms, and 32 per cent of local native Algarobbo drought-resistant trees were found to be dying due to water shortages. This against a predicted lithium deficit by 2023. “Chile’s aspiration to toughen regulation remains high but action remains scarce”.

We require a governing engineering-led body to holistically assess and establish from the many energy dilemmas the optimum choices to maximise what is achievable in respect of net zero.

As professional engineers and scientists we must continue to technically question what we may wish to be true to enable us to advise those who consider their unquestioned opinions hold as much weight as fact.