Letters to the editor: volume 16, issue 3

Renewable threat to grid stability

Steve Macken (Letters, March 2021) expresses excitement at the prospect of the transition to a zero-carbon electricity system. After 39 years in the supply industry, initially in distribution and latterly in transmission, I regrettably do not share his optimism that renewable energy sources, coupled with grid-​connected storage, increased interconnection with other countries and “smarter use of electricity”, will diminish the need for baseload generation.

The technical issue that appears to be glossed over is the critical one of power-system stability. The safe and reliable operation of an integrated power system such as the UK National Grid requires a significant percentage of synchronous generation to be connected to the system at all times, to provide the necessary system inertia to ride through disturbances.

The increasing proportion of non-synchronous renewable generation connected to the system diminishes the ability of the system operator to ensure system stability. The allied issue of adequate transmission-system fault levels is of growing concern, with the potential to lead to insufficient fault current in some parts of the transmission network for system protection to operate for fault conditions.

The uncertainty created by the fluctuating output of renewables adds significantly to the complexity of the operation of the system, especially as much renewable generation is connected at distribution voltages and is thus invisible to the transmission-system operator. Grid-connected energy storage may assist with load and generation matching, though the battery option may not be economically and environmentally viable.

Demand-side management has the potential to be politically explosive as the smart meter roll-out continues and consumers begin to realise that variable-rate tariffs may have significant social impact. Electricity may well become unaffordable at the very time that it is required – for example, during intensely cold adverse weather conditions.

The only realistic answer is a substantial increase in nuclear generation to secure base load and provide adequate synchronous generation.

EurIng Steve Proud CEng MIET

Swansea

The importance of applied knowledge

It was a breath of fresh air reading the account of Simone Wilson’s route to becoming an IET Engineering Horizon Bursary recipient in the March 2021 issue of IET Member News. I have always believed that the apprentice route was the best way to create the best engineers as problem-solvers and the most creative engineers, as the applied knowledge based on hands-on experience is just as important, if not more so, as the academic engineering route. Not because I came up through the ranks via a similar route, but because qualified engineers must have theoretical and applied knowledge in equal amounts and the latter of course cannot be taught in books, but on the job itself.

Having had 55 years within industry, 34 years of that in private consultancy, I have found through my 34 years as an expert witness how professionals can be deficient in the applied side and this comes out clearly within the courts. In more than three decades of court work, the applied side has provided my clients through my technical reports and evidence, judgement in their favour in every case, both for claimants and defendants.

Dr David Hill FIET

Huddersfield

Recovering from Covid

We are all, in one way or another, grappling with the economic crisis created by the Covid-19 pandemic. However, institutional and savvy retail stock market investors have a special question to address, once some sense of business normality returns to their local markets. Which companies are best placed to quickly track and remove any virus damage, then speedily install feasible remedies that maintain profitability at a competitive advantage level?

While not a question amenable to a full answer, my working knowledge and studies across various industries and in several countries suggests at least a partial answer. Namely, that the best-placed companies are those who, prior to the virus pandemic, had the foresight to invest in funds, skills and time to methodically plan and implement a fully integrated strategy. One encompassing and knitting together all business administrative and productive features and their resources in ways needed to achieve the best company performance. As well as accommodating critical associations with customers, suppliers and any business partners.

A detailed architectural model of such a fully integrated organisational strategy is usually kept for periodic management review, often via computerised screen and keyboard. However, it now takes on the unintended additional role of ‘IF this/THEN that’ Covid-recovery simulator, enabling management to quickly locate and assess any virus-related problems, then test recovery solutions to determine the most appropriate to apply within affected organisational sectors such as the following. Corporate objectives and success goal timelines. Business-critical functional activities structure. Communication network of key data inputs, outputs and storage facilities. Human resource job specifications at decision-making, back-office or shop-floor positions. Internal and/or internet-based computer systems and similar technology used for either automation or staff interface support purposes.

Such a convenient Covid-recovery tool is usually only found in larger enterprises having the wherewithal to realise fully integrated business and technology strategies. The good news is that such companies exist in a wide variety of manufacturing and service industries across the business world.

George H Kelly MIET

By email

Brexit setbacks

Before the UK joined the EU, I was a young engineer working for a medical equipment company. We had just made our first sale in France, to a large hospital in Paris. The machine developed a fault, and although our engineers were on site, the technical director, my boss, decided that we needed to be seen to respond quickly. So, I was on a ferry the same evening with a spare unit in the boot, and some hastily prepared paperwork.

The douanes were not happy with my documentation so seized the goods and my passport. I was, in effect, arrested and the goods bonded. I eventually got my passport back, but not until my company had paid a fine by bank transfer of 100,000 francs, then about £10,000.

The UK joined the EU shortly after that, so visiting and exporting to Europe really did become ‘frictionless’. I feel very sympathetic with those companies and their lorry drivers struggling with post-​Brexit paperwork. When will governments start learning from history? Brexit has set us back over 40 years. Small entrepreneurial companies now face an uphill struggle to sell and support their products in Europe.

Graham Collins CEng MIET

Builth Wells

Three more steps to net zero

I was disappointed that ‘Ten Steps to Net Zero’ (February 2021) did not mention three very major and essential requirements.

Grid-scale storage is essential with the increase of intermittent renewables – in particular, when the whole of western Europe experiences periods of low wind and low solar-generation and international interconnectors cannot be relied upon to provide any shortfall. Batteries cannot supply sufficient storage and are not environmentally friendly either, when their use of rare materials and complete lifecycle is considered. Technologies that can supply the required grid-scale storage include compressed-air energy storage, liquid-air energy storage and pumped hydro (though there are few practical UK sites for this).

There is also the need for inertia to maintain grid stability. There have already been issues with the lack of stability that are set to increase with the increased use of renewable generation and retirement of rotating capacity. National Grid is having to pay increasing amounts to mitigate effects and there were blackouts in August 2019.

National Grid has declared that it needs a minimum level of power flowing to avoid ‘black-start’ conditions. The increase in renewable generation has already meant that there have been periods when this has not been met. The situation caused by this, as well as the above two requirements, will only get more onerous and critical as the planned changes for net zero proceed.

Grid-scale storage technology can be implemented in ways that can inherently assist with the requirements for grid stability and black-start capability. Also, I would have thought that tidal power generation, again not mentioned in the article, would be an essential part of the mix due to its predictable nature.

Henry Kafeman MIET

By email

Still going strong

In 1954, having passed my second-year exams in light-current electrical engineering – the word electronics wasn’t in use then – and having some money left from my grant, I lashed out and bought an Advance E2 Signal Generator, 100kHz to 100MHz in six bands.

I still have it, and the other day I decided to check its calibration. The original spec was +/-1 per cent. I checked the top, bottom and mid-frequency in each of the six bands and the range of errors was between +0.2 and -2.3 per cent. If I could rotate the dial very slightly it would just about meet its original spec. For a device that’s about 67 years old, I think that says something about British engineering.

It has needed a little tender loving care over the years; the double-diode rectifier valve was replaced with silicon diodes and a capacitor had to be replaced to restore the audio modulation. Also, the two valves ECC91 and 6SN7 may have been changed, but I still have replacements so I think it will see me out.

Tony Meacock CEng MIET

By email

Norway’s wealth

According to ‘North Sea Oil: A Tale of Two Countries’ (February 2021), the UK and Norway “have produced similar amounts of hydrocarbons”, within 7 per cent of each other. Once you realise that, in the UK, the wealth generated is spread across a population 12 times larger, you understand why Norway has ended up richer per capita.

Patrick Macdonald CEng MIET

By email

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