Efficiency matters, but resilience matters more, and resilience is inefficient.

Within a little more than a decade, it’s feasible that 4 GW of wind generation capacity will be sited within the immediate vicinity of Shetland. This capacity will likely rise further over the years that follow. Part of the development attraction is that these installations will be amongst the most efficient in the world, a claim supported by the world record holding efficiency factors of Shetland-turbines past (c. 60%+). At that efficiency, over 7 million homes could be powered by 4 GW of installed wind capacity in this location, but that’s unlikely to be the best way to utilise these electrons.

Shetland is currently an islanded grid, but we’ll soon sit at the end of a 0.6 GW interconnector to the UK national grid. Firstly, there is the obvious challenge of trying to cram 4 GW of electrons down a cable that could be 6 times too small for Shetland’s generation capacity within a decade, but parking that impossibility for a moment, an arguably bigger challenge is concerned with the structure of the UK grid that Shetland will be connected to.

The grid is setup such that even the imminent 0.6 GW export potential from Shetland will often be constrained (i.e. unable to deliver additional power into the UK network because it is already fully saturated with ‘green’ electrons). This challenge will likely become more pronounced as additional generation capacity is added south of Shetland, which is what we’ll see as ScotWind sites start to spin to life over the coming years.

If it’s windy in mainland Scotland, you can bet your house that it’ll be windy in Shetland, and those electrons will need somewhere to go, otherwise the most efficient turbines in the world will have to be ‘switched off’.

Taking a step back in time, my parents like to tell a story about 4-year-old me, thudding my way to their bedroom on an early December morning, where I proclaimed “Mam, am gon blinnd!”. Thankfully I hadn’t gone blind, but the power had gone off during the night, and the pitch-black Shetland morning didn’t offer the usual confirmation of continued vision.

At the time, we had one fireplace in our house, and our heating came from burning peats – the fire heated the water that fed the radiators. In the winter, the house was cold every morning and every day after school, until we got the fire going. Like most families, we had a peat bank. I’d accompany Dad to the peat hill, where several weeks of hard labour every summer, cutting, casting, drying and bagging peats would assure our warmth through the winter months.

Power cuts happened more regularly then than they do now. I remember having most of the family at our house during the 1992 New Year storm. One weather station nearby recorded a gust of 197mph, a UK record, before the measurement equipment itself blew away. There was no power, but we were warm and safe.

During this time, the only external factor that had an economic bearing on the price of our heating was the wages that Dad didn’t earn due to working at the peat hill for those few weeks – there was essentially zero volatility on the cost of staying warm.

A few years later, like many Shetlanders, we had a Kerosene fired boiler installed, and our days of hard labour at the peat hill became a thing of the past. My grandparents did similar. We still had power cuts, but the tiny amount of power that the boiler needed to function could be met with a small generator, so we could stay warm, and stay resilient to the elements. Earlier this year, my Grandparents, almost 90, opted to have a heat-pump installed... You can see where this is going.

This week, we’ve had some of the worst disruption to Shetland’s power systems in years, driven by a combination of freezing snow and gales. Miles of snapped and fallen electricity poles, thousands of homes without power, heating, or communication, including my parents and my grandparents. My parents can keep their kerosene boiler running, but a heat-pump is too much for most domestic sized generators, and so like my grandparents, hundreds of Shetlanders will be sitting in houses that are slowly approaching the freezing outdoor temperatures, with the prospect of not having power for a week.

So, what are our options for resilience in an ecosystem that can’t survive continued hydrocarbon combustion; where our economic resilience must be protected from the interests of distant heads of state; where we can utilise some of the most efficient means of green electron production in the world without constraint (remember that 4 GW of wind on our doorstep)?

These questions can be scaled up to the national energy system level, and still maintain relevance. Hydrogen makes sense in many settings where there is an abundance of available electrons, as does ammonia, methanol and even synthetic green hydrocarbons.

Unfortunately, these potential fuel sources have accumulated many detractors, some with specific and understandable reservations about the safety of certain applications, whilst other more partisan commentators seem to be swept along in a slipstream of anti-green-molecule sentiment. System inefficiency is often decried as the Achilles Heel of many of these emergent energy carriers.

Of course efficiency matters. But for the increasing number of people struggling with the cost and even the availability of energy simply to heat their homes, the reality is that resilience matters more, and resilience can often be inefficient.