So, Mastodon . I’m on it. After a little wandering I’m currently at That instance feels comfy for now, but I might move in future. Somebody has set up, which is nice, but they have no moderation or federation policies, which makes me think that they haven’t thought through running a social media instance, and that they might not be prepared to respond when (not if) something abusive happens (example here. Content warning for highly offensive language.).

I don’t know yet how much I’ll use it. A lot will depend on how both it and Twitter develop; it’s hard to find time to participate in both. If you are also on Mastodon (or something else in the Fediverse), feel free to give me a follow.

Cute model of an owl, wearing headphones and using a tiny laptop
Photo: Public domain.
Posted by simon

A Psalm for the Wild-Built

I try to keep this blog focused on the professional, or at least the energy-related, and so I doubt that I’ve ever mentioned my love of speculative fiction (a broader term for what might, in the past, have been named “science fiction and fantasy”). But in the last few days, after many recommendations, I’ve been reading Becky Chambers‘s “A Psalm for the Wild-Built“, and that deserves mention here. So here’s this blog’s first book review. Sort of.

The book is short, and enjoyable, an easy read, and excellent in many ways that I won’t get into here. I’m not going to discuss most of its themes, nor even its plot; what has made me post is the world in which it’s set. It’s “bright green”, but beyond bright green. It’s what some would now call “solarpunk”. It’s a society that has de-industrialised and become sustainable, and has completely changed in order to do so, but rather than doing that by reverting to a pre-industrial way of life it has done something new: it has retained technology, but without consumer culture or (we assume) mass production.

“It was a good computer, given to them on their sixteenth birthday, a customary coming-of-age gift. It had a cream-coloured frame and a pleasingly crisp screen, and Dex had only needed to repair it five times in the years that it had travelled in their clothes. A reliable device built to last a lifetime, as all computers were.”

This is, I assume, the kind of world that many environmentalists yearn for – especially those who want to decentralise, for villages to live locally and within their means, and so forth. This is sometimes expressed, at least by those in the first world, as a yearning for the past, for pre-industrial society, which is something that I can’t get behind for fairly obvious reasons. But some also see it as a brave new future, as something that hasn’t been tried before. The huge missing piece is usually a plan to get from here to there…

Anyway. The book is lovely, and provided me with a calm and enjoyable few hours. You should read it, not just for the setting but also for the many other things it explores.

“Farmers and doctors and artists and plumbers and whatever. Monks of other gods. Old people, young people. Everybody needed a cup of tea sometimes. Just an hour or two to sit and do something nice, and then they could get back to whatever it was.”

A glass cup of herbal tea, presented on a hemp mat.
Photo:, CC0 public domain
Posted by simon in Reflective, The wider world

The name of natural gas

I’ve seen some recent tweets, and partisan websites, claiming that calling geologically-stored methane “natural gas” was a major greenwashing achievement by the fossil fuel industry – that it’s meant to imply a benign fuel.

I can see why people think that. It’s the sort of steering of language that the modern fossil fuel industry might try to do. But in this case, I don’t think that happened: the term “natural gas” is older than “greenwashing”, older than most of the people using it, and arguably older than the environmental movement as a whole.

When natural gas was introduced, it was called that to distinguish it from “town gas” or “coal gas” – a nasty, noxious and somewhat toxic substance made from coal in each town’s gasworks, which used to cook our food and perhaps heat some homes. When the UK switched to natural gas in the 1970s there was a huge, co-ordinated campaign of technicians visiting every gas-connected home to adjust or replace appliances ready for the switchover… and that shift is why the old, often Victorian, gasworks in most cities – eye-catching for their “gasometer” storage systems – are no more. Calling it natural gas, rather than just gas, is also helpful when in the company of Americans, lest they think that we fry our eggs on petrol 😉.

None of this means, of course, that the fossil industry doesn’t benefit from the terminology. This paper (paywall), reported in Vox, suggests that people feel more positive about “natural gas” than “fossil gas” or “methane”. But in this case, so far as I know, it wasn’t a cynical ploy by the industry to call it that. They just lucked out with what it was already called.

Atmospheric view of gas being flared into an evening sky.
Image: Blake Thornberry, CC-BY-NC-ND 2.0
Posted by simon in The wider world

How droughts can cause energy shortages

An exposed riverbed rock with carvings of dates visible back to 1616. Some people are resting their bare feet against it.
Image: Libor Elleder (distributed via, licensed CC-BY-3.0

Today I learned about “hunger stones“. These are rocks in the River Elbe that are submerged in all but the lowest water conditions. Carvings on them commemorate historical droughts back to the fifteenth century and warn that if the stone is visible, famine will follow. One of the most poignant inscriptions translates as “If you see me, weep”. As Europe faces what may be its worst drought in 500 years, these stones are appearing… and while famine is less inevitable in a world of globalised food supply, it’s interesting to see the knock-on effects on energy.

Shipping companies have been warning for some time that water levels on Europe’s rivers have been approaching a level at which cargo traffic would have to stop. Indeed, when I was sitting by the Rhine on holiday two weeks ago I noticed that the laden barges were sitting higher in the water than usual – that they were sailing with reduced loads to cope with a shallower river. Since then parts of the river have effectively closed as predicted, as shipping companies decide that there is not enough water to operate safely or economically.

The closure of major transport routes is concerning for supply chains in general, but one of the major cargos carried by these rivers into inland Europe is coal, for power stations. So a shortage of water can translate to a shortage of energy.

Over in France, meanwhile, the country’s major rivers are at historically low flow rates… and that, combined with high water temperatures from this summer’s heatwave, has obliged nuclear power stations that rely on rivers for cooling to reduce their output to comply with environmental regulations. With reduced outputs on top of a lot of maintenance shutdowns this year, the country most famous for embracing nuclear power has become an energy importer.

Norway is another nation that is traditionally energy-independent: while they do have a lot of oil and gas, they use little of it domestically because their electrical grid runs almost entirely off hydro power, and on top of the fossil fuels they are usually a net exporter of clean electricity. But without rainfall there’s less hydro power, and with their reservoirs at unseasonally low levels the Norwegian authorities are considering restricting electricity exports to protect their domestic supply.

None of that affects the UK directly: we don’t use inland waterways for cargo, our nuclear plants are all on the coast, and we only have a small amount of hydroelectricity. But the knock-on effects of a worsening energy shortage in Europe will certainly be felt here, in the form of higher wholesale energy prices.

I mention all of these things together because they’re a clear demonstration of the interconnectedness of the systems that we take for granted. Our power and other industrial infrastructure was designed for the time in which it was built, plus forseeable changes – and nobody (a figurative nobody) foresaw parts of the Loire running dry, or the Rhine becoming impassable to coal barges.

This is a part of something sometimes referred to as the “Energy-water nexus“: the idea that energy supplies depend on water, and water supplies depend on energy, and that developing more of one usually requires more of the other. It’s interesting to think about whether this interdependence might be weakened by increasing use of renewable energy. Wind and solar probably rely on water less than thermal plants do… but in the future, will we see drought-related curtailment of freshwater hydrogen production?

Posted by simon in The wider world

Here’s why UK tides are soon going to play a much bigger part in powering your home

I wrote this article at the request of an editor from The Conversation, who wanted to know about the current state of, and future prospects for, tidal energy. It was published there on 14th April 2022, and is licensed CC BY-NC 4.0.

The Conversation

Tidal energy has long lurked at the back of the UK’s renewable energy arsenal, outshone by its wind and solar counterparts due in part to early issues with technology readiness and high costs.

Yet with recent research showing it could provide 11% of the UK’s electricity needs – and with significant government investment in the pipeline for UK projects – its future is looking ever brighter.

Tides are large movements of water around the Earth, powered by the gravitational pull of the Sun and Moon. In areas with particularly strong tides, we can harvest some of this power using turbines – similar to wind turbines, but underwater – that turn as water flows past them. This approach is more popular at present than previous ideas of using tidal barrages which are similar to dams, mostly because its environmental impacts are less severe.

In the last decade, the global tidal energy industry has demonstrated that siphoning energy from the sea works predictably and reliably. Around a dozen experimental turbine designs have been generating electricity in Scotland, Wales, Canada, China, France and Japan, many of them supplying power to homes and businesses.

The UK’s first “commercial” tidal energy projects, led by developers SIMEC Atlantis and Nova Innovation, both have multi-turbine arrays in the water in Scotland. The largest of these can currently produce six megawatts of power: that’s about the same as two or three onshore wind turbines, providing enough energy to run a few thousand homes. Expansion of the project is already underway. Over in the Faroe Islands, tidal developer Minesto has just announced plans for a 120 megawatt array which would supply 40% of the islands’ energy needs.

A ship's crane lifting a turbine from a quay
Green Energy Futures/Flickr, CC BY-NC-SA

Tidal turbine designs tend to be divided by one big question: whether it’s best for them to float, or to be mounted on the seabed. Floating turbines are easier to access for maintenance, and they benefit from faster-flowing water near the surface. But those on the seabed are less affected by storms and – in deep enough water – could allow ships to sail freely above them. It’s not yet clear whether one approach will win out, or whether the choice will depend on the location.

Either way, now that it has working technology in its hands, the tidal power industry needs to demonstrate that it can bring costs down. Luckily, there’s precedent here in the story of offshore wind. With the help of government support in the UK and elsewhere, offshore wind developers around the world have cut costs by close to a third over the last decade, and further reductions are expected thanks to ongoing research and development.

Money Matters

The cost of tidal energy may never be as low as that of wind. That’s partly because tidal turbines can’t be scaled up in size in the same way as wind turbines (in a limited depth of water, you can only build so big), and partly because doing things under the sea is usually more expensive than doing them on the surface (it’s a harsher, less accessible environment). But matching costs may not even be necessary.

As critics are keen to point out, the wind does not always blow, the sun does not always shine, and the tide is not always flowing: so to build a resilient low-carbon electricity system, we’ll need to use a range of different energy sources rather than relying only on that which is cheapest.

A ship lowing a turbine into the water
Glen Wallace/Flickr, CC BY-ND

Tidal power offers the unique advantage that while its output will vary over time, that variation is predictable years in advance by understanding the orbits of the Earth and Moon. This means that grid operators will be able to plan for the varying output of tidal turbines, and schedule other sources to fill in the gaps.

Fortunately, the UK government seems to be stepping up to help the tidal industry. The latest round of the UK’s “Contracts for Difference” renewable energy funding contains a “pot” for tidal energy, so that it doesn’t have to compete with cheaper technologies like offshore wind – for now. And the recently published British Energy Security Strategy promises rather fiercely to “aggressively explore” tidal and geothermal energy technology.

Tidal energy is never going to be a big player at the global scale in the same way as wind or solar, because only a few parts of the world have strong tides. And unfortunately, it won’t be ready in time to help with the energy price crisis that we face right now.

But for those places with strong tides, including the UK, it has significant prospects, with a global market estimated by some analysts at £130 billion. And there may be potential in developing turbine tech further to take advantage of slower, but more consistent, ocean currents like the Kuroshio current off the coast of Japan.

Tidal energy technology works, and it’s here to stay. Now, the most efficient way to get it powering our homes and businesses is to build more of it.

Posted by simon in Publications, Written elsewhere