Storing Energy: Watt does the Future Hold?

5 days a week, 9 to 5 - that is the employment pattern most jobs have adopted ever since its introduction in the 1920s. In the century that's followed, productivity has soared but working hours have remained the same. And with the pandemic provoking many to reconsider their priorities in life, old working patterns have started to be questioned. Can employees maintain 100% of their output for 100% of their wages but work 80% of the time instead? That is the hypothesis being tested in a new trial which began for some UK businesses this week. Julia Ravey spoke to Brendan Burchell, from the University of Cambridge, who is monitoring the trial data, to find out more…

Brendan - We've got a big trial in the UK. It's following the model in other countries. We've got 70 employers covering about 3000 employees who all are going to go down to a working time reduction model. Typically it'll be a 20% reduction in their working week while aiming that people shouldn't get a pay cut and will be just as productive as they were before. They'll be doing the same amount of work, but working smarter and getting it done by Thursdays, so they can have a three day weekend.

Julia - So you're getting a bit less time in work, but the expectation is to have the same output. Is there a science behind that being possible?

Brendan - We've got some experience of other organisations who have experimented with this and overall, the results seem to be very positive. People really enjoy having that extra leisure time. Being able to have a more relaxed weekend, being able to do things in their own time and realising that there are ways in which they could work more effectively. Whether it can work in all situations, how we need to tailor it to different situations, what sort of mentoring and assistance we can give to organisations; those are still open questions and we'll know the answer to lots of these things in six months or so when the trial ends.

Julia - And how are you going to monitor the success of the trial?

Brendan - We're taking lots of different measures. But for instance, for productivity, we rely on organisations to define the output themselves. What is the most important output they want? Is it to do with the profit? Is it to do with the quality of their service? We'll use their own metrics. We'll also be looking at the employee's wellbeing, looking at their mental health, and also trying to get some indication of the carbon footprint that we are hoping is going to be improved by these changes to people's working lives.

Julia - Was this an opt-in process?

Brendan - It was, and there's been publicity around a small number of organisations in the UK that have done this. It's interesting just how much interest this has had both from employees, but also from employers.

Julia - On the employer side of things, I was surprised that so many were keen on it. Have any had the attitude of "if my employees can do it in four days, I should just pay them for four days"?

Brendan - I haven't come across that. Again, they're all different. Employers tend to be very proud of what they're doing and want to work with employees on this, that's the impression we're getting from talking to the employers anyway. Sometimes it's because they want to recruit and they were finding it difficult to recruit and thought that would be one way that could really attract the best talent. In other cases, it was because they were particularly in the business of welfare. And in some cases, the profit motive wasn't the main thing that they were interested in. They were more interested in their service to the local community and in how they treated their employees.

Julia - This type of trial can apply to many different industries. Are there any industries which would struggle to adopt this? I'm thinking like the healthcare industry, because at the minute, in the UK at least, we're massively understaffed with healthcare. Would we have to up the staff numbers to maintain this type of model?

Brendan - Certainly there are some sorts of employers that can do it more easily, that's our experience so far. Particularly when you've got professionals working quite autonomously like architects or people doing programming. And often people's initial reaction when I tell them about this is "well, you couldn't do it in hospitals", for instance. But of course, when you think about it, hospitals, typically in some parts of them anyway, do run 24/7, but nobody's expected to be there for the whole time. You are trying to run a seven day service using typically people working five days at eight hours a day. So it's actually relatively easy to think how you'd modify that. As you say, there are recruitment problems and staff shortages in lots of parts of the UK economy at the moment. There's also lots of people who I think would be better off if they had some work and if work was made available to them, instead of only in a full-time manner, but where they could get good quality jobs, that would also allow them more time off to do whatever they want to do. So if we can provide work to people that allows them a better work life balance, then I'm hoping that we get a lot more people who are currently out of the labour market into work.

Julia - Are you working a four day week at the minute?

Brendan - No, I reduced my hours down to three days a week, that year and a half ago with the university. I definitely have been enjoying a slightly more relaxed pace of work, spending a lot more time with my grandchildren. Yes, I definitely recommend it.

Earlier studies on the modern chicken, Gallus domesticus, had claimed it originated some 10,000 years ago in China and South East Asia, with the earliest European chickens supposedly dating back 7000 years. Now, scientists around the world have been collaborating to put this claim to the test, and have found that certain samples had been inaccurately dated by thousands of years, meaning chickens are actually much younger in evolutionary terms than we first thought. The two studies, published in the journals Antiquity, and The Proceedings of the National Academy of Sciences USA, were carried out by academics at a number of universities around the world including Cardiff, where Julia Best is based. She told James Tytko what they’ve found...

Julia - The methods that have been used prior to our studies to assign the age to these chickens have been indirect. That means they've been associated by the archaeological context in which the bones were found; things like types of pottery, coins, things that can give us an approximate date. One of the methods we used is radiocarbon dating, which is a direct form of dating; analysing the levels of unstable and radioactive carbon 14 present in the ancient chicken bones. That rate of radioactive decay gives us as archaeologists a ticking timer to measure.

James - And what sort of errors were you able to rectify with this much more accurate dating technique?

Julia B - One really good example comes from Bulgaria where a specimen was thought to be about 7,000 years old. But when we did radio carbon dating, it was actually revealed to be less than a hundred years old and it was a modern intrusion. Other ones were still ancient, but were much more recent than previously thought. For example, maybe being Roman and medieval in date, rather than much earlier such as bronze age or iron age.

James- That's incredible how far wrong that previous dating was to me. Can I move us on to think about what we know about when chickens were first being domesticated, what their evolutionary ancestors may have been and what instigated people taking them into their homes and communities?

Julia B - The theory we are putting forward at the moment is that it may have been to do with rice cultivation. As cereal crops start to be domesticated in this area, such as Thailand, what we are seeing is a really nice correlation between the date of this crop domestication and the date where we're first seeing chickens in the archaeological record. So, maybe the clearing of jungle areas for rice cultivation fields could have created an appropriate environment for the red jungle fowl, the chickens ancestor or primary ancestor, which could have then been attracted into the human niches based on the availability of food among other things.

James - And when we start to see chickens coming over to the West, firstly, when? And secondly, are they coming over the animal that we now view as a common source of food, whether for their eggs or for their meat, or were they coming over in a different capacity?

Julia B: - We now think that they did not arrive in Europe until the first millennium BC, probably about 800 BC. So, out of the 23 bones that we radio carbon dated, 18 of them were much more recent than had been claimed. So now that we can rule out those intrusive chickens, we can get a better understanding of what people were actually doing with them and how they were interacting. Let's take Britain as an example for now, when these animals first arrive chickens do not seem to be primarily considered as food. The earliest chickens that we have in Britain are buried alone in pits. They're whole animals, they're not butchered. And they seem to have lived quite a ripe old age. This indicates more that they have a special status. Maybe they're considered exotic. Maybe they are a status symbol and they might also have ritual religious connotations. It takes perhaps up to 500 years from a chicken's first appearance in an area for them to be more considered as a common food.

James - That's really amazing to me. They're first viewed as these interesting exotic animals. Do we have a sense of what changes the chicken has gone through since it was first domesticated? Because it strikes me that the modern chicken serves a lot of purposes for humans as they currently are, which may have not been so useful in the wild being such efficient layers of eggs, for example, or having such meaty flesh.

Julia B - Exactly. That is a really important change. Some of the early changes may have been to do with their outer aesthetic: what they look like. But some of the key changes you pick up on there are things like the ability to lay frequently. We know that it must be quite soon after chickens are domesticated that they have the capacity to lay regularly, but we don't know whether that was actually selected for until much later on. So maybe things like egg laying weren't the most important to begin with.

James - Chickens are obviously such a hugely culturally significant animals, it seems pretty much all across the world. That's maybe even more apparent now that they're becoming more expensive thanks to a variety of factors...

Julia B - Of course the more we learn about animals and where they came from, how they were domesticated, and how we've changed them, that can feed into things such as looking forward to sustainability. Things like avian diseases, thinking about how we interact with our food animals. And, of course, that's a really contemporary key theme: how we get our food, food miles, consideration of animal human relationships. So I think it provides a great lens to look at both modern society and ancient society.

The world needs ways to make metaphorical hay - electricity - when the sun is shining, store it, and then redistribute it efficiently when we need it. We have multiple challenges standing in our way for this happen; ranging from economic systems and government policies, to smarter technologies and perhaps even new ways of working or organising our lives. Simon Harrison is an electrical engineer and head of strategy for the engineering company Mott Macdonald...

Julia - Simon, this is not just a case of putting up more wind turbines or solar panels, is it?

Simon - No I'm afraid it isn't. Those are component parts of an energy system that we need to decarbonise globally by 2050. That's not very long away, it's only 330 months I calculated. We have to do that affordably, we have to do that in a way that is resilient and reliable, and that's a massive challenge. So that's not about picking a few technologies and deploying them. It needs an approach that considers the energy system as a whole, at a strategic level. We have to worry about economics, policy, technology, networks, digital markets, supply chains, regulation, how efficiently we use energy and how we behave. At the same time, we have to think about that at all scales; national, regional, city, community - they all have different parts of play. And we have to make all of that fit together in the best way that produces an affordable answer for you and me.

Julia - It sounds like a lot of steps to consider. So what is the order in which we need to put these things in place?

Simon - The issues that drive all this I think are pace and scale. There's a lot of discovery involved because we don't yet know all of the best answers even though we probably know most of the technologies and we need to test and deploy multiple approaches at scale, we can't assume that we make a policy based on something working. There may be all sorts of issues as to how much things end up costing, whether there are supply chains that can produce things at scale, and how that's working out around the world. We need to learn fast, change our approach, and then scale again. There are some clear immediate needs. We need a policy environment, a digital backbone on what I would expect to be a much more digitalised system, and support for innovation, both at big scales, things like better nuclear or offshore wind, and innovation at perhaps much more local scale about how energy needs to be better integrated locally.

Julia - And we're currently in this cost of living crisis. So all of these interventions that are needed in the future, they sound great, but are probably very costly. Is this going to be cost effective down the line?

Simon - We have to decarbonise by 2050. If we don't do that in a thoughtful, planned way that thinks about the system as a whole, it will end up costing a lot more money. So this will cost money, but this is about spending as little money as we have to to achieve the end goal. If we don't take a system's view, we'll make far more mistakes, we'll have to rectify things later or alternatively, we might well end up missing the target. If we find out how to scale new approaches, costs tend to come down dramatically and the evidence from say solar and wind is very much the case. Both of those are much, much cheaper than they were 10 or 15 years ago.

Julia - So with these interventions in place would the hope be that prices of electricity will be more stable in the long run because we have these storage systems?

Simon - An energy system based on a much broader mix of sources, including much more renewable energy and appropriate and well integrated storage and smart end use using energy demand as something that can be varied as the wind blows and the sun's out, all offers opportunity to a much more price stable energy system in the long term. Although none of these things will have a big impact on prices in the short term, unfortunately.

Another way to store energy is to use gravity. If you use electricity to push something up a hill, you’ve given it gravitational potential energy and you can get that energy back by letting the thing roll back down the hill. If you do this with water, you’ve got the basis of what’s called a “pump storage hydroelectric system”, and this is what engineers have been able to do in one part of Queensland in Australia. In a world first, they’ve turned a flooded abandoned mine pit at Kidston into a system that uses solar energy to pump water out of the mine pit during the day to provide power for the nearby town at night. Mott MacDonald’s Ashley Grohn told me how it works…

Ashley - The Kidston project converts a 100 year old gold mine and repurposes it into a gravity hydro pump storage project. It's a fascinating project because the mine workings left a 300 metre pit in the ground which, for reference, now that I'm sitting in London, is about the height of the Shard. Over time, it has filled with water and what the project does is it uses that 300 metre height differential to store energy in a top reservoir and generates energy through turbines, dumping the water into the lower reservoir. Then, it recycles the water back up to the top reservoir to store it so that it can be used on a daily basis.

Chris - Is this an open-cast pit, or are we talking old mine workings, tunnels, etc.?

Ashley - It is an open-cast pit and the spoil left from the mine workings has created the upper reservoir and the 300 metre deep pit is the lower reservoir for the pump storage scheme.

Chris - And how big is that pit then?

Ashley - If you were a golfer, it's about a driver, approximately 300 or 400 metres - depending on how good you are at golf -across. If you can, imagine a conical shaped pit in the ground.

Chris - How much water is in there?

Ashley - It's in excess of 3000 Olympic swimming pools and the pump storage scheme basically pumps 2000 Olympic swimming pools up the hill over an eight hour period. Then, it can flow the same quantity of water down through the turbines to generate the power in an eight hour period.

Chris - I presume that the rationale for doing this is you could use electricity that you've produced in a green way to power those pumps. So, you're basically using renewables to push the water uphill and store that energy as gravity. Then, you can turn the taps on when you want that energy back when the sun isn't shining or the wind isn't blowing?

Ashley - That's absolutely correct, Chris. In Australia in particular, we have excess solar power generated during the day, so there is excess and very cheap solar energy to pump the water up the hill. Then, when everybody comes home of an evening and switches on their air conditioning in Australia, or boils their kettle in the morning, we can generate power from that water stored during the day to meet the needs of consumers during the night and the morning peaks.

Chris - How much energy will this thing put out? How powerful is it?

Ashley - In technical terms, it's a 250 megawatt scheme and can generate for eight hours. As a point of reference, that's basically enough to power 100,000 homes.

Chris - Right. When those people come home from work, this thing just basically turns on and runs all night. And so they've got power coming from this project all night?

Ashley - It has the potential to run all night. That's correct. Really, its primary purpose is, as we are retiring conventional coal fired power plants, there is potential for pump storage and even bigger projects than this in Australia, basically to keep the lights on and keep industry moving that works on a 24 hour cycle.

Chris - I suppose one other benefit here, you mentioned coal, is that traditionally when people have turned the TV on and then the adverts have come on and they've put the kettle on, or their favourite programme finishes and they put the kettle on, or there's just anticipation of people coming home in the evening and putting the air con on, they have to turn the coal fired power stations on an hour or more before they want that surge because it takes that long to heat things up. Presumably, yours, because the water is sitting there ready to go, it's just a press of a button and you're up to full output instantly?

Ashley - That's a good analogy, Chris. Whereas a coal fired plant will take hours to heat up, a pumped hydro scheme can basically go from zero to full output in one to two minutes.

Chris - How much does it cost to implement? Is this something which is a realistic prospect or do you need very specific conditions to make something like this work?

Ashley - Yes. At the moment, when we look at the energy trilemma - that balance between sustainability, energy security, but also importantly price - especially in the Australian market, you really do need a pump storage scheme that works in your favour economically, for it to be comparable with other technologies. That was the beauty of the Kidston project because, essentially, the big holes were already in the ground and there was already significant infrastructure at site including actually a solar farm that had already been built. It economically stacked up and it is the first project in 40 years built in Australia in terms of hydro and it is the first project that has actually been privately financed.

Chris - I presume one could now take the blueprint for doing this because you must have data to die for in terms of how to implement this, how it works, what the pitfalls are, literally as well as metaphorically, in terms of being able to extrapolate this, upscale it, downscale it and distribute it across the world. There must be lots of places where this would be an ideal fit.

Ashley - Absolutely. There are a lot of learnings, especially when you are looking at repurposing an old mine workings. Certainly, the international hydro association has been looking at this, as well as most countries globally, looking at the opportunities. There is absolutely no shortage. In Australia alone, there are literally thousands of potential opportunities for pump storage that have been identified.