Archive for July, 2020|Monthly archive page

Why solar power is the answer

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Demonstrations against nuclear power, Hull, 1983

Again, showing my age, there was a time before chiller vending machines. I had just started at college and one arrived on campus. There seemed to me to be two things instantly wrong with them. First, the drinks – sticky water really – were packaged in aluminium cans. Giving back aluminium cans to supermarkets had been one of my earliest experience of environmental activism. I’ve never liked them because of the energy required to make single-use containers. Second, chillers used energy to chill something that really did not need chilling. It was purely an aesthetic, especially in the middle of winter. Chillers just multiplied from that point onward. It seemed to me throughout my formative years that we used energy for things that did not need energy. Shop windows at night. What was that all about?

It kind of didn’t matter in those days. Aluminium smelters were located near to hydro-electricity stations and there was plenty of coal¬†and generating capacity to burn it. Plus, chillers and lit shop windows made life better. Apparently. It is true, it was a piffling amount of energy relative to the big users: iron and steel producers, paper mills, bitumen manufacturers, water-treatment works, industrial-scale refrigeration. What I did not know before reading Chris Goodall’s book, The Switch, was that some smart people run businesses that sign up some of these large energy users and gain permission to turn off their equipment when the grid is under pressure at peak times. One Belgian company, REstore (now part of Centrica), operates a platform that monitors the real-time use of electricity of its clients and gauges whether they can be taken off-grid for a certain amount of time to level out demand. The platform is clever – or at least the people behind it are – in that it works out just how much energy can be taken from a big customer without affecting production. For example, molten steel stays that way for some time. Even 5 minutes off-grid can provide enough capacity to keep everyone else secure in supply. The company receives money from the grid in exchange for its clients coming off grid when requested to do so.

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Hastings Railway Station: why no solar panels?

Why is this important? it is important because despite the startling fact supported by a logic that I am not going to argue with, photovoltaics (PVs) can supply humanity with all of the electrical energy that it needs more cheaply than by any other renewable mode. Contrary to what I had thought about chillers and well-lit shop windows, actually energy consumption is declining in developed countries. In the UK, apparently, we are back down to levels of consumption as of 1970 driven by two things. First, it is actually difficult for those in the rich west to consume much more. There is unlikely to be more chillers because – probably – there is nowhere to put them and we cannot realistically drink more sugared water. Second, many of the things we still consume are getting more efficient, in particular lighting (see below). Semi-conductors, too, are becoming energy efficient, exponentially so.

How much electrical energy does humanity need? Goodall thinks that a decent standard of living can be achieved by a total running energy demand of 3kw per person (one-third more than the running demand in 2015). Scale that up, that is about 30 terawatts of power (twice the level in 2015). Goodall notes, too, that the amount of available solar energy is: ten times that of the nearest renewable alternative, wind; one-hundred times that of biomass; wave and hydro are some 13 times less than biomass. All we have to do is collect the solar energy and covert it. Well, not quite.

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Roofs in Hastings. Spot the solar panels

PV cells are getting cheaper. Goodall uses the concept of the learning curve to explain this. Essentially, the more units manufactured, the more learning about how to manufacture them quicker and more efficiently. The decline in the costs of manufacture has a name, Swanson’s law (Like Moore’s law in semi-conductors, but bigger).

And maybe my chiller and shop window lighting gripes are actually valid? In a solar-dominated world – and especially in the temperate North – energy use peaks between 1600 and 2000 daily. There is an overlap between businesses shutting down and people arriving home, turning on lights and cooking dinner. Goodall reminds us how crazy it is that we do not have demand pricing for energy at these peak times. In the zero carbon world, we are going to have to turn off our lights and appliances at peak times. Ensuring that all light fittings are LEDs, seemingly would make a huge difference – demand can be reduced by one-third by this very simple change. Goodall goes further and advocates we all sign-up for smart meters on the basis that, in the washingend, suppliers will be able to shut off energy-hungry appliances at times of stress for the grid. He’s thinking particularly of our washing machines, tumble driers and dishwashers. My supplier invites me weekly to install a smart meter; I have been reluctant to let them into my house, but maybe there is a utilitarian case for it?

So, controlling demand at peak times is one element of the solution. Another element is alternative sources. As noted above, wind is the second-best option here; conveniently there is an inverse relationship between solar and wind – when it is not sunny, it is often windy. Wind turbines, however, cannot compete on price with solar. At the time of Goodall’s writing, the best solar conversions were coming in at US$0.06 per Kwh. Swanson’s law suggests that this conversion can go down further. However, such prices are half that of the best performing fossil fuel sources (p47). Wind can do about US$0.07 in its best places (Texas, for example), so it is a good complementer, and works at night and when the sun does not shine so brightly. Wind’s experience curve, however, is much less steep and sustained. It is also more expensive to site turbines (rental charges can be quite high; offshore has quite high maintenance costs).

SpongThere is also room for public policy Рa south-facing roof in a city should have solar cells mounted on it. Equally, dwellings need to be made energy-efficient. A bit of insulation is insufficient. Rendering UK housing stock energy-efficient, in particular, is a major task. It is going to take central government support to transform regular houses, but companies like Energie Sprong (right) in the Netherlands (operating in the UK) show the way; though at £30k, it is quite a commitment. One house in a block seems a little pointless. We may need to do a bit of getting together to make this happen. Though disappointingly, there was no sign of money for these kinds of developments in UK budget statement of 8 July 2020.

Then there is the battery solution which has been driven by a rapid diffusion of electric cars. Elon Musk’s Tesla vehicles’ high performance depends on high capacity battery storage – in his case based on lithium ion technology (fast discharge). Seemingly there is enough lithium on the planet to build the necessary batteries. The United States Geological Service estimates that there is 13.5m tonnes available, which is more than enough and is recyclable. What Goodall doesn’t tell us, however, is whether this lithium is accessible, subject to geopolitics and/or would have environmental implications if it was exploited. There are other battery technologies – flow batteries are slow discharge, so not much use for cars, but work for other less dynamic applications such as mobile phone masts.

illustrativeThen there is pumped hydro – excess daytime electricity is used to pump water up for hydro-release when the sun does not shine. There is one in the UK at Dinorwig in Snowdonia (left). It can react quite quickly at peak times. But scaling up is not easy; there would be more damning needed and lots of power lines. Effectively, we are still short.

Fuels are stores of energy. Fossil fuels are particularly good because they are concentrated stores which means you get a lot of energy per bundle rendering it possible to have meaningful fuel tanks in cars and aeroplanes. Goodall doesn’t hold out too much hope in the hydrogen economy – it is way too dangerous and difficult to store and is not particularly dense in its energy. Time to turn to microbes. Carbon neutral fuels are possible. Here’s the logic: take hydrogen and carbon dioxide, literally feed it to known microbes in return for energy-rich molecules containing hydrogen, carbon and oxygen. These can be stored in existing oil storage infrastructure – a bonus for what will need to be a rapid switch.

Goodall advises us to keep an eye on a couple of pioneering companies – Electrochaea and LanzaTech. Both use microbes to convert various elements and compounds – carbon dioxide, carbon monoxide oxygen and hydrogen – often taken from the environment, sewage installations or from industrial plants such as cement factories before emission, and converted into a liquid fuel – methane and ethanol – that can be stored and used when needed. Just like with hydro, excess summer electricity is used in the conversion process. The excess, argues Goodall, is actually worthless. PV generates more electricity than is needed in the summer, so putting it to good use is no bad thing.

Finally, there is air capture of carbon dioxide. This is inherently a good thing as it would actually remove carbon dioxide from the atmosphere. It does not require the burning of fossil fuels to capture it to then use it to make liquid fuels. A company called Climeworks in Switzerland leads the way here. Carbon dioxide is captured, combined with other elements to produce liquid fuels. It is expensive at the moment and would benefit immensely from the world adopting realistic carbon taxes as Climeworks’ carbon dioxide would be tradeable. Investment costs are equally important. Low interest rates help in the development of technology and installation, particularly of PVs for consumers.

I am still convinced that saving energy is still important and might contribute to reducing the deficit between what renewables can achieve in the winter and dark months. It does not seem to me just to be a case of our appliances becoming more energy efficient. Those drinks chillers and shop windows can still be turned off.

Pictures:

Energie Sprong – https://www.energiesprong.uk/

Dinorwig – https://www.fhc.co.uk/en/power-stations/