Sheffield’s Giant Battery

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Kirsty Broughton

A major step towards greener energy in the UK was taken last month with the opening of an industrial-scale ‘mega-battery’ site owned by E.ON in Sheffield.

The Sheffield site located in Blackburn Meadows is being hailed as the first of its kind in the UK. It has the capacity to store or release 10MW of energy – the equivalent of half a million phone batteries, and is contained in four 40 foot long shipping containers. The batteries are from the next generation of battery energy storage, and can respond in less than a second to changes in energy output – ten times faster than previous models.

Such promising technology has naturally lead to further investments, and the Sheffield site will soon be dwarfed by significantly larger plants. Centrica (the owner of British Gas) and EDF Energy are both in the process of creating 49MW facilities in Cumbria and Nottinghamshire respectively.

When more energy is being put out into the national grid than is being used by consumers, the batteries will take in the excess power and store it. Then, during periods when consumers are using more energy than the grid can provide, the batteries can release this excess energy into the grid, to ensure that everyone has access to power.

This is especially important considering that the UK energy mix is containing an ever-increasing proportion of intermittent sources, such as wind and solar power. June this year saw 70% of the electricity produced from nuclear, wind and solar sources. For the government to hit legally-binding carbon-cutting targets this needs to be the standard for electricity production, but storage is likely to be necessary to balance the intermittency of renewable supplies.

To meet these targets the government introduced a ‘capacity market’ – a subsidy scheme integral to the shake-up of the electricity market. It is designed to ensure energy security particularly during times of high demand, such as the winter months. The scheme has a pot containing £65.9 million, which it will divide between energy suppliers than can guarantee a constant energy supply. It may sound surprising that in the age of austerity the government that is ever-interested in penny pinching is wanting to hand out money. However, it is estimated that the Sheffield site alone could save £200 million over the next four years by increasing energy efficiency. This certainly makes the £3.89 million awarded to E.ON a worthy investment.

E.ON has seen share prices in Germany dramatically fall as it is undercut by abundant, cheaper renewable energy from other suppliers. Germany is often hailed as world leader in renewable energy production, and during a weekend in May of this year 85% of energy production was from renewable sources. E.ON in the UK was following down the same path, as in recent years UK profits have stagnated, and trade has fallen by up to 9%. It was only in March of this year that profits began to pick up again, due to the company shifting away from fossil-fuels and towards green energy production. The battery site in Sheffield is an excellent next step in this major shift.

The Butterfly Molecule

Jonathan James

If you cast your mind back to chemistry class at school, you’ll probably remember learning about various types of atomic bonds. Typically, we think about the way atoms bind to one another in a couple of ways – ionic bonding, where oppositely charged ions are held together by electrostatic interactions, and covalent bonding, in which electrons are shared between atoms. For a long time, these looked like the only types of bonding that could exist under our current understanding of how atoms bind one another, but a recent discovery has unveiled a whole new type of bonding that seems to defy our understanding of chemistry.

Let’s quickly recap what we know about atoms. In the traditional model, atoms are made up of a positively charged nucleus, made up of protons (which give it its positive charge), and neutrons. This nucleus is tiny, and the clear majority of the atom’s size is empty space. Surrounding the nucleus are negatively charged electrons, which orbit in ‘shells’, a bit like planets around the sun (but not really… That could be an article all by itself!) Typically, atoms take up a volume so small, that you could fit 200,000,000,000,000,000 of them inside the dot on this exclamation point!

Recently, however, scientists have been able to confirm a theory that they’ve had since 2002. The existence of ‘Rydberg molecules.’ Affectionately referred to as ‘Butterfly molecules’ because of the butterfly like distribution of the orbiting electrons, Rydberg molecules are enormous. In fact, at a millionth of a meter across (huge for an atom!), they are about the same size as an entire E. coli bacterium. Their electrons are anywhere from 100-1000 times further away from the nucleus than they should be. At these distances, the electrons become ‘super electronically excited’, which allows them to act like a lasso, grabbing nearby atoms and forming weak interactions with them.

The researchers created the molecules by super cooling Rubidium gas to a just above absolute zero, before exciting them into their Rydberg state using lasers. They then kept the atoms under observation, looking for changes in the frequency of light that they would absorb, as this would show that a bond had been formed. Eventually they discovered that they had indeed triggered the formation of these butterfly molecules.

But why should you be excited about this discovery? After all, it’s just another type of dull chemical bond that kids will be forced to learn about, right? Actually, there is a lot of excitement around Rydberg molecules and how they might be used in nanotechnology and small scale electronics to make them much more efficient. There are even hopes that they might be used in quantum computing, pushing technology even more into the future!

Metallic Hydrogen: 80 years in the making

 

Ashley Carley

Rocket fuel, lightning-fast supercomputers and levitating trains are just three uses of the newly discovered metallic hydrogen – if, the Harvard scientists say, everything goes to plan.

Hydrogen is the lightest and most abundant of all the elements. It forms two thirds of every drop of water, and almost 75% of the gas in the Sun’s core. Alone, hydrogen is most often found floating around in its gaseous phase, but it has been predicted a metallic form may exist when exposed to intense pressure.

Two physicists at Harvard University claim to have isolated this incredibly rare form for the first time, in a paper published this week. By squeezing solid hydrogen between two diamonds at temperatures well below freezing, the researchers created pressures larger than those found at the centre of the Earth. In these conditions, the hydrogen atoms began to share their electrons. Using this new electron cloud, they could conduct electricity.

Isaac Silvera, who made the discovery alongside his colleague Ranga Dias, recognises the importance of his achievement, calling it the “holy grail of high-pressure physics.”

This breakthrough has been a long time coming; it has been over 80 years since Eugene Wignar and Hillard Bell Huntington made the first predictions about metallic hydrogen. Since then the goalposts have continually shifted. Estimates of the pressure required to make the substance have been continually revised upwards, from 25 gigapascals (GPa), 250,000 times above atmospheric pressure, in 1935, to the most recent estimate of 400-500 GPa.

Each time the prediction changed, it moved out of the range scientists were capable of recreating in a lab environment, making it somewhat of a carrot on a stick for researchers in the field. Jeffrey McMahon, theoretical physicist at Washington State University, told New Scientist that if the results were reproducible, the recent experiments had solved “one of the major outstanding problems in all of physics.”

It wasn’t easy – the synthetic diamonds had to be flattened, polished and heated to remove any imperfections that could result in cracking. They were then covered in alumina, an extremely hard material made from aluminium and oxygen that hydrogen could not leak through. The two diamonds were then crushed together with great force, and Dr Dias watched as the hydrogen between them turned from clear to black, until it began to shine. The force required was 495 GPa – higher than the pressure at the Earth’s core. Dr Dias then called Professor Silvera, and they took the measurements that would confirm their discovery.

The next step is to see if it retains its structure when compression is relaxed. Some predictions suggest it will be too unstable to survive at room temperature, and will gradually decay, although others have more hope. Graphite forms diamonds under high pressures and temperatures, but when the sources of compression and heat are taken away – the diamond remains. Scientists are hoping metallic hydrogen could act the same way once released from its diamond vice.

If it does, its potential applications are exciting. If the amount of energy used to create the metallic hydrogen can be released by breaking it down again, it could become the most powerful rocket fuel ever made. “We would be able to put rockets into orbit with only one stage, versus two, and could send up larger payloads, so it could be very important,” Professor Silvera says. Electronic systems would also be revolutionised, as “superconductors” could be made which reduce energy wastage in wires.

When Professor Silvera is asked what thinks will happen next, he responds “I don’t want to guess, I want to do the experiment.” After an 80-year wait, perhaps the suspense is great enough.