Renewable energy sources are naturally inconsistent, and thus require new energy storage technologies. Supercapacitors offer rapid charging and long-term storage, but it is important to be able to monitor their working state. To tackle this issue, a team including Tuan Guo and Wenjie Mai at Jinan University adapted an approach based on an optical fiber-based plasmonic sensor. The sensor is embedded inside the capacitor and is able to measure the state of charge of the electrodes and electrolytes in real time, while operating, and over its lifetime. The sensor demonstrates a clear and repeatable high correlation between measurements of the optical transmission of the fiber device and simultaneous supercapacitor‘s state of charge, offering a unique, low-cost method for real-time monitoring of energy storage devices in operation.

This result has been published in Light: Science & Applications (July 11, 2018), with a manuscript title of “In Situ Plasmonic Optical Fiber Detection of the State of Charge of Supercapacitors for Renewable Energy Storage. ”

Electrochemical energy storage devices (such as supercapacitors) are considered to be the next generation of energy storage devices with the highest energy storage efficiency and very promising prospects. They are widely used in clean electric power, electric vehicles, mobile medical, portable electronic devices and other fields. In situ and continuous monitoring is a key method for understanding and evaluation of their performance and operation quality. However, the present methods cannot offer the real-time charge state information when the energy storage devices are in operation. They are required to take the supercapacitors offline (thus interrupting their function) and carry out electrical measurements, and in some cases, opening up the supercapacitors to examine their components by electron microscopy.

To address this fundamental challenge, Prof. Guo and Prof. Mai and their colleague developed optical fiber devices small enough to be inserted near the surface of the capacitor electrodes. Based on telecommunication-grade fibers, they can be left there and monitored remotely at any time and from any distance. Another important aspect of their approach is that in contrast to current techniques that rely on an indirect estimate of the state of charge from current/voltage tests, the optical fiber devices detect the amount of charge accumulated in a sub-micrometer-sized layer on the electrodes and the adjacent electrolyte directly through its impact on the plasmonic properties of a nanometer-scale gold coating applied to the fiber surface.

The role of energy storage batteries in Australia’s future electricity market is critical, claims the Clean Energy Finance Corporation (CEFC).

The comments come as the corporation released record renewable investment figures for 2017-18.

The government-funded finance body directly committed to 39 projects in the past financial year, up from 36 the previous year.

The CEFC invested $1.1 billion in renewables and $939 million in energy efficiency projects between 2017 and 2018. Total new commitments of $2.3 billion were made during this time. This compares with $2.1 billion in the previous financial year.

Energy storage batteries play larger role in CEFC projects

According to CEFC CEO Ian Learmonth, the battery increase is because storage technologies extend the benefits of low-cost wind and solar installations across the network.

The CEFC has contributed to four large-scale renewable projects featuring energy storage since starting in 2013. Twenty-four smaller storage projects have also been co-financed by partners.

The Federal Government is keen to develop battery and pumped hydro storage. This will counter the intermittency of wind and solar power generation. It’s also an effective way to exploit falling solar costs.

Major storage projects around Australia include:

• The 212MW Lincoln Gap Wind Farm planned for Port Augusta in South Australia with  around 10 MW of battery storage.
• Kennedy Energy Park in central north Queensland will be Australia’s first fully integrated wind, solar and battery project. It features 15 MW of solar generation and 2 MW of storage.
• Kidston Renewable Energy Hub near Townsville will be Australia’s first large-scale solar farm co-located with pumped hydro storage.
• Sandfire Resources’ DeGrussa Copper-Gold Mine in remote WA will also feature a 10 MW solar plant with 6 MW battery storage.

Energy storage is the key bottleneck of today’s power industry, attracting greater levels of investment to find alternatives to the ever popular, and intensely fought-over, lithium resources. Here, Scarlett Evans rounds up the new material contenders in battery technology.

As global power demand grows, so does the necessity to find sustainable alternatives to traditional battery storage systems – not only to extend smartphone and laptop life but also to power electric vehicles (EVs) and store energy from wind and solar sources.

Lithium-ion (Li-ion) batteries have long been the favourite power source for modern technologies, overtaking lead-acid batteries due to their longevity and energy density. However, lithium’s rising costs – going up by 240% in 2017 according to the Financial Times – in addition to fears over supply chain, resource depletion and reports of sudden battery drains, have caused developers to look elsewhere for effective, low-carbon battery bases.

So far, the search has uncovered a range of materials with potential to solve the energy storage problem, including sodium, cobalt, water and gold. But with lithium now a staple of modern technology, will other materials ever reach the same level of commercial-scale success?

Ammonia boosts efficiency

Most recently, German industrial firm Siemens announced the launch of a £1.5m pilot project trialling the use of ammonia as a new form of energy storage. Traditionally used as a fertiliser, Siemens has voiced its belief that the ammonia project may have an advantage over other energy storage methods due to its repurposing of pre-existing technologies and hardware.

The project will take place at a proof-of-concept facility in Harwell, Oxfordshire, UK where the team will attempt to turn electricity, water and air into ammonia without releasing carbon emissions. The ammonia produced will then be stored in a tank, to be burned to generate electricity, sold as fuel for vehicles, or used for industrial purposes such as refrigeration.

In the instance of ammonia powering electric vehicles (EVs), rather than use the chemical directly, the scheme will extract the hydrogen only for use hydrogen vehicles.

The main benefit, Siemens claims, is cost-effectiveness, as is the case for many alternatives to lithium. Indeed, for many the aim is to simply find a cheaper battery that can provide the same storage capacity and longevity.

Imagine if the US had these three things: access to unlimited electricity from clean sources everywhere in the country, an electricity grid impervious to outages and electricity prices that were even cheaper than they are today.  These aspirations can become reality with advancements in energy storage.

This technology was developed right here in the good ole’ US of A, but unfortunately, the US is now falling behind other countries in this increasingly lucrative global market, and our outdated electric grid is growing more vulnerable to increasing threats like cyber-attacks and extreme weather.  So how do we regain our leadership in this critical technology, and how can we increase the development and deployment of energy storage here at home?  The answer is innovation.

What are the experts in the field saying?

Back in March, with the help of the Bipartisan House Advanced Energy Storage Caucus, UCS convened twenty-one experts on energy storage research, development and demonstration from around the country.  The goal was to develop recommendations for congress on how the federal government could best support innovation in this game-changing technology.  Our new policy brief, “Federal Support for Electricity Storage Solutions: State Perspectives on Research Development and Demonstration”, synthesizes the convening dialogue and includes a brief analysis of the applications and benefits of energy storage.  It also identifies and prioritizes the most important research questions and breakthroughs needed to advance the technology.  The brief highlights important ongoing work on energy storage across the federal government.  And most importantly, it contains recommendations for policy-makers on how the federal government can best foster and support innovation in energy storage.

We wanted to hear diverse perspectives, so we included a broad cross section of technical experts from different states and regions, including university professors, start-ups, the national labs, small rural electric co-ops and big utility representation, conservative political voices, the defense community, former state and federal officials, and financial analysts.

Three important points of unanimous agreement at the outset of the convening:  1) Energy storage RD&D across the federal government is underfunded relative to the strategic importance of innovation in this technology.  2) “The U.S. is no longer the global leader in energy storage technology.”  3) The private sector is not making the needed investments in energy storage RD&D to achieve transformational change.  Specific, strategic efforts are needed by the federal government to advance the technology.

This summer’s heatwave is a stark reminder: we need to change how we use energy. Our towns and cities, swelled by population booms and choked on a grim dependence on dirty energy, have become sweltering, pollution-riddled health hazards.

Despite the signing of the Paris Agreement, an essential accord that the US has brainlessly disavowed, renewables remain a tiny part of the global energy mix. Excluding hydropower, they produce just eight per cent of the world’s electricity. Commitments made to date are widely recognised as not being sufficient to keep global temperatures from reaching a potentially catastrophic tipping point. Change, as ever, is slow.

Naked profiteering aside, divesting from fossil fuels will require a fundamental – and technically challenging – rethink of the infrastructure that keeps the lights on. The problem? You can’t turn the sun off. Or the wind. And the more renewable energy floods the market, the cheaper it becomes. Renewables are unpredictable – and existing systems are built on predictability.

Enter batteries. Until we can store the vast quantities of energy generated by renewable sources, they remain too volatile as large-scale components of the global energy mix. And so, once again, technologists and scientists must rise to the challenge. The first challenge will be to crack how to make a lithium-ion battery that can store solar energy reliably over long periods.

The smartphones in our pockets, engineered into a dead end of thinness and fallibility, are close to breaking point. It might sound trivial, but the limits of lithium-ion batteries in smartphones hint at problems to come: aerospace companies are racing to create electric planes for short haul flights and Silicon Valley dreamers are set on reinventing the helicopter in the guise of an all-electric, flying car. This will all require huge advances in battery technology.

Here, the flaws of current lithium-ion batteries come to the fore. In labs around the world, researchers are still trying to crack a problem that has persisted for three decades: how do we make a battery that’s fit for the (near) future?

And that problem is only going to get greater. As Tesla (for all its flaws) continues to champion an electric vehicle future, it finds itself increasingly overshadowed by a phalanx of epic-scale Chinese electric vehicle (EV) manufacturers. While mass-market adoption of EVs will help clean up our polluted cities, it will put huge strain on grids ill-equipped to cope with everyone plugging in, rather than filling up, their cars.

In its latest report on funding and mergers and acquisitions (M&A) activity for the Battery Storage, Smart Grid, and Energy Efficiency sectors, Mercom Capital Group, llc finds that battery storage continued to be an attractive proposition.

Indeed, VC funding in this category attracted US$539 million from 34 investors in H1 2018, up 12% on the same period a year earlier, where $480 million was raised. Deals here included $80 million by Stem and $71 million raised by sonnen.

Overall, 14 categories were targeted, including, Energy Storage Systems, Lithium-based Batteries, Solid State Battery, Flow Batteries, Energy Storage Downstream, Fuel Cells, Nickel-based Batteries, Energy Storage, and Management Software.

Representing an increase of 10%, debt and public market financing activity grew to $142 million across five deals, compared to $129 million raised across nine deals in H1 2017. In terms of project funding, H1 2018 saw $34 million was raised across four deals, up significantly from the $5 million in two deals in 2017.

Finally, the first half of this year saw eight Battery Storage M&A transactions, up from two in 2017.

Performing markedly worse were the Smart Gird and Efficiency categories, which chalked up declines across the board, and accounted for the overall decrease – 14% or $2.4 billion raised compared to $2.8 billion – in total corporate funding.

Of the two, smart grid companies saw the biggest declines, with VC funding in H1 2018 falling a massive 56%, from $304 million raised in 1H 2017, to $135 million via 19 VC investors.

Marking the only increase – and a significant one at that – in this category, $1.3 billion was raised via debt and public market financing, across two deals, compared to $9 million.

Regarding M&A activity, just five transactions were recorded, down from 13 a year previously.

Efficiency companies also fared badly, with VC funding in the period falling 32% to $165 million via 20 investors, compared to $242 million.

As power grids seek to adapt to the transition to renewable power generation, energy storage solutions, including battery storage, gas peaking plants and hydroelectricity, are touted as one solution to grid volatility.

As nations make the transition from coal-based power economies to renewable power economies there is anticipated to be a massive impact on power grids. In the UK, for instance, the government has committed to a programme that will phase coal out of all electricity generation by 2025.

Future energy needs will be met by renewables, nuclear power and power sharing via interconnectors with neighbouring countries (more on this in our feature on interconnectors). “Coal and gas-fired power stations have been the absolute main baseline capacity drivers of the UK’s grid for decades and decades, says Duncan Gordon, renewable energy broker at Alesco. “Now that’s changing, and the grid has needed to adapt”

“In terms of the overall contribution to the grid it’s definitely wind that’s been the major success,” he continues.”2017 was a headline year, with wind providing 15% of the UK’s annual electricity supply and the grid has come to rely on it. Combined cycle gas turbines and nuclear provide the baseload capacity requirements but the increasing contribution of solar and wind to the grid has raised the volatility profile and increased the need for new capacity to run and be available intermittently.”

2017 was a headline year, with wind providing 15% of the UK’s annual electricity supply and the grid has come to rely on it

Unlike traditional coal power, electricity production by weather-dependent renewables such as wind and solar can vary quite considerably depending on the time of day, time of year and whether or not the wind is blowing. This causes peaks and troughs in supply that older grids were not designed to cope with, leaving grids more susceptible to sudden variations in power generation or consumption.

Any shortfalls are most likely to be experienced during the November to January winter period when the days are shorter and colder. On top of this, there are variations in energy demand. Take the World Cup for instance. National grid operators know there will be a surge in demand at half time when England is playing and when up to 20 million viewers switch on their kettles at the same time.

As power grids seek to adapt to the transition to renewable power generation, energy storage solutions – including battery storage – are touted as one solution to grid volatility. “Whilst grid stability has largely been supported by interconnectors, demand-side response, gas plant upgrades and gas peaking plants the National Grid’s storage contracts have also provided entry for battery asset systems to be installed” says Gordon.

“Initially the utilities installed large battery systems, but in time private developments have completed with project finance taking advantage of short-response contracts, two to four years, followed by longer term capacity contracts.”

While Tesla is best known for making electric cars, it also has an interest in solar roofing thanks to Solar City and energy storage devices with Tesla Energy. It is these two brands that will likely be most affected by a new patent application that was published today by the U.S. Patent and Trademark Office that describes a new, safer storage battery.

The patent was originally filed January 20, 2017, and specifically mentions, “energy generated from photovoltaics” and is basically an “improved energy storage system” that is designed to release the hot gases that can be generated in the charging and discharging process if cells fail. The gases would be released thanks to two “interconnects” (one on the positive ends, the other on the negative ends) that have weak spots (made from a thin layer of mica, perhaps) that would rupture and vent the gases when necessary.

This is how the patent application describes the process in detail:

The energy storage system includes a module housing having multiple battery cells positioned inside the module housing. Each of the battery cells has a first end and a second end. Further, each of the battery cells has a positive terminal and a negative terminal. A first interconnect is positioned over the multiple battery cells. A second interconnect is positioned over the multiple battery cells. Multiple first cell connectors connect the positive terminal of the battery cells to the first interconnect. Similarly, multiple second cell connectors connect the negative terminal of the battery cells to the second interconnect. A top plate having an interior side and an exterior side is positioned over the first interconnect and the second interconnect. The top plate includes one or more weak areas above the one or more battery cell. The weak areas are regions that have less integrity and thus, where mechanical failure is more likely to occur if a battery cell releases gas. These regions may be physically weaker areas compared to the surrounding areas and may rupture when pressure builds up due to a failed cell. Alternatively, the weak areas may be chemically weaker and preferentially rupture when exposed to the caustic gases released by a failed battery cell. The weak areas may also fail due to a combination of physical and chemical weakening.”

In other words, a patent for better, safer energy storage, brought to you by a car company.