Lithium-ion batteries can help to safeguard the grid
From wind farms on the remote Faroe Islands to data centres in the heart of Europe, lithium-ion batteries are an increasingly attractive solution to high-density energy storage.
A quarter century ago, Sony commercialised a technology that within the space of a decade pervaded consumer electronics. Despite its problems with flammability, the ability of the core lithium-ion chemistry to hold larger charges than any other commercially available technology so far is beginning to see it change the way society manages electrical energy.
A project far to the north of the UK is a prime example of the role the technology can play. The Faroe Islands are isolated in the Atlantic Ocean between Iceland and Norway and have no option of importing electricity. They currently use oil, wind and hydro to generate electricity but the Faroese government has set a target of increasing renewable generation from 38 per cent in 2011 to 100 per cent by 2030. With such an unpredictable means of generation, though, how can the Faroes keep the lights on while striving to achieve this goal?
Publicly-owned power generation and grid utility SEV opted to use storage to capture excess energy from the 12MW Húsahagi wind farm north of Tórshavn. As Europe’s first commercial use of lithium-ion energy storage to support a wind farm, the system comprises containerised battery systems made by Saft and able to store 700kWh combined with a 2.3MVA power-conversion system made by Enercon, which is also built into a container. The system was installed in spring 2016 and has been in operation since May, primarily to mask the effects of rapid changes in output on the local grid as the wind picks up or dips.
SEV research and development manager Terji Nielsen says grid stability is as important as energy storage to the islands: “Stability is crucial as we, as the utility, are obliged to serve our customers with high quality electricity and in order to do so grid stability is a requirement.
“On the other hand, storage is also a very important parameter. We have great potential in wind and hydro and to a certain degree solar photovoltaic. All of these are variable resources which call for storage as a bridging technology when there is no rain, no wind or no sun.”
Nielsen says he expects battery-storage systems will be installed at other renewable energy sites in the Faroe Islands, adding: “If it turns out to be a more central storage system or a few distributed storage systems is not clear yet. There are pros and cons in both strategies.”
Batteries may not be enough to handle all of the islanders’ demands. Nielsen says both short- and long-term forms of energy storage are needed to bridge the capacity shortage at times. The summer months may not bring enough rain and wind for renewables to meet demand, highlighting need for seasonal storage.
“Whether it will be in terms of battery storage, hydro storage, hydrogen etc is yet to be found out. It is important to map all possibilities and implement the different solutions at the right time,” Nielsen says. “If the battery system installed in Húsahagi proves to be as good as up to now, I certainly believe that battery storage will be a part of the overall strategy.
“The reason for us to pursue a lithium-ion battery [today] is that we would like to have a system optimised toward power and not energy. The type of battery technology is very much linked to the application, that is, energy or power. Lithium-ion batteries have a high energy density making them interesting in order to minimise the physical footprint.
“The disadvantages of lithium-ion batteries are the fact that they have ageing issues if you operate them inappropriately and, of course, the cost of lithium-ion batteries has been an issue, but this is about to change due to expected cost reductions.”
Ongoing reductions in prices are already beginning to see lithium-ion technology become a viable option for one of the largest commercial applications for battery storage: the uninterruptible power supply (UPS). As they move into place, companies are beginning to adopt the same approach to energy as the Faroe Islands: not just to ride out outages from the grid but to integrate renewables.
Analysing their use for electricity backup in data centres, Schneider Electric found lithium-ion could produce savings of 39 per cent over a ten-year period compared with traditional valve-regulated lead-acid batteries despite a higher initial cost.
Giovanni Zanei, AC power product marketing director at Emerson Network Power in EMEA, says: “Until fairly recently in the UPS market, lithium-ion batteries have been restricted to very specific requirements because of their traditionally high cost of investment. Now that battery suppliers are seeing decreasing pricing trends, we’ve seen lithium-ion options becoming increasingly within reach. The reduced total cost of ownership has presented the solution as a more viable investment for many businesses.
“Large solar and wind power systems are already leveraging UPS technology to benefit from edge-technology power converters along with flexibility of installation and wide monitoring options. The increasing use of renewable energies at both large and small scales is making energy storage applications more and more appealing to the market.
“In the future we expect an increasing demand of energy storage applications as part of a wider change in the use of energy, so this will undoubtedly mean it will be at the heart of businesses strategies.”
Cyrille Brisson, vice president of marketing for Eaton Electrical EMEA, points out that businesses are always looking to find ways to lower their energy bills: “Energy storage adds new and compelling capabilities for achieving clean, low-cost energy, while also improving resiliency to ensure the power is stable and available when most needed. For this reason, energy storage will play an important role in the future of businesses that face challenges and uncertainty about the cost and availability of their energy supply.”
Brisson forsees energy storage becoming critical to businesses where energy bills are a significant cost to the business, for example in multi-tenant data centres, water utilities, heavy industry and mining.
“The challenge will be compounded if the business may receive penalties from its utility company for being considered a ‘bad’ load, due, for example, to harmonics, sags and surges caused by the operation of large electrical motors,” he adds.
Local, high-capacity storage makes it possible for building and factory owners to create their own micro-grids: electrical networks that can operate independently of the main grid when they need to. The micro-grid approach lets the organisation control how electricity is acquired, generated locally, stored and used according to its own rules. The connection to the national grid can be managed through power conditioners that ensure the installation acts as a good load and to watch for brownouts and outages, disconnecting the micro-grid from the network if the connection becomes unstable.
“A very important development, made possible by the industrialisation and mass-production scale of storage systems is the creation of micro-grids that are relatively simple to deploy and operate,” Brisson says, adding that users in emerging economies with relatively poor grid stability will see high benefits.
Installations are already up and running in the developed world. Eaton’s storage systems have been used by telecoms firm Webaxys at its newly launched data centre in Saint-Romain de Colbosc, France. The system, which is regarded as a pilot scheme, runs entirely on renewable energy.
“People are developing new business models that can benefit from the availability of energy storage systems. We’re already talking with businesses that want to use storage to gain better efficiency from their renewable sources, become the energy supplier to neighbouring businesses, go off-grid, provide their own regional UPS, and attract better tariffs by using storage to enable them to supply on demand at better rates,” said Brisson.
Eaton has entered into partnerships with both AES Energy Storage and Nissan to deploy energy storage and management solutions in commercial environments. Nissan batteries, developed initially for the Leaf electric vehicle, are given a new lease of life in this way before they need recycling.
Sunderland-based Hyperdrive Innovation, which develops lithium-ion battery systems for vehicle and storage applications, announced in September that it has begun to use Nissan Leaf batteries not only for its niche, off-highway vehicles but also for fixed energy storage in both domestic and commercial markets.
AGM Batteries, based on the north coast of Scotland, sees a natural alignment between vehicle and fixed-storage batteries. AGM is the lead partner in the £5.4m UK Automotive Battery Supply Chain project.
“The needs are similar. In both cases you need good energy density so the battery is not too big or heavy, it needs to be reliably controlled, safe, have long life and low cost,” says AGM business development director Ian Whiting. “One of the technologies we’re scaling up, sodium-ion, fits these requirements very well. We’re seeing interest in parallel markets such as oil and gas, and aerospace, where energy density is an advantage but safety is even more critical.
“In energy storage, we’re working on technologies that can cover the whole range of applications from residential and micro-grids to multi-megawatt systems for storing energy from renewable sources such as wind and solar farms,” he says.
Whether they are in fixed systems or in cars like the Leaf may not matter that much for large-scale energy storage. Electric vehicles connected up to the supply in the car park can provide some of the energy needed during an outage.
“This could be a challenge for business parks, supermarkets and fuel stations with insufficient grid connection to recharge electrical vehicles,” Brisson says. “It is also an issue for distribution system operators in cities with high concentrations of electric vehicles, such as Oslo, and operators in relatively remote areas where the grid had not been sized for this use.”
According to Whiting, the drive to bring automotive batteries into an energy-storage mix is “happening at a real pace now, but Government legislation is not keeping up”. For example, using electrical vehicle batteries as part of a home storage system still needs standardisation before it could make a significant contribution, he adds.
Although interest in lithium-ion technology has built up, Emerson Network Power’s Zanei says traditional battery chemistries still have a role to play: “Solutions vary greatly depending on whether you’re implementing them in utilities and small-scale businesses or for residential and consumer purposes. Our experience has shown that the most desirable option will depend on the customer.
“While there are clear advantages of lithium batteries, traditional technology will not become obsolete in the short term, so companies like ours will continue to offer a wide range of standard and innovative solutions that can be scaled up or down to every company’s need.
“Understandably, complexity increases with the size of the energy storage system, however what’s important to remember is that all systems share the same concept of having batteries capable of high cycling and long life along with a power converter.”