Renewables Integration and the Smart Substation
Written by Peter Vaessen
As we have heard time and time again, two key issues with our future energy systems are the integration of huge amounts of renewable energy sources into the grid, and the realization of active demand through customer involvement. These two issues combine to create the need for a smarter grid that can cope with generation and load with high coincidence factors without significant reinforcements.
Our future transmission system will likely be very similar to that of the present day, aside from the increase in power flows across the transmission network due to trading, and the additional presence of large-scale intermittent sources, such as (offshore) wind power plants and remote large scale photovoltaic systems. On the other hand, the local power distribution system(s) might be quite different from what we see today.
The future of the local power distribution system offers us (nearly) self-supporting rural, urban or industrial energy environments, compared with today’s more traditional (consumption only) behavior. A number of generators utilizing different technologies, based on renewable energy or combined heat and power, will be present at the distribution level. Furthermore, the future electricity customer will be more directly involved in the power system as he may own part of the assets at the local distribution level.
In this scenario, the goal of the future power grid operator is to achieve the best possible security for the network using the available facilities. This requires tools for assessing the vulnerability of the grid to possible contingencies, implementing protection and control that is responsive to the prevailing system conditions and minimizing the likelihood of blackouts resulting from various forms of instabilities and external threats. The goal is for the network to be adaptive and self-healing through quick and accurate assessment of the degree of damage and the pace of affected area expansion – reducing the effect of the disturbance by breaking it up and isolating it. The remaining parts of the network can then operate on a (slightly) degraded level. After the “storm,” the entire system can be restored again.
A crucial element of the future smart grid is the smart substation, and how this power and information exchange will be connected to the regional transmission and local distribution grid. The smart substation is, on one hand, the gateway to the many prosumers connected to the low voltage grid and, on the other, the connection to the higher voltage levels of the transmission grid and interconnectors.
DNOs are faced with an ever-increasing uncertainty for planning and operation. The size, location and timing of generation and load are often unpredictable. Investments in grid reinforcements may turn out to be uneconomic for the DNOs. This stimulates them to maximize the use of the existing network and to consider installing flexibility and intelligence in the grid instead of traditional grid reinforcements. Smart substations are capable of aggregating customer demand and supply. They can guarantee power quality, allow for controlled islanding, optionally store energy, and serve as an information and control gateway. This last part is possible through exchange agents between customers and the grid. And of course, smart substations are capable of physically facilitating the delivery of electric power.
An important question to consider in regard to the smart substation is how the power exchange layer will develop between existing large-scale generation – including, for example, offshore wind power – and the numerous distributed resources. Two scenarios are possible: the Camel scenario and the Dromedary scenario.
The Camel scenario envisages large power plants connected to one another via a high-voltage (HV) transmission network, while a low-voltage (LV) distribution network interconnects the micro grids that are (nearly) self-supported. Power is exchanged between the HV and LV layer over a relatively lightweight medium-voltage (MV) network. Alternatively, the Dromedary scenario assumes that both the large-scale plants and micro grids are connected to each other via a strong medium-voltage network.
If the Camel scenario becomes a reality, investments will be made mainly in the HV and LV network. When looking at the LV network, substantial investments would be made locally (probably at the customer site) to balance local supply and demand as much as possible, maintain voltage levels within tolerances, and control the power quality and reliability at the connection points. Because maintaining the voltage levels and control of the power quality is a difficult task in the LV network with a relative weak MV coupling, this, along with the function to allow controlled islanding, will probably be the main function of the intelligent node. Because the customer is largely involved, this model gives rise to public/private investment questions about who is responsible for what part and which costs, and who receives what benefits.
In the case that the Dromedary scenario becomes a reality, the MV network will be reinforced and serves as a strong primary means for keeping the voltage levels of the LV feeders within limits, and maintaining a certain level of power quality and reliability. This resembles most closely the present (ideal) network situation. Even in this strong MV network, maintaining the voltages within the tolerance band and assuring power quality and reliability with a number of small-scale, embedded generators will become increasingly difficult with direct control functionality only at the entrance point of the feeders. It is therefore likely that there will again be a demand for smart substations equipped with two-way communication and grid support functionality. The question that then arises is how the dispersed generators are controlled to offer grid support.
The conclusion here is that smart substations are an essential element for a reliable and sustainable power supply in the future and, depending on which scenario becomes a reality, will have a different function and a different realization path.
Sakuu Corporation creates 3D printer for EV batteries
Sakuu Corporation has announced a new industrial-grade 3D printer for e-mobility batteries which it claims will unlock the mainstream adoption of electric vehicles.
Offering an industrial scale ‘local’ battery production capability, Sakuu believes the technology will provide increased manufacturer and consumer confidence. Sakuu’s Alpha Platform for its initial hardware offering will be available in Q4.
Backed by Japanese automotive parts supplier to major OEMs, Musashi Seimitsu, Sakuu is set to enable fast and high-volume production of 3D printed solid-state batteries (SSBs) that, compared with lithium-ion batteries, have the same capacity yet are half the size and almost a third lighter.
The company’s KeraCel-branded SSBs will also use around 30%-50% fewer materials – which can be sourced locally – to achieve the same energy levels as lithium-ion options, significantly reducing production costs. Sakuu anticipates the 3D printer’s attributes being easily transferable to a host of different applications in other industry sectors.
"For the e-mobility markets specifically, we believe this to be a landmark achievement, and one that could transform consumer adoption of electric vehicles,” said Robert Bagheri, Founder, CEO and chairman, Sakuu Corporation. “SSBs are a holy grail technology, but they are both very difficult and expensive to make. By harnessing the flexibility and efficiency-enhancing capabilities of our unique and scalable AM process, we’re enabling battery manufacturers and EV companies to overcome these fundamental pain points."
The ability to provide on-demand, localised production will create more efficient manufacturing operations and shorter supply chains, he added.
Sakuu will initially focus on the two-, three- and smaller four-wheel electric vehicle market for whom the company’s SSB proposition delivers an obvious and desirable combination of small form factor, low weight and improved capacity benefits. The agility of Sakuu’s AM process also means that customers can easily switch production to different battery types and sizes, as necessary, for example to achieve double the energy in the same space or the same energy in half the space.
Beyond energy storage, Sakuu’s development of print capability opens complex end device markets previously closed off to current 3D printing platforms. These include active components like sensors and electric motors for aerospace and automotive; power banks and heatsinks for consumer electronics; PH, temperature and pressure sensors within IoT; and pathogen detectors and microfluidic devices for medical, to name a few.
"As a cheaper, faster, local, customisable and more sustainable method of producing SSBs – which as a product deliver much higher performance attributes than currently available alternatives – the potential of our new platform offers tremendous opportunities to users within energy, as well as a multitude of other markets," said Bagheri.
Ongoing research and new funding collaborations
Omega Seiki, a part of Anglian Omega Group of companies, has partnered with New York-based company C4V to introduce SSBs for EVs and the renewable sector in India. As part of an MoU, the two companies are also looking at the manufacturing of SSBs in the country, according to reports.
Solid Power, which produces solid-state batteries for electric vehicles, recently announced a $130 million Series B investment round led by the BMW Group, Ford Motor Company and Volta Energy Technologies. Ford and the BMW Group have also expanded existing joint development agreements with Solid Power to secure all solid-state batteries for future EVs. Solid Power plans to begin producing automotive-scale batteries on the company's pilot production line in early 2022.
"Solid-state battery technology is important to the future of electric vehicles, and that's why we're investing directly," said Ted Miller, Ford's manager of Electrification Subsystems and Power Supply Research. "By simplifying the design of solid-state versus lithium-ion batteries, we'll be able to increase vehicle range, improve interior space and cargo volume, deliver lower costs and better value for customers and more efficiently integrate this kind of solid-state battery cell technology into existing lithium-ion cell production processes."
A subsidiary of Vingroup, Vietnam’s largest private company, Vinfast has signed an MoU with SSB manufacturer ProLogium - which picked up a bronze award at the recent Edison Awards - to accelerate commercialisation of batteries for EVs (click here).
Xin Li, Associate Professor of Materials Science, Harvard John A. Paulson School of Engineering and Applied Sciences, is designing an SSB for ultra-high performance EV applications. The ultimate goal is to design a battery "that outperforms internal combustion engines so electrical vehicles accelerate the transition from fossil-fuel-based energy to renewable energy," according to The Harvard Gazette.
The dramatic increase in EV numbers means that the potential battery market is huge. McKinsey projects that by 2040 battery demand from EVs produced in Europe will reach a total of 1,200GWh per year, which is enough for 80 gigafactories with an average capacity of 15GWh per year.