Energy storage installations for homes and businesses — involving battery technology — are on the rise in areas where extreme weather threatens the electric power grid, such as flood-prone Houston, wildfire-stricken California and hurricane-ravaged Puerto Rico.

Energy storage installations for homes and businesses — involving battery technology — are on the rise in areas where extreme weather threatens the electric power grid, such as flood-prone Houston, wildfire-stricken California and hurricane-ravaged Puerto Rico.

A sustained power outage can lead to serious consequences, such as loss of income and even death. Because of climate change, the frequency of these extreme weather events and outages will climb.

Traditionally, buildings would rely upon gas-powered diesel generators during outages. These generators have their own problems and do not necessarily help the electric grid become more resilient.

With recent technological changes, could batteries become the new generators?

Tracking sharp growth in the past year
Small-scale, so-called behind-the-meter energy storage accounted for 60% of battery capacity in the United States during the first quarter of this year.

Deployments grew 138% in the past year, driven in part by families and business leaders who are seeking resilience against power disruptions in our increasingly volatile climate.

When properly designed, electric energy storage can not only provide additional grid resilience, it can further minimize greenhouse gas and local air emissions compared with the conventional gas generators.

The EU’s latest Clean Energy Package (CEP) is “undoubtedly positive” for energy storage, with the technology expected to play a key role in meeting the legislation’s ambitious “32% by 2030” renewables target, Brittney Elzarei, senior policy officer at trade organisation EASE has said.

In an article for Volume 20 of PV Tech Power, the quarterly technical journal from our publisher Solar Media, Elzarei takes a close look at the CEP, noting that recognition by EU policymakers of the value of energy storage has greatly evolved in just the past decade since its third iteration in 2009.

“The CEP is undoubtedly positive for the storage sector. By establishing a binding renewables target of 32% by 2030 – along with targets for renewables in transport, heating and cooling – the package sets a high level of ambition that can only be achieved with the widespread deployment of flexibility solutions such as storage.”

Barriers still exist to the market, Elzarei argues, with so-called ‘double-charging’ – levying energy storage systems grid fees when both ‘consuming’ or ‘generating’ power from and to the grid – still in place and the lack of investment certainty that still exists when brokering contracts for services from energy storage, due to the limiting in duration of balancing services set out in the CEP.

Nonetheless, progress has been made, the EASE senior policy officer writes, taking a deep dive into the role of transmission network and distribution network operators, the scope for deploying non-battery energy storage technologies including hydrogen, and other topics. The article also takes a look further ahead to plans for full decarbonisation across the EU by 2050 and the Commission’s own analysis of the various different types and amounts of energy storage that will need to be deployed to meet 80% greenhouse gas (GHG) emissions reductions by that year.

Utility Ameren Missouri is planning three grid-scale solar facilities with energy storage, marking what is claimed will be the first ever instance of an energy company in the US Mid-West state powering its customers’ homes with batteries.

A release from the utility, a subsidiary of Ameren Corporation, said that it filed plans today with the Missouri Public Service Commission (MoPSC) for the building of three power plants, for which Ameren Missouri said it will invest around US$68 million.

The plants will be built in Green City, Richwoods and Uticah, dotted around the mostly-rural state, with each plant of 10MW solar PV capacity and an unspecified output and capacity of battery energy storage. Via Twitter, the company released a short publicity film which said the plan to build the solar capacity with batteries is an “innovative, cost-effective solution to help maintain reliable energy service in rural communities.”

“If an outage is detected, solar energy stored in batteries will help keep your lights on,” the video said.

The company just launched its first ever community solar facility mid-way through August, allowing customers to sign up to buy solar energy generated in 100kWh blocks at Ameren Missouri Lambert Community Solar Center. Meanwhile, it has also launched a Smart Energy Plan.

In addition to beefing up energy security with upgrades on transmission networks to cope with severe weather, the plan includes a reduction of carbon dioxide emissions by 80% from 2005 levels by 2050, with interim targets for 2030 (35%) and 2040 (50%).

The California Energy Commission (CEC) Oct. 30 will release two energy storage solicitations totaling $31 million to support the state’s goal under SB 100 of attaining 100% fossil-free electricity by 2045.

The commission wants to get the word out now because preparing energy storage projects and proposals can be time consuming, said Mike Gravely, CEC research program manager.

“We are doing this to bring new technologies that are cheaper and better performing to meet SB 100,” he said, adding that existing technology isn’t capable of meeting the requirements of the legislation.

Among the new technologies the commission focuses on are microgrids — and energy storage plays an important role in them, he said.

“Microgrids help integrate these clean technologies. These are the solutions we need to reverse the impacts of climate change.” Gravely noted that the focus on energy storage will help move microgrids along. All the microgrids that have received commission funding include energy storage.

Details on energy storage solicitations
Proposals for the energy storage projects will be due by the end of the year, and the commission will issue the awards between April and June, he said.

The first of the two energy storage solicitations is for $20 million and seeks technology demonstration projects in four categories.

“This is for projects that are maybe on the second generation of design,” said Gravely.

The solar power panel–level energy storage developer Yotta, based in Austin, Texas, has received $1.5 million in funding to continue work on SolarLEAF, the company’s energy storage solution. (Several hundred thousand dollars in grant money has also been obtained.) The funding will be used to continue with technological development and commercialization.

Additionally, the company hired former SunPower employee Phil Gilchrist to be the Director of Mechanical Design Engineering. Yotta’s CEO, Omeed Badkoobeh, answered some questions about the SolarLEAF technology for CleanTechnica.

What is the capacity of each panel-level energy storage unit, how much does a unit weight and what are the dimensions?

Each unit has 1kWh of capacity, weighs 52.6 lb, and has dimensions that are approximately 15” x 26” x 4”.

What are the advantages of using panel-level storage?

Panel-level storage shares a lot of the advantages that other module-level power electronics — microinverters, DC optimizers, etc. — bring to the industry, such as the simplification of design, power efficiency, and power optimization. Unlike other large stationary ESS systems, the SolarLEAF™ simply integrates with the same racking system as the solar module and uses the same balance of system. This is advantageous in situations with limited space or where the placement of stationary storage may add significant trenching costs. Additionally, the distributed design of the SolarLEAF™ with lithium-iron-phosphate technology is the safest way to integrate storage, as there is no risk of a cascading thermal runaway. In commercial rooftop systems with ballast racking, the SolarLEAF™ offsets the additional weight needed, which is typically accomplished with concrete ballast blocks.

Where are your energy storage units located in relation to the solar panels in a solar power system?

SolarLEAF™ is designed to be mounted directly behind the solar module that is powering it. The SolarLEAF™ can install electrically between the PV modules and the inverter because it can work with microinverters, string inverters, and battery inverters.

Can your storage units be used with ground-mounted solar?

Yes, Yotta is developing attachment brackets for various ground-mount racking solutions.

Could they be used on motorhomes, travel trailers, or mobile homes?

The SolarLEAF™ is generally not recommend for moving vehicles unless the installation is completed via a professional attachment process.

What battery chemistry do your storage units use?

Lithium-Iron-Phosphate.

As battery owners and operators seek to maximise the returns from their assets, they simultaneously face the Herculean challenge of managing degradation. This remains one of the most prominent challenges in the industry, where assets are expected to last around 15 years before reaching End-of-Life (EoL).

Degradation manifests itself in several ways leading to reduced energy capacity, power, efficiency and ultimately return on investment.

Put simply, battery degradation is a serious economic problem which will vary according to how the battery is used. It is therefore essential to monitor factors which drive degradation. These include temperature, ramp rate, average State of Charge (SoC) and Depth of Discharge (DoD).

Analysing the impact of these factors is vital to assessing the cost-benefit of decisions to charge or discharge a battery in response to different market signals.

This is especially important as single/multi-service batteries have the option of participating in a variety of markets, such as frequency regulation or the Balancing Mechanism (BM), and each market can have a different risk level according to the asset’s load profile and cycling behaviour.

Back to basics: what ‘exactly’ is a charge cycle?
Unfortunately, and confusingly, the industry has different definitions for what ‘a cycle’ actually is. In commercial documents, such as warranties, a cycle is calculated via energy throughput. This tallies the energy going in/out of the battery and divides total energy throughput by capacity. Even though this is a relatively simple calculation, it actually only tells you the number of ‘Equivalent Full Cycles’, or EFCs.

EFCs do not quantify DoD, which factors how deep charge cycles are. As can be seen below, EFCs would be unable to distinguish 1 cycle of 100% DoD vs 2 cycles of 50% DoD vs 10 cycles of 10% DoD. Cycle depth is completely ignored in EFCs! For this reason, KiWi Power utilises the Rainflow algorithm as a tool for profiling each ‘real cycle’ in terms of DoD.

The stationary energy storage industry, with batteries as the prime mover, has enjoyed a series of record years of deployment across North America, Europe and Asia in particular, but what comes next after that first wave? What are the challenges still posed for the ‘mainstream’ adoption of cost-effective energy storage technologies in a modern, low-carbon grid?

PV Tech Power, the downstream solar industry journal from our publisher Solar Media, has reached its fifth ‘birthday’ and Volume 20 of the quarterly magazine, out now, includes a special report on energy storage. In addition to some excellent technical papers and guest submissions, every edition of the magazine has for more than five years brought you the latest news and feature articles from writers and industry experts at PV Tech, Energy-Storage.news and our other channels including energy transition site Current± and Solar Power Portal (UK).

It’s got the usual great solar PV industry analysis on everyone’s favourite topics, technologies and gripes. From bi-facial modules in a post-trade tariff environment, to president Emmanuel Macron’s attempts to revive French solar makers, to the impact of digitalisation on the solar industry, PV Tech Power 20 has it covered across its mammoth 126 pages. Better understanding of corporate solar PPAs, the ‘terawatt opportunity’ of floating PV, utility-scale solar site safety and much more, from the worlds of solar technology, business and inevitably, policy.

But this issue’s Special Report focuses squarely on energy storage, with no less than seven feature articles and technical papers looking at everything from the policy and regulatory initiatives that still need to happen, to bankability and profitability of ESS, system technologies and architecture, all the way to recycling and end-of-life care for batteries. Additionally, Energy-Storage.news’ contributed section of the journal, Storage & Smart Power, returns once again, with feature articles on the UK’s recent blackouts and how batteries can help maintain system stability, the role of flexibility in smarter energy networks and finally a fascinating technical paper on the role batteries can play in delivering a ‘synchronous grid takeover’.

Knowledge transfer between academia and industry has the potential to affect a lot of change for a small off-grid solar company like M-KOPA Solar, a Kenya-based company and 2015 recipient of the Zayed Future Energy Prize. This is why Harini Hewa Dewage joined M-KOPA Labs, the research branch of M-KOPA, in November of 2016 as its battery technology specialist.

She has been connecting academia to industry in the battery storage sector ever since.

Now Battery Research Lead for M-KOPA Labs, Dewage believes in the mission of M-KOPA: providing access to energy through high-quality solutions that are affordable for all. As of November 2018, M-KOPA has over 700,000 total households subscribing to their services. But while typical businesses or nonprofits working in the low-cost distributed solar industry focus on the potential for solar power to support lights, M-KOPA has worked to meet demand for larger appliances such as TVs or refrigerators.

“Coming from the western world, we have this idea that access to energy is being able to get lightbulbs and light,” explained Dewage. “And I think that’s a fantastic first move to be able to displace candles and kerosene for light, but I think where you see people’s quality of life really improve is with access to appliances and other services.”

At M-KOPA, Dewage believes in giving people not just access to lighting, but the full range of what energy can provide. She explained that a common assumption is that if you ask people what’s the first appliance they want, it would be a fridge or a washing machine. While those two appliances are important, however, the first appliance most people want is a TV.

But with larger appliances, it requires more battery understanding and development. And that is where things get tricky.

“Any problem you have on a smaller battery it might be magnified on a larger one by the sheer fact that you have more cells,” said Dewage. “But also new challenges will appear. For example, as your pack increases in size you might have to put in cooling systems, you might have to manage, you know, thermal radiance better within the pack.”

“Any problem you have on a smaller battery it might be magnified on a larger one by the sheer fact that you have more cells,” said Dewage. “But also new challenges will appear. For example, as your pack increases in size you might have to put in cooling systems, you might have to manage, you know, thermal radiance better within the pack.”

The energy storage market enjoyed another record year for deployment in 2018, according to a new study by Navigant Research.

The news is not so surprising for a growth sector that is just finding its feet. However, while that growth is driving energy storage into new applications and in increasing volumes, the geographic distribution remains concentrated in just ten countries. Those being U.K., France, Germany, U.S., Brazil, India, China, Japan, South Korea and Australia.

Navigant expects these countries to install 1,242.1MW of energy storage in 2019, which it predicts will represent 80% of the market all in all.

As costs fall and the regulatory goalposts shift (in a positive direction) more and more use cases become economical in more territories.

Most new energy storage markets start off with systems providing short-duration discharges that provide services to the grid such as recalibrating the frequency. These are often rewarded through specifically designed market structures.

“In terms of applications for new utility-scale energy storage projects, solar plus storage has emerged as a major opportunity and driver of new growth,” says Alex Eller, senior research analyst at Navigant Research. “The rapidly falling costs for both technologies have made combined solar plus storage plants economically competitive against conventional fossil fuel plants in a growing number of markets, which allows a solar plant to be a predictable resource for grid operators.”

With around 100GW of solar installed annually the scale of that particular opportunity is significant.

Discharging batteries storing renewable electricity to meet peaks in demand instead of starting up natural gas peaker plants is proving increasingly economical. U.S. developer Fluence has commissioned research that found the economics could work not just in the very peakiest moments of demand but further down the shoulders of these peaks as well.

Storage facilities, particularly battery-based storage can also deliver extremely fast start-up times responding to momentary fluctuations on the grid that can trigger blackouts.