As we move towards renewables in our efforts to decarbonise our economies, energy storage is becoming increasingly important. Could householders become an integral part of national electricity networks?

When Adam Courtney decided he wanted to reduce the energy bills at his “not particularly energy efficient” Grade II listed house in Godmanchester, England, solar panels were the obvious answer.

But, he says, he soon realised that the savings weren’t as great as he’d hoped. Renewable sources of energy don’t necessarily deliver at the right time and cloudy days saw his family drawing heavily on the national grid.

Meanwhile, he had spare capacity on sunny days, but got very little in return.

“We’d ended up feeding back into the grid, but the payment is tiny, so I ended up thinking ‘why do that?’,” he says.

Instead, the data centre owner decided that he himself could make better use of the electricity he was generating, if only he were able to store it for when it was needed.

He started researching battery storage – even at one point considering building his own system – before opting for a Tesla Powerwall that can store the excess energy generated by the solar panels.

The unit and supporting hardware costs just under £6,000, with installation costs of up to £3,000 on top. But it enables him to buy energy at cheaper times, lowering the running costs of both his home and the family’s two electric cars.

“With Economy 7 there’s cheaper electricity at night and the Powerwall knows it’s going to be sunny tomorrow so it knows how much power to buy,” he explains.

“My bill was £140 a month, but I spend £25 a month now on electricity, and most of that goes on the cars.”

More energy storage providers – such as Ovo Energy, Powervault and Moixa are entering the market – particularly as electric vehicles (EVs) promise to become a useful addition to the domestic energy mix. BMW i3 batteries are already being used to store windfarm energy in Wales, so it makes sense to integrate such car battery tech into homes.

A key factor when planning energy storage systems (ESS), for example for a microgrid, is to determine the expected cost savings and performance benefits provided by various ESS configurations.

Battery modelling offers a powerful way of predicting the lifetime performance and return on investment that will be provided by each ESS option.

Fuel savings are often a key factor in the choice of energy storage configuration, especially for microgrids which are often located in remote communities and rely on diesel generation, with logistical challenges around fuel delivery. However, cutting fuel consumption is just one of the purposes of battery modelling for microgrids.

Battery modelling techniques continue to evolve to better address the wider context of microgrid and renewable energy deployments. For example, simulations are now key to the project development process, as they deliver insights into renewable and storage applications ahead of deployment and help determine how much power and energy are required overall.

PRECISE MODELLING

Modelling an entire microgrid at a high level is a valuable exercise in assessing the viability of different deployments of renewable energy schemes with storage. However, when it comes to modelling the detail of these systems – such as bridging between multiple diesel generators in a large microgrid, or optimizing the set-points for operating with diesel generators in a smaller microgrid – more precise modelling is required.

High-frequency data, with granularity of no more than ten-minute intervals, is valuable. Such modelling provides insights into system operation, including diesel synchronization and cool-down times, to minimize diesel starts, maximize fuel savings and optimize battery
life.

High-level modelling is typically based on hourly data, and the granularity of ESS dispatch is correspondingly coarse. This kind of modelling is feasible even with minimal data input.

For example, an initial model of a microgrid can be constructed with minimal inputs, such as the coordinates of an island village off the US Pacific coast having a peak load of 150 kW in January. Based on this information, high-level modelling can be used to construct a typical load profile, and location-specific solar or wind data can be downloaded.

The modelling software can then quickly carry out multiple simulations to discover the optimum renewable energy power rating, along with an appropriate level of energy storage. The results illustrate fuel savings and, if sufficient inputs are provided, ROI.

Even among high-level stakeholders, there are real gaps in education, knowledge and understanding of what energy storage is, and what it can do. Not long ago, the constant use of hyped and inaccurate terms such as ‘silver bullet’ or ‘Holy Grail’ by some in the industry to describe energy storage technology, almost as if batteries are some sort of miracle cure for decarbonisation, probably did more harm than good for the overall perceptions of the industry.

So if energy storage is not a ‘silver bullet’ – and it’s becoming clear that it is not – then what exactly is it?

We were privileged at last week’s Intersolar Europe/ees Europe shows in Munich, Germany, to be joined by four leading thinkers – and doers – in the energy storage industry, who helped us tackle this difficult question.

1. Marek Kubik – Market director – Fluence
2. Scott McGregor – CEO – RedT
3. Emilien Simonot – CTO, Renewables – InnoEnergy
4. Jean-Baptiste Cornefert – MD, e-services – Sonnen

Throughout the 45-minute discussion, you will hear how the economics of clean energy are changing rapidly, how batteries and other energy storage can play a huge role in decarbonisation – if used correctly – and what needs to happen now to create and maintain a sustainable, profitable and socially beneficial industry.

“Energy storage is just a box…The [real] silver bullet is cheap solar and cheap wind, that’s what’s driving energy storage,” Scott McGregor from redox flow energy storage provider RedT said.

The energy dynamic around renewables is changing so quickly in Colorado that Zach Pierce, a senior campaign representative for the Sierra Club, can hardly keep up with it. “I feel like we’re having to rewrite the talking points on the drawing board every month in Colorado,” he said.

In December, the state’s largest utility — Xcel Energy — released a short report summarizing the responses to the solicitation it had issued to power suppliers for bids to bring new sources of electricity to the grid. The utility received 430 bids, and 350 of those were for renewable energy projects.

That was remarkable on its own, but what surprised people even more were the bids for projects that added battery storage to the mix. They were cheaper than anyone expected.

“It’s a testament to how quickly the market is changing,” Pierce said.

Changing attitudes

For years, renewable energy advocates have pushed utilities and regulators to consider adding battery storage to their electrical generation portfolios for flexibility and to reduce intermittency problems that come with solar and wind. Until recently, it wasn’t considered a realistic option: Batteries were expensive and largely untested by utilities, and risk-averse regulators mostly let grid managers ignore them in their bids, statements and long-term planning documents.

Analysts say that’s starting to change as batteries come down in price, as momentum builds behind renewables and as renewables create a natural market for storage. Utilities increasingly look at batteries as a tool for leveling out power available over the course of the day and for replacing bulky and expensive peaking power plants that have high costs but only occasionally run at or near full capacity to meet peak demand (in the Southwest, this might be one hot day in the summer when everyone has their air conditioning turned up).

NEC Energy Solutions announced that they have completed and commissioned an energy storage system for Germany-based EnspireME, a joint venture between Eneco, a Netherlands-based renewable energy company and Mitsubishi Corp.

The 48 MW energy storage system located in Jardelund, Germany has over 50 MWh of storage capacity and will generate revenue from the primary reserve market by providing reactive power to stabilize the transmission grid.

NEC provided turnkey engineering, procurement and construction services which included its GSS end-to-end grid energy storage solution and its AEROS proprietary energy storage controls software to build the largest energy storage system in Europe. The 48 MW energy storage system built for Germany-based EnspireME, a joint venture between Eneco and Mitsubishi Corp., has over 50 MWh of storage capacity. The system will generate revenue from the primary reserve market by providing reactive power to stabilize the transmission grid.

Transmission system operators (TSOs) in Europe are required to secure a certain number of capacity reserves to prepare for sudden power loss or an extensive blackout. The storage capacity from the system will be sold to the German electricity market through weekly common auctions where European grid operators purchase the reserve capacity they require in the primary reserve control market to guarantee the 50 Hz (Hertz) frequency on the grid. The energy storage system can also take over the role of primary reserve provider and become a more sustainable alternative to coal and gas fired plants.

In addition, Eneco and Mitsubishi Corp. will investigate connecting the battery to local wind farms, providing further value for wind farm owners by storing excess electricity generated during periods of curtailment.

California is generating a ton of solar power–some days, more than people can use. It could power the whole state soon, except for one problem: There’s no way to hold on to all that energy at night.

Some of the country’s biggest energy companies are trying to figure out how to store the power. They’re buying giant lithium batteries, and imagining ways to tap the batteries in electric cars. But there’s another option.

Today on the show, we visit the world’s largest battery, built out of a mountain and a lake.

European Commission vice president for energy, Marcos Sefcovic has referred to an EU action plan for ‘green batteries’ to be made in Europe, citing the technology as vital for renewable energy integration as well as giving the continent a ‘competitive edge’.

At an industrial forum hosted at the Intersolar Europe conference centre in Munich on Thursday, Sefcovic was the invited guest of trade group Solar Power Europe, which hosted the event. His appearance followed opening remarks from SPE chief Christian Westermeier, who said that despite enormous progress and successes in the deployment of solar PV in the continent, there had historically been not enough effort made to support the whole value chain including manufacturing.

Conversely, measures such as trade disputes with China on module imports had backfired, resulting in sluggish downstream activity in some areas, while not having the desired effect of boosting upstream manufacturing, Westermeier said. Nonetheless, Westermeier credited the European Commission’s Renewable Energy Directive for its role in getting EU member states to a 100GW installed base of PV capacity today.

Westermeier also applauded the recent creation of an EU Battery Alliance, referring to batteries and energy storage as “vital” to the progress, development and deployment of solar. Westermeier concluded with the remark that EC Industrial Strategy legislation could bring about an “industrial renaissance”.

The EC’s Sefcovic, having called PV an “unlimited clean source of energy”, agreed that while there have been renewables success stories in Europe, there had also been failures, namely in that aforementioned lack of support for manufacturing across the whole value chain, meaning European makers have lost out “to our competitors”, Sefcovic said.

As with other shows in Europe this year, Sefcovic said it was good and important to see emphasis on sector coupling, where synergies between the areas of electricity, heat, cooling and transport can be fully capitalised upon.

Sefcovic mostly talked about batteries in context of electric vehicles (EVs), stating that European countries have to “be leaders in this important technology” and to “make sure the cleanest batteries are made in Europe”. Sefcovic said he was somehow taken aback that electric taxis in Brussels were Chinese made, making him think it was “high time we did something about that”.

June 22 (Renewables Now) – New York governor Andrew M Cuomo on Thursday unveiled a roadmap with a set of recommendations aimed at facilitating the state in reaching its goal of deploying 1,500 MW of energy storage by 2025.

The comprehensive plan is part of the measures addressed towards fighting climate change, improving power grid resilience and enhancing the benefits of renewables generation to meet peak demand for electricity. “This Roadmap is the next step to not only grow our clean energy economy and create jobs, but to improve the resiliency of the grid to keep our power running in the face of extreme weather and other emergency situations,” Governor Cuomo said.

The short-term recommendations include the provision of USD 350 million (EUR 301m) in incentives to speed up deployment of advanced storage systems, as well as additional funding storage capacity linked to solar projects developed under the NY-Sun initiative. The proposed measures also include regulatory changes to utility rates, solicitations and carbon values, facilitating the project permitting and siting process so as to cut indirect and soft costs, and modifications to wholesale market rules.

The plan was developed by the Department of Public Service and New York State Energy Research and Development Authority (NYSERDA).

Separately, the NY Green Bank has committed to provide at least USD 200 million for storage-related investments. The state-sponsored investment fund is also expected to launch a Request for Proposals (RfP) later this year for projects incorporating solar and energy storage technologies.

As the utility industry comes to grips with the coming of age of energy storage (see the T&D World April 2018 Energy Storage Supplement), residential storage also is ramping up.  According to the latest quarterly update of the U.S. Energy Storage Monitor from GTM Research/ESA, the  residential storage increase in the 4th quarter of 2017 was the highest on record and combined behind the meter energy storage for all customer categories accounted for 55% of the additions during 2017.

California and Hawaii lead the country for residential deployments in the 4th quarter, and GTM is predicting a breakout year for storage of all types in 2018.  Falling costs and favorable regulatory policies are part of the equation.  No doubt, FERC’s hugely significant decision that outlines a path for integrating energy storage resources into the U.S. wholesale markets is a big part of the optimism. However, GTM also suggests that storage may be negatively impacted by the tariffs imposed on solar cells and modules in early 2018.

Despite the solar tariff issue, there are a number of reasons to expect residential storage will continue to break records in 2018.  For one, the IRS issued a Private Letter Ruling in March (PLR 201809003) that permitted a customer to take the 30% solar Investment Tax Credit (ITC) for a storage system retrofitted to an existing solar PV system. Previously, residential storage retrofits could not claim the ITC. Consequently, we could see a significant uptick in the demand for retrofit targeted storage systems.

Legislation in a number of states for behind the meter (BTM) storage tax credits supports the case for greater residential storage demand.  Finally, when a major industry player decides to enter a particular market, it sends a strong signal that the market has growth potential.  Consider the new offering by ABB of a flexible, modular residential storage system. The system consists of the new REACT 2 inverter and a high-voltage lithium ion battery that can be installed in capacities of 4 kWh, 8 kWh and 12 kWh.  The system can be installed on both the AC and DC side of an existing or new photovoltaic system and it can be configured to provide backup power in an outage.

Interestingly, other companies have entered the residential energy storage market, presumably to compete with Tesla and its Powerwall offering, for the PV packaged system and PV backup system demand.   Mercedes-Benz started a new energy subsidiary last year with a modular home battery pack program that it installed itself and offered to solar companies.  In fact, Nissan, Audi and other auto companies with electric vehicle offerings all are attempting to lever their technology to break in to home storage and other markets.  Mercedes-Benz has already decided the home storage market is not a good fit for its battery technology and ended its new program in April.

Automakers like Daimler have been eager to leverage their battery operations connected with their electric vehicles (EV) programs. Late in 2016, Daimler hired Boris von Bormann, a former top executive at Sonnen, to launch Mercedes-Benz Energy Americas to market batteries to residential, commercial and utility consumers.

Daimler says the Elverlingsen facility will provide “efficient double usage of battery systems” that will improve “the life cycle assessment” and the life cycle costs of its EV program.

The facility, built in conjunction with GETEC ENERGIE and The Mobility House, will provide “active” storage of 1,920 lithium-ion battery modules at the ENERVIE AG power station site in Elverlingsen.

Daimler called it “a fountain of youth” for the battery systems used for its EVs.

Putting the batteries through deliberate, battery-conserving charging and discharging cycles at the plant prevents exhaustive discharge which can lead to battery defects before they are potentially used in Daimler EVs. At the same time, the energy storage system can provide “an attractive business case” by securing compensation for providing the grid with primary balancing power.

The Elverlingsen plant is the third such storage facility for Daimler. The automaker opened a 12.8 MWh second life battery storage plant in Elverlingsen in 2016, and in 2017 brought a 17.4 MWh replacement part energy storage facility in Hanover online.

When available, former generating plants make good sites for large energy storage facilities because of their location at a critical juncture on the grid and their access to grid connections.

In 2016, Younicos selected the former Roosecote coal- and gas-fired station in Barrow-in-Furness, Cumbria, U.K., for a 49-MW battery storage system that will be owned and operated by Centrica and used for frequency regulation.

That same year, AES Energy Storage brought a 20 MW, 20 MWh storage facility online at the site of Indianapolis Power & Light’s former coal-fired Harding Street station in Indianapolis.

Daimler is not the only automaker to focus on energy storage.