The Energy Storage Report 2024

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US solar-storage projects that decarbonise, save energy costs from Ameresco, ENGIE and Invinity

Solar panels alongside Invinity’s vanadium flow battery units. Image: Invinity Energy Systems.

A few years ago, any project with over half a megawatt of battery storage was rare and significant enough to be immediately worthy of consideration for coverage on Not long after that, about five or six years ago, there would comfortably be two or maybe three projects a week from around the world that exceeded the megawatt mark and one or two that might exceed 10MW.

Well, unquestionably a new era is upon us, where projects in the tens of megawatts and megawatt-hours are no longer a rarity and the world’s largest operational battery storage systems run into the hundreds of megawatts of power and even exceed the thousand megawatt-hour mark for energy capacity in some cases.

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In the US, which has for some time now been the biggest global market for battery storage, we focus increasingly on these large-scale projects, many at utility-scale and front-of-the-meter, and many of them pairing batteries with renewables — more typically solar PV than wind or other generation types. Nowhere is this more true than in California, where many of those largest projects in the world, both standalone energy storage and solar-plus-storage, are located.

But it’s important to remember that the smaller projects are not necessarily lesser projects: often they can provide targeted value to behind-the-meter customers where their economic value can immediately be quantified, not to mention the value of resilience they offer. Here are three interesting new behind-the-meter California projects using solar and storage storage we’ve learned about in the past few days that combine technologies and applications to maximise the benefits of battery storage and solar.

Ameresco helps army training centre to meet net zero objective by 2022

Energy efficiency and renewable energy solutions provider Ameresco is no stranger to equipping various US government facilities with clean energy technology upgrades.

In February the company announced a microgrid project for Norfolk Naval Shipyard in Portsmouth, Virginia, that is guaranteed to save the facility money on its energy bills through the use of 3.5MW of battery storage in a microgrid that also has a sizeable combined heat and power (CHP) plant.

Yesterday, Ameresco told that it has broken ground on another project for the nation’s defence forces, an electrical distribution microgrid at Fort Hunter Liggett, a US Army Reserve training centre in California’s Monterey County.

The training centre is targeting a rapid switchover to net zero energy use by 2022 and Ameresco has been contracted to install 3.75MW of solar PV, along with 5MWh of battery storage and a microgrid control system. The other major demand of the site is that it has to be resilient in its power supply to meet US Army Directives for Critical Mission Resiliency, in other words any failure to maintain reliable and quality power onsite is not acceptable.

The autonomous microgrid can be islanded from the main grid network in the event of an emergency or outage and the US$21.6 million project will included the installation of medium voltage switches that are automated to allow facility managers to control energy intake at any of Fort Hunter Liggett’s buildings. The project builds on efficiency upgrade work that has taken place over the past decade at the site on its heating systems with the installation of ground source heat pumps and other equipment.

Doing projects for the military and other federal agencies in the US is demanding work in terms of the must-run metrics and mission critical nature of the work, while projects tend to have to prove they will enable energy cost savings. However success can be a big step towards proving the effectiveness and value of clean energy solutions, Nicole Bulgarino, executive VP of federal solutions at Ameresco told in a feature interview on the topic earlier this year.

ENGIE North America saves non-profit group US$65 million with solar, storage and EV chargers

ENGIE North America began construction last week on solar, energy storage and EV charging solutions at seven sites around California for the State Compensation Insurance Fund (State Fund).

State Fund is a non-profit group that provides compensation insurance for workers. The group will be able to offset greenhouse gas emissions (GHGs) and energy costs using the 9.8MW of solar, 2MW / 4.3MWh of battery storage and 150 Level II and DC charge stations that ENGIE affiliate ENGIE Services US and professional services firm JLL will install.

The sites’ charging stations in Vacaville, Pleasanton, Redding, Fresno, Bakersfield, Sacramento and Riverside will be available for use by State Fund’s employees and its fleet vehicles, while the 311GWh of solar generation will go towards saving the group nearly US$65 million in energy costs over the 20-year lifetime of the project, ENGIE said.

“In addition to supporting State Fund’s greater environmental strategy, the construction helps the California economy during this critical time for recovery after the pandemic,” ENGIE North America’s general manager and VP for cities and communities, Courtney Jenkins, said.

ENGIE also began construction on a programme with the City of Milpitas in California which will help the city save energy and water by upgrading infrastructure and implementing energy and water conservation measures.

In addition to retrofitting street lights with LEDs, deploying 15,600 advanced water meters with leak detection, automation of various aspects of the city’s water infrastructure, deploying EV chargers and other smart equipment, ENGIE will install 200kW of solar and install an energy storage and microgrid solution which will enable backup power capabilities at the local senior centre and community centre.

“The goal of the City’s energy and water savings program is to upgrade critical infrastructure with an eye on three major pillars: economic benefits, environmental benefits, and human benefits,” City of Milpitas Mayor Rich Tran said.

“Through this programme, we will leverage guaranteed energy and water savings to pay for the programme and save the City money, while reducing our energy and water usage, improving community safety, and enhancing building comfort and usability.”

The project is expected to save the city over US$1.5 million in energy and water costs per year, adding up to more than US$30 million of net savings over its lifetime. ENGIE recently completed installation and commissioning of a 2.45MW / 4.9MWh battery storage system in New Hampshire for member-owned electric distribution cooperative New Hampshire Electric Cooperative (NHEC).

In related news, ENGIE announced in April that it will be selling its 60.5% ownership stake in Italy-headquartered stationary storage and e-mobility solutions company ENGIE EPS to Taiwan Cement Corporation (TCC), but will retain a commercial relationship with the ENGIE EPS, which will be rebranded as New HOrizons Ahead (NHOA) once approvals and regulatory consent have been granted for the transaction. 

Invinity wins latest California flow battery project at US Marine Corps Base

Another military facility in California is getting an emissions-free solar-plus-storage system, this time using battery storage technology from Anglo-American vanadium flow battery company Invinity Energy Systems.

Invinity will provide a 0.5MWh vanadium flow battery system to the project at an unnamed US Marine Corps base, working with developer Indian Energy. The deal is worth around US$450,000 of revenue to the flow battery provider and the equipment is expected to be delivered during the fourth quarter of this year. Invinity’s contract was negotiated with construction firm Webcor, which is also working with Native American owned Indian Energy on a project supported by the CEC which will combine and then assess the use of four different types of non-lithium technologies for long-durations of energy storage.

In the event of electricity outages, wildfires, or the public safety power shutoff (PSPS) events which California utilities have introduced in the past couple of years to prevent wildfires from spreading due to ageing electrical transmission infrastructure, the Invinity VS3 system, paired with solar PV, will provide energy security and resilience to the base.

The battery system can provide up to 10 hours of storage duration, using technology that decouples the power driven by the battery’s cell stack, from the energy stored in the system’s vanadium electrolyte tanks. As with the Ameresco project above, the system can operate either in grid-connected or islanded modes. It will also enable the site to peak shave — reducing energy costs by reducing the amount of power drawn from the grid at times of peak demand — and do time-of-use rate arbitrage which will further reduce costs.

It is actually one of four projects for which the flow battery company was awarded funding by the California Energy Commission in 2020. Totalling 7.8MWh of systems which will have an expected 20-30 year lifetime, Invinity announced the first sealed contract in November 2020, for a project which will add 10 hours of continuous backup power capability to a fire station in wildfire-hit San Jacinto, Southern California.

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