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The Latest Generation Of Stackable Battery Power Stations Is Not Only Green But More Economical


Thanks to the modular design, which enables users to simply add more ‘energy blocks’ to increase each unit’s storage capacity and power output, the new portable power stations are scalable and more economical to operate than fuel-driven and battery-driven generators with pre-set capacities.

An increasingly “wired” world requires unprecedented amounts of reliable, uninterrupted electrical power to support the livelihoods, lifestyles, and the health and well-being of its 7.87 billion people.[i] In the U.S. alone, electricity use has increased 13-fold since 1950[ii], and consumption is expected to rise in the coming decades. Although the Digital Era electronics – computers, cell phones, medical devices, etc. – on which many of us rely have contributed to the rising consumption, the biggest users of electrical power predate the internet: air conditioners, water heaters, washers, dryers and lighting.

Thanks to our growing reliance on digital devices, however, even relatively short-term power outages can have a more significant impact than they did 30 years ago. And as climate change (caused by the burning of fossil fuels to generate much of our electricity) contributes to the frequency and severity of weather-related disasters, more Americans will soon experience power outages that last for days or weeks, not just a few hours.

To cope with these outages, many homeowners and businesses will turn to a device that 1.5 billion people[iii] in the developing world have long used to generate back-up power (or all their power): portable generators fueled by gasoline or diesel.

Fossil Fuel Portable Generators: Obvious (and Not-So-Obvious) Drawbacks

For decades, gasoline and diesel generators have been used for a variety of applications – from powering tools and equipment on construction sites to heating the grills and griddles of food trucks and tailgaters to electrifying the stages of outdoor music festivals. Worldwide, the combined commercial and residential market for portable generators (which encompasses products with a capacity of less than 5 kilowatts (kW), 5 to 10 kW and 10 to 20 kW) was $1.8 billion in 2021. Driven largely by concerns over power stability and potential business interruptions caused by natural disasters, the market is expected to grow to $2.5 billion by 2026.[iv]

The ubiquity of fossil-fuel portable generators is largely the result of two factors: (1) affordable purchase prices (quality 3 kW units are available for as little as $500, while 8 kW products can be purchased for $1,500, and 10 kW products for $2,000)[v]; and (2) the absence of economically attractive alternatives.

However, the purchase prices of these units can be deceptive, as they don’t include the costs of actually operating the units, which include fuel, regular maintenance and repairs. Moreover, every conventional fuel generator has a limited capacity. In other words, the amount of power that it can generate to start up and sustain electrical applications is limited to a pre-set maximum – e.g., 1 kW, 5 kW, etc. If the user’s power needs increase, they will have to purchase a replacement generator with a higher capacity and power output – or buy additional generators – to supply the extra power.

Last, but hardly least, fossil-fuel generators are noisy, dirty and potentially hazardous to both human and environmental health. In addition to emitting planet-warming carbon dioxide (CO2), generator exhaust fumes contain a cocktail of chemicals that include carbon monoxide (CO), particulate matter, ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2).

At certain levels, five minutes of carbon monoxide exposure can be fatal. Colorless and odorless, CO can quickly build to lethal levels, especially in enclosed spaces, and a typical generator produces as much CO as 450 cars. In the U.S., more than 900 people died of CO poisoning caused by portable generators from 2005 to 2017. During that same period, an estimated 15,400 people received emergency room treatment for CO poisoning related to portable generator use.[vi]

Barriers to Battery Power

As an alternative source of power, batteries have existed alongside fossil fuels for more than a century. However, before the introduction of lithium-ion batteries in 1991, and the subsequent decline in their production costs (a decline of 97% over the past 30 years[vii]), battery-driven portable power generators were not economically competitive with generators powered by gasoline or diesel fuel.

Although sealed lead acid batteries (SLA batteries), like those found in most automobiles, are less expensive than lithium-ion batteries, SLA batteries are a less-than-ideal technology for portable generators. Compared with lithium-ion batteries: SLA batteries weigh about nine times as much, have about 1/10th the usable capacity, and have relatively short useable lifespans.

By the end of their lifecycle (usually 3 to 5 years), SLA batteries effectively cannot hold a charge and must be replaced. By contrast, lithium-ion batteries can hold up to 80% of their capacity after 1,200 complete charge-discharge cycles, which would typically take 10 years. (Thus, there is potential for a viable secondary market in used lithium-ion batteries.)

A New, and Scalable, Alternative

Thanks to declining costs and recent advances in battery technology, a new generation of “clean and green” portable power stations from Joule Case is able to compete with fossil fuel generators, starting in the 1- to 5-kW market segment. Powered by stackable lithium-ion “energy blocks,” these scalable power stations generate silent, emissions-free electricity whenever and wherever they’re needed.

The biggest differentiator of Joule Case portable power stations from both fuel generators and competing battery-driven products is their modular design. For example, Joule Case’s new Sigma power platform is composed of modular “energy blocks” that can be stacked – one block atop another (like children’s building blocks) – to provide users with a number of benefits.

To start, the platform’s stackability allows users to quickly and easily scale the capacity and power output of every unit to suit their evolving power requirements. Because the Sigma system is equipped with a patented 120A, 48V pass-through DC power/data bus that enables the batteries and inverters to be stacked in any imaginable combination, a homeowner who initially purchases a portable power station with a 4-kW capacity to power a few household appliances during electrical outages could easily expand the station’s capacity to 5 kW, 8 kW or more by stacking additional energy blocks.

Stackability also allows consumers to more easily “dip their toes” into the portable generator market by purchasing more affordable, lower-capacity/output units and then “growing into” higher capacity/output products as their budgets permit.

Minus stackability, consumers have no choice but to purchase additional generators (or a single generator with more capacity) if their power needs increase. In such cases, users might find themselves paying hundreds or thousands of dollars extra for a higher-capacity generator, even though that capacity might rarely (if ever) be needed.

As an added benefit, Joule Case portable power stations don’t require installation or electrical expertise to operate. Instead, users can simply plug their appliances into the unit’s outlets.

Stackability = More Personal Freedom

Beyond their economic benefits, stackable/scalable portable power stations offer consumers a higher level of safety and freedom. Unlike fuel generators, stackable battery power stations give users the ability to recharge their units without having to transport and store flammable liquids. They also enable users to operate power stations in enclosed spaces without any noise and toxic emissions. And unlike competing battery-driven generators with pre-set capacities, Joule Case’s stackable/scalable products enable users to keep their units operating for significantly longer periods – even without access to a grid – through solar-energy capture and/or by keeping extra energy blocks on hand.

Thus, like a fuel generator, the user of a stackable power station can ensure uninterrupted electricity by simply adding more “fuel” (in the form of “green” energy blocks). But unlike either a fuel- or battery-driven generator with a pre-set capacity, the Joule Case power station can be easily scaled up to supply more energy when needed. The best of both worlds.

For manufacturers, benefits of standardized modular design include the ability to compete in a variety of different markets and to continually lower manufacturing costs through economies of scale. Although portable generators driven by lithium-ion batteries are currently more expensive than comparable fuel-driven models, by manufacturing energy blocks in higher volumes at lower prices, Joule Case expects to gain a competitive pricing advantage in the near future over companies making both fuel- and battery-driven portable generators.

A Range of Applications

Already, Joule Case’s stackable systems have proven well-suited to a range of applications – from powering a single weed whacker to replacing the noisy diesel-based systems that electrify the stages, vendors and infrastructure of outdoor music festivals. A study of U.K. summer musical festivals in 2011 found that the generators used roughly 2.6 million gallons of diesel fuel and pumped 3,300 tons of carbon dioxide into the atmosphere.[viii] By contrast, the quiet, battery power stations made by Joule Case produce zero emissions and can be recharged with renewable energy, including solar panels.

In 2021, large parts of Camp EDC, which hosts more than 25,000 attendees of the EDC Las Vegas music festival, were powered by Joule Case portable power stations. For four days, the power stations supplied electricity to concept tents, which contained lighting, air conditioning and other devices. Solar was used to charge power stations during the day while Joule Case battery power was used at night. More recently, Joule Case products powered 25 different application areas, including food trucks and multiple stages, at Treefort Music Fest in Boise, Idaho. Joule Case supplied green power for all of the decentralized locations, including the Box Office, the First Aid, Merchandise Sales and Information station, and Alefort – the festival’s craft beverage and food tasting experience.

And because its power stations can be safely operated indoors, Joule Case was able to supply electricity for the interactive kiosks at a major medical device manufacturer’s national sales training and partner conference. The venue lacked power outlets in the center of the ballroom, so three Joule Case portable power stations were employed to power the six kiosks. Each kiosk comprised a 46-inch LED monitor, tablet, laptop and accent lighting, and required 180 Watts for a daily operation of 10 hours.

Not so long ago, some of these applications would have been technically or economically impractical.

Powering the Transition to Electric Vehicles

Looking ahead, Joule Case is spearheading development of battery systems that could facilitate America’s transition from internal-combustion-engine vehicles to electric vehicles (EVs). Specifically, the company is focusing on how battery systems could help service stations lower the costs of installing and operating Level-3 charging stations for EVs.

Recharging the millions of EVs expected to roll onto U.S. roads and highways in the next few years presents a daunting challenge to America’s aging electrical grid, as well as the tens of thousands of fuel station owners who are willing to install EV charging stations, but lack the financial resources to do so. Though many service station owners are, no doubt, eager to embrace Level-3 chargers, which would keep vehicle owners on their premises (buying more food and beverages) far longer than it takes to “gas up” a conventional vehicle, the upfront investment required to add electrical capacity is substantial – beyond the reach of some operators.

Fortunately, a new patent granted to Joule Case may well provide fuel-station operators, electric fleet managers, and EV advocates with a more affordable alternative for EV charging.

Put simply, US Patent #20210111582A1 allows Joule Case to create and deploy energy storage systems encased in mobile, 20-foot shipping containers, each of which contains enough energy to power 100 homes for a day. These energy storage systems would enable fuel stations to become self-contained utilities, thanks to solar or other energy-generating sources, despite the massive power demands of Level 3 charging. This would provide a distinct competitive advantage for fuel station owners, as well as countless other users, as electrical grids reach capacity and electricity prices continue to rise.

For example, if a fuel station loaded the canopy over its fuel pumps with solar panels, this would likely cover the energy needs of the convenience store. Adding panels to the store itself could supply much (though probably not all) of the Level 3 charger demand. Energy storage would be needed regardless, and because Joule Case is now able to make storage more mobile, the company could supply numerous locations with the energy storage they need, when they need it, at a profitable rate. The bottom line: each fuel-station location could generate and store the bulk of the energy it needed to support all vehicles – no utility, no retail rates, more profit margin, plus a competitive edge over stations that continue to rely on power sources beyond their control.

At Joule Case, we also believe that stackable/scalable battery technology could play a pivotal role in harnessing clean energy production. If we truly want to move away from fossil fuels, we may also need to move away from being connected to a central power grid. Given how energy is distributed today, transmitting power across miles and miles of line, there will never be enough solar power to meet demand because it isn't (yet) an efficient way to produce energy. (At present, the vast majority of solar panels aren’t even connected to storage.[ix]) However, if we were to adopt a distributed model – one in which energy needs were fulfilled via the solar panels on homes and businesses and stored locally – we could reduce fossil-fuel burning far more quickly. 

Seamless Integration of New Battery Tech

Just as Joule Case’s stackable portable power stations enable customers to quickly scale their systems as their power needs change, the company itself is positioned to quickly adapt to, and adopt, emerging innovations in battery technology. Because Joule Case operates at the nexus where battery chemistry meets the electrical system – at the external terminals of the battery – the company’s battery management systems are designed to be agnostic to whatever chemistry powers those batteries in the future.

Because Joule Case systems rely on certain terminal characteristics that are flexible, and that generally fall within the realm of whatever battery technology is likely to emerge in the coming years, the company will be able to integrate that technology without having to “retool” its production processes. Just as Dell, Gateway and HP are able to seamlessly integrate the latest Intel processor into their systems, Joule Case will be able to seamlessly integrate the latest battery chemistry into its systems.

As a result, Joule Case can direct its focus to the continuous improvement of its battery management systems, and to enhancing the efficiency, and lowering the costs, of its scalable power stations, providing customers with clean and reliable power whenever and wherever they need it.


[i] World Population, 30 October 2021,

[ii] Bruna Alves, “Electricity consumption in the U.S. 1975-2020.”, July 6, 2021.

[iii] “The Dirty Footprint of the Broken Grid: The Impacts of Fossil-Fuel Backup Generators in Developing Countries.” International Finance Corporation, World Bank Group, September 2019.

[iv] “Portable Generator Market by Fuel (Gasoline, Diesel, Natural Gas, Others), Application (Emergency, Prime/Continuous), Power Rating (below 5 kW, 5–10 kW, 10–20 kW), End User (Residential, Commercial, Industrial), and Region - Global Forecast to 2026.”

[v] Wendy Paris, “Portable Generators: Backup Power at a Lower Cost.”

[vi] Rachel Treisman, “Carbon Monoxide Poisonings Spike After Big Storms. Portable Generators Are A Culprit.”, December 4, 2019.

[vii] David L. Chandler, “The reasons behind lithium-ion batteries’ rapid cost decline.” MIT News, November 22, 2021.

[viii] Josh Mandell, “Joule Case Brings Battery Power To The Festival Circuit.” Forbes, April 1, 2020.

[ix] Peter Maloney, “Growth of solar-plus-storage not fully explained by economics: Berkeley Lab report.” American Public Power Association, July 27, 2021.

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