Getting Specific About Effective Energy: The Truth About Comparing Batteries

Getting Specific About Effective Energy: The Truth About Comparing Batteries

Don't be mislead: apples-to-apples battery measurement

In the race for dominance in the energy storage market, battery manufacturers like to brag about a battery’s specific energy: how many watt-hours are delivered by each kilogram. But is it the right way to compare battery technologies? In short: no. It glosses over some critical real-world issues and results in misleading comparisons.

To use a very simple analogy, imagine you want to ship a gift to a friend. You have the choice between a selection of cheeses or a book. They both weigh the same and are about the same volume, and they should cost the same to ship, right? Wrong. While the weight and volume of the gift is the same, the effective weight and volume of the shipped package won’t be, and neither will the cost. One requires icepacks and a cooler to arrive fresh while the other can simply be put in a box. To make a meaningful comparison, you need to compare the whole package.

And it’s the same with battery systems. Comparing the innermost component of the system—a cell—does not result in an accurate comparison.

Cells make up modules which make up packs. And that’s not all; we must consider the whole battery system. For electric cars for example, the lithium-ion battery system also needs the Battery Management System (BMS), the active cooling system or Thermal Protection System (TPS), and protective armor. Each system adds weight, volume, and cost.

Why are these three measures important? The two most looked at numbers are specific energy in Wh/kg (watt-hours per kilogram) and energy cost in $/kWh (dollars per kilowatt-hour). The first tells you how much energy you can store for a given weight. The second tells you how much this energy costs you. In applications where space is limited, a third measure, energy density measured in Wh/l (watt-hours per liter) can also be essential. They are a way to compare battery chemistries and battery system designs.

Specific energy vs. effective specific energy

Typically, articles about batteries focus on the specific energy of just the cell, the innermost component of the battery system. The numbers can look good: after all, it is light without its supporting systems and relatively inexpensive. But what’s more revealing is the effective specific energy: how the whole system measures up.

It is fair for cell manufacturers to simply compare the cell, the smallest component in the battery, because they do not know how the cell will be used. But as soon as you know how a battery will be used, there’s other important information to consider. For example, the battery for an electric bike is small in capacity (Wh), does not need a sophisticated BMS, just uses air to cool it, and doesn’t need much armor to protect it.

Next time you hear an analyst predict an aggressive target price for lithium-ion batteries or an entrepreneur pitch a new battery chemistry, raise the discussion up to the whole system level.

However, a passenger electric vehicle, which weighs more than an e-bike, carries more people, and travels much faster and further. So it requires a much higher capacity battery pack, an active cooling system moving a cooling fluid through channels to cool the cells (since it gets hot moving and accelerating), a sophisticated BMS with computer, sensors, and cabling, and armor to protect the installation in case of a crash which could penetrate the pack and set the pack on fire. These three main subsystems add weight, volume, and cost.

For specific energy, increasing the weight (kg) decreases specific energy. For energy cost, increasing the dollars obviously makes it go up. And for energy density, increasing the volume lowers the energy density. In other words, while the cells still supply the same Watt hours, the battery system installed in an EV is effectively heavier, more expensive, and bulkier per unit of energy than the battery system installed in an e-bike.

When comparing different battery chemistries, the comparison should be at the system level. The discussion needs to be about the effective (or installed) specific energy, energy cost and energy density so it’s an apples-to-apples comparison.

One car, two ways to look at its battery

Let’s take a real-world example. The Chevy Bolt uses LG NMC cells with a specific energy of around 220 Wh/kg and a cell cost of $145/kWh. After all the pack level hardware and protective subsystems are accounted for the installed specific energy drops to 135Wh/kg and the installed cost rises to $225/kWh.

The numbers look even worse when the current recall of all Chevy Bolts due to fire risk is taken into account. Because every battery pack is being changed out, one could say the effective energy cost is really $370/kWh.

Changing the size and the chemistry of the battery pack can make a significant difference. For example, if the Bolt had a lower range vehicle for use in an urban setting, say 40kWh pack with a 200 mile range (after all, 95 percent of trips are under 30 miles), it could use a different type of lithium battery, lithium ferrous phosphate (LFP), or a nickel zinc (NiZn) battery. Both have a cell specific energy of 130Wh/kg and a cell cost of $100/kWh. And because they are both less prone to fires, they do not need a sophisticated BMS, no TPS and no armor.

This means that the installed specific energy would be 115 Wh/kg and a cost of $160/kWh. Why only 200 miles? That’s where energy density comes in: both of those chemistries have a lower energy density than lithium ion, so only a lower range battery pack will fit in the space in the Bolt and not change the weight significantly.

Looking beyond battery marketing

It’s popular to think that lithium-ion batteries have already won the race to dominate most energy storage markets, and much of the argument is centered on its competitive specific energy and cost. But with a true comparison of the effective or installed specific energy and cost, it’s clear that it’s not the natural winner for many use cases.

Next time you hear an analyst predict an aggressive target price for lithium-ion batteries or an entrepreneur pitch a new battery chemistry, raise the discussion up to the whole system level. How do the numbers look once you have accounted for the full system for the energy use case, whether it’s an e-bike, EV or grid storage? The first answer might not be the most relevant answer for the economics. Or for the environment which is the subject of another article.


Image: Photo by Waldemar Brandt on Unsplash 

India looks to locally-made batteries for an energy independent future

India looks to locally-made batteries for an energy independent future

An Interview with Michael Burz, President and CEO

The future of the planet depends on moving rapidly away from polluting fossil-fuel-based energy systems, and nowhere is that need for an energy independent future more apparent than in some of the fastest developing countries in the world. Nearly one in five people on the planet live in India or Bangladesh, and both countries have their sights set on decarbonizing their transportation systems and building a more resilient grid to serve their burgeoning populations. We asked Michael Burz, President and CEO of Enzinc, for his observations after returning from a ten-day whirlwind tour of New Delhi and Hyderabad, India, and Dhaka, Bangladesh. 


Michael Burz on stage at the International Zinc Association Global Summit 2023 in New Delhi

What took you to India?

We were asked to speak at the International Zinc Association’s fourth global zinc summit on the use of zinc for advanced batteries and decided to take advantage of the fact that we would be in India to meet with additional potential Industry Advisory Group (IAG) members. So, we combined the conference with a trip to talk to some of the largest lead acid battery companies in India and Bangladesh.

What surprised you most about the market and the companies you met there?

First, how large they are. As you know, India has about 1.4 billion people and it’s projected that, by the end of the year, it will have more people than China. Bangladesh itself is approaching two hundred million people. It’s one thing to talk about the aims and growth of a country, but it’s another to be there and see how rapidly they’re moving. To see how committed they are to the electrification of both mobility and stationary and storage was very inspiring. If you look at what they intend to do, they are a model for rapidly growing markets in the 21st century: rapid deployment of electrification for both mobility and stationary energy storage with a focus on safety, high performance, and recyclability.

What did you see in the mobility market there? Many of us have an image of Indian transportation including rickshaws, are you seeing those being electrified? Are you seeing other modes get deployed?

There’s an intent on the part of the Indian Government to electrify as much as possible. At the moment, the three-wheeled market is very large, but most of those come from China and are powered by internal combustion engines. The Indian government’s primary focus is to take the mobility arena—two-wheelers and three-wheelers, and urban four-wheelers or what one of our IAG members calls Last Mile Mobility (LMM)—and electrify all of them.

What about stationary storage? What are some of the differences that you see there versus the U.S. market?

It’s interesting: their version of residential energy storage is not the same as ours. In the United States, we tend to think of residential energy storage on the multi-kilowatt hour scale, say 15 kWh batteries to provide backup power for six to eight hours, overnight. In India and Bangladesh, what they’re interested in is essentially grid stability: batteries that can recharge quickly and be used for when the power drops out, with only two to four hours of discharge time. It is not just the way in which they want to use it, but how affordable it needs to be for people buying small backup battery systems for their apartment or house.

decarbonizing transportation systems and building a more resilient grid to serve burgeoning populations.

There have been a lot of news stories about fires caused by cheaper lithium-ion batteries, such as a tragic fire that engulfed a hotel above an e-scooter shop in Mumbai. Can you talk about the concerns you’re hearing about lithium in that market?

It’s obvious when you take a look at photographs of large-scale Indian and Bangladeshi cities that they’re very, very dense, so safety is absolutely critical. We heard that a number of times: for this highly dense urban environment, safety is absolutely paramount.

If you combine that, with wariness of the supply chain from China—whether it’s the materials to make lithium batteries or the offer to build the factories for them—the Indians and the Bangladeshis are very, very keen on domestic control. What they recognize is that if China controls, as they do, 60 to 80% of the battery materials, they’ll actually be building batteries domestically that will compete with batteries from their very suppliers: the Chinese manufacturers. They want to decouple that.

What they were looking for is something that they can build domestically under their own control, using their materials. And that offers them both safety and affordability. That’s why they were interested in Enzinc’s nickel zinc technology.

You spoke at the Global Zinc Summit in New Delhi. Do you think the global zinc industry understands the potential of zinc as a battery material?

Frankly, up until we presented at the conference, I don’t think that the potential for zinc to be used as a high-performance battery that is equivalent to Lithium Iron Phosphate (LFP) was even on people’s radar. In fact, Andrew Green, who is the Executive Director of the International Zinc Association shared a chart that was done by Bloomberg, which showed that zinc batteries could require almost one million tons of additional zinc by the year 2030. But all of that assumed that zinc was relegated to small-scale or niche markets around stationary energy storage. The fact that batteries with “Enzinc Inside” can offer an equivalent performance LFP opens up so many more applications that we estimate that it can quadruple that million tons of demand and add somewhere between $20 to $40 billion in additional value to the zinc industry.

Any closing thoughts?

What was encouraging was the national commitment in both India and Bangladesh to move aggressively to bring high-performance batteries that were safe, recyclable, and don’t rely on Chinese products or materials to their respective nations. We hear that they’re interested in additional technologies, but to see how fast they want to move—probably quicker than even the United States—was both encouraging and surprising.

Image: Photo by Akshay Nanavati Waldemar Brandt on Unsplash

Scaling Energy Storage Manufacturing is Essential for U.S. Energy Independence

Scaling Energy Storage Manufacturing is Essential for U.S. Energy Independence

Energy Independence Day, Part II

For the United States to get even close to energy independence it needs to invest not only in traditional energy infrastructure—especially the electric grid—but also in the new technologies to enable that infrastructure. And the most important piece of that more broadly-defined infrastructure is, arguably, energy storage.

Why? Even if the clean energy provisions that were pushed out of the infrastructure bill are revivified in a reconciliation bill, the United States cannot meet its clean energy goals without moving rapidly to electrify (almost) everything and doing that requires massively scaling energy storage.

Just as investment in the grid’s transmission is essential to move energy from where it is produced to where it is needed, investment in energy storage is essential to move energy from when it was produced to when it is needed.

This goes both for short-term energy storage—moving energy produced by wind mainly at night or by solar in the height of the day to the early evening peak—and long-term energy storage—moving summer’s excess solar production to the middle of the winter when days are shorter, and panels may be buried by snow. It also applies to energy needed for mobility: EVs, electric buses and urban electric vehicles and electric micro mobility are all part of electrifying everything.

Aiming for energy independence

Energy independence involves having some control over the materials in energy storage, as explored in our recent blog U.S. Energy Independence Depends on a Smart Supply Chain Strategy. But it also involves having some control over energy storage manufacturing.

Most people don’t think about infrastructure until it fails. When it’s headline news—a pipeline shut down by hackers leading to gasoline shortages, abnormally cold weather resulting in a massive grid failure, extreme fire danger prompting preemptive power shutdowns—infrastructure’s essential role is brought into the spotlight. However, the time to think about infrastructure is before you need it, because planning and building infrastructure takes time. The same is true of the means of production for infrastructure.

Just as investment in the grid’s transmission is essential to move energy from where it is produced to where it is needed, investment in energy storage is essential to move energy from when it was produced to when it is needed.

Like mining and refining energy storage materials, manufacturing energy storage is largely done in other countries. If the U.S. wants better control of the supply chain, that has to change.

Time is not on our side. It will take decades to create lithium battery infrastructure, both materials and manufacturing plants.

Innovation in energy storage manufacturing

The good news is there is a way to leapfrog the conventional path of mining lithium battery materials, setting up plants to refine the material and building new Gigafactories.

The U.S. can meet this urgent need with an innovative approach. We already have significant manufacturing capability and capacity when it comes to lead acid batteries. The U.S. can take advantage of that energy storage manufacturing by converting existing lead acid plants and NiMH/NiCad plants to make advanced zinc-based batteries. Taking those factories’ output capacity in terms of specific energy, this effectively doubles or triples their energy storage manufacturing capacity.

We need to think outside the lithium-ion box if we are to move towards energy independence. By taking advantage of our existing leadership in lead-acid manufacturing plants we can make them Gigafactories in two years instead of ten, catapulting the U.S. into advanced battery manufacturing far sooner and with a lower capital investment while retaining and expanding American jobs.

Image: Idaho National Laboratory’s Battery Test Center includes test chambers for batteries of all shapes and sizes. 

Diversifying energy storage is vital for the global industry’s health

Diversifying energy storage is vital for the global industry’s health

Extract of contributed article published in Energy Storage News

The battery industry is at risk of falling into the trap of becoming too dependent on a single ingredient, and failure to diversify and address the issue now will hinder the energy transition in the long run, writes Michael Burz, CEO, founder and president of Enzinc. 

A glance at any energy analyst’s predictions shows demand for batteries is strong and only getting stronger as the energy and transportation industries embrace decarbonisation. And while the industry may feel well established to those who have been working in it for the past decade, it’s still relatively early days when it comes to influencing the mix of batteries deployed.

The battery industry can derisk this coming wave of demand by ensuring that it meets the needs with a diversity of technologies.

Risk of battery chemistry concentration

The energy storage industry only needs to look as far as the solar industry to see why it’s unwise to tie a fast-growing industry to a single input or region. More than half of the key ingredient for solar panels, polysilicon, comes from one province of China.

Not only has it meant that the country producing it, China, is getting first dibs on the volume produced, but also it opened the rest of the industry to political risk as evidence of human rights abuses in China’s Xinjiang Province mount and supply chain risk as trade tensions wax and wane.

Even in established industries, lack of diversification harms markets. The recent disruption to global fossil fuel markets has reminded governments and consumers alike of the power wielded by OPEC members, which control 60% of all petroleum exports. It’s a lesson gasoline-powered car drivers have revisited many times since the 1970s oil shortages.

Today, lithium-based batteries dominate the emerging energy storage markets, from EVs to home energy storage, to utility-scale batteries.

While the industry’s nascent, it doesn’t seem problematic. However, as the industry matures, today’s concentration will seem shortsighted. Why? Because the rapidly rising demand for batteries means growth may be stymied by a lack of supply of lithium globally if we don’t diversify now.

U.S. Energy Independence Depends on a Smart Supply Chain Strategy

U.S. Energy Independence Depends on a Smart Supply Chain Strategy

Energy Independence Day, Part 1

For the renewable energy industry in the United States, the new administration brought with it hope: hope for a voice in the country’s energy policy, hope for incentives that support the growth of renewables, and hope that the federal government’s focus on clean energy infrastructure will bring states slow to encourage renewables into the fold.

But hope is not enough. Neither are policy, incentives, and a shared will. Meeting the President’s energy independence and climate change goals will take something a whole lot more basic. And without it, even a move to 100% clean energy won’t result in true independence.

Energy independence is not just about producing and storing energy, but also about having some modicum of control over the means to produce and store energy. The clean energy industry is learning this the hard way.

The oil and gas industry likes to claim it has made America energy independent by producing energy using on- and off-shore reserves and exploiting less-accessible reserves reached through fracking. It produces so much energy that the United States is now a net energy exporter, but what is the value of energy independence if it results in climate change? Carbon-based energy independence leaves America vulnerable to forces much larger and more chaotic than global markets. The United States will never be energy independent while we depend on dirty energy.

Challenges to energy independence

The solar industry may have limitless access to its input—sunshine—but it is far from independent when it comes to the means of production. The U.S. controls very little of the materials and manufacturing facilities that make the solar panels, inverters, and steel mounting or tracking hardware in a solar PV system.

With almost half of the global supply of the polysilicon that is used to make solar cells coming from one region of China, 45% comes from Xinjiang Province, and another 35% coming from other regions of China, the industry is vulnerable to supply limits. The issue is not just that China’s support of its solar industry has pushed down global prices and driven foreign competitors from the market, or that China’s rapid scaling of its solar industry is consuming much of the output, but—most concerningly—there is increasing evidence that China may have built its dominance using forced labor.  The United States has dipped its toes in the roiling political waters by banning imports from one supplier that is alleged to use forced labor, and the industry is scrambling to develop protocols to verify supply chain integrity.

The energy storage industry faces similar issues: little of the lithium and the cobalt used in lithium-ion batteries comes from the U.S. or even from friendly countries. Globally, the largest lithium reserves are in Bolivia, Argentina, Chile and Australia, though Australia leads production. While production is being ramped up quickly—so quickly that prices are taking a hit—the United States only produces lithium in one place: a brine  operation in Nevada. This is why energy storage innovation is critical.

The solar industry may have limitless access to its input—sunshine—but it is far from independent when it comes to the means of production. The U.S. controls very little of the materials and manufacturing facilities that make the solar panels, inverters, and steel mounting or tracking hardware in a solar PV system.

But Australia’s friendly and stable, so concerns about the lithium supply chain are not as great as concerns about cobalt’s supply chain. About 95,000 of the 140,000 metric tons of cobalt produced globally comes from the Democratic Republic of Congo, which also has more than half of the world’s known accessible deposits. When it comes to ethical supply chains, DRC is about as far from Australia as can be. It is not stable, its mines are alleged to have a range of human rights abuses, and on top of that, China has a near monopoly on refining DRC’s cobalt, again leaving the United States with little to no supply chain autonomy.

There is no quick fix here. It will take years for the U.S. to develop any significant sources of polysilicon, lithium and cobalt, and it may never get close to supplying its own needs. This means that the U.S. clean energy industry also needs to diversify not only where it gets its inputs from today but also what materials it needs.

But there are other ways to increase energy independence.

Materials-based energy storage innovation

Energy storage innovation—Enzinc’s reason for existing—means looking at alternative battery chemistries that leverage metals other than lithium, metals such as iron, lead, zinc and vanadium. The batteries being developed may not be suited for every application, for example, both iron and vanadium are used in bulky flow batteries which may work well in stationary applications such as deployment at a utility-scale solar plant but will never be used for electric vehicles.

Zinc stands alone in energy storage innovation. It occupies the ideal position in the Venn diagram of the dream battery: it’s mined in the U.S., it’s plentiful, it’s inexpensive, it’s not prone to thermal runaway, it’s fully recyclable, and it can be used to make energy-dense batteries. While not quite the same energy density as lithium-ion batteries, without the need for thermal management systems and protective casings, it’s a serious contender for all mobility applications like Urban Electric Vehicles, that is, anything except the longest-distance vehicles.

Ultimately, it’s unlikely that the U.S. will develop, or even want to develop, complete independence all the way back to materials extraction. However, today all of our clean energy eggs are in other countries’ baskets, leaving the industry at risk. We will be stronger the sooner we both support U.S. manufacturing and develop new clean energy technologies that have a supply chain that starts in our own backyard.