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Is the Government playing Russian roulette with green energy storage?

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With the race for green energy ramping up, whether that be solar or wind, the need to store energy in rechargeable batteries for later use has both metaphorically and in some cases quite literally exploded in just a few short years, so how safe are they?

These industrial scale installations, usually comprising of many individual batteries are known as Battery Energy Storage Systems and commonly referred to using the acronym BESS. The batteries are used to meet electrical demand to reduce any imbalance between energy demand and energy generation. Clearly whether solar or wind, neither can be guaranteed and therefore to maximise the energy generated, BESS installations have become hugely important and offer significant commercial advantages.

However, concerns have been raised following a number of serious fires with Lithium-ion batteries at BESS installations, and whilst relatively rare, have seriously dented public perceptions.

It probably will not help much then when you learn that the outcome of a six year study by Denver-based consultancy Clean Energy Associates (CEA) found quality issues with key components that identify and suppress fire in more than a quarter of the 52 BESS systems they audited.

The CEA report states that “The past several years have shown that thermal runaway poses a significant risk to the energy storage industry.”

What is Thermal Runaway?

Thermal runaway is a chain reaction within a battery cell that can be very difficult to stop once it has started. It occurs when the temperature inside a battery reaches a point that causes a chemical reaction to occur inside the battery. This chemical reaction produces even more heat, which drives the temperature higher, causing further chemical reactions that create even more heat.

One of the most significant drawbacks of using batteries is that they’re required to operate in a relatively narrow temperature range. If thermal runaway does occur, at best the battery will be destroyed but there is also a significant risk of a fire breaking out and/or the release of toxic gases.

What happens if a fire starts?

Once a lithium-ion battery catches fire, you can’t really put it out.

Therefore, proper consideration and planning for fires and the worst-case scenario of a thermal runway event are absolutely critical.

Fighting such fires has increasingly shifted to a ‘let it burn’ approach with more focus on containment, making sure the fire does not spread to adjacent batteries.

Fires can last for days….

A blaze at an Australian Tesla Megapack battery facility undergoing testing in 2021 took four days, 30 fire engines and 150 firefighters to bring under control. Last September, another Tesla battery in Australia nicknamed “Big Bessie” suffered a similar fate.

A few years earlier in the US, a lithium-ion battery system exploded, hospitalising four firefighters. A more recent spate of battery fires in New York prompted the launch of a task force into their safety.

In 2019 the South Korean government ordered a string of extra safety measures after an investigation into 23 fires at battery energy storage systems, most linked to wind and solar plants.

Conservative MP for Basingstoke Dame Maria Miller told the Commons last year that the “potential fire risks” of lithium battery energy storage systems (BESS) were now “widely acknowledged”.

She said “The only way to stop a battery fire is to cool it down with a constant stream of water and wait for the fire to go out, which might take days, creating huge quantities of water containing highly corrosive hydrofluoric acid and copper oxide—by-products of battery fires. These toxic chemicals cannot be allowed to seep into watercourses, because they would cause immense environmental damage.” 

Hampshire's chief fire officer, Neil Odin, who was concerned about a potential fire breaking out at a BESS facility located at Basing Fenn said his crews would face an “impossible choice” between protecting the community from a potential toxic or explosive gas plume or applying water that would pollute local waterways for years.

Fires and explosions might not happen that often, but they do happen.

US non-profit Electric Power Research Institute (EPRI), which began collecting data after dozens of safety incidents in South Korea and the US in 2018 and 2019, maintain that while fires do occur and receive a lot of media attention the rate of these incidents is decreasing.

Looking at their data below, you might be forgiven for thinking that last statement does not hold much water, however there are significantly more BESS installations coming online as each year passes, so perhaps it might be more appropriate to suggest that the number of major incidents is stabilising.

However, their data also shows that fires are more likely to occur in newer installations and that the risk of fires appears to diminish over time. Although it is worth noting that there are not that many years of data on which to base these assumptions, so that may be a bit premature.

Planning for the worst

Given that fires are going to happen, you would think this would be a very tightly regulated industry, however in the UK there is a distinct lack of national guidance from government.

In fact, our government appears to have all but effectively abdicated responsibility for such matters placing the onus firmly on local authorities. Who, you won’t be surprised to learn, are not always best equipped to make sound judgements on such matters.

In the UK the National Fire Chiefs Council (NFCC) has produced guidance to promote consistency around fire service arrangements at BESS sites, however it is not a requirement for local fire services to rigidly adhere to this guidance.

Phil Clark, the emerging energy technologies lead at the National Fire Chiefs Council is on record saying  “the National Fire Chiefs Council are still learning about the potential impact of the exponential introduction of lithium batteries. Without an understanding of the risks and appropriate control measures required, we risk as a society creating the next legacy fire safety issue”

Conservative MP for Basingstoke Dame Maria Miller told the Commons last year that  “The evidence shows that the current regulations for lithium-ion battery storage facilities do not reflect the true risk”

Current regulations do not require battery storage planning applications to be referred to the Environment Agency, the Health and Safety Executive or, indeed, the fire service. Planning permission is being granted near nurseries, hospitals, houses, rivers and even industrial chemical manufacturing plants.

Battery Types

Lithium-ion batteries are by far the most commonly found type of battery in large-scale Battery Energy Storage Systems. Lithium-ion batteries encompass various chemistries, including lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, and lithium nickel manganese cobalt oxide, among others.

However, the two most commonly used in BESS installations are Lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NMC). The disadvantages of this battery technology include excessive cost, inflammability, intolerance to extreme temperatures, overcharge, and over-discharge.

Looking at the safety plan for the Cleve Hill Solar Farm in Graveney which was recently rejected by Swale Borough Council, I note that the applicant planned on using Lithium iron phosphate (LFP) on the basis that they are less likely to catch fire or explode than other types of lithium-ion batteries and indeed this does appear to be the general direction of travel for the industry as a whole.

However, according to Professor Sir David Melville acting on behalf of the Faversham Society in relation to the Cleve Hill Solar Farm, LFP batteries are more subject to explosion risk than NMC batteries and it would not be possible to mitigate against such an incident should it occur.

There are also risks from the emission of toxic gases including Hydrogen Cyanide, Hydrochloric Acid and Hydrofluoric Acid and these can be deadly.

A fire at The Victoria Big Battery 300MW/450MWh project in Moorabool, Australia in 2021 burned for over three days and created an area of toxicity covering some 30 km2 and reaching distances of up to 9 kilometres from the fire. Residents were warned to move indoors, close windows, vents and fireplace flues and bring their pets inside.

Emergency Water Supply

The National Fire Chiefs Council guidance states that

“As a minimum, it is recommended that hydrant supplies for boundary cooling purposes should be located close to BESS containers (but considering safe access in the event of a fire) and should be capable of delivering no less than 1,900 litres per minute for at least 2 hours. Fire and rescue services may wish to increase this requirement dependant on location and their ability to bring supplementary supplies to site in a timely fashion.”

Unfortunately, this guidance is being applied quite literally with a 2-hour water supply taken as the gold standard.

In light of the incidents that I have come across in researching this article, this would appear to be quite literally a drop in the ocean of what might be required if the worst were to happen and in my opinion is an extremely high risk strategy, because at some point it will happen somewhere and the local fire service will be incapable of properly dealing with the incident leading to further issues.

The minimum guidance provides a capacity of 228,000 litres in the event of an emergency.

However, according to Professor Sir David Melville an explosion at Moorabol, Victoria, Australia took 900,000 litres over 6 hours for a 4.25MWh fire while a 1MWh fire in Drogenbos, Belgium took 1,400,000 litres.

Understanding the scale and capacity of BESS installations

BESS installations are measured as a ratio of power and energy. The power in megawatts (MW) and the energy in megawatt-hours (MWh) with higher ratios symptomatic of situations where large amounts of energy is required to be discharged in a short period of time.

A battery with 1MW of power capacity and 6MWh of usable energy capacity will have a storage duration of six hours.

A megawatt hour (Mwh) is equal to 1,000 Kilowatt hours, enough to supply the average power requirement for around 2,000 homes for 1 hour.

As you might imagine, with any new technology both the scale and number of installations is expanding exponentially.

At the larger end of the spectrum, located in California are two of the world’s largest BESS installations. The Vistra Moss Landing Energy Storage Facility which is a 750MW/3,000 MWh installation and the 1,300MW/3,287MWh Edwards & Sanborn solar-plus-storage installation.

By comparison here in the UK around half of all BESS installations have a capacity between 50MW and 100MW with the remainder somewhere between 100MW and 200MW.

Currently the Pillswood BESS is the largest in operation in the UK providing a capacity of 98MW/198MWh, but this set to be overtaken by the Monk Fryston project in Yorkshire which will have a 320MW/640MWh. 

The proposed BESS installation at Cleve Hill, Graveney which was recently rejected by Swale Borough Council comes in at 150MW/300MWh, however the applicant has ambitions to expand this into a significant 350MW/1,4000MWh installation which would make this a very large BESS by current UK standards and indeed the government defines this as nationally significant infrastructure.

However, this might not be for long as there plans for a 600MW BESS at the Cottam Solar Project in Lincolnshire. Just one of four projects in the area that would consume a colossal 10,000 acres of farmland.

Currently there around 1,200 ground-mounted solar farms in the UK and a further 350 in the pipeline, however only around 160 or so also accommodate a BESS installation.

A staggering 43% of the 1,200 ground-mounted solar farms are located in the south east and south west of England.

Environmental Concerns

Besides the potential for serious environmental harm resulting from fires or explosions if not properly planned for i.e. the installation of appropriate drainage to deal with the attenuation and treatment of any contaminated water resulting from fires to prevent toxic chemicals from seeping into the watercourse, there are a few other pitfalls.

One issue that you might not be aware of is noise pollution.

Unlike some parts of the USA and Australia where BESS installations can be located in deserts or other remote locations, many developments in the UK and Europe are being built nearer to populations and in more population-dense regions where concerns about noise have rocketed.

BESS units primarily emit noise from their cooling systems, but balance of system (BOS components like inverters and transformers also produce noise emissions.

The UK is also subject to seasonal weather risks. During the summer months, higher temperatures could potentially overwhelm the cooling systems within batteries. Colder, winter months expose batteries to freezing, flooding, or excess moisture which could damage the batteries. Heavy rain can make sites site susceptible to flooding. Strong winds, hailstones, storms and the proximity of trees could affect transmission lines or nearby infrastructure.

Land Usage

The loss of agricultural land to solar and wind is very contentious.

The amount of land covered by a solar farm can vary significantly depending on the site and the associated infrastructure, especially if it also includes a battery energy storage system.

The government estimates that a typical solar farm requires between two and four acres of land for each MW of output. It also estimates that a 50 MW solar farm consisting of around 100,000 to 150,000 panels will cover between 125 and 200 acres.

In fact there was a good example featured on Countryfile recently where a 10.9MW solar farm was located on 46 acres which equates to 4.2 acres per MW and this did not feature a BESS so the government estimate may be on the optimistic side. This apparently powered around 3,000 homes.

This appears to be in line with figures provided by GreenMatch who suggest that approximately 25 acres of land are required to power 1,500 homes.

For large scale projects, which the government has arbitrarily defined as those over 50MW capacity, the government advises that solar farms should be located on previously developed (brownfield) land and non-agricultural land which is not of “high environmental value”.

For small scale projects the government advises that solar farms, are not “appropriate” development for green belt land except in “very special circumstances”.

So where do we go from here?

Solar is and will continue to be a key tool in achieving the government’s aim of reaching net aero by 2050. Clearly, we have to reduce our reliance on fossil fuels and increase the use of renewable and low-carbon energy sources, such as wind and solar power, but not at any cost.

I can relate to the concept of good and bad solar as mentioned several times in the recent BBC Countryfile broadcast.

We need to think carefully and be far more imaginative about the location of such installations and not be simply resorting to the easy option of selecting green field locations consuming vast amounts of agricultural land isn’t the answer.

There was another point raised in the Countryfile piece in terms of the return to agriculture at the end of the 40 year life cycle of the solar farm, yes they don’t last forever, and that was the question of land designation once a solar farm had planning permission.

I checked this out with Swale Borough Council and unfortunately the planning department were none committal saying "There isn’t one answer. The designation would depend on the specific details of the site."  

With regards to BESS installations the government needs to step up and properly regulate the industry, because at this point its not a case of if, but when a fire or explosion will occur. It’s a ticking timebomb with potentially devastating consequences for the environment.

Also, given that the government has classified the larger installations as “nationally significant infrastructure” where is the risk assessment identifying potential security threats.

Andy Hudson


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