THE EDGE ithium-ion ( Li-ion ) batteries have developed significantly

Apart from the business and technical trade-offs that must be considered , decision-makers today must also address the issue of sustainability . Data centres are estimated to represent between 1 – 2 % of global electricity consumption and when combined with the continued growth of data centre capacity , efficiency and sustainability have become more critical than ever .

It is , therefore , important to evaluate the environmental costs to be incurred by a wider adoption of Li-ion batteries at the expense of traditional lead-acid systems .

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Raw materials

Any assessment of environmental impact must consider all parts of the product life cycle , from raw material extraction through to disposal and / or recycling of component parts at the end of life .

As a mature battery technology , lead-acid cells are supported by a long-established recycling ecosystem designed to minimise waste and repurpose components . Plastic parts are recycled into more battery plastic ; sulfuric acid is collected and resold as commodity acid ; lead is smelted and returned to batteries or applied to other uses . One study suggests that lead-acid batteries have a return for recycling rate of 99.3 %.

As a newer technology , Li-ion still relies mainly on mining extraction for raw materials as the necessary recycling practices are still being developed . However , when contrasting the two during the extraction process , there are three main areas to consider .

Firstly , the toxicity of lead is hazardous to human well-being and we have seen the elimination of lead in many aspects of our lives as safer alternatives become available . In contrast , Li-ion batteries contain less toxic material and are generally classified as non-hazardous .

Secondly , many of the questionable mining practices for Li-ion stem from the inclusion of the raw material cobalt which is often used in larger 3-phase UPS batteries . Cobalt is largely mined in the Democratic Republic of Congo and is not always regulated and practices of unethical mining take place . It is therefore essential that UPS vendors only source batteries from manufacturers who are signed up to the ‘ Responsible Minerals Initiative ’ which ensures that companies adhere to ethical practices .

Thirdly , weight is another major aspect to consider , namely the mass of material required and the significant differences between the energy density of Li-ion compared to VRLA equivalents . A Li-ion battery can often be as little as a quarter the weight of lead-acid . Even considering the relative infancy of its supply chainprocesses , the environmental impact of Li-ion batteries remains lower than VRLA .

Manufacturing and lifespan

The manufacturing process of VRLA batteries is also less complex than Li-ion and the conclusion is that the manufacture of a Li-ion battery has a greater environmental impact than a lead-acid alternative . The reality , however , is that this is a biased comparison and true sustainability requires that the full life cycle of both solutions be addressed to gain an accurate understanding .

One feature of Li-ion cells is that they are more sensitive to external factors such as voltage and temperature and as such , cannot withstand the same level of variation of charging / discharging parameters . Consequently , they incorporate battery management circuitry , which can complicate the manufacturing process and increase the carbon footprint .

Although the components of the system are more complex , Li-ion batteries have a far longer lifespan and therefore require servicing and replacement less often

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