Lead-acid batteries

Lead-acid batteries are an older technology used mostly as car batteries (gasoline-powered cars, to start the engine). Could they help solve the energy storage problem?

Viability

#Need for lead	Maybe an issue
Toxicity	Probably an issue
#Suitable for electric vehicles?	Unknown
Charge/discharge losses	Inferior to other battery types
#Good enough for DIY projects?	Probably

Need for lead

Lead is usually considered an abundant (cheap) metal - but apparently, not abundant enough to really scale up lead-acid batteries for on-grid energy storage:

other_energy.tfc

3290.73 Mtoe/year

Global energy usage, total final consumption minus transport and industrial

Source: Key World Energy Statistics 2020 (IEA report)

Note: This is roughly the amount of on-grid energy consumption that we might need energy storage for. It consists of - for example - lighting, heating, appliances, and other energy used in homes and other buildings. We don't count industrial here, because we can assume (in principle) that most factories could operate during peak sunlight/wind, needing negligable energy storage.

storage_timescale

24 hours

How big the "buffer" of energy storage would have to be to be resiliant against weather fluctuations

The exact number could be up for debate. Join the discussion.

lead.reserves

90 million tonnes

Global lead reserves 2010-2021 - Statista

lead.resources

2 billion tonnes

USGS Mineral Commodity Summaries 2021

lead_acid.energy_by_mass

38 watt hours per kg

Specific energy of a lead-acid battery

Source: Lead-acid battery - Wikipedia

lead_acid.lead

60%

How much of a lead-acid battery is lead, by mass

Source: Lead-acid battery - Wikipedia

% lead.reserves (calculation loading) But lead resources are a lot higher than lead reserves, for some reason (yes there's a difference): % lead.resources (calculation loading) So from that perspective, lead is in fact abundant enough, but the environmental footprint of mining it might be quite high.^{[QUANTIFICATION needed]} And we still haven't counted the need for energy storage in electric vehicles.

Suitable for electric vehicles?

Lead-acid batteries are already used in gasoline-powered vehicles, but you'd need to stack a lot more of them to make a fully electric vehicle. This might not be safe.^{[RESEARCH needed]}

Good enough for DIY projects?

If you have some extra car batteries, may as well use them for a rooftop solar project. They probably won't store enough energy to power your whole home, but it's better than nothing. Beware of safety issues.^{[ELABORATION needed]}