{"id":7225,"date":"2016-09-01T20:33:18","date_gmt":"2016-09-01T11:03:18","guid":{"rendered":"http:\/\/www.solarquotes.com.au\/blog\/?p=7225"},"modified":"2024-10-02T10:35:38","modified_gmt":"2024-10-02T01:05:38","slug":"does-battery-storage-help-or-hurt-the-environment","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/does-battery-storage-help-or-hurt-the-environment\/","title":{"rendered":"Does Battery Storage Help Or Hurt The Environment?"},"content":{"rendered":"
\"an

If you want to save the environment and have limited funds, then buying batteries should not be a priority.<\/p><\/div>\n

Millions of Australians have installed rooftop solar to help the environment and save money.<\/p>\n

Many are hoping home battery storage will soon let them do the same.<\/p>\n

The cost of home energy storage is falling rapidly and it may not be long before it pays for itself.\u00a0 But at its current price it will not save money, even under favourable circumstances, when used on-grid.\u00a0 Despite this, there have been hundreds, or possibly thousands, of people who have installed home battery systems because they want to help the environment.<\/p>\n

Have these\u00a0people \u00a0made a horrible mistake?<\/p>\n

In Australia, with one main exception, on-grid home energy storage does not reduce greenhouse gas emissions but instead contributes to them.\u00a0 While battery storage is likely to reduce emissions in the future, systems installed now are almost certain to only contribute to global warming over their entire lifespan.\u00a0 Early adopters would have helped rather than harm the environment if they had instead spent their money on installing larger solar systems<\/a> or on improving energy efficiency<\/a>.<\/p>\n

Manufacturing And Using Batteries Results In CO2 Emissions<\/h2>\n

Home battery storage contributes to increased emissions in two ways.\u00a0 Firstly, manufacturing batteries results in CO2 being released.\u00a0 And secondly, home storage results in clean solar energy being lost because no battery is 100% efficient at storing electricity.\u00a0 More electrical energy has to be put in than can be taken out.\u00a0 If that energy had been sent directly into the grid it would have decreased fossil fuel generation.<\/p>\n

Embodied Energy Of Batteries<\/h2>\n

The world is still heavily dependent on fossil fuels and almost everything you buy has a significant carbon footprint from CO2 emitted during its production and transportation.\u00a0 Batteries are no exception. Emissions from manufacturing will decline as the world uses more renewable energy and recycled material, but currently making batteries\u00a0 releases considerable CO2. This is often referred to as a\u00a0battery’s embodied energy.<\/p>\n

How much CO2 is released manufacturing a typical battery system is difficult to determine, as it depends on the type of battery, the materials used, how they were produced, how far they were transported, and how much recycled material was used.<\/p>\n

One very simple rule of thumb is that the average manufactured good, containing an average amount of recycled material, will have a carbon footprint of around 2.\u00a0 That is, for every kilogram of an item’s weight, 2 kilograms of CO2 were emitted producing it.\u00a0 This is only an approximation, but is surprisingly accurate for a wide range of manufactured goods.<\/p>\n

However, for one of the most common type of new batteries, lithium-ion, the carbon footprint may be much higher.\u00a0 One study<\/a> found the carbon footprint to be 173kg per kilowatt-hour<\/a> of storage.\u00a0 For the battery pack they looked at, 18kg of CO2 were emitted per kilogram of weight.<\/p>\n

That study was from 2013.\u00a0 Because battery technology is advancing so quickly I expect the carbon footprint of lithium-ion batteries to be considerably lower now.\u00a0 But because I don’t have any solid information, I will simply guess it has fallen by 13% to give a nice, round number: 150kg of CO2 per kilowatt-hour of lithium-ion battery storage. Although I suspect the decrease would actually be greater than this.<\/p>\n

Powerwall, LG Chem RESU, And ZCell Carbon Footprints<\/h2>\n

The most famous home battery system is the Tesla Powerwall<\/a> which weighs 100kg.\u00a0 The less well known, but well regarded, LG Chem Resu<\/a> weighs 60kg.\u00a0 They are both lithium-ion battery systems with 6.4 kilowatt-hours of storage.\u00a0 Because the LG Chem RESU weighs less, presumably less emissions were released in creating it, but for the sake of simplicity I will assume each kilowatt-hour of lithium-ion storage releases 150kg of CO2 for a total of 960kg each.<\/p>\n

A battery that uses a completely different chemistry is a zinc bromide flow battery.\u00a0 The Australian designed Redflow ZCell<\/a> is of this type.\u00a0 Its storage capacity is 10 kilowatt-hours and with its 50kg enclosure weighs 290kg.\u00a0 Because I have no information on the carbon footprint of these these sorts of batteries I will simply use the rule of thumb that emissions from manufacture equal 2kg of CO2 per kg of weight.\u00a0 Since around 100kg of the ZCell’s weight is distilled water which has a low carbon footprint, that means around 39kg of CO2 would be released for each kilowatt-hour of storage or 390kg in total.<\/p>\n

Just estimating the CO2 emissions per kilowatt-hour of battery systems isn’t very useful as the total amount of electricity they can store over their lifespans can very considerably.\u00a0 A better measurement would be CO2 emissions from manufacturing per stored kilowatt-hour over their lifetime.<\/p>\n

Fortunately, it is not difficult to determine how many kilowatt-hours a battery system is warrantied to store if it is cycled once per day, as most are likely to be. For the Tesla Powerwall, going by its old warranty<\/a>, it comes to 16,000 kilowatt-hours. For the LG Chem RESU it is 17,192 kilowatt-hours. And for the Redflow ZCell it is 30,000 kilowatt-hours.<\/p>\n

But that is only what they are warrantied for.\u00a0 Their actual total output should be better as they are unlikely to die as soon as their warranty is up.\u00a0 I would say a reasonable estimate for the average lifetime stored energy of these systems would be 120% of what they are warrantied for.\u00a0 I hope this estimate is low, but battery systems do degrade and can’t be expected to operate too far beyond what their manufacturers promise.<\/p>\n

So by taking the rough estimate of emissions resulting from their manufacture and dividing it by the estimate of their lifetime storage we get the following:<\/p>\n