{"id":66070,"date":"2022-10-27T10:50:22","date_gmt":"2022-10-27T00:20:22","guid":{"rendered":"https:\/\/www.solarquotes.com.au\/blog\/?p=66070"},"modified":"2023-01-23T16:21:56","modified_gmt":"2023-01-23T05:51:56","slug":"co2-solar-land-clearing","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/co2-solar-land-clearing\/","title":{"rendered":"I’ve Calculated CO2 Emissions From Solar Farm Land Clearing: It’s Bugger All."},"content":{"rendered":"

\"Australian<\/p>\r\n

The best place for solar panels is on your roof. Despite this, over one-third of our solar electricity comes from large-scale solar farms. Their construction can involve land clearing that releases carbon dioxide into the atmosphere. \u00a0<\/p>\r\n

These emissions aren’t good, but they are trivial next to those from fossil fuel generation.<\/p>\r\n

This is because:<\/p>\r\n

    \r\n
  1. Burning Australian coal releases roughly 1,000 times more carbon dioxide per kilowatt-hour generated.<\/li>\r\n
  2. Coal mining results in vast amounts of land clearing. Even before the coal is burned, this may result in more emissions per kilowatt-hour generated than solar farms.<\/li>\r\n
  3. When the land beneath the solar farm returns to its original use, regrowth will absorb carbon dioxide from the atmosphere roughly equal to what was originally released by land clearing. \u00a0<\/li>\r\n<\/ol>\r\n

    Unlike coal mines, solar farms and agriculture can be combined. Under the right conditions, solar farms can increase the amount of vegetation land can support. But even in an — imaginary — worst-case situation where some lunatic bulldozed an old-growth forest to build a solar farm and no regrowth allowed, coal power will still emit over 300 times more\u00a0 CO2 per kilowatt-hour generated.<\/p>\r\n

    If you want to check my figures for this worst-case scenario, you can find them below. But first, I’ll make you read about how much land coal mining requires and how solar farming and real farming can go together.<\/p>\r\n

    Solar Farms — Big But Not That<\/em> Big<\/h2>\r\n

    Last financial year, solar energy provided 14% of Australia’s on-grid electricity. As most of our solar power capacity is on roofs, the approximately 11 GW of solar farms only produced about 5% of generation.<\/p>\r\n

    If we installed modern, 20% efficient, solar panels<\/a> flat on the ground without gaps between them, 11 gigawatts would take up 57 square km. In practice, most solar farms have rows of solar panels with space between them to prevent shading. Land is also used for other purposes such as inverters and vehicle access. In total, Australia’s solar farm capacity would cover around 100 square km. This figure may not be spot on, but it’s nice and round, so I’m running with it.<\/p>\r\n

    Update 23rd of February 2023:\u00a0<\/strong><\/em>It has kindly been pointed out to me in the comments that 100 square km is too small an area for Australia’s existing solar farms.\u00a0 Even if only the ground the solar panels cover was counted they would cover over 200 square km. Please imagine the black squares in the maps below as being at least twice as large.\u00a0 But solar farms being built today can potentially take up much less space per megawatt of capacity, with 5B<\/a> claiming they can get up to 150MW per square km<\/a>.<\/em><\/p>\r\n

    If all of Australia’s 100 square km of solar farms were arranged in one large square just outside of Sydney, it would look something like this:<\/p>\r\n

    \"Land<\/p>\r\n

    While 100 square km is a lot of land, you can see it’s not that much in relation to a major city of 5.3 million.\u00a0<\/p>\r\n

    Here’s what it would look like at the national level:<\/p>\r\n

    \"Australian<\/p>\r\n

    I’ve put a black square representing 100 square km of solar farms right under the letters “NT”. A nice, sunny, location for it. Since it’s hard to spot, I’ve also included a large red arrow. As you can see — or not see if your vision isn’t acute — Australia’s solar farms don’t take up a lot of land.<\/p>\r\n

    Even if Australia decided to generate its entire current grid electricity consumption from solar farms and increased the area they cover by a factor of 18, they’d still only cover this much of the country:<\/p>\r\n

    \"Amount<\/p>\r\n

    While they cover a lot of land, it’s still not that much in relation to the continent. Also, if it was all located in the middle of the Northern Territory, the black square would be smaller thanks to the location’s very high solar power output. If closely spaced solar panels were used, it could be about half that size.\u00a0<\/p>\r\n

    Even if national electricity consumption doubled, we would not devote that much space to solar farms. Not when we still have so many rooftops we can put it on. But there is a possibility we will end up building considerable solar farm capacity to meet overseas demand through intercontinental electricity connectors such as Sun Cable’s<\/a> Australia-Asia Power Link (AAPowerLink) project.\u00a0<\/p>\r\n

    Coal Clears More Land<\/h2>\r\n

    Solar farm land use is tiny in relation to how much has been cleared for coal extraction. For example, South Australia’s Leigh Creek coal mine — now closed — covers a total area of around 70 square km.<\/p>\r\n

    \"Leigh

    This image is from the South Australian Government’s page on Leigh Creek Mine remediation<\/a>. (I’m not going into coal mine remediation here, as that would require a hole article.)<\/p><\/div>\r\n

    Here’s what a black square representing the area of all Australia’s solar farms looks like next to it:<\/p>\r\n

    \"Land<\/p>\r\n

    In 2007, its highest output year, coal from this mine generated 5,188 gigawatt-hours of electricity. Last financial year, Australia’s solar farms generated approximately 12,200 gigawatt-hours. In a year of below-average sunshine, Australian solar farms produced over two-thirds more electricity per square km than the Leigh Creek mine in its best year.\u00a0<\/p>\r\n

    But solar power actually did better than that. Solar farm capacity is expanding rapidly and Australia had less at the start of last financial year than at its end. After accounting for that, solar farms produced approximately 84% more energy per square km than the Leigh Creek coal mine’s best year. This figure will increase as the efficiency of solar farms improves.<\/p>\r\n

    Not every coal mine is as spread out as Leigh Creek. But most of Australia’s production comes from open-cut mines rather than underground ones. I don’t have good figures for how much land is taken up by coal mining for domestic consumption. But, as most of our solar energy generation comes from rooftops, it seems almost certain to me that solar power requires less land clearing per kilowatt-hour generated than coal.\u00a0<\/p>\r\n

    Solar Farms Don’t Have To Remove Vegetation<\/h2>\r\n

    Solar farm construction often involves the removal or reduction of existing vegetation, but it doesn’t have to. Here’s an example from Germany of dual-use solar power and agriculture:<\/p>\r\n

    \"Agrivoltaics

    Image Credit: Fraunhofer Institute<\/p><\/div>\r\n

    The French decided that didn’t look weird enough and came up with this:<\/p>\r\n

    \"Agrovoltaics

    Image Credit: PV Magazine<\/p><\/div>\r\n

    Despite their efforts, as I pointed out years ago<\/a>, the best solution may be to vertically install bidirectional solar panels that use sunlight falling on either side:<\/p>\r\n

    \"Bidirectional

    Image Credit: Photon Magazine<\/p><\/div>\r\n

    This leaves the space between panels wide open for agriculture, whether grazing or cropping.\u00a0<\/p>\r\n

    In Australia, it’s usually not the amount of sunshine but water availability that limits vegetation growth. Ground-mounted solar panels can increase water availability by providing shade, cooling the ground, slowing wind speed, and allowing dew to drip from them. This can increase the total amount of vegetation that can be sustained. The fact less sunshine can help plants grow is familiar to many Australians who have struggled to mow thick grass in sheltered areas of the lawn that receives less sunshine.\u00a0<\/p>\r\n

    Numurkah Solar Farm: Solar Energy + Grazing<\/h2>\r\n

    It’s not just whacky Europeans who have combined solar power and agriculture. Here’s a video showing the Nurmurkah solar farm. It was built on grazing land and continued to be used for the same purpose after the solar farm was completed:<\/p>\r\n