Environmentalists rejoiced when
In a paper published
'If we think of any major technological change, they always have costs and unintended consequences,' Galelli said. 'The sooner we realize and address them, the more sustainable and equitable the energy transition will be. We have to do it right.'
Decarbonizing the grid by 2060 may be technically feasible, but would require building several dams for hydropower production (roughly 32 GW) and converting about 40,000 square kilometers of cropland to support growth in solar and wind, Galelli said. Most of the dams would be placed on transboundary rivers, meaning those shared by two or more countries, resulting in potential negative ecological impacts in both
'A fundamental problem is these dams will alter the river flow,' Galelli said. 'Changing the way water flows in the river has huge impacts on the riverine ecosystems and the communities that rely on them.'
Two major transboundary river basins that will be impacted are the Salween and Mekong, both major biodiversity hotspots, Galelli said. The Salween is shared by
As an example, he said,
Dams block the transport of sediments and nutrients from the upper reaches to the river mouth, and this reduces the productivity of ecosystems and fisheries. Blocking the transport of sediments also affects river deltas: If sediments do not reach the delta, saline intrusion becomes a bigger problem. Dams can also impact migratory fish species.
'The costs may outstrip the benefits,' he said. 'It would be important to account for these impacts when planning large-scale decarbonization efforts.'
Decarbonization would also lead to ecological and sociological trade-offs in terms of land use, he said.
'Excluding sites that are protected - cities and national parks, for instance - what you're left with is cropland on which to build solar and wind power,' Galelli said.
And with
And that space required for the construction of solar and wind plants may not be equitably divvied up: Their research shows that 43% of the total land requirements would likely be focused on the
Many new solar technologies are being developed, he said. Floating solar panels could cover some of the surface of lakes behind existing and planned dams (fully covering the surface of these lakes would impede their oxygenation). Solar on roofs is also viable, but in general represents a small amount of surface area and can be plagued by mechanical problems.
Galelli lists agrivoltaics, which combines solar with agricultural activities; carbon sequestration from gas and coal plants; more efficient batteries; and electricity demand management as other promising technologies.
'Our work is based on projection of need in 2060, but need is not set or known, and 36 years is a lot of time for technical innovation,' he said.
As we make strides toward decarbonizing, he said,
'Doing it in strategic ways is very important. We have to start with ones that are less impactful,' Galelli said. 'We can make decisions that balance decarbonization efforts with the protection of local communities, water and land resources.'
His co-authors are from
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