By Ajit Niranjan
It's a question that preys on our readers' minds: Can we invent our way out of climate breakdown?
But experts say there is no silver bullet to protect the climate — and that keeping fossil fuels in the ground is the surest known way to prevent further warming.
Solar Panels and Wind Turbines<p>What may be the biggest innovation to combat climate change has been around for decades.</p><p><a href="http://www.ecowatch.com/tag/solar" target="_blank">Solar panels</a> and <a href="http://www.ecowatch.com/tag/wind" target="_blank">wind turbines</a> turn sun and wind into electricity without releasing greenhouse gases. As the technologies have scaled up and converted energy more efficiently, they have come down in price to become <a href="https://www.dw.com/en/green-growth-africa-chooses-between-renewables-and-fossil-fuels/a-51510277" target="_blank">cheaper than fossil fuels</a> globally.</p><p>"Solar and wind being cheap and reliable and performing well opens up a lot of possibilities," said Gregory Nemet, a professor at the University of Wisconsin-Madison who has written a book on how solar energy became cheap. "Even as we've had 30 years of politicians dithering and not as much progress as most people would have hoped, in the background, technology has been progressing."</p><p>But generating clean energy is one thing — storing and distributing it is another. This is particularly important for renewables that cannot generate electricity without the sun shining or wind blowing.</p><p>Three things suggest innovation is overcoming these hurdles, said Nemet. "That's renewables getting better, batteries allowing you to store electricity and then information in the system allowing you to manage it better."</p>
Batteries for Electric Vehicles<p>The Royal Swedish Academy of Sciences awarded three scientists a Nobel prize in October for their work in <a href="https://www.dw.com/en/nobel-prize-for-chemistry-awarded-for-the-development-of-lithium-ion-batteries/a-50737075" target="_blank">developing lithium-ion batteries</a>, which they say have "revolutionized our lives since they first entered the market in 1991" — and continue to advance.</p><p>Lighter and smaller than earlier rechargeable batteries, lithium batteries can also be charged faster and more often. As their weight and price continue to fall, they are playing an increasingly pivotal role in decarbonizing the transport sector by making <a href="http://www.ecowatch.com/tag/electric-vehicles" target="_blank">electric vehicles</a> cheaper.</p><p>"Battery storage will be critical," said Joao Gouveia, a senior fellow at Project Drawdown, a research organization that analyzes climate solutions. "It will allow the integration of more and more renewable tech. We cannot have 70 percent [of renewable energy by 2050] coming from wind and solar if we don't apply battery storage systems."</p><p>Holding batteries back are aging electricity grids and costs that, despite falling each year, remain high.</p><p>But electric vehicles could act as a storage system, said Gouveia, with owners buying electricity at night to charge their cars and selling it to the grid when demand is high and cars are parked, idle, during the day. "We are finding new lithium reserves because this is a tech for both markets, so we're innovating more and more."</p><p>While the global electric vehicle fleet has grown rapidly — passing 5 million cars in 2018, data from the International Energy Agency shows — this progress has been dwarfed by a rise in larger and less efficient SUVs that run on fossil fuels. Four in 10 new cars sold globally in 2018 were SUVs.</p>
Power-to-X<p>Another way to store renewable energy is using electrolyzers to extract hydrogen from water. The process, also known as power-to-X, is a way of storing energy in different forms. Engineers run an electric current through water and collect the hydrogen molecules that break off. These can be burned for heat, stored in fuel cells or turned into chemicals such as methane for processes that require fossil fuels.</p><p>"It's a great way to decarbonize the heating, mobility and chemical sector," said David Wortmann, a board member of Energy Watch Group, a German NGO. "It's scaleable — the tech is all there. The industry is young, you have manufacturers out there to produce an electrolyzer. But the demand is not there yet, the regulations are not in place."</p><p>Hydrogen could also help decarbonize a high-polluting sector that has mostly been overlooked: heavy industry.</p><p>The high heat needed to process industrial materials — such as concrete, iron, steel, and petrochemicals — is responsible for about 10 percent of global CO2 emissions, according to a report from the Center on Global Energy Policy in October. The cement industry alone is responsible for about 8 percent of CO2 emissions, mostly in production. This is more than three times the CO2 emissions of the aviation industry.</p><p>Burning hydrogen from renewable energy sources could meet industrial heating needs cleanly, said Jeff Rissmann, head of modeling at Energy Innovation, a research firm. "Moving to hydrogen can have a huge impact across many sectors, and would be one of the biggest ways to decarbonize the global economy."</p>
Carbon Capture and Storage<p>Even under optimistic scenarios for reducing greenhouse gas emissions, scientists say we will not meet targets to limit global warming to 1.5 degrees Celsius without removing some of the CO2 we have already emitted. The IPCC projects between 100 billion and 1 trillion tons of CO2 would need to be removed this century.</p><p>Trees and plants that extract CO2 from the atmosphere and turn it into oxygen through photosynthesis are one way of doing this. But they take up large tracts of land — which is needed for other purposes such as growing food — and are not a secure way of storing carbon, because they may be felled for firewood or burned in forest fires.</p><p>Some companies are experimenting with <a href="https://www.dw.com/en/carbon-capture-expensive-risky-and-indispensable/a-43172422" target="_blank">capturing CO2</a> from power plants and storing it deep underground. By doing this with biomass plants — where recently-grown plant matter is burned and not ancient fossils — then power can be produced while reducing the amount of CO2 in the atmosphere.</p><p>But with just 19 facilities running such systems, its deployment is not happening quickly enough to meet emissions reductions targets, according to a report from the Global Carbon Capture and Storage Institute.</p>
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By Tim Radford
Geologists have resolved one great problem about the capture of carbon dioxide from coal-fired or gas-fired power stations and its sequestration deep in the Earth, with what appears to be the prospect of rock-solid carbon storage.
Once there in the right rock formations, there's no reason why it should escape. That is, it won't react with groundwater, corrode the rocks around it and dissolve its way back to the surface in 10,000 years—or even 100,000 years.
Can carbon dioxide be safely stored deep underground for tens of thousands of years?
And scientists report in Nature Communications journal that they can say this with confidence because they have identified natural reservoirs of CO2 at least 100,000 years old, deep under the rocks near the town of Green River in Utah in the U.S. and they have drilled into the formation to check the water chemistry
The implication is that the rock that caps the reservoir can resist corrosion for at least 100,000 years. In the timetables of climate change, this is long enough to be considered safe.
Costly and Risky
The research resolves just one concern about the challenge of carbon capture and storage. An experiment in Iceland confirmed that it could work in the short term, but the latest study suggests it could go on working in the long term.
The bigger problem is whether it can be made to work at all. Independent studies have decided that the technology is both costly and risky and in any case the response by the energy industry suggests that the approach is not being prosecuted with any enthusiasm.
But since carbon dioxide emissions from the cities and power station chimneys of the planet are driving global warming, sea level rise and potentially catastrophic climate change, humans must either drastically reduce fossil fuel use or find ways of capturing carbon dioxide emissions from fossil fuel combustion.
And since international action so far—despite firm promises and declared intentions—looks like falling short of the reductions required, scientists keep checking the other possible options.
"Carbon capture and storage [CCS] is seen as essential technology if the UK is to meet its climate change targets," said Mike Bickle, director of the Cambridge Centre for Carbon Capture and Storage at the University of Cambridge, who led the study.
"A major obstacle to the implementation of CCS is the uncertainty over the long-term fate of the CO2, which impacts on regulation, insurance and who assumes the responsibility for maintaining CO2 storage sites. Our study demonstrates that geological carbon storage can be safe and predictable over many hundreds of thousands of years," Bickle added.
Carbon dioxide would have to be injected into rocks in liquid form, to replace the natural brines already in the rock pores and crevices. This raises the specter of a carbon dioxide and water reaction, with potentially corrosive chemistry and some computer simulations suggested that this could happen.
A cold water geyser from an unplugged oil exploration well drilled in 1936 into a CO2 reservoir in Utah, U.S. Mike Bickle / Cambridge Centre for CCS
So, with the support of Shell, the petroleum company and money from Britain's Natural Environment Research Council and the UK government, the Cambridge scientists took a close look at the evidence deep under the sedimentary rocks of Utah.
Instead of the predicted layer of corrosion many meters deep, they found a band of rotten or decayed stone measuring seven centimeters. The researchers looked at the mineralogy and the geochemistry and they even bombarded samples of the rock with neutrons to try to understand the chemical changes to the stone.
They also turned to computer simulations to see how long it took the geological structure to form and to work out how long it must have trapped CO2. The answer was: at least 100,000 years.
The thinking is that although CO2 would be a dense liquid, it would still be less dense than any brine in the porous rocks, so it would rise, sit above the ground water and do little damage to the cap rock that contains it—literally, rock-solid carbon storage.
"With careful evaluation, burying carbon dioxide underground will prove very much safer than emitting it directly into the atmosphere," Professor Bickle said.
This article was reposted with permission from our media associate Climate News Network.