Carbon capture, use and storage were presented as a provisional solution for increasing emissions. But the leakage of long -term disposal sites is a great technical risk, write David Dempsey and Andrew La Croix.
The government has recently announced a structure to regulate carbon capture, use and storage (CCUS) by New Zealand companies.
The Minister of Change of Energy and Climate, Simon Watts, described new rules that would allow the broadcasters to capture their carbon dioxide emissions (CO₂) and injected them into the underground for permanent disposal. They would avoid having to pay for these emissions under the emission negotiation scheme.
Globally, CCUs are currently used mainly by coal or gas plants, liquefied natural gas plants and oil refineries. There are 41 commercial operations around the world and capture about 40 million tons of CO₂ annually.
Our colleagues (Australia, the United States and the European Union) already have CCUS structures and storage projects. The Intergovernmental Panel on Climate Change recognizes CCUS’s role in reducing emissions, but highlights the challenges in the readiness of scale and technology.
New Zealand faces the challenge of reducing emissions from strategic industries such as steel, concrete, fossil fuels and their derivatives (methanol, ammonia). CCUS was presented as a provisional solution, strongly supported by the fossil fuel industry. However, critics warn that it can reduce incentives to eliminate fossil fuels.
The government argues that its structure CCUS aligns New Zealand with international standards. This claim has merit, as the successful climate action probably requires international collaboration and technology transfer.
CCUs in New Zealand could allow the reinjection of CO₂ produced from the Kapuni Gas Field in Taranaki, with “use” involving a little gas deviation for use in the food and beverages or horticulture industries.
However, the leakage of CO₂ of long -term disposal sites is a great technical risk and the structure of New Zealand should be clear about how it would deal with this responsibility.
Boehmer Lake and how things can go wrong
The rules for CCUS projects usually require operators to monitor, report and remedy any CO₂ leakage. But as the industry is young, it is useful to take a wider look of the geological leakage in the past to reveal how future challenges happen.
Lake Boehmer, in the west of the west of Texas, was not always there. But 20 years ago, an old irrigation began to leak salt water and has not stopped since then.
The well was drilled in 1951 by a oil and gas company. No oil was discovered, so the well was handed over to the landowner for irrigation. Well -produced water, but also the poisonous hydrogen sulfide, enough to kill a farm in 1953.
In the 1990s, the well began to leak. The water of a deep aquifer had risen beside the well through the geological layers of salt. The water dissolved the salt, worsening the leak and emerged from the underground three times more salty than seawater.
The Railway Commission, which regulates the oil and gas industry in Texas, says it is not responsible for connecting the well because they only have jurisdiction about oil wells. The original operator, who claims to have promised to connect the well “whenever he polluted with mineral water,” is no longer in the business. No one can find the landowner.
After 20 years, Lake Boehmer grew to 60 acres. Its coast is thrown into salt crystals and the strange dead bird of hydrogen sulfide exposure. No one can agree who should fix it.
Could something like to happen to CCUS? Exacerbating factors in the Boehmer case include deterioration of an aged well – almost 50 years since the leak began – and the absence of a backstop part as the final holder of responsibility. Both can happen to CCUS in the wrong circumstances.
Best ways to deal with leaks
The Decatur CCUS project in the US state of Illinois has a coa injection produced from corn ethanol two kilometers deep into sandstone. For about a decade, 4.5 million tons of CO₂ were injected – diverted emissions from the atmosphere.
The US government imposes strict monitoring rules on CCUS projects. Special monitoring wells are drilled in the disposal aquifer to measure pressure changes and to what extent CO₂ has traveled.
Unfortunately, one of these wells began to leak, possibly due to corrosion. It allowed about 8,000 tons of CO₂ to escape to overjard geological layers.
This is precisely worrying, but to put it in perspective, the size of the leakage is 0.2% of the volume of injected CO₂ and none of this escaped to the atmosphere or shallow groundwater. The leak was detected, the US Environmental Protection Agency (EPA) intervened, issuing a warning that the leak is remedied and the company connected the well.
This illustrates a CCU structure in operation. The monitoring requirements ensured that the leakage was discovered and the regulator was trained to dictate corrective actions.
However, critics questioned the punctuality of the operator’s dissemination. The site remains on hold, but can resume operations if the EPA is satisfied with the correction.
Lessons for New Zealand
A proposal released last year suggests that the government will model its legislation in Australia and the EU, with CCUS operators being responsible for leaks during disposal operations and a while after the venue closes.
It is like the situation of Decatur. It makes sense to operators to fix leaks because they have technical experience and are the direct financial beneficiaries of emission disposal.
It gets more complicated in generational deadlines. Companies can leave the business or leave the country. In such cases, the government is responsible for long -term leaks and may seek the operator’s financial security to cover future costs.
A leak that comes decades after closing may be harder to detect and expensive to correct, especially if kept by a prolonged struggle around responsibility. This is the example of the Boehmer Lake.
Some CCUS seem inevitable for the world to achieve climate goals. Therefore, it is important to prepare for the possibility of a leak, having robust practices and clear responsibility.
Although it may seem unfair to overload future generations by taking care of Co₂’s disposal sites, we argue that it is preferable to a legacy that has these same gases of weathering the climate in the atmosphere.
This article is republished from the conversation under a Creative Commons license. Read the original article.
