海上风电场可以帮助从大气中捕获和长期储存二氧化碳

据海上工程师网报道，在美国马萨诸塞州和纽约州海岸，开发商正准备建造美国第一个政府批准规模的海上风力发电场——总共74个涡轮机，可为47万户家庭供电。美国 东海岸还有10多个其他海上风力发电项目正等待批准。  

美国政府的目标是到2030年前拥有30吉瓦的海上风电，足够为1000万户家庭供电。 

用风电等清洁能源取代化石燃料为基础的能源，对于阻止气候变化导致的日益恶化的影响至关重要。 但这种转变的速度还不足以阻止全球气候变暖。 人类活动向大气中排放了如此多的二氧化碳，我们也必须将二氧化碳从大气中去除，并将其永久封存起来。

海上风力发电场具有这种独特的优势，既能做到这两点，又能省钱。  

美国大西洋沿岸的可再生能源租赁区大多位于大西洋中部各州和马萨诸塞州附近。 纽约湾大约48万英亩的土地计划在今年2月拍卖，用于建造风力发电场。

作为海洋地球物理学专家，研究者一直在探索将风力涡轮机与直接从大气中捕获二氧化碳并将其储存在海底天然储层中的技术相结合的可能性。 这些技术结合起来，可以降低碳捕获的能源成本，最大限度地减少对陆上管道的需求以及减少对环境的影响。

从大气中直接捕获二氧化碳 

一些研究小组和科技初创公司正在测试直接从大气中捕捉二氧化碳的设备，这种设备可以直接从大气中吸收二氧化碳。 这项技术是可行的，但到目前为止，早期的项目都是代价昂贵且是能源密集性的项目。 

这个系统使用过滤器或液体溶液，从吹过的空气中捕获二氧化碳。 一旦过滤器满了，就需要电力和热量来释放二氧化碳，并重新启动捕获循环。

为了实现净负排放，电源必须是无碳的。

目前，世界上最大的主动直接空气捕获厂通过利用废热和可再生能源来实现这一目标。 然后，位于冰岛的这种工厂将捕获的二氧化碳泵入底层的玄武岩中，在那里，二氧化碳与玄武岩发生反应并钙化，变成固体矿物。

类似的过程也可以用海上风力涡轮机实现。  

如果直接空气捕获系统与海上风力涡轮机一起建造，它们将从过剩的风力发电中获得直接的清洁电力，并可以将捕获的二氧化碳直接泵送到海底下储存，从而减少对大规模管道系统的需求。

瑞士的Climeworks公司拥有15个空气直捕工厂，将二氧化碳从大气中去除。

研究人员目前正在研究这些系统在海上条件下是如何工作的。 空气直接捕获技术在陆地上的应用才刚刚开始，而且这项技术可能还需要进行改进，以适应恶劣的海上环境。 但现在就应该开始规划，这样风电项目就能充分利用碳储存地点，并在设计上实现平台、海底基础设施和电缆网络的共享。

合理利用过剩风电

从本质上讲，风电是间歇性的。 对风电的需求也各不相同。 当风能产生的电力超过需求时，风电产量就会减少，本可以使用的电力就会损失。

这些未使用的电力可以用来去除大气中的二氧化碳，并将其封存起来。

例如，美国纽约州的目标是到2035年前拥有9吉瓦的海上风力发电。 预计这9吉瓦发电能力每年将提供27.5太瓦时的电力。  

根据美国历史上的风缩减率，随着海上风力发电场的扩大，预计每年将有825兆瓦时的电力过剩。 假设空气直接捕获的效率继续提高并达到商业目标，这些过剩的电力每年可用于捕获和储存50万吨以上的二氧化碳。 

如果系统不利用剩余电力，那么这些剩余电力就会被浪费掉。 如果系统使用更多的风电，其碳捕获和储存潜力将会增加。

一些租借给海上风力发电场的大西洋中部地区也有在海底储存二氧化碳的潜力。 这种能力是以每平方公里排放数百万吨二氧化碳为单位来衡量的。 美国每年从能源中产生大约45亿吨二氧化碳。

政府间气候变化专门委员会预测，为了将全球气候变暖控制在与工业化前水平相比的1.5摄氏度(2.7华氏度)以内，在本世纪内必须从大气中去除1000至10000亿吨二氧化碳。

据研究人员估计，在美国东海岸计划进行的海上风力开发项目附近的海底地质构造具有储存超过5000亿吨二氧化碳的能力。 玄武岩有可能也存在于这一地区的一系列地下盆地中，这将增加更多的储存能力，并使二氧化碳与玄武岩反应，随着时间的推移而固化，尽管地质调查还没有测试这些沉积物。

同时计划捕获和储存可以节省时间和成本  

用空气直接捕获技术建造的新风电场可以向电网交付可再生电力，并为碳捕获和储存提供多余的电力，从而优化这一大规模投资，以获得直接气候效益。

但这需要在建设之前就做好规划。 同时启动风电和储存的海上地球物理调查、环境监测要求和审批流程，可以节省时间，避免冲突，改善环境管理工作。  

李峻 编译自 海上工程师网

原文如下：

Offshore Wind Farms Could Help Capture Carbon from Air and Store It Long-term

Off the Massachusetts and New York coasts, developers are preparing to build the United States’ first federally approvedutility-scale offshore wind farms – 74 turbines in all that could power 470,000 homes. More than a dozen other offshore wind projects are awaiting approval along the Eastern Seaboard.

By 2030, the Administration’s goal is to have 30 gigawatts of offshore wind energy flowing, enough to power more than 10 million homes.

Replacing fossil fuel-based energy with clean energy like wind power is essential to holding off the worsening effects of climate change. But that transition isn’t happening fast enough to stop global warming. Human activities have pumped so much carbon dioxide into the atmosphere that we will also have to remove carbon dioxide from the air and lock it away permanently.

Offshore wind farms are uniquely positioned to do both – and save money.

Most renewable energy lease areas off the Atlantic Coast are near the Mid-Atlantic states and Massachusetts. about 480,000 acres of the New York Bight is scheduled to be auctioned for wind farms in February 2022.  

As a marine geophysicist, I have been exploring the potential for pairing wind turbines with technology that captures carbon dioxide directly from the air and stores it in natural reservoirs under the ocean. Built together, these technologies could reduce the energy costs of carbon capture and minimize the need for onshore pipelines, reducing impacts on the environment.

Capturing CO2 from the air

Several research groups and tech startups are testing direct air capture devices that can pull carbon dioxide directly from the atmosphere. The technology works, but the early projects so far are expensive and energy intensive.

The systems use filters or liquid solutions that capture CO2 from air blown across them. once the filters are full, electricity and heat are needed to release the carbon dioxide and restart the capture cycle.

For the process to achieve net negative emissions, the energy source must be carbon-free.

The world’s largest active direct air capture plant operating today does this by using waste heat and renewable energy. The plant, in Iceland, then pumps its captured carbon dioxide into the underlying basalt rock, where the CO2 reacts with the basalt and calcifies, turning to solid mineral.

A similar process could be created with offshore wind turbines.

If direct air capture systems were built alongside offshore wind turbines, they would have an immediate source of clean energy from excess wind power and could pipe captured carbon dioxide directly to storage beneath the sea floor below, reducing the need for extensive pipeline systems.

Climeworks, a Swiss company, has 15 direct air capture plants removing carbon dioxide from the air. Climeworks

Researchers are currently studying how these systems function under marine conditions. Direct air capture is only beginning to be deployed on land, and the technology likely would have to be modified for the harsh ocean environment. But planning should start now so wind power projects are positioned to take advantage of carbon storage sites and designed so the platforms, sub-sea infrastructure and cabled networks can be shared.

Using excess wind power when it isn’t needed

By nature, wind energy is intermittent. Demand for energy also varies. When the wind can produce more power than is needed, production is curtailed and electricity that could be used is lost.

That unused power could instead be used to remove carbon from the air and lock it away.

For example, New York State’s goal is to have 9 gigawatts of offshore wind power by 2035. Those 9 gigawatts would be expected to deliver 27.5 terawatt-hours of electricity per year.

based on historical wind curtailment rates in the U.S., a surplus of 825 megawatt-hours of electrical energy per year may be expected as offshore wind farms expand to meet this goal. Assuming direct air capture’s efficiency continues to improve and reaches commercial targets, this surplus energy could be used to capture and store upwards of 0.5 million tons of CO2 per year.

That’s if the system only used surplus energy that would have gone to waste. If it used more wind power, its carbon capture and storage potential would increase.

Several Mid-Atlantic areas being leased for offshore wind farms also have potential for carbon storage beneath the seafloor. The capacity is measured in millions of metric tons of CO2 per square kilometer. The U.S. produces about 4.5 billion metric tons of CO2 from energy per year. U.S. Department of Energy and Battelle

The Intergovernmental Panel on Climate Change has projected that 100 to 1,000 gigatons of carbon dioxide will have to be removed from the atmosphere over the century to keep global warming under 1.5 degrees Celsius (2.7 Fahrenheit) compared to pre-industrial levels.

Researchers have estimated that sub-seafloor geological formations adjacent to the offshore wind developments planned on the U.S. East Coast have the capacity to store more than 500 gigatons of CO2. Basalt rocks are likely to exist in a string of buried basins across this area too, adding even more storage capacity and enabling CO2 to react with the basalt and solidify over time, though geotechnical surveys have not yet tested these deposits.

Planning both at once saves time and cost

New wind farms built with direct air capture could deliver renewable power to the grid and provide surplus power for carbon capture and storage, optimizing this massive investment for a direct climate benefit.

But it will require planning that starts well in advance of construction. Launching the marine geophysical surveys, environmental monitoring requirements and approval processes for both wind power and storage together can save time, avoid conflicts and improve environmental stewardship.