China: an $18 billion hydropower plant

Started in 2015, China’s Wudongde hydropower plant finally began operations in July this year. The $18.6 billion project — built near the provincial border of Yunnan and Sichuan on the Jinsha River in the southwest of the country — has 10.2 gigawatts of installed capacity and is a key component in China’s quest to reach net-zero by 2060. According to the constructors, the dam will offset the use of 12.2 million tons of coal and reduce CO2 emissions by 30.5 million tons per year.

The massive dam, topping out at 240 meters, has also been labeled one of the smartest in the world. The foundation was constructed with low-heat cement, where pipes in the concrete detect the temperature and adjust the flow of water automatically to cool the concrete and avoid cracking.

That's double the size of China's Three Gorges dam.

Of course, any mention of large-scale hydro projects must also include the famed Inga 3 Dam on the Congo River in the Democratic Republic of Congo — part of Africa’s largest electricity project. Although the Inga-3 project has a bumpy past with the World Bank withdrawing funding in 2016 after three years of delay and controversy, it was revived in 2018 following a $14 billion joint development between a consortium of Chinese and European companies.

In its final stage, Inga 3 would add another 11,050 megawatts to the two existing dams — completed in 1972 and 1982 with a combined installed capacity of nearly 1,800 megawatts. However, the Congolese government has proposed an expansion of six more dams that would bring total capacity to over 40,000 megawatts. To give an idea of the scope, that’s double the size of China's Three Gorges dam, currently the world's largest, and roughly one-third of the electricity currently produced in all of Africa.

UK: a wind farm providing power to 1.3 million homes

Danish company Ørsted has been developing Hornsea Project Two in the UK since August 2015. It’s intended to be part of the wider Hornsea Zone, located approximately 89km off the coast of East Riding, Yorkshire, and will be adjacent to Hornsea One, the world's largest offshore wind farm.

Expected to be completed in 2022, the $7.8bn project features 165 turbines installed in water depths between 30 and 40 meters, with tip heights of 204 meters and a total installed capacity of 1,386 megawatts.

The farm will connect to the grid at the North Killingholme National Grid transmission station in North Lincolnshire with onshore cable construction having begun in 2019. Once operational, Hornsea Two will span an offshore area of 462km² and provide power to more than 1.3 million homes.

Ghana: a huge tidal energy farm

Ghana intends to harness tidal energy to generate 100 megawatts of power as part of the broader goal to provide electricity to one million households in the future. The project, located on the Ada Estuary, had been stalled for many years before it was revived in 2020 when a Swedish-American-Chinese consortium of companies agreed to finance what will become one of the world’s largest tidal energy farms.

Working with TC Energy’s Ghanian counterpart, the three companies will continue beyond the test phase which was concluded in 2015 as a 1-megawatt pilot project that successfully fed power into the national grid. The park will use a series of buoys connected to linear generators as wave energy converters. Power is generated by the motion of the buoys while switchgear makes the electricity suitable for grid use.

The U.S.: a $22 billion wind farm

In a bid to rid Texas of its oil dependence, the Mariah Wind Farm project, a $22bn onshore wind farm, is currently being built across the Parmer, Sherman and Dallam counties. With construction commenced in 2013, the first 600MW of the project has been completed and sold.

The project turbine locations have some of the best US onshore wind resources at a height of 137 meters. While still under construction, the completion of the project will make it one of the largest wind farms in the country, totaling 10,000 megawatts of power. The completed form will also tie into the proposed Tres Amigas SuperStation — a planned project to unite North America’s two major power grids and one of its three minor grids.

India: the largest solar farm in the world

In India, the government has proposed a 10,000-megawatt solar farm along with 5,000-megawatt battery storage — the biggest project in the world. With the high-altitude Himalayan regions thought ideal for solar power generation, the planned project — comprising three individual phases spread over the Leh and Kargil districts of Jammu and Kashmir — will connect to a transmission network extended 850 kilometers to Punjab. During the day, part of the solar power will be used to charge the batteries, which will feed the northern grid during evening peak hours.

However, according to theEconomic Times the mammoth project has stumbled many times since the first tender was issued in December 2018. Being the first multi-gigawatt tender in the subcontinent, development has faced a series of policy issues ranging from environmental issues as well as industry turmoil over policy matters. The latest hurdle appeared earlier this year as the project fell foul over the presence of a water body in the 20,000-acre land invented for the PV installations. Still, the farm remains set for commissioning in 2023 and will save 12,750 tons of carbon emissions per year.

Iceland: the world's largest carbon capture storage plant 

Icelandic carbon capture company Climeworks recently launched Orca, the world’s largest direct air capture and storage plant that permanently removes CO2 from the air.

With construction starting in May 2020, Orca now has the capacity to capture 4,000 tons of CO2 per year, according to Icelandic business weekly Viðskiptablaðið. Through a partnership with Carbfix, experts in rapid underground mineralization, the air-captured CO2 is mixed with water and pumped underground where it is trapped in stone through a natural process that takes less than two years.

The project is strategically located adjacent to one of Iceland's major geothermal power plants and runs fully on renewable energy. According to Climeworks, the plant will eventually expand to megaton removal capacity by the second part of this decade.