There's a global race to extract a largely untapped fuel source beneath the ocean floor – methane hydrate, nicknamed "flammable ice". And China is in the lead. In our special series Tides of Change, which is tracking China's maritime economy, our reporter Huang Fei spoke to a Shenzhen-based company that built a deep-sea drilling rig.

These flames are proof that the future of energy may be within our reach. The flare comes from methane hydrate: it's a natural gas locked in ice crystals at the bottom of the ocean. Last year China stunned the world with a second successful attempt at harnessing the precious resource in the South China Sea. The first attempt in 2017 lasted 60 days – that's an unbeaten world record, both in terms of the amount of fuel retrieved and how long the operation lasted. Deep-sea rig "Blue Whale One" did the job. The mega-project was built by a Shenzhen company better known for logistics.

FENG WEI Deputy Director China International Marine Containers Group Engineering Lab "Our platform was designed to operate in the North Sea, which has the roughest conditions in the world for offshore oil and gas production. So our specifications are among the best in the world. This enables us to continue operation in a typhoon, as long as the storm doesn't hit the platform head-on."

The semi-submersible rigs are the product of over a decade of innovation to conquer a field previously dominated by Japan. The resource-starved island was the first in the world to extract flammable ice from its seabed in 2013, but had to stop after six days due to a sand blockage in its well.

HUANG FEI Shenzhen, Guangdong "The stakes are high for deep-sea exploration. On the one hand, experts say gas hydrates are cleaner than other fossil fuels like oil and coal. If a country can produce methane from these deposits on a commercial scale, it could provide a vital transitional energy source as we shift towards renewable energies. And the cutting-edge technology required to access the ocean's depths will likely benefit other parts of the marine economy."

Some of this expertise has already been applied in deep-sea fisheries and floating wind farms.

FENG WEI Deputy Director China International Marine Containers Group Engineering Lab "The scale and complexity of the equipment required to access ocean resources are exceptionally high. For example, our offshore wind farms require GPS designs as well as repair and maintenance. These are all very long supply chains, which help the city of Shenzhen develop its marine economy."

Experts say China's efforts to develop its "blue economy" will help create a more sustainable future. Deep water aquaculture, for example, can ease the impact of over fishing and industrialization closer to our shores. And upgrading offshore oil rigs is an important step towards meeting climate change goals.

TAO SHU Presidential Chair Professor Chinese University of Hong Kong (Shenzhen) "So currently, in China, coal provides sixty percent of our energy. These days I think offshore drilling can provide much cheaper oil and natural gas and help China gradually upgrade its energy structure and reduce carbon emissions."

China aims for its emissions to peak over the next decade and then rapidly decrease to reach carbon neutrality by 2060. The oil and gas industry will have to play a big part and the hope is that having some of the world's best tools to hand will help them achieve this. Huang Fei, CGTN, Shenzhen.