Tidal energy is still largely untapped as a source of energy for several reasons, notably that it requires a suitable site as well as huge investment. While some countries have tidal potential and interest in this resource, use of tidal energy is also constrained by other factors such as potential environmental impacts and technical complexity.
Using underwater turbines, tidal power harnesses the ebbing and surging movement of ocean tides to produce electricity. Tidal power offers several advantages – most notably tidal movement is regular and repeated every day, and therefore more predictable compared to other rather intermittent renewable resources such as solar and wind.
Yet, according to a 2016 report by the World Energy Council, the total installed tidal power plant capacity amounts to only about 0.5 gigawatts (GW), with another 1.7 GW under construction.
I was able to see an awesome tidal power plant first-hand during a recent visit to Sihwa tidal power plant in Ansan, Republic of Korea.
The tidal power plant was constructed in 2004-2011 and is operated by the Korea Water Resources Corporation (K-water). It is the world’s largest tidal power plant equipped with 10 25.4-megawatt (MW) turbines and eight floodgates with gross installation capacity of 254 MW. According to K-water, the plant reduces petroleum imports for the country’s electricity generation by 862,000 barrels annually, which cuts carbon dioxide emissions by 315,000 tons per year.
K-water is the government agency in the Republic of Korea for water resource development and public and industrial water supply. It runs more than 20 multipurpose dams that supply water, generate power, and control floods.
Aside from being a water resource manager, K-water is enlarging its mandate to include renewable energy other than hydro, and is now actively implementing floating solar photovoltaic (PV) plants in its reservoirs across the country. Also, the agency aims to create a cluster of renewable energy facilities in the Sihwa area by adding wind and solar PV capacity to complement the tidal power plant.
The Sihwa tidal power plant offers an exemplary development story. It is a landmark facility not only because of its capacity but also because of how it approached various environmental issues.
A 12-kilometer long Sihwa embankment was constructed in 1994 from reclaimed land, and a freshwater lake meant to supply water for irrigation was created behind the embarkment. However, the freshwater lake became severely polluted due to spilled sewage from a nearby industrial complex. The government created the tidal power plant to make the best use of the seawater that comes and goes with significant tide range difference.
The surrounding environment has significantly improved since the commissioning of the plant. The Sihwa area has now become home for birds, including protected species. Also, K-water has developed a public recreational area by creating a 75-meter high observatory and park around the plant. The success of these environmental initiatives is borne out by the fact that the Sihwa tidal power plant has had more than 1 million visitors since the observatory opened in 2014.
Since power plants are generally associated with degrading not only the environment but also the aesthetics of their surroundings, the Sihwa tidal power plant’s achievement is all the more amazing – it actually improved its immediate environment and made the area more accessible to the public.
Renewable energy sources such as tidal power are the key to heading off climate change and reducing its impacts, while meeting the energy needs of Asia and the Pacific. ADB can take inspiration from initiatives such as Sihwa as it strives to support its developing member countries in their quest for innovative pathways to low-carbon energy infrastructure that deliver on greenhouse gas emission reduction but care for the surrounding people and environment.