अगस्त 15, 2012
Climate proofing hydropower
Changes in rainfall and water availability, protracted droughts, fluctuating temperatures, and more frequent and severe weather events, including floods, are already impacting the hydropower sector. As such, many countries are trying to better understand these changes and adjust their development plans accordingly.
Tajikistan is leading the way in Asia. The European Bank for Reconstruction and Development is providing concessionary financing to upgrade the Qairokkum dam in northern Tajikistan is bolster its resilience to climate change. Tajikistan relies on hydropower for 98% of its electricity from rivers fed by glaciers and snowmelt. In recent years, lower river levels in winter have reduced power outputs and led to significant power cuts. The Qairokkum plant is also being expanded to take advantage of higher peak flows from melting glaciers in summer months.
Outside Asia, Iceland’s Búrfell station was expanded by 100 MW with the expectation of increased glacial run-off as a result of a warming climate. Increased run-off has already been observed in Iceland, and is taken into account in the operation of the country’s existing hydro systems. Other countries are likely to follow suit.
More private players
Across the region, there is growing private sector involvement in dam development, backed with guarantees from large multilateral agencies such as the World Bank. Hydropower also attracted strong interest from the climate bonds market last year – representing 13% of the USD 41.8 billion of labelled “green bonds” issued worldwide in 2015.
Some major projects in 2015:
- The Dagacchu 126 MW run-of-river scheme in Bhutan began commercial operation, marking the first public–private partnership in infrastructure investment in the country. Tata Power, an Indian utility, owns 26% of the project, and has signed a power purchase agreement to import electricity generated at the site to India.
- For the first time, India approved preparatory work for a hydro project by a 100% foreign-owned company. The French REG-Velcan SA plans to develop three projects in the Brahmaputra basin of Arunachal Pradesh: Heo (240 MW), Tato-1 (186 MW) and Pauk (145 MW). This cascade of dams received final environmental clearance from the Indian government in December 2015, though NGOs have been crying foul over “shoddy” environmental impact assessments.
- Pakistan also broke ground on a number of private power projects in 2015, including the 720 MW Karot dam east of Islamabad on the Jhelum River, an Indus tributary; and the 102 MW Gulpur hydropower plant on a tributary of the Jhelum. The 147 MW Patrind hydropower project in Khyber PakhtunkhwaProvince, part of the Indus basin, is also being built by Star Hydro, a subsidiary of K-water, and is expected to start operating in 2017.
Pumped hydroelectric storage is becoming a major focus for the industry. This is the oldest kind of large-scale energy storage whereby water in a reservoir stores electricity like a massive rechargeable battery. At times of high demand, power is generated by releasing water through reservoir turbines. When demand is low, water is pumped back up to recharge the upper reservoir using lower-cost electricity from the grid.
The value of pumped storage is being recognised worldwide, accounting for over 97% of global energy storage capacity, and will continue to grow. China has more than 27 GW under construction but progress has been far slower than hoped (the target is 70 GW by 2020). Now China is rapidly developing pumped storage to complement growing nuclear, wind and solar generation – and in this way hydropower is seen by the Chinese government as the backbone of the future low carbon smart grid.
Pumped storage could also help ease energy shortages and facilitate the uptake of renewables in India, Nepal and Pakistan.
Innovative hydropower control systems
Hydropower and pumped storage are set to play an increasingly vital role balancing out fluctuations in the electricity grid – smoothing out between peaks and troughs of demand or when the wind drops and the weather becomes cloudy.
In 2015 China connected the world’s largest solar hydro hybrid station to the grid; the Longyangxia complex now consists of an 850 MW photovoltaic park, fully integrated with a 1,280 MW hydropower peaking station. An advanced control system allows the turbine to regulate the variable supply from the solar park before dispatching firm power to the grid.
This minimises the grid’s need for reserve capacity (or base load which is normally provided by coal plants). It also provides frequency control and voltage regulation, and maximises PV utilisation and conserves water.
Pumped storage can also prevent curtailment from other renewable energy sources. In China, nearly one-fifth of the country’s installed wind power output was curtailed in 2014. Electricity that could have been generated by wind farms was not accepted, due to excess power in the system.
Large-scale hydro often produces more power than is required to meet current national demand. Therefore, regional interconnections are essential to make projects financially viable. Many cross-border projects reached milestones in 2015, including: stations commissioned along the Turkey-Georgia border that utilise the recently completed Black Sea transmission line; the Dagachhu station in Bhutan, which will export power to India; further development of Laotian hydro resources for export to Thailand; and plans for a Northern Pass US–Canada interconnection to meet growing demand for clean energy in the US.
In China, the development of energy transmission infrastructure linking remote supply centres to coastal areas, where demand is concentrated, lags behind the rapid increase in generation capacity. Coupled with slow local demand growth, this has resulted in curtailment of both hydropower and wind. As a result, China is trying to upgrade its domestic grid infrastructure and connect the Chinese grid to Russia, Kazakhstan, Mongolia and Pakistan to export the extra power.
China continues to go global
China alone accounts for almost one-third of global hydropower capacity. Approximately 19.4 GW of new capacity was added there in 2015 – more than the rest of the world’s additions combined. In 2015, China produced over 1,126 TWh of hydroelectric energy, a 5% increase from 2014, while fossil fuel production dropped by almost 3%. Hydropower accounts for 20% of the country’s total power production.
China will continue to increase its hydropower capacity, aiming to achieve its ambitious targets of 350 GW of hydropower and 70 GW of pumped storage by 2020, and 510 GW of hydropower and 150 GW of pumped storage by 2050.
China is also continuing to promote regional hydropower development in Eurasia and Africa through the One Belt, One Road initiative. The Karot project (720 MW) in Pakistan is the first project to be financed by the Silk Road Fund. State Grid Corporation of China was also awarded the contract for Brazil’s longest transmission line (2,550 km), connecting the Belo Monte dam project to Rio de Janeiro.
And focus on transboundary rivers
According to the National Energy Agency of China’s 2016 work plan, hydropower development will focus on Tibet and the country’s southwest (Yunnan and Sichuan provinces) .
The key focus over the next year will be:
- TheBaihetan dam on the Jinsha River, a tributary of the Yangtze in Sichuan. This will be the world’s highest arch dam (at 277 metres) and the second largest hydroelectric power plant in the world after the Three Gorges Dam in terms of generating capacity (1,600 MW). Construction began in 2008 and is expected to be complete in 2021
- Developing hydropower on the Nu river (even though the provincial authorities have announced a ban on small hydropower, it seems the large projects are on track).
- Finishing the initial studies and plans for hydropower development in the lower reaches of the Brahmaputra
- The 2,800 MW Yebatan dam, also on the upper Jinsha, on the Sichuan-Tibet border
- The Kala dam on the Yalong, another tributary of the Yangtze.