15 Hydro Power
Today the technical potential for hydropower development around the world is much greater than the actual production: the percent of potential hydropower capacity that has not been developed is 71% in Europe, 75% in North America, 79% in South America, 95% in Africa, 95% in the Middle East, and 82% in Asia-Pacific.
This is significant if you think about transition we need to make.
Due to the political realities of new reservoirs in western countries, economic limitations in the third world and the lack of a transmission system in undeveloped areas, perhaps 25% of the remaining technically exploitable potential can be developed before 2050, with the bulk of that being in the Asia-Pacific area.
Some countries have already developed their hydropower potential and have very little room for growth: Switzerland for example produces 88% of its potential and Mexico 80%.
Today we have around 1,300 GW of installed hydropower capacity globally. According to the International Renewable Energy Agency (IRENA)’s Global Renewables Outlook 2020, this figure will need to grow by around 60 per cent by 2050 to help limit the rise in global temperature to well below 2 degrees Celsius above pre-industrial levels.
While a large hydropower facility can often provide low-cost electricity for 50 to 100 years after being built, the upfront construction costs can be large. This, combined with the fact that suitable places for reservoirs are becoming rarer over time, means that large-scale hydropower plant construction costs may continue to rise.
A study by researchers from IIASA and China investigated the impacts of different levels of global warming on hydropower potential and found that this type of electricity generation benefits more from a 1.5°C than a 2°C climate scenario.
Environmental concerns about dams typically centre on their blockage of fish migrations or their upstream impacts, such as the inundation of habitats and the displacement of human communities. However, dams can cause serious downstream impacts as well. Although the public generally thinks of threats to aquatic organisms solely in terms of water quality, hydrological alteration – the modification of downstream water flow regimes caused by dams and infrastructure – is one of the primary causes of the degradation of freshwater ecosystems worldwide.
Unfortunately, hydropower’s global track record of managing environmental and social impacts and assuring equitable distribution of social benefits has been less than stellar. So the occasional generality thrown out by the most vigorous proponents, that hydro is ‘environmentally friendly’, rings hollow and calls for a more careful analysis.
No hydropower project is likely to be 100% sustainable. All projects must be viewed as more or less sustainable.
To address the environmental and social concerns and guide the pursuit of sustainability, several entities have developed policies that articulate ‘sustainable hydro power’, including Green Hydro in Switzerland and the Low Impact Hydropower Institute in the US, in addition to the guidance on sustainability presented in the World Commission on Dams report.
Recently, the International Hydropower Association (IHA) has developed both sustainability guidelines and a sustainability assessment protocol. Collectively, these documents describe specific measures for hydropower planning and operation that can be used to evaluate the sustainability of a hydro project or programme.