Familiar old water remains the most widespread renewable source

Traditional or modern renewable? Hydropower plants belong in both categories. Unlike photovoltaics and modern giant wind farms, water as an energy source is certainly no historical novelty. And according to the World Energy Council, this by far the most widespread renewable source is set to see further capacity growth of at least three percent a year.

When SolarCity, the company founded by visionary entrepreneur Elon Musk, decided in 2014 to build a giant solar panel factory in Buffalo, New York, one of the major incentives was the opportunity to obtain cheap electricity from Niagara Falls. It was precisely the cheap energy from this source that the state of New York offered.

Whatever the outcome of the SolarCity project, it is an interesting symbol. Hydropower plants remain by far the most widespread renewable source, and without their contribution it would not be possible to meet various ambitious targets for the “expansion” of green energy.

Hydropower plants still account globally for around 80 percent of electricity generated from renewable sources. Their share of total electricity production on our planet stands at roughly 16 percent.

Those seeking to achieve a 100 percent transition to renewable sources at any scale – national or local – must rely on water. A study by US research and advisory firm Clean Edge cites, among other examples, Costa Rica, which recently achieved the target of generating 100 percent of its electricity from renewable sources – during the first 100 days of 2015. Heavy rainfall contributed to this, helping raise hydropower’s share to 68 percent.

In Europe, hydropower plants significantly improve the overall renewable energy balance in countries such as Norway, or regions such as Scotland and Austria’s Carinthia, which boast local pumped-storage plants.

In addition to the SolarCity project, the Clean Edge study highlights the example of Google’s data centre in Oregon, whose location in the city of The Dalles on the Columbia River was determined precisely by access to hydropower resources.

An increasing number of companies are choosing locations for their energy-intensive operations where electricity from hydropower sources is available.

Clean Edge study

Small yes, large no?

However, hydropower plants’ reputation among advocates of environmentally clean sources is far from unambiguous. The main targets of criticism tend to be giant hydropower projects, which entail the resettlement of large numbers of people and the flooding of extensive areas. Opponents of new dams in Latin America object that such structures lead to the destruction of local rainforests.

Plans for large dams are still alive today. The monumental Belo Monte dam project, which is expected to have a capacity of more than 11 gigawatts, is causing a storm in Brazilian politics. While this case concerns a corruption scandal, there are many other criticisms from environmental activists regarding such large projects. People’s access to water is worsened, complicating life for farmers, as does the loss of agricultural land. Major dam construction threatens natural wealth, flora and fauna in flooded areas, as well as biodiversity in rivers. Water quality deteriorates. And the construction of large hydropower plants itself involves significant greenhouse gas emissions.

Nevertheless, the World Energy Council (WEC) predicts that large hydropower plants will account for the overwhelming majority of new hydropower capacity to be built in the coming years. Just as large wind farms will be built, because decentralised energy alone will not deliver all the ambitious renewable energy development targets.

However, it should be added that hydropower does not necessarily have to involve projects as enormous and expensive as the aforementioned Belo Monte dam or China’s much larger Three Gorges, the world’s largest power plant. The WEC classifies plants with capacity above 100 megawatts as large.

And the assumption is increasingly being voiced that the future lies not so much in building new sources as in refurbishing old ones. Particularly in Europe and North America, there are quite a number of hydropower plants that can be modernised, refurbished, rebuilt and have their capacity increased. The US Department of Energy also sees potential in the number of dams that have not yet been used to generate electricity.

In connection with the decentralisation of energy, small plants of up to ten megawatts, or medium-sized plants with capacity between ten and 100 megawatts, are becoming popular. These are mostly considered environmentally clean, although in some cases strong concerns are also voiced that they may threaten surrounding natural assets. While these smaller sources will not yet provide the majority of new capacity, they may proliferate like mushrooms after rain.

Although pumped-storage and small hydropower plants will provide less than ten percent of future capacity, these sources will be the most common.

World Energy Council outlook

Renewable, yet stable

The refurbishment and rebuilding of old power plants is one of the key trends that will undoubtedly shape the future of hydropower in the coming years. And what are the others?

First of all, let us return to the question of how hydropower fits among modern renewable sources. Probably the most important factor strengthening the “bet” on water is the fact that, under the new conditions, it is becoming a pillar of stability. While the output of photovoltaics and wind turbines depends on the weather, hydropower production can be flexibly regulated and adjusted to current needs. Hydropower should therefore facilitate the overall transition phase on the path towards renewable sources.

On the other hand, problems may arise where hydropower plants face prolonged periods of drought. It is no secret that, for example, lower output from hydropower sources in the Balkans has also posed a problem for the Czech transmission system – leading to higher surges of electricity flows from German wind turbines across Czech territory.

It has long been said that countries such as Norway, with abundant hydropower resources, will become Europe’s batteries and balance the instability of other renewable sources. A new submarine electricity interconnector from Norway to Britain is currently being built, and at 740 kilometres it is set to be the world’s longest.

And until new methods of energy storage begin to see wider deployment, the most powerful “batteries” will remain the familiar old pumped-storage plants. Analyst William Steel notes that pumped-storage facilities with capacity of 8,600 megawatts are currently planned or already under construction in Europe, of which 2,500 MW is in the Swiss Alps and 2,000 MW in Portugal.

In many parts of the world, particularly in developing countries, hydropower sources are becoming a solution for remote areas that are not connected to transmission networks. And after all, we can also expect the continuation of a long-term trend – investment in hydropower pays off where the aim of generating energy is linked with efforts to prevent floods or drought.

The author works as a consultant and energy project specialist at the HATcom agency.

Source of the lead photograph: Ontario Power Generation