Natel Energy's turbines with lower steel and cement content that allow safe passage for fish herald a new dawn for the world's biggest source of renewable energy. Mark Hillsdon reports

As wind and solar continue to grab the headlines, it’s easy to forget that hydropower remains the world’s largest form of renewable energy, contributing around 70% of all green electricity.

The trio of China, North America and Brazil remain the world’s biggest producers, and last year saw the latter open the colossal Belo Monte project. Capable of generating 11,233MW and providing electricity to 60 million people, it dwarfs the second-largest individual hydro scheme of 2019, the 1,285MW Xayaburi project in Laos.

In total, 50 countries added new hydropower to their electricity grids in 2019, totalling 15.6GW, but according to the International Renewable Energy Agency's (Irena) 2020 Global Renewables Outlook, to have an effect on limiting global temperature rises to below 2C, installed hydropower capacity across the world needs to grow by 850GW by 2050, requiring an investment of $1.7tn.

Unlocking this new hydropower growth requires alternatives that do not need big dams

However, the days of vast projects such as Belo Monte may be numbered amid a growing consensus that the future of hydropower is in smaller, more distributed projects, often called “low-head” or “run-of-river”.

“Unlocking this new hydropower growth requires alternatives that do not need big dams, that reduce the cost of civil works, improve environmental performance and maintain or support watershed health,” says Gia Schneider, CEO of Natel Energy, a Californian-based hydropower startup.

With $11m in funding from Schneider Electric Ventures and the Bill Gates-led Breakthrough Energy Ventures, Natel has developed a new turbine that updates technology and lowers construction costs by requiring less cement and steel. Natel’s “restoration hydro” turbine also allows for safer passage for fish, which has become an important regulation for hydro projects in the US and Europe.
Its first commercial-scale project wiil be central Oregon, in a project that will generate 5MW of electricity, enough to power a small town, for Apple’s Prineville, Oregon data centre.

Hydro has been dogged by environmental concerns for years, but it isn’t just huge dams that are causing alarm. Plans to develop some 3,000 small hydro schemes across the Balkans, for instance, have been widely criticised as effectively damming the last free-flowing rivers in Europe, with a mish-mash of schemes that would harm fish and adversely affect communities living along the rivers.

The Nature Conservancy (TNC) has been at the forefront of the campaign to prevent this proliferation of hydro, but the agency still sees a role for the technology in a wider energy mix.

According to Mark Lambrides, TNC’s director of global energy and infrastructure, if planned intelligently “small hydropower, and particularly micro-hydro, can provide essential electricity supplies to remote communities or contribute to decentralised ‘mini-grids’.”

1MW of hydropower enables 5MW of wind or solar power, meaning hydro can offer important back-up, stepping in when solar and wind aren’t generating

Hydro has leant a lot from wind and solar, especially around power electronics and control, and now plays a much greater role in adding distributed energy to the grid by dovetailing with other renewables.

The World Bank estimates that 1MW of hydropower enables 5MW of wind or solar power, meaning that hydropower can offer important back-up services, stepping in when solar and wind aren’t generating. It can also offer storage facilities when they are generating too much power and can even absorb surplus power by pumping water up to a higher elevation, to be released on demand when it is needed.

Dubbed the world’s “water battery”, pumped storage hydropower (PSH) uses an upper and lower reservoir, connected by two pipes, with the first letting water flow downhill, driving turbines, the second pumping it back up again. It is already used by the power industry for peak saving and load balancing, while accounting for 94% of installed global energy storage capacity.


The Three Gorges dam on China – one the world’s largest producers of hydropower.  (Credit: Isabel Kendzior/Shutterstock)

Innovative hybrid projects are also emerging that involve connecting hydropower with wind or solar projects, enhancing efficiency and reducing infrastructure costs.

“Global decarbonisation efforts rely not just on the clean electricity hydropower produces, but also the storage, flexibility and resilience it offers power grids that are increasingly reliant on intermittent renewables,” says Eddie Rich, CEO of the International Hydropower Association (IHA).

This was recently illustrated in India, he says, when the country’s hydropower plants played a pivotal role in successfully restoring electricity to tens of millions of households following an unprecedented plunge in demand, when people were urged to switch off their lights for nine minutes to express solidarity amid the Covid-19 pandemic.

Modernising and optimising plant facilities will help ensure hydropower’s vital role in energy systems is sustained and enhance

In terms of investment, hydropower could be on the verge of dipping into green bonds. The sector’s involvement in this market, which helps to finance projects that address environmental and climate risks, has been held back by concerns around environmental issues and its sustainability. But with these now easing, the IHA has started consultations with the Climate Bonds Initiative to introduce a new hydropower package.

But increasing the sector’s contribution to renewable energy supply isn’t just about building more hydro. More than half of the current global fleet of hydropower plants were built before 1990, and the US Department of Energy alone estimates that by upgrading existing infrastructure it could generate an extra 4,300MW.

Modernisation, explains Rich, means bringing a plant to optimal operating conditions so it can provide increased generation output, and provide ancillary services that support the addition of intermittent renewable energy into the system.

The IHA has been working with the Inter-American Development Bank (IDB), and identified 20 stations with an installed capacity of over 15GW that were in need of modernisation, representing over $5bn of estimated investment in electrical and mechanical systems.

In Europe, the XFLEX HYDRO initiative is an €18m EU-funded project demonstrating how more flexible hydro technologies can help countries and regions to meet their renewable energy targets. The four-year project is being tested across seven power plants in Portugal, France and Switzerland, harnessing innovations such as variable speed turbine systems and electro-chemical batteries, which will further push the frontiers of storage.

“Modernising and optimising plant facilities will help ensure hydropower’s vital role in energy systems is sustained and enhance,” says Rich. “This will improve electricity security, reduce prices and build resilience to a crisis like Covid-19.”

Mark Hillsdon is a Manchester-based freelance writer who writes on business and sustainability for Ethical Corporation, The Guardian, and a range of nature-based titles including CountryFile and BBC Wildlife.

Main picture credit: venusvi/Shutterstock
renewable energy  energy transition  hydropower  belo monte  Xayaburi  Low-head hydropwer  Natel Energy  TNC  IHA  XFLEXHYDRO 

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