هل سمعت عن مجمع Tâmega؟

The New York Times has just published an extensive article with some amazing photos. Why? I believe it’s because Portugal is becoming a World leader in developing every form of energy independence.

This is a project I have read little about, but it is one of Europe’s largest energy storage facilities with an investment of more than €1.5 billion. It comprises three reservoirs (Gouvães, Daivões and Alto Tâmega) and three hydroelectric power plants with 1158MW capacity on the Tâmega river, a tributary of the Douro.

This gigantic hydroelectric project was initiated in 2007 as part of the Portuguese National Programme for Dams with High Hydroelectric Potential (PNBEPH), the project aims at supporting the increase of electricity generation from renewable sources in Portugal as well as contributing to security of electricity supply by providing system flexibility and system services in the joint Portuguese-Spanish electricity market.

The technology being used is known as pumped storage. This does not rely on rainfall, which after the last dry summer we know can be an ‘issue’. This system relies on existing dams, one high up, and one over 500 metres below. The minute electricity is needed the valves, nine feet in diameter open, allowing water draining from a high reservoir four miles away to begin streaming through four massive turbines and produces power. The water surges through at 42,000 gallons a second and produces up to 1,158 MW almost instantly. The top dams, or reserves, can be re-filled at night as water is pumped back when electricity is cheaper.

The dam was officially opened last year, although it is still in construction. Despite that it is already generating electricity, with much more to come when it is completed next year. Figures vary on what amount of power this installation can provide in terms of Portugal’s needs, but it will supply Spain as well. It’s vast.

Wave power as well

Why is this such an important project? Portugal is making massive strides towards non-fossil fuelled electricity generation, wind power, solar even wave power, though there is little information about this available. Pelamis Wave Power’s Aguçadoura Wave Farm was the world’s first commercial wave energy project located 5km off the Aguçadoura coast. The farm started delivering 2.25MW of electricity produced by three Pelamis generators in September 2008. Sadly, it hit technical problems after four months and had to be towed back to port. In November 2014, Pelamis went into administration and ceased trading. P2-001 was acquired by Wave Energy Scotland and was decommissioned in April 2016 and sold to Orkney Island Council. The P2-002 device was sold to European Marine Energy Centre and was decommissioned in 2016. But the powerful Atlantic waved we have all along the coast are another potential source of ‘free’ energy.

Wave power could supply 30% of Portugal’s power needs

Estimates predict that wave power could make up to 30 percent of the country’s gross domestic product by 2050. Wave power also has the potential to become one of the lowest-cost forms of electricity generation with costs now approximately half of wind energy and a quarter of solar.

Swedish wave power developer CorPower Ocean has set up an R&D and manufacturing facility for a flagship demonstration project in northern Portugal in Viana do Castelo, with an eye on having a three-unit array online this year.

Harnessing the power of waves is notoriously difficult. The Swedish approach is different. The WEC design from CorPower – which captures energy from the rise and fall of waves using a buoy tethered to the seabed with a tensioned mooring system – is engineering to be built in 10MW clusters, with 30 units connecting to a collection hub through which the power is exported to shore via 33/66kV cables, such as are used on offshore wind farms.

Their approach to capturing the power of Atlantic waves is different to previous designs. Wave Energy Converters are a ‘heaving buoy’ on the surface absorbing energy from waves. The buoy is connected to the seabed using a tensioned mooring system.

Energy stored in waves are converted into electricity through the rise and fall as well as the back-and-forth motion of waves. The buoy, interacting with this wave motion, drives a ‘Power Take Off’ inside the buoy that converts the mechanical energy into electricity. In other words, their system uses the rise and fall of the sea level rather than trying to harness the power of waves.

Portugal is using every possible power source

Wherever there is a possible power source, Portugal is harnessing it to produce energy independence and lower-cost electricity. Solar power, wind power, sea power and water power. The new Tâmega complex is yet another major step in the direction of non-fossil power production.

The World Economic Forum this month announced that the time has come for Spain and Portugal to step forward: they are uniquely positioned to start producing green hydrogen at scale. They listed seven reasons why the Iberian Peninsula is so well placed. Not least they say Spanish and Portuguese-produced green hydrogen can be very cost-effective.

Perhaps Putin did us a favour in making us aware we can’t rely on others to supply our power. Energy independence in Portugal is progressing at high speed. That has to be very good news for us all.

Resident in Portugal for 50 years, publishing and writing about Portugal since 1977. Privileged to have seen, firsthand, Portugal progress from a dictatorship (1974) into a stable democracy. 

Paul Luckman