Spain's blackout emphasizes the challenge of renewing the new values

The cause of the massive power failure of last week in Spain and Portugal remains unclear, but it has a spotlight for solar and wind energy that blamed critics to strive for power grids.

The rise of renewable energies is a challenge for electricity grids that have to develop to adapt when the countries remove fossil fuels.

Maintain stability

The network operators must ensure that the electricity between demand and supply is constantly balanced.

A metric of this balance is the frequency of the electricity that flows through the network and is set in Europe to 50 Hertz (Hz) and 60 Hz in the USA. If this number drifts too far, it can endanger the network.

In the past, the electricity system has based on conventional power plants – gas, coal, core and hydropower – that use spider turbines to generate electricity.

These machines keep the frequency stable.

With their gigantic rotors that rotate at high speed, they deliver inertia for the system.

If a power plant fails or if the electricity requirement increases too quickly, it helps to stabilize the network by releasing the kinetic energy stored in the rotors.

Instead of spinning machines, solar and wind farms use electronic systems that feed the power supply into the network, which makes it more difficult to maintain this sensitive balance.

Renewable energies will have to supply more than carbon-free electricity in the future, said Jose Luis Dominguez-Garcia, expert for electrical systems at the Catalonia Energy Research Institute (IREC).

You have to “support the system with additional controls to support the network, especially in indolence,” he said.

Marc Petit, professor of electrical systems at the Top French Engineering School Centralesupelec, argued that the withdrawal of fossil fuels hydropower and nuclear power plants “would make even more important for the stabilization of the system when using rotation machines”.

Swinging wheels

There are already a number of technical solutions to compensate for the lack of inertia through renewable energies and thus support the stability of the grids.

This includes heavy power, cryogenic liquid air, compressed air and concentrated solar power.

Since it is a transition from coal, Great Britain relies on flywheels, a tried and tested system.

Excess performance of solar and wind farms is used to turn the large bikes and generate kinetic energy.

This stored energy can then be converted in order to deliver electricity into the network if necessary.

No sun or wind

Shortly before the massive blackout on April 28, wind and solar energy delivered 70% of the power endurance of Spain. However, renewable energies are intermittent energy sources because they rely on nature.

If the wind stops blowing or hiding the sun, other sources must step within minutes, or appropriate systems must be available for storage and then in place in place.

Depending on the country, the backup supply currently comes mainly from heat power plants (gas or coal), nuclear reactors or hydropower.

In order to cope with the heights and depths of the renewable power supply, the countries must increase the storage capacity.

The most widespread method is the pump storage hydropower from the water reservoirs.

But large stationary batteries that resemble shipping containers are increasingly used next to wind and solar parks – a segment dominated by China.

According to the International Energy Agency, the storage capacity must increase six times in order to achieve the global goal of tripling the renewable capacity by 2030.

Another way to reduce the pressure on the system is to move the power consumption – for example when loading your automotive battery – to the middle of the day when the solar energy is at the peak.

Enclose the network

Widespread power failures “were practically always triggered by transmission system errors, not through generation, renewable energies or otherwise,” said Mike Hogan, consultant of the Regulator Assistance Project (rap), an NGO, the aim of which is to achieve a clean, reliable, just and inexpensive energy future.

Tens of billions of euros, perhaps hundreds of billions, are needed to renovate aging power lines and replace them with new ones that are more powerful.

The need to modernize or expand the lines is to press because energy -hungry data centers grow and the factories are increasingly consuming electricity.

The countries also have to strengthen the connections between their power supply systems.

Such cross -border connections contributed to restoring the power supply of Spain when France came up to share electricity during the power failure.

By 2028, the exchange capacity between the two neighbors will increase from 2.8 to 5.0 gigawatts and reduce the relative electrical insulation of the peninsula.