OPINION: Christian Kjær in Brussels

At noon on 11 May, nearly 75% of Germany’s electricity supply was supplied by renewables — 67% from PV and wind alone.

More impressively, in the first quarter of the year, 27% (40.2 terawatt hours) of the electricity supply in Europe’s largest economy came from renewables.

And these figures are not even world records. Denmark (admittedly a far smaller economy) produced 33.2% of its electricity from wind in 2013. Wind met 54.8% of demand in December, and during one hour on 1 December, wind’s share of demand was 135.8%, according to system operator

Last year was the first in which wind power was the largest contributor to electricity demand in Spain (21.1%), marginally beating nuclear (21%). Renewables as a whole contributed 42.4% to Spain’s demand last year — an increase of more than ten percentage points compared with 2012. The green rise came at the expense of coal (down 27%) and gas (down 34%). Wind now meets 8% of EU electricity demand and 4.1% in the US. The switch away from fossil fuels and nuclear is accelerating.

Over the past 20 years, opponents of renewables have used three main arguments against deploying renewable-energy technologies: they are too small to matter; too unreliable; and too expensive.

Well, the cost argument is rapidly being eroded as PV and onshore wind are becoming fully competitive with fossil fuels and far cheaper than nuclear.

Nobody can credibly claim that renewable energy is small-scale when it supplies more than a quarter of the electricity in the world’s fourth-largest economy. As for unreliability, it is difficult to argue that variable renewables will cause blackouts when the Danish system can absorb 136% of total demand.

It is not a big technical challenge to manage annual shares of 5-10% of variable renewable electricity, as pointed out in an International Energy Agency (IEA) report in February, which concluded that annual shares of 25-40% can be achieved with current levels of system flexibility, increasing to 50% in more flexible systems such as the Danish, with some curtailment during extreme variability events.

However, we are approaching the point at which variable renewables are beginning to absorb most of the power system flexibility in some markets. expects wind to meet 58% of Denmark’s power demand in 2020. Germany’s goal is for renewables to provide 80% of demand in 2050.

We must take the warnings on grid reliability and system integration seriously. We must acknowledge that the first 25% is technically much simpler to reach than the next 25%. And we must recognise that additional power system flexibility is needed much sooner than most people expect.

At EU level, the renewables sector — and decision makers — have a tendency to think that the integration challenge can be solved with a supergrid, consisting of large high-voltage direct-current (HVDC) lines.

However, more than 80% of all renewables installations in Europe are connected to the distribution grid.

Let’s build all the cross-border transmission lines we can, but the electricity still needs to get to the consumer. As 70% of power is consumed by residential and small commercial and industrial users, the biggest challenge for our industry is the integration of technologies in new and actively managed local grids.

The PV sector is most active on this front, because it is directly engaging in the market for rooftop panels. As turbines grew bigger over the past 25 years, the wind industry increasingly distanced itself from the user, technically and commercially. But even the electricity from a 500MW offshore wind farm that is fed into a fat HVDC transmission cable will end up in the distribution system, which must be more actively managed.

It is not a question of supergrids versus smart grids. We desperately need both. However, we cannot blindly add generating capacity and raw copper to the system, without providing more intelligent, IT-based demand response and storage solutions at the distribution level.

Eighty per cent of renewables capacity is installed at distribution level, and most consumers are connected at the distribution level. Still, all Europe’s attention is on the transmission system. More balance is needed.

Christian Kjær is a former chief executive of the European Wind Energy Association and founder of Faraday Consult. He is also a member of the Recharge