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Too much to handle? Germany’s solar power plan takes it toll

The head of the German energy agency DENA has warned that a surge in solar power is overwhelming Germany’s grid. Solar power’s advocates claim it alleviates pressure on the grid as it is generated and used locally, but the threat highlights fundamental issues with intermittent power generation.

ࢀ¢à¢€¢à¢€¢ BY TIM PROBERT ࢀ¢à¢€¢à¢€¢

Germany is without doubt a world leader in solar power. This central European country, by no means a magnet for sun-worshippers, has installed a world-beating 700 000 grid-connected solar PV systems with a total capacity of 14 680 MW, close to 11 per cent of Germany’s total power plant capacity of 130 GW.

This was no accident. In 2000, the German federal government introduced a then revolutionary system of feed-in tariffs that rewarded the installation of solar panels with a guaranteed 20-year subsidy for the generation and then sale of solar energy to utilities at highly preferable rates.

The impact of the 2000 Renewable Energy Act is profound. More than half the world’s solar power is produced in Germany and around 80 000 people are employed either directly or indirectly by the solar power sector in production, distribution, installation and maintenance.

Freiburg in Germany is the home of one of the most modern housing estates in Europe, the Solarsiedlung am Schlierberg (Schlierberg Solar Estate)
Source: Andrew Glaser

Germany’s success in developing its solar industry more or less from scratch to become a world leader is often cited as a vindication of forward-thinking industrial policy by the previous Social Democratic Party administration. As ever with well-meaning government policy, however, the law of unintended consequences has reared its ugly head.

The runaway success of solar power has caused fundamental problems with load management. The sheer volume of solar power being generated is leading to grid congestion at peak output. In other words, when the sun shines there is too much solar power on the system and the grid cannot cope.

Of course, the power industry has been aware of this issue for some time, but now some powerful voices are calling for Germany to drastically scale back installations of new solar PV systems to keep the increasing problem of grid congestion in check. None more so than Stephan Kohler, chief executive of the German Energy Agency (DENA), whose shareholders include the German federal government, Deutsche Bank and Allianz.

In a recent interview with the Berliner Zeitung newspaper, Kohler warned that at current rates of installation solar capacity would soon reach capacity level, i.e. at certain times of day (during weekends) the output of solar power would exceed national demand even with all other sources of generation turned off. This scenario, which could cause blackouts, could arrive as soon as the end of 2011, when solar installations may total 30 GW, as Kohler suggests.

At the current blistering rate of expansion, the installed capacity would amount to 50 GW by 2013, which would be “disastrous and not manageable for the grids”, he said. Therefore, Kohler has called upon politicians to cap new PV systems at just 1 GW per year so that the 30 GW capacity level would be reached in 2020, buying Germany enough time for the expansion of storage capacities and the grid, he said.

Not everyone agrees that the rapid installation of solar panels is disastrous. In response, the German Solar Industry Federation said Kohler’s concerns are exaggerated. Far from placing an intolerable burden on the grid, additional solar energy takes the pressure off high-voltage power lines because it is generated and used locally, it said. The grid would only need to be strengthened in those rural areas where solar supply can exceed demand, said the federation.

The author agrees that the fear of blackouts is exaggerated, but the issues highlighted by Stephan Kohler go right to the heart of the problems with intermittent sources of power generation. And his warning is set to echo around the world as more countries seek to ramp up generation of renewable energy.

As ever more solar panels and wind turbines are installed, the problems of ‘grid swamping’ will only be exacerbated. And, of course, while there will be times when there is too much renewable power; there will also be times when there is too little.

It is estimated that for every megawatt of solar capacity installed in Germany, only 100 kW is generated per annum, a capacity factor of a really rather pathetic 0.1. With 15 GW+ installed by the end of the year, this requires more than a few peaking gas turbines on standby; it needs large-scale power plants capable of both economical baseload and peaking power.

This is not to argue that renewable energy is an expensive waste of time and should be necessarily scaled back. Rather, if it is to be harnessed efficiently there needs to be massive investment in the power grid. That means more high and ultra-high voltage transmission across long distances and across borders, more energy storage solutions (particularly electric car batteries), and more demand response. Whether industry, governments and ultimately end-users will stump up for the expensive option, only time will tell.

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