As Germany makes a transition away from fossil fuels to renewables traditional power plants are being increasingly used for backup purposes. The amount of conventional generation needed will only decrease as flexibility options such as demand side management, batteries and pump storage take hold. In addition, there will be further optimization across Europe and the end result will be that the residual will be met by highly flexible gas power stations.

There are three phases in this move to renewables:

Phase I – past and present

a) Capacity

Currently, there is a significant amount of power generation overcapacity in Germany which is responsible for the ten year low power prices we are currently seeing. In addition, despite the fact that there are no new coal or gas plants being planned in Germany there are several plants coming online which were started many years ago. To make matters worse Germany has added each year over the last decade at least 5GW of new renewables and Germany on a good weather days has now enough renewables to meet its peak demand needs (80GW).

b) Availability of primary energy resources

One of the main strategies in Germany is to cut down natural gas usage by replacing it with biogas, efficiency measures and other renewables in the heating sector. The result is that we have seen a significant drop in gas usage for power generation but the biggest use case for natural gas remains heating and in this area efforts to move away from gas have been half-hearted. This however is likely to change going forward.

Replacing natural gas by biogas is the most obvious way forward. As of the end of 2015 there were 9,000 biogas systems installed across Germany with a total installed base of 4.2GW. Going forward we will see an increasing amount of biomethane feed in systems whereby biogas is fed directly into the gas distribution system. This will give new opportunities for long term storage.

Phase II – near future

a) Capacity

Going forward conventional power plants will close and overcapacity will start to shrink. Germany will phase out nuclear by 2022, which means that 8 reactors will close between now and then. We will also see a sharp reduction in the amount of coal power plants, noting that about a dozen closures have already been announced.

At the same time, we will likely see mothballed gas power plants come back online and we will also see biogas plants become much more flexible in how they produce power. Currently, the German biogas fleet of 4GW in capacity runs 8,000 hours a year. A target might be to double the capacity of those plants to 8GW while at the same time cutting in half the full load hours, the result of which is that no more additional biomass will be needed. And if you make them more flexible some 10 GW of supply would be possible with the same amount of biomass input. Additionally, you could work with improved biogas technology and feed the bacteria with different kind of biomass, meaning that high reactive biomass can be used in times of high energy demand and low reactive biomass in times of low demand.
And if we decide to feed in the biogas into the grid rather than burning it for 4GW of power for 8,000 hours you could run 64GW of power capacity for 500 hours, which would be enough to power Germany’s power needs for 21 days!

b) Availability of primary energy resources

The next phase will be shaped by

– the transition of biogas to flexible production (as stated above)
– increase of efficiency efforts in the heating sector and
– sector coupling.

Increasing efficiency efforts in the heating sector and the usage of renewables is probably the easiest way to save natural gas. Technologies are widely available. All that is lacking is the capital and some will power.  But to reach climate targets there is no other way than to decarbonize the heating sector.

Sector coupling involves the connecting of the electricity with other sectors such heat or industry.  Several projects for e.g. in Münster, Berlin, Kiel, Nürnberg, Biberach and Hamburg already combine electrical heaters with combined heat and power generators (CHP). During times when there is a lot of wind or sun power production, the CHP switches off and uses the electrical heaters for heating. Going forward the CHP will only be used when there is no wind or solar production.

We will also see sector coupling between industry and the energy world and we will likely replace natural gas and naphtha for hydrogen production. Instead, power to gas technologies such as PEM-electrolysers will be used to produce hydrogen. This technology is already available and learning curves are promising. It is also promising that the German Chemistry Association (VCI) recently published a position paper which examined long term storage including hydrogen production for chemical usage.

What this all means is that gas demand in Germany is likely to continue falling over the next 20 years despite the fact that gas will be the chosen backup energy source for the system.

Phase III – long term

a) Capacity

The closure of all nuclear plants and coal plants across Germany is only a matter of time. Short term storage and other flexibility options are most of the time sufficient for back up to intermittent renewables. Other renewables such as hydro, solid biomass and maybe geothermal will play an increased role. Longer term back up needs will be filled mainly by gas. The costs of gas turbines are extremely low in comparison to coal or even nuclear capacity. If we compare costs with “alternatives” one could install for the present proposed costs of the Hinkley Point nuclear power station in the UK with a total of 3.2 GW capacity for some 60(!) GW of gas turbines.

b) Availability of primary energy resources

Biogas will probably account for most of the gas which is needed for backup purposes; a bigger share of the biogas will probably be fed in to the grid and burnt at places where the heat also can be used (though CHPs). The remaining share of gas needed can either be filled by natural gas or by power-to-gas. But still the demand for gas will be much lower than today.


Primary energy is no obstacle for the back up of the German renewables, neither now nor tomorrow and not in the further future. The technology is either already available or on a good commercial track. So all I can do is to repeat what I said in my last blog: storage is actually an already solved problem.

Carsten Pfeiffer, Head of Strategy and Politics, German Renewable Energy Federation; @PfeifferCarsten

  • Tags:
  • biogas ,
  • CHP ,
  • coal ,
  • decarbonization ,
  • efficiency ,
  • Germany energy ,
  • natural gas ,
  • renewables ,
  • storage ,


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