The most recent quarterly figures of the German Federal Network Agency instil a slight sense of hope, for they confirm what industry insiders (in German) have been saying for some time now: grid expansion is gaining traction. This means, according to the most recent Report on Network and System Security Measures (in German) for 2018, that the integration of renewable energy is improving.
This meant that green electricity producers were less likely to have to throttle their plants in 2018. This ‘feed-in management’, at the behest of the transmission grid operators, is necessary at times when a section of the grid is threatened with congestion. This is the case when more electricity is generated than is consumed or can be transferred to other areas of the grid. The operators of renewable energy plants are compensated by the distribution system operator for this forced suspension.
After a record high of 5,518 gigawatt hours (GWh) in 2017, a solid two percent less output had to be throttled in 2018. And this despite the fact that the amount of green electricity generated was up 5.5 percent versus the previous year. In total, 2.6 percent of green power was regulated – i.e. virtually thrown out the window. The change was even more prominent when it came to redispatch measures, which fell more sharply, by almost a quarter, from 20,439 to 15,529 GWh. Power plants – conventional ones in particular – are ramped up or down depending on the load distribution in the power grid. As such, power stations in southern Germany, which remain unused during the summer months, are recommissioned in the winter.
The transmission system operators’ overview clearly shows that in the southwest of Germany (TransnetBW and Amprion), power plants must predominantly increase feed-ins whereas feed-ins must be reduced in the northeast (50Hertz). TenneT alone, which operates the transmission grid in the entire central corridor from the North Sea coast to the edge of the Alps, is balanced.
The reasoning for this is similar to that for feed-in management: The high quantities of wind power in the north cannot always be transferred quickly enough to the main areas of consumption in the west and south of Germany. The increased demand for electricity in winter further exacerbates the situation.
But according to the Federal Network Agency, the expansion of the transmission grids is already having a positive effect here as well. The commissioning of the Thüringer Strombrücke (Thuringian Electricity Bridge) in autumn 2017 in particular has helped significantly relieve the pressure on the transmission grids. The 190-kilometer-long ultra-high-voltage line can transmit 5 gigawatts (GW) of electricity from Saxony-Anhalt to Bavaria. As such, its transmission capacity thus amounts to 97 percent of the total wind power capacity installed in Saxony-Anhalt (in German).
However, this has not done much to reduce the overall costs of the grid interventions. When it comes to feed-in management, the numbers have in fact risen. “Offshore wind turbines were more affected by the regulation of renewable energy in 2018. As such, the increased compensation claims play a role in this regard,” explained a spokesman of the Federal Network Agency when asked by en:former. It is more difficult to determine why redispatch costs have not fallen proportionately to the measures: “The power plant used, its marginal costs and other cost factors as well as prices on the energy exchange play a role here.”
Nevertheless: After forking out more than 1.5 billion euros in 2017, grid operators ‘only’ had to spend 1.4 billion euros in 2018 to stabilise the German electricity grid. The costs are passed on to consumers via the network charge by the operators.
This means there has been no increase in the urgency of expanding transmission capacity. On the contrary, the Federal Network Agency is currently checking the new Grid Expansion Plan (GEP) (in German) of the transmission system operators. In its current version, they are demanding 12,000 km of reinforced lines and new ‘power motorways’ by 2030.
Of the previously budgeted 7,700 kilometres of grid expansion, only 1,100 km had been finished by the first quarter of 2019, according to the Federal Network Agency. Another 800 kilometres have been signed off, 4,650 kilometres are currently in the approval stage, and approval procedures for the remaining 1,150 kilometres are yet to be initiated.
The amendment to the Network Expansion Acceleration Act is intended to remedy this state of affairs. ‘NABEG 2.0’ came into force in mid-May and aims to shorten approval processes. It shall also allow for the construction of individual power line sections before the final kilometre of a construction project has been approved.
Transmission system operators estimate that by 2030, the price tag on grid expansion will clock in at 62.5 billion euros. However, if grid expansion is not expedited, these figures could skyrocket. In order for Germany to achieve its climate goals, the proportion of renewables will need to continue to grow. And as it stands, wind power from the north will be instrumental in this regard.
If there is then not enough to transport power to southern Germany, grid operators will have to up their game, which would not only cause costs to soar but would also have a negative effect the carbon footprint. At the end of the day, conventional power plants deal with more than two-thirds of redispatch measures. In fact, grid reserve capacity is entirely covered by gas, hard coal and oil-fired power plants. And this demand, in particular, could rise again in future.
Recently, the Federal Network Agency noted a decline in demand for reserve capacity: Instead of the 10,400 megawatts (MW) needed in the winter of 2017/2018, only 6,600 MW were necessary in 2018/2019. “An important factor in this development is the improvement to the efficiency of the existing network, in particular with regard to weather-dependent overhead line monitoring,” says the Federal Network Agency. This is based on the fact that cables can transport more electricity at lower temperatures; until now, winter capacity utilisation had been calculated based on summer temperatures. In addition, electricity consumption was somewhat lower due to mild winter weather.
But when the last nuclear power plants are taken off the grid in late 2022, the north-south divide in generation capacity and electricity consumption will become even more pronounced than before. The Federal Network Agency estimates that demand for reserve capacity will then reach a record high of 10,647 MW.
As a precautionary measure, the authorities have therefore temporarily prohibited the complete decommissioning of 27 power stations. The operators intend to take a total of 110 power plant units with a combined capacity of 22,000 MW of the grid because their operation is no longer financially viable. The Federal Network Agency can prevent this by classifying plants as system-critical. The Federal Association of Energy and Water Industries (BDEW) (in German) has been stressing the impending lack of secure generation capacity for some time now. The result would be that Germany would have to import larger quantities of electricity than before. Faster network expansion could cushion this shortage.
Photo credits: NewSs, shutterstock.com