Expanding Germany’s transmission grid in order to accommodate increasing amounts of renewable energy is a well-known cornerstone of the country’s effort to meet its 2020 climate targets.
And just as well-known are the problems Germany has had in trying to make its transmission blueprint keep pace with the number of renewable projects ” particularly offshore wind farms ” being developed.
However, new research conducted by renewables consultancy Ecofys and the Smart Energy for Europe Platform (SEFEP) concludes that “even without any grid expansion by 2020, Germany can still deploy significant renewable electricity sources within 15 years”.
The key question behind the report is: Can high shares of renewable energy be achieved in Germany even if transmission grid expansion turns out to be too slow or not feasible at the level assumed by other studies? And the answer from the authors is a resounding ‘yes’.
“High shares of renewable energy can be achieved, even if the grid expansion is substantially delayed,” they state. “A delayed grid expansion is not a show-stopper for large-scale investments into renewable energies.”
The study is keen to stress that transmission grid expansion in Germany should be implemented, because “it is the cheapest way to integrate high shares of renewables and because it makes the power system more resilient”.
However, the report states that “even in case of very substantial delays in grid expansion, high shares of renewable electricity can be integrated in the power system, with only a moderate increase of total system costs. Therefore, possible uncertainties about the speed of grid expansion are no reason to slow down the expansion of renewable generation.”
The authors add that “such uncertainties may be a good reason to start steering the geographical distribution and the generation profiles of additional renewable capacities, taking into account the predictable transmission grid bottlenecks and favouring a balanced distribution of renewable generation within Germany, for instance more wind in the south and PV close to areas with strong daytime demand such as urban areas in the north”.
|“If more offshore wind is added, grid expansion becomes more urgent,” states Ecofys
In order to reach ambitious climate targets, “dedicated policies effectively able to reduce CO2 emissions from the power sector need to be implemented. This is even more important in case of rapid transmission grid expansion, in order to counterbalance the favourable effects it has on the use of lignite.”
In arriving at their conclusions, the authors say that they have debunked “two persistent myths regarding the Energiewende: the first that if Germany’s grid expansion plans are delayed, a slowdown in renewable energy investment will happen in the coming years, and the second that wind should be built where it’s windy, and solar should be built where it’s sunny”.
The study found that Germany can still meet its target of getting 72 per cent of its energy from renewable sources by 2030 even if grid expansion is limited to projects that were already under construction by December 2012.
And it adds that the costs of this limited grid expansion would be manageable: “System costs would only increase by 0.8 to 3 per cent depending on the geographical distribution and generation profile of the nation’s renewable energy sources.”
Christian Nabe, electricity market specialist at Ecofys, said: “If grid expansion is delayed, about €800 million in transmission costs can be saved per year if we spread wind and photovoltaic installations more evenly across the country.”
The study concludes that increased amounts of PV and onshore wind, with a decreased share of offshore wind, would create a system that was more robust against grid expansion delays.
|Lignite-fired Lippendorf power station: Grid expansion creates “favourable conditions for the steady operation of plants that burn lignite,” says Ecofys
“If more offshore wind is added, then grid expansion becomes more urgent as, for example, offshore wind power generated in the northern part of the country needs to be transported to southern population centres,” states the report.
It adds that replacing 10 GW of offshore wind with PV and onshore wind would not disadvantage the total system cost, create more emissions or require increased curtailment.
Ecofys said that “system flexibility will also be key to Germany’s energy future”.
It said if “grid expansion as a source of flexibility is limited, other options such as compressed air energy storage and load shifting will be the most cost-effective means”.
“An investment into about 5 GW of compressed air energy storage appears to be cost optimal, if higher shares of offshore wind are assumed,” it states. “If the renewable generation is based more on onshore wind and PV, the optimal CAES capacity is 2 GW.”
The report dismissed battery storage as not being “a cost-optimal technology”.
The report also says that the “myth that wind should be built where it’s windy, and solar should be built where it’s sunny” is “simplistic”.
“It reduces the complexities of the Energiewende to a question of wind and solar resources. But other economic and non-economic factors also need to be considered, including the costs of land, capital and project development, the availability of skilled labour, policy certainty, social acceptance, the need for regional and national self-sufficiency and regional development concerns.”
The report’s authors say that they focused only on the impact of rapid/slow grid expansion and did not reproduce most of these “other factors”.
Therefore, they conclude that their “findings are even more remarkable: a scenario with more wind where it is less windy (more onshore wind in the south of the country and less concentration of onshore and offshore wind in the North) is more robust against the probable risk of delayed grid expansion”.
Effect on emissions
|Berlin: System flexibility will be key to Germany’s energy future, says Ecofys
With emissions taking political centre stage across Europe, what effect would any clawback of T&D expansion have on Germany’s CO2 output?
The report states that emissions from the power sector would be “substantially reduced to about a third of the 2011 level” and “a delayed grid expansion leads to slightly lower CO2 emissions in 2030 than full expansion”.
It explains this by stating that “transmission grid expansion tends to favour technologies with high investment cost and low marginal generation cost, such as renewable energies but also lignite, as they benefit from the additional flexibility”.
“As a consequence, further policy measures such as emission standards would need to be introduced to ensure a decrease in CO2 emissions, as the assumed cost of CO2 in 2030 (40 €/t) is not high enough to prevent an increased use of lignite.
“An intended delay of grid expansions as a measure of CO2 reduction in the power sector does not seem to be appropriate as the long-term effects of such a strategy would lead to higher costs and CO2 emissions.”
The study also claims that if Germany delayed its grid expansion, it could result in slightly lower CO2 emissions in 2030, compared to full grid expansion.
“This is because grid expansion creates favourable conditions not only for the integration of wind and solar, but also for the steady operation of inflexible, low marginal cost power plants such as those that burn lignite.”
It added that in all scenarios modelled by the report authors, 2030 emissions are cut to about one third of 2011 levels due to an increasing share of renewables in the mix.
The authors make a point to note that “the year 2030 is not the end of the Energiewende”.
“It is likely that further deployment of renewable energies after 2030 requires more flexibility of the power system,” they write, and this “stronger transmission grid” would be greater than the one assumed in their study. “Therefore, building transmission is basically a no-regret strategy, especially since actual construction is often slower than hoped for.
“If transmission materialises faster than expected, it is very likely that, within the next few years, this grid capacity turns out to be necessary.
“Additionally, transmission helps to prevent the manifestation of local market power. Other sources of flexibility would be new storage options.” Those would include power-to-gas storage as well as all options which increase flexibility between the power sector and the heat and transport sector.
However, the authors cautioned that their results “should not be interpreted to mean that grid expansion is not important for the Energiewende”.
“Grid expansion will increase the stability and resilience of Germany’s power system and reduce the costs associated with ancillary services and a strong grid is a good investment toward the expansion of renewables over the coming decades.”
And they add: “There are good reasons to pursue a strong expansion of the transmission grid: for instance, increasing the stability and the resilience of the power system and reducing the costs of providing important ancillary services.
“Furthermore, a strong grid ” possibly even a slightly over-dimensioned transmission grid in 2030 ” will be a very good starting point for the further expansion of renewables in the following decades, and therefore in any case a good investment.”
Raffaele Piria, SEFEP’s programme director, said: “The study shows that rapid expansion of renewable energies can continue. If grid expansion is delayed, we need to manage the geographical distribution of renewables wisely.”
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