دانلود رایگان مقاله انگلیسی ادغام کوتاه مدت هزینه های انرژی تجدید پذیر متغیر: کاهش اجباری توان تولیدی باد - الزویر 2018

ABSTRACT

Britain and Germany saw unprecedented growth of variable renewable energy (VRE) in the last decade. Many studies suggest this will significantly raise short-term power system operation costs for balancing and congestion management. We review the actual development of these costs, their allocation and policy implications in both countries. Since 2010, system operation costs have increased by 62% in Britain (with a five-fold increase in VRE capacity) and remained comparable in Germany (with capacity doubling). Within this, balancing costs stayed level in Britain (–4%) and decreased substantially in Germany (–72%), whilst congestion management costs have grown 74% in Britain and 14-fold in Germany. Curtailment costs vary widely from year to year, and should fall strongly when ongoing and planned grid upgrades are completed. Curtailment rates for wind farms have risen to 4–5% in Germany and 5–6% in Britain (0–1% for offshore and 15–16% for onshore Scottish farms). Policy debates regarding the balancing system are similar in both countries, focussing on strengthening imbalance price signals and the extent that VRE generators bear the integration costs they cause. Both countries can learn from each other's balancing market and imbalance settlement designs. Britain should reform its balancing markets to be more transparent, competitive and open to new providers (especially VRE generators). Shorter trading intervals and gate closure would both require and enable market participants (including VRE) to take more responsibility for balancing. Germany should consider a reserve energy market and move to marginal imbalance pricing.

5. Conclusions

This paper examined recent developments of short-term integration costs of variable renewable energy (VRE) sources, congestion management and balancing costs, in Britain and Germany. Congestion management costs have increased recently in both countries to unprecedented levels. In Germany, these costs are dominated by compensation payments to wind farms for curtailment, whereas in Britain the costs for redispatch of gas plants make up the bulk of costs. Ongoing and planned major grid upgrades are expected to relieve congestion to a large extent in both countries. We show that 4.4% of German and 5.6% of (metered) British wind energy was curtailed in 2016, a total of 4.65 TWh. This energy cost €426 m to curtail, and could have saved approximately 2.1 MT of CO2 if it had been utilised.10 Balancing costs have stayed constant in Britain and have decreased in Germany, despite VRE capacity increasing five-fold and two-fold respectively. This goes against most modelling studies which predict an increase of reserve requirements and costs with increasing VRE penetration levels. This supports the hypothesis that significant flexibility already exists in these systems, and so accommodating more intermittent renewable output can be managed by improved system operation without necessarily raising costs. Three policy goals should be pursued to enable and incentivise such improved system operation by system operators as well as market participants: