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A systematic review of the costs and impacts of integrating variable renewables into power grids


The impact of variable renewable energy (VRE) sources on an electricity system depends on technological characteristics, demand, regulatory practices and renewable resources. The costs of integrating wind or solar power into electricity networks have been debated for decades yet remain controversial and often misunderstood. Here we undertake a systematic review of the international evidence on the cost and impact of integrating wind and solar to provide policymakers with evidence to inform strategic choices about which technologies to support. We find a wide range of costs across the literature that depend largely on the price and availability of flexible system operation. Costs are small at low penetrations of VRE and can even be negative. Data are scarce at high penetrations, but show that the range widens. Nonetheless, VRE sources can be a key part of a least-cost route to decarbonization.

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Fig. 1: Breakdown of dataset by category of impact.
Fig. 2: Data for operating reserve, capacity adequacy, aggregated and profile costs.
Fig. 3: Operating reserves costs.
Fig. 4: Capacity adequacy costs.
Fig. 5: Operating reserve, capacity adequacy, aggregated and profile costs.
Fig. 6: Capacity credit data by VRE type.

Data availability

The quantitative data shown in Figs. 26 and described in this paper (and in the Supplementary Information) are available in the Supplementary Data. The data are also deposited with the UKERC Energy Data Centre, a UK Research Councils funded data repository hosted by the STFC Rutherford Appleton Laboratory (, with serial no. EDC0000162 at


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Both authors contributed extensively to the work presented in this paper, including conception of the study, data identification and analysis, and drafting of the manuscript.

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Correspondence to Philip J. Heptonstall.

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Supplementary information

Supplementary Information

Supplementary Table 1, Notes 1–4 and Figs. 1–3.

Supplementary Data

Systematic review data sources and dataset.

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Heptonstall, P.J., Gross, R.J.K. A systematic review of the costs and impacts of integrating variable renewables into power grids. Nat Energy 6, 72–83 (2021).

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