Comparative net energy analysis of renewable electricity and carbon capture and storage

Abstract

Carbon capture and storage (CCS) for fossil fuel power plants is perceived as a critical technology for climate mitigation. Nevertheless, limited installed capacity to date raises concerns about CCS ability to scale sufficiently. Conversely, scalable renewable electricity installations-solar and wind-are already deployed at scale and have demonstrated a rapid expansion potential. Here we show that power sector CO 2 emission reductions accomplished by investing in renewable technologies generally provide a better energetic return than CCS. We estimate the electrical Energy-Return-on-Energy-Invested ratio of CCS projects accounting for their operational and infrastructural energy penalties to range between 6.6:1 and 21.3:1 for 90% capture ratio and 85% capacity factor. These values compare unfavorably to dispatchable scalable renewable electricity with storage, which ranges from 9:1 to 30+:1 under realistic configurations. Therefore, renewables plus storage provide a more energetically effective approach to climate mitigation than constructing CCS fossil power stations.

Day-Ahead Optimal Battery Operation in Islanded Hybrid Energy Systems and Its Impact on Greenhouse Gas Emissions

“…Battery voltage (U B(t) ) and efficiency (η B(t) ) are defined according to charging and discharging processes using Equations (5) and (6), respectively.…”

“…Regarding the parameters of the VRFB model previously described in (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), specifically the parameters U a ch − U h ch , U j ch − U n ch , U p ch , U q ch for charging and U a dis − U h dis , U j dis − U m dis for discharging; they can be found in [35][36][37]. Similarly, the parameters P a C and P b C related to the power converter efficiency have been obtained from the experimental data published in [38].…”

“…Combination of carbon capture and storage devices with conventional generation units is also an option to reduce GHG emissions. However, the combination of renewable generation with ESS can be energetically more effective [5].Historically, the acquisition costs of a battery energy storage system (BESS) have been considerably high, limiting their economic performance and consequently their mass adoption. However, when very low GHG emissions are required, BESS can be a critical device to achieve such an ambitious goal.In the case of energy provision for an isolated hybrid energy system (HES), incorporation of BESS becomes profitable due to the fact that the fuel consumption and operating hours of a conventional generator are considerably reduced.…”

“…Combination of carbon capture and storage devices with conventional generation units is also an option to reduce GHG emissions. However, the combination of renewable generation with ESS can be energetically more effective [5].…”

Beyond the grid: the promise of solar concentration for non-electrical energy generation

“…As the need to decarbonize the world's energy systems becomes increasingly evident, renewable energy, in particular wind and solar, has proven itself a cost-effective way to meet this need [1,2,3]. Due to outdated perceptions of their economics, the fact that solar and wind power are now cheap, compared with fossil fuel generation, over a large part of the world, is often overlooked in policy discussions.…”