A review of potential routes to zero and negative emission technologies via the integration of renewable energies with CO2 capture processes

This paper broadly reviews the integration of different renewable energy sources including solar, bioenergy, wind, and geothermal energy with CO2 capture processes and evaluates the possible contribution to achieve net-zero or negative CO2 emissions. Each renewable energy integration option possesses advantage points, which may help reducing the CO2 capture cost and potentially realize the net-zero or negative emission ambitions. In power sector, renewable energy integration encounters a number of challenges such as high upfront investment, large fluctuation in the CO2 capture rate, and electricity cost. Nonetheless, those drawbacks can be minimized by flexible designs that would optimize renewable energy contribution with steam extraction to improve power plant efficiency and install on/off function to exploit low electricity price periods and to alleviate the effect of the intermittent nature of those renewable energy options. Although, many integration scenarios have been proposed in literature, there is a lack of consideration with recently advanced CO2 capture technologies in the hard-to-abate emission sectors such as heavy industries and heavy transport. Renewable energy integration may also bring a promising revenue to advance the ambitious goal of direct air capture (DAC) technologies due to the flexibility in location and operation modes, nevertheless, it draws a little attention. In this analysis, the ad-vantages and disadvantages of each renewable energy source when it is integrated into a CO2 capture process are discussed and thereby potential research directions are identified. It is emphasized that renewable energy integration could autonomize carbon capture retrofits to provide convenience to power/industrial plant oper-ators and/or to realize the ambitions of installing independent and scalable DAC systems on inexpensive land or in vicinity of the CO2 storage/utilisation sites.