A system for producing hydrogen gas, the system comprising: - a reformer reactor for containing a carbon dioxide capturing sorbent, ∘ wherein the reformer reactor is configured to allow reforming of a feed material and a steam to produce a reformate gas mixture comprising a hydrogen gas ( H 2) and a carbon dioxide gas ( CO 2), ∘ wherein the reformer reactor comprises a reformer inlet for feeding at least one of the feed material and the steam into the reformer reactor and a reformer outlet for ejecting the hydrogen gas ( H 2) and a used sorbent ( A *) produced within the reformer reactor, the used sorbent ( A *) being defined as a the product resulting from reaction between the sorbent and the carbon dioxide ( CO 2), - a regenerator reactor comprising ∘ a regenerator vessel, ∘ a regenerator inlet for receiving at least a portion of the used sorbent ( A *), ∘ a regenerator power source system configured to provide sufficient heat to the received used sorbent ( A *) to allow release of carbon dioxide ( CO 2) from the used sorbent ( A *) and to regenerate the carbon dioxide capturing sorbent, and ∘ a regenerator outlet for ejecting the regenerated sorbent, - a regenerator transport line (150,320) for transporting the used sorbent ( A *) from the reformer outlet to the regenerator inlet and - a recycling line for transporting at least a portion of the regenerated sorbent from the regenerator outlet into the reformer reactor, wherein the regenerator power source system comprises - a gas burner comprising ∘ a first burner inlet for feeding a first burner gas into the burner, ∘ a burner outlet for ejecting an exhaust off-gas produced inside the gas burner and ∘ a burner transport line for transporting the exhaust off-gas from the burner outlet to an internal volume of the regenerator reactor vessel, and - a return line (226,226') for transporting at least a portion of the cooled exhaust off-gas from the internal volume of the regenerator reactor vessel into at least one of the gas burner and the burner transport line. - a reformer reactor for containing a carbon dioxide capturing sorbent, ∘ wherein the reformer reactor is configured to allow reforming of a feed material and a steam to produce a reformate gas mixture comprising a hydrogen gas ( H 2) and a carbon dioxide gas ( CO 2), ∘ wherein the reformer reactor comprises a reformer inlet for feeding at least one of the feed material and the steam into the reformer reactor and a reformer outlet for ejecting the hydrogen gas ( H 2) and a used sorbent ( A *) produced within the reformer reactor, the used sorbent ( A *) being defined as a the product resulting from reaction between the sorbent and the carbon dioxide ( CO 2), ∘ wherein the reformer reactor is configured to allow reforming of a feed material and a steam to produce a reformate gas mixture comprising a hydrogen gas ( H 2) and a carbon dioxide gas ( CO 2), ∘ wherein the reformer reactor comprises a reformer inlet for feeding at least one of the feed material and the steam into the reformer reactor and a reformer outlet for ejecting the hydrogen gas ( H 2) and a used sorbent ( A *) produced within the reformer reactor, the used sorbent ( A *) being defined as a the product resulting from reaction between the sorbent and the carbon dioxide ( CO 2), - a regenerator reactor comprising ∘ a regenerator vessel, ∘ a regenerator inlet for receiving at least a portion of the used sorbent ( A *), ∘ a regenerator power source system configured to provide sufficient heat to the received used sorbent ( A *) to allow release of carbon dioxide ( CO 2) from the used sorbent ( A *) and to regenerate the carbon dioxide capturing sorbent, and ∘ a regenerator outlet for ejecting the regenerated sorbent, ∘ a regenerator vessel, ∘ a regenerator inlet for receiving at least a portion of the used sorbent ( A *), ∘ a regenerator power source system configured to provide sufficient heat to the received used sorbent ( A *) to allow release of carbon dioxide ( CO 2) from the used sorbent ( A *) and to regenerate the carbon dioxide capturing sorbent, and ∘ a regenerator outlet for ejecting the regenerated sorbent, - a regenerator transport line (150,320) for transporting the used sorbent ( A *) from the reformer outlet to the regenerator inlet and - a recycling line for transporting at least a portion of the regenerated sorbent from the regenerator outlet into the reformer reactor, wherein the regenerator power source system comprises - a gas burner comprising ∘ a first burner inlet for feeding a first burner gas into the burner, ∘ a burner outlet for ejecting an exhaust off-gas produced inside the gas burner and ∘ a burner transport line for transporting the exhaust off-gas from the burner outlet to an internal volume of the regenerator reactor vessel, and ∘ a first burner inlet for feeding a first burner gas into the burner, ∘ a burner outlet for ejecting an exhaust off-gas produced inside the gas burner and ∘ a burner transport line for transporting the exhaust off-gas from the burner outlet to an internal volume of the regenerator reactor vessel, and - a return line (226,226') for transporting at least a portion of the cooled exhaust off-gas from the internal volume of the regenerator reactor vessel into at least one of the gas burner and the burner transport line.