The $1 profit goes towards paying for capturing carbon. Every 150 barrels of captured fuel you sell, you make $75 profit you could spend on either not selling a barrel, or some more efficient way of reducing our climate impact like maybe buying a solar panel or sponsoring a windmill.

Or what the sibling suggests, you keep the money as profit / funds for growing the business so you displace traditional oil and you prevent the increase of CO2 in the atmosphere that way.