"Just as converting chemical energy in the form of fuel into electricity endures 45-75% thermodynamic losses, converting electricity back into chemical fuels loses 60-70% of the energy in the process. Converting solar power into natural gas only to burn it in a gas turbine power plant could help with long term seasonal energy storage but is so much less cost competitive than other ways to stabilize electricity supply that we should expect this usage modality in, at most, niche cases."
If the chemical fuel can work in a fuel cell, then where it's relevant (high latitudes in winter), you can get 100% efficiency in the chemical->used energy step by using the fuel cell for heating.
The electricity->fuel step struggles to heat 50%, which is not a deal breaker compared to other sources.
"Just as converting chemical energy in the form of fuel into electricity endures 45-75% thermodynamic losses, converting electricity back into chemical fuels loses 60-70% of the energy in the process. Converting solar power into natural gas only to burn it in a gas turbine power plant could help with long term seasonal energy storage but is so much less cost competitive than other ways to stabilize electricity supply that we should expect this usage modality in, at most, niche cases."