Thought this was interesting:
Exclusive: Pioneering scientists turn fresh air into petrol in massive boost in fight against energy crisis - Home News - UK - The Independent
Obviously it's not something "that promises to solve the energy crisis", and is reliant on us one day having a sufficiently well developed renewable energy network to power it. Nonetheless, we're likely to still want petrol both for its qualities as an energy storage medium and for its wider applications (e.g. plastics, fertilisers etc.), so it'll be interesting to see whether this develops.