even with long term storage?

Gathering solar power isn't a problem, but storing it is. Lithium-ion batteries can be cheap now, but I am afraid that we just have not enough lithium sources to build as many batteries as we need.

Also it's unclear for me how to deal with winter. Storing energy gathered in summer for consuming it during winter isn't viable, sine it requires too much storage capacity. The only way left is to have enough solar cells to produce enough energy in winter, but it may be too costly, since typical winter power output is several times less than during summer.

> £0.02 to produce one unit of power

And what unit of power would that be? Why be so vague?

solar is bieng deployed very quickly in many parts of the world, and at wildly different scales. Sodium batteries and high density capacitors and a long list of other chemical,heat and mechanical, energy storage and conversion technologies are maturing quickly. Anybody or any country that is lagging will get out competed in a world where fossil fuels costs can only rise. Hydrogen is complicated by it's physical properties, of bieng so tiny and light, that containing it during storage and transfer is still very difficult and expensive. Liquid solid, and gasious, Hydrocarbon fuels are tied to large ,complicated and expensive industrial operations, with feed stocks that require huge field operations, that NOBODY wants. Solar just sits there, a "solar spill" is just another sunny day.Realy realy hard to compete.

I guess technically speaking, the world's cheapest source of power is nuclear fusion!