In the early 1980s, the BBC's Television series The Great Egg Race pitted teams of engineers against each other in a bid to solve technical challenges against the clock.

Apart from the unlikely star host, Professor Heinz Wolff, the attraction lay in the range of solutions teams came up with to solve the same problem.

There is something reminiscent of this in the plans of those bidding to win the Scottish Government's Saltire Prize for tidal energy. Four companies are in the race, offering a range of potential technologies in a bid to use wave power to deliver a continuous and reliable source of energy.

The solutions under development have included a seabed 'flap', underwater devices similar to wind turbines and a snake-like wave energy converter designed to ride on the surface of the Pentland Firth.

As in the TV series, the prize is of limited value. The £10m at stake is dwarfed by the development cost inevitably incurred by any winner. It is also considerably less than the sums already poured into funding tidal power companies and initiatives by ministers.

We do not mean to trivialise the efforts of those involved, or the goal - albeit that this Prize was always politically-driven. The Saltire Prize was designed to reinforce the Scottish Government's claims that Scotland could become the Saudi Arabia of renewables.

Now the prize appears to be unwinnable. One of the leading players, Pelamis, went bust, while none of the remaining four are remotely likely to be in a position to deliver in time for the 2017 deadline.

This is somewhat embarrassing for the government. Critics would say this shows former first minister Alex Salmond was living in cloud cuckoo land when he made the Saudi Arabia comparison. Even supporters would have to admit the vision was over optimistic.

This does not mean the prize has not had value in raising the profile of the wave power industry and encouraging companies to think big.

Neither does it mean the goal of leading the field in tidal technology should be written off. The lesson from the past is that Scotland lost out almost completely to Denmark in the race to develop commercial wind power, by hesitating at crucial moments. Nurturing such young industries takes patience and a commitment to long-term investment.

The Saltire Prize was and remains an innovative approach and a worthwhile statement of intent.

However ministers have been guilty of suggesting that renewables offer a cheap or easy fix. That is not the case, and rejecting fracking and nuclear power means Scotland is likely to remain dependent on traditional fossil fuels for the forseeable future.

Yet the government should hold its nerve on renewables. There may come a time when it becomes clear that no more money should be risked on a technology which cannot deliver. That time is not yet.

Setbacks are to be expected. As Professor Wolff would have said, in his near-parody Germanic tones: you can't make an omelette without breaking eggs. But another relevant metaphor also applies. Ministers must not put all their eggs in one basket. As well as ambitious, Scotland's energy policy must also be stable, viable and realistic.