This noisy Independent piece argues for a huge increase in roof-top solar panels on British homes.

Its arguments are based on the success of an earlier government scheme to bribe people to instal solar panels: "When first launched two years ago, the grants – which, for example offered up to £7,500 to install photovoltaic panels – were an instant hit."

That’s a surprise. Imagine being offered up to £7,500 for free and not wanting the deal.

Obviously it was crushingly expensive to roll out such state-funded incentives to everyone, so the scheme promptly withered.

Germany continues to subsidise these installations – total cost to the German taxpayer of course not mentioned in the article.

Why not let market forces do the business instead?

When I was in Belgrade I asked the Embassy to look hard at the options for installing solar panels on the roof of my Residence. This may be a perfect place for such devices. A large, flat space blasted by the sun from February through to November.

Yet our analysis concluded that it made little financial sense to make the change. Solar panels were too costly and generated too little power.

This was a few years back. Did we look at the wrong kit?

And how best to work out what these panels ‘actually’ cost anyway?

This is an an interesting snap-shot of an attempt to answer these questions:

Bizzarri and Morini point out that cost should not be the only consideration. The total energy and pollution involved in sourcing the raw materials, manufacturing, installing, and maintaining any particular system should also be considered. After all, if it uses far more energy to build a wind farm or install solar panels than the energy they can produce during their lifetime then it does not make environmental or economic sense to install them …

 … With this in mind, the researchers analysed all the costs from cradle to grave – in terms of energy use, pollution and carbon footprint, and economic – to find out whether photovoltaic cells are a truly viable alternative energy source …

… In their assessment of the three different PV panel types on the south-facing roof of a school in Ferrara, northern Italy, the team found that the energy produced by the panels over their lifetimes considerably overcomes the energy needed during manufacture. In fact, energy costs are recovered within two years in this medium sunshine climate.

The team also showed that carbon dioxide emissions are significantly lower over the PV panel lifetime from cradle-to-grave compared with conventional electricity generation. Economic costs, the team found, would only be recouped if the panels remained fully functional for more than twenty years.

If even a simple installation on a sunny school-roof takes 20 years to pay off, maybe better to do all this on a large scale in a desert?

There is a point in the Independent article, even if the article does not make it.

Namely, if the taxpayer is directly to subsidise energy production one way or the other over decades to come, which sort of subsidy is ‘better’?

Next to impossible to agree even the basic factual and economic assumptions for beginning a serious debate about this, let alone concluding it in a way which will command consensus?

At least a system based on (as far as possible) encouraging mass energy-producing decentralisation will not be vulnerable to terroristic or other centralised breakdowns?

But we need to get on with deciding if we are to avoid South Africa’s fate…