We are the Human Family and until we get to learn that money is not everything the better. We need to grow our own food. Raise our own livestock. We need the land that the Kings of England stole from the common people. We need to have water supplies. We need to suppport each other in small village communities.

We need to lower our population or nature will lower it for us. One way this might happen is through oil running out in 25 years. Then it will be rationed until it is no more. At that point, we’ll be forced to grow our own food, and live without medicines. I predict millions will perish in a world without oil with diminished gas and coal because of the lack of that oil. Sustainable development is an oxymoron. Sustainability cannot occur if we develop, only if we decline and undevelop. Growth is the politicians God. But sustainability is the people of the future’s requirement. these two are incompatible.

I think Monbiot, Porritt and Leggett need to rethink their ideas of sustainability and do some maths.

The first is to do with the cost-effectiveness of the carbon savings achieved by investing public money in this way as opposed to other ways. As I try to argue on my blog, the “overheads” in microgeneration systems form a larger part of the overall cost than they do in larger projects.

These overheads include everything from the inverter to the scaffolding required to put it on someone’s roof. They also include the administration of the project.

Indeed if we were recommending – in the absence of subsidy – a solar roof to somebody we would really recommended it be installed at a time when their roof was going to be replaced and the installation would be building-integrated. This would give it the greatest cost effectiveness.

Jeremy Leggett and others in their response to Monbiot’s article quote levels of insolation directly from solar insolation maps, in kilowatts per square metre. They seem to give the impression that this is what will be generated from an installation in a given location. However we all know that this is not the case. Actual generation is never more than two thirds of this figure. And it is an average over the whole year. And it depends on on the installation being correctly aligned. None of this happens in the real world.

This is why I am trying to find as many as possible monitored case studies from actual installations. Most of the figures I find farm industry which are not independently verified. Some of the reports available in the UK give a very different picture.

These independent reports that are available which I reference on my blog indicate that the most cost-effective measures – expressed in carbon savings per unit of public money spent – for maximum carbon reduction are windfarms, or certain kinds of district level interventions.

They also indicate that there just isn’t enough sunshine in the UK, even in the sunnier spots in Devon and Cornwall, to generate electricity at a time when it is most needed: in the winter when the lights need to be on. Perhaps in the future when photovoltaic technology is much cheaper and has achieved much higher levels of efficiency, it will be able to do so.

The second point is this: the tariff comes from an amount added to everybody’s electricity bill. People on lower incomes pay a higher proportion of their income on energy that people on higher incomes. It is the middle and upper class who will be installing these measures.

Poorer people will therefore be subsidising them so that they can receive an income. Government in the UK has argued that there exist social housing organisations which will tackle this this by installing solar on rented accommodation. However the benefit of the income will not go to the individuals paying the electricity bills but to the associations.

They also argue that the carbon emissions reductions target (CERT) which obliges energy companies to take steps to ensure that the amount of CO2 from homes is reduced, is targeted at the fuel poor, and it is true, but there are a great many fuel poor that it does not reach because of the way its criteria for eligibility are designed.

We take the point that feed in tariffs are intended to reduce the cost of solar installations and that this has happened in Germany. But we do not think that the poorer people in society should have to pay for this.