Biofuels – we drive and the world starves

 

Sometimes you can only see a picture clearly if you step back from it, so you can see the whole canvas. So it is with energy. Without any doubt we are heading for an energy crisis. The oil will probably peak – that is to say reach its maximum production in ten years time. Oil companies are discovering smaller and smaller fields – not by chance or by accident or a run of bad luck, but simply because there is less oil in the ground to be discovered.

 

The same scenario exists with coal, natural gas and uranium. These will probably all peak at around the same time (give or take a decade) as developing countries ape the habits customs and lifestyles of the developed countries. With this in the back of some politician’s minds (and in the forefront of others) many developed countries are looking for new sources of energy which are, in the current jargon, sustainable.

 

Biofuels – that is fuel made from growing crops – seemed like a good idea at the time. Continue reading

Wind turbines or peat lands Scotland makes a wise choice

The Scottish Parliament has always been a supporter of renewable energy; its record is exemplary – far better than Westminster’s on renewable energy, so when it announces a decision to reject an application to build 181 wind turbines to generate electricity on the Isle of Lewis some eyebrows were raised.

 

I am sure that the application was not rejected lightly. The plan had the support of the local authority and of many local businesses but over 11,000 objections to the plan were made. The plan was rejected because of the adverse impact it would have had upon the Lewis peat lands at Bravas Moor.

  Continue reading

Solar panels – different types of absorbers -what they do and how they work

Solar panels for heat have been around for about a hundred years and in that time they have developed by a process of continuous improvement. The solar panels that you can buy today are, in many cases, very different from ones that were used 20 years ago. Some manufacturers have not improved the panels at all while others have made tremendous strides, so if you are in the market for solar panels for water or pool or space heating look for the latest panel type.

 

At the heart of every good panel is the absorber. This is the black looking surface which reacts to light to generate heat energy. On every panel there is such a surface which when light strikes it there absorber’s surface molecules vibrate, which causes friction. Friction creates heat and thus the process of vibration turns the energy in light into heat, which is captured by the panels.

 

There are different types of absorber surface. Continue reading

Good decisions and bad decisions

In life we all make some good decisions and some bad decisions. Decisions that are right are good; decisions that are wrong are bad. In business I make lots of bad decisions but I hope to make more good decisions than bad decisions.

 

In the strange world of government, we find that governments do not admit that they make bad decisions from time to time. If they were to admit making a bad decision I expect that they are frightened of being criticised, first for making a bad decision and then for reversing the bad decision because in our society reversing a decision is seen to be even worse than making a bad decision.

 

Right now the government has got itself into a big hole with its threatened abolition of the 10% tax band for the very low paid, who will now have to pay tax at 20% on all the earnings instead of paying 10% on the first £2,230 of taxable income. It must have sounded like a good idea at the time Continue reading

How to choose a cylinder and cylinders working with solar systems

Solar panels are critical to an excellent solar system performance, but just as critical is the place where the energy is stored. In Britain these are called cylinders, in other places “tanks” and in other places “geysers” but they all look the same and serve the same purpose.

 

I will explain cylinders insofar as they affect the United Kingdom; other countries have different plumbing laws and regulations as well as different ways of getting potable water into homes, so I shall concentrate on the United Kingdom position.

 

Most homes have a small cylinder – typically 80 litres or so, hidden in an airing cupboard. Before homes had central heating (like my home in Poplar when I was a child) the cylinder had an immersion heater, just like an electric kettle. When you needed hot water in the bathroom you turned on the immersion heater and the cylinder warmed up.

 

Most homes have central heating these days and although the cylinder usually has an immersion heater this is there for back up. The central heating boiler usually has a pipe connecting to a heating coil inside the cylinder and then back to the boiler (a flow and return). When the cylinder needs hot water the boiler pumps hot water through the coil. This exchanges heat from the boiler into the water inside the cylinder. That way the potable water is kept apart from the boiler and central heating water, making the heating of water hygienic.

 

When water is heated in a cylinder it will expand, and you need somewhere for the water to expand into. Traditionally this has been a tank in the loft (or higher than the cylinder), open to the air. A pipe runs from the cylinder to the tank and terminates over the tank leaving the cylinder open to the air. This is called a vented cylinder.

 

Many quality systems prefer to use a sealed boiler which is connected to a pressure vessel close to the cylinder. That covers the safe expansion of water, and the resultant hot water pressure provides an excellent shower pressure without pumps and can usually be arranged so that there is no pressure loss or hot water imbalance when several hot water taps are turned on at the same time. This is called an unvented cylinder.

 

Unvented cylinders have to be made well, and out of strong durable materials such as stainless steel, and they have a long life span, subject to the water hardness where you live.

 

When you have a solar system installed in most cases it is better to change the cylinder. A solar cylinder is much larger than a traditional cylinder – usually between 150 litres and 200 litres. As a rule of thumb a two square metre Genersys panel is sufficient to heat 100 litres of stored water. As you can store your solar heat energy in the cylinder it makes sense to store what you need for toady and a little to tide you over for the next day. An average home uses around 113 litres of hot water a day.

 

There is another important difference with a solar cylinder; it has two coils. The coil connection to the boiler should be in the upper part of the cylinder and a much larger coil will be in the lower part of the cylinder connected to the heat transfer pipes that connect to the panels. If you reverse the connection the performance will be poor because the solar will ”fight” with the fossil fuelled coil.

 

An average lifespan of a vented cylinder is less than ten years but people tend to replace them at longer intervals (usually when they break) because out of sight is out of mind. They still get hot water from their system with an old cylinder but do not appreciate that it operates more inefficiently and more expensively in fuel terms with age.

 

If you do need to change your cylinder my advice is

 

  • Also think about a solar system at the same time
  • If you can go for a stainless steel unvented cylinder – you will lose a lot of tanks and pipes in the loft and will have drinking water from bathroom taps, but you need your plumber to check the local water pressure first
  • Go for quality; the more expensive cylinders have better insulation and you will save the price differential in the long run
  • Get a competent plumber who has the qualifications to work with unvented cylinders – not every plumber has these.

 

I am not an expert in plumbing so I ran this post past Chris Flaherty of Vietec Heating who helped me out with it and I thank him for it. You can find him at www.vietec.com

 

 

The money you save with a solar system

There are some positively misleading reports about what solar water heating does and what it saves. In the Telegraph on Saturday one “expert” who turns out to be a builder claiming to “give it to you straight, Jeff Howell, claims that the annual savings are less than £70 per year and that at this time of the year the solar system will only slightly warm the water, in an advice column published on 12th April 2008.

 

It is positively wrong. I do not know why the Daily Telegraph thinks it right to hold out a builder with the knowledge and expertise of a thermal solar engineer, but they do and as a result Mr Howell misleads the Telegraph readership. Mr Howell may be an excellent repository of advice about building but he knows little about solar. Continue reading

How much will sea levels rise and what will be the consequences?

New research has indicated that sea levels are likely to rise more than the Intergovernmental Panel of Climate Change has predicted. The IPCC forecast a rise of between 28cm and 43cm by 2100 but a latest study by the Proudman Laboratory suggests that the rise could be between 800cm and 1500 cm. This higher figure has also been suggested by other researchers at the using different methodology who suggest a rise of between 600cm and 1500cm. Continue reading