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.
Firstly, let us deal with the performance of solar at this time of the year. In January 2006 Genersys supplied two solar panels to the New and Renewable Energy Centre (NaREC) in Bligh, Northumberland, who wanted to carry out some tests for the National Energy Action charity. We offered to show them how to install the panels but they wanted to tests to be independent of us, and I understood that.
NaREC are an independent laboratory with a great deal of expertise, but in the UK there is not too much solar thermal expertise and they wanted to test, learn about it and assess our product without our input in the first instance.
After the installation our engineer, Michaela Sadovska, reviewed their test site and found that they had used high quality heat resistant plastic pipe to connect up to the panel. In our view the temperatures generated by our panels would cause the heat resistant pipe to melt. They should have used copper pipe which was brazed, not soldered.
We predicted that the pipe would melt on the first sunny day in March.
It did. On 1st March 2006 the panels generated enough heat to melt the pipe which resists temperatures around boiling point, as you can see from the picture, which was sent to us by NaREC.
So much for Mr Howell’s advice about heat generated by a solar system in April.
As far as Mr Howell’s claim about savings is concerned, he fails to appreciate that water heating, according to the government, accounts for 24% of your household energy, on average. If you use electricity for heat and water heating the calculation is simple. If you use heating oil or gas, then according to government statistics, about a third of the gas or heating oil is spent on water heating.
Virtually all modern solar systems cover between a half and 70% of the water heating in the United Kingdom, so you can calculate the basic savings. Once you have done that you should factor in the fact that you have pre-purchased your energy with a solar system so you are insulated from a proportion of the energy price rises, and that your boiler will suffer less wear a tear, which means lower repair bills. Modern solar systems do not require any significant maintenance, except inspections and possibly changing the heat fluid every ten years or so.
We constantly get feedback from customers, as do Genersys installers. One installer reported that one lady told him how pleased she was with her solar system (not one of ours) which saved her one oil fill a year which for her meant £500 savings this year.
It is difficult to provide averages for savings on hot water bills because everyone has different experiences; I heard on the BBC’s Radio 4 of a lady whose heating oil bill had risen to £260 every six weeks, not an uncommon experience. She would save around £520 a year with a Genersys system. The savings for electricity will be higher but lower for gas. So much depends on individual systems, individual use and lifestyle and we can only give guidelines but they will all be much more than £70 a year!
I did run across Mr Howell’s web site some months ago which had misleading information on it. I wrote to him and offered him our facilities, to talk with our engineers and evidence so that he could change his views. He closed his mind to my offer, preferring to retain his misguided inaccurate opinions, which is a shame, especially when they are published in a quality newspaper which has a Saturday readership of over 2.6 million people.
I expect you know that you should not believe everything that you read in the papers, and when it comes to solar it is better to get your advice from a qualified solar thermal engineer, not a builder.
Filed under: carbon emissions, climate change, electricity, energy, energy statistics, gas, heat, microgeneration, oil, solar, solar energy, solar panels | Tagged: calculation of solar savings, Jeff Howell, NaREC, proportion of household energy on water heating, savings when solar displaces oil, solar system payback, the daily telegraph |