THE ECO HOUSE

Ron finds a very real "Eco House" here in Stoke Ferry and is finally converted to the benefits of wind power.

Regular readers will know that I have been scornful of the big wind turbines on more than one occasion. My views were further strengthened when I learned recently that their average power output is about one third of their maximum capability. The first Swaffham windmill had a max. output of 1.5MW, the later one is 2MW. It would take 2000 windmills like the Swaffham pair to equate to one medium size conventional power station, even then, of course, they would produce their power in a variable and unpredictable manner, sometimes with a power output of zero.

I have always held the view that the real advantage of wind power and solar power is that the distribution is free and that it makes little sense to try to collect the energy in large installations and then suffer the cost and losses associated with the distribution. Ideally in my view, wind and solar energy should be collected at the point of use. I have thought that it would be good to see small windmills and solar panels installed in domestic situations, on farms and in small industrial units. With this in mind I was delighted to learn of an excellent small scale installation of wind and solar power for a bungalow right here in Stoke Ferry.

Mick Pick, who will be known to many of you, has his bungalow in Great Mans Way and has endeavoured to minimise his dependency on the utilities; he has succeeded to an amazing extent. With the combination of solar heating of his hot water and wind and solar energy for generating electricity he has gone a long way to achieving self sufficiency in energy; about the only significant inconvenience he is likely to suffer in the event of a power cut would be that he could not use his oven. Making maximum use of rain water he has also greatly reduced his demands on his Anglian Water supply.

The electricity he generates is wired into the bungalow in a separate ring so that there are dual sockets at each power point location, thus lights and appliances may be plugged into either home generated or mains electricity. In practice Mick's home generated electricity is able to provide all of his lighting, run his frig/freezer, kettle, toaster, slow cooker, TV etc, he even has a directly heated non-stick cooking utensil that enables him to 'hob-cook', he can also run his washing machine on a cold wash. Whilst he cannot run all these things simultaneously, he can generally run any one of them at the same time as his lights, TV and frig.

The wind turbine is mounted on a pylon 7 metres high, the turbine itself is 8ft (2.44m) in diameter, hence the distance from the ground to the tip of the rotor blade is just over 8m. Mick is concerned, however, that he is not obtaining the maximum energy from the wind; ideally he believes it should be significantly higher. The turbine was built from a kit and the whole system built by Mick himself. The turbine rotates at speeds up to 400 rpm and has an ingenious method of self adjusting to excessively strong winds, it generates d.c. Electricity at a nominal 24 volts and, in a reasonably good wind, is able to generate up to a little over 500W. This electricity is used to charge a bank of 6 24V batteries with a total capacity of 690Ah (16.5 kWh) at a charging rate of more than 25A. The output from the batteries drives an inverter to produce 240V a.c. up to a maximum power output of 1.5kW. The inverter has a built in sensing system such that it only operates when a load is applied on the circuit in the bungalow.

The photovoltaic solar panel is 1 m2 in area and converts solar energy directly into electricity and can produce up to 180W at 24V in full sun, and will produce some power under practically all lighting conditions. The electricity generated by the solar panel is also used to charge the batteries and provides a useful supplement to the wind turbine at times of light wind. On a sunny windy day the total generating power is potentially up to almost 700W. (I note that our average consumption for the first quarter of this year, a time of high use, was 623W which would indicate that a steady supply of electricity at 700W would meet the needs of most homes if it could be satisfactorily stored, unfortunately the power requirements of cookers, washing machines, some freezers, and immersion heaters are such that they are outside the capability of a system the size of Mick's). Mick Pick is a very capable man who takes a pride in his work, practically everything has been done by him, the whole electrical system appears to be superbly constructed and engineered. Whilst the system could be left largely to run itself, it is true to say, however, that, in order to achieve optimum results and in order to maintain the life of the batteries, it does require some monitoring.

Rain water from the roof of the bungalow is collected and passed through a filter to a 1000 gallon tank buried in the garden under the wood shed. This water is pumped to a separate loft tank and is used to supply all the taps apart from the cold tap in the kitchen and the cold tap in the washbasin. It supplies soft water for bathing, showers, washing clothes and washing dishes. Despite the abnormally dry weather this year, rain water met all Mick's needs until late June, and no doubt the recent heavy downpours will have topped up his reservoir. It would seem that in a bad year it is able to supply all the water for almost 9 months of the year; in a good year the tank may not run dry at all. Hot water is supplied by a solar panel set in the roof of the bungalow. The hot water supplied by solar heating can be at a temperature as high as 80C in hot weather, quite close to boiling and far far too hot to put your hand in. This solar energy is used to heat water in a separate hot water tank; in summer water is drawn directly from this tank, in winter this tank supplies pre-heated water for a conventional hot water tank. Of course the system is arranged so that if the rain water runs out mains water is used. The solar hot water panel has an area of about 18 ft2 and was constructed by Mick using a salvaged heat exchanger comprised of copper pipes soldered to a flat plate which Mick painted matt black and installed beneath a transparent panel of double glazed plastic. The water in the panel is part of a closed loop which heats water in the separate hot water tank indirectly by means of a coil.

The bungalow does have conventional central heating with a boiler burning bottled gas, needless to say, consistent with the overall ethos it is a condensing boiler, but Mick relies on a wood burning stove to provide the base heating and minimise his gas consumption. The construction of the bungalow itself (also largely a self build project) is to a high standard with thicker walls than usual and exceptional thermal insulation.

I have considerable admiration for the manner in which Mick has pursued his aim and for the thoroughness and standard of workmanship in everything he tackled, only someone with his level of ability could undertake such a project. Even with so much of the work done by himself, however, it has cost a good deal such that, at present day energy prices, it will take a very long time to pay for itself. Nevertheless it may be a model for the future, fuel prices may rise a lot further yet. Mick has the enormous satisfaction of knowing that he has minimised his requirements for help from the service utilities and minimised his contribution to CO2 emissions. He also has the additional satisfaction of being paid 4.5p for every unit of electricity that he produces, even though he uses it all himself. This is because of the manner in which the electricity supply companies are required to sell a proportion of their electricity generated from renewable sources, and because renewable energy is subsidised. By including Mick's electricity within their total the company is helped to meet their target.

Ron Watts