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The Centre for Alternative Technology

The Centre for Alternative Technology
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We are constantly being bombarded to save energy and recycle everything, but even with the best intentions it is not always easy.  On a recent trip to Wales, Brian Spencer picked up a few hints and with constantly rising energy costs, maybe saved himself some cash in the long run.

On a wooded hillside high above the Dovey valley in mid-Wales, what began as a kind of alternative hippy-style community around 40 years ago has blossomed into a highly efficient organisation. Spread across a clearing in what was once a slate quarry, the site is filled with ideas about how to create a carbon-free environment and save money into the bargain.

To reach the centre, or CAT as it calls itself, visitors climb the 34° hillside on one of the steepest cliff railways in the world. Travelling at a stately 1.5 miles per hour, the cabins are powered not by electricity or steam, but by water. Two carriages connected by a cable via a drum at the top of the slope run in opposite directions. There is a tank under each cabin and when water fills the upper one, it can travel downhill by gravity to the lower station, while hauling the other cabin to the top. Reaching the bottom the tank empties and the whole operation can then be repeated.

The speed of descent is controlled by a hydraulic pump combined with a regenerative breaking system, allowing surplus energy to pump some of the water back uphill. Water used to power the lift comes from a small lake behind the upper station and where wildlife has been quick to establish itself – along with woodland birds, the pond and its surrounding woodland is host to otters, polecats together with red kites and peregrine falcons always on the lookout for a quick meal.

What is hard to appreciate is that until CAT took over, the site was many feet deep in quarry waste where nothing could grow. From compost mostly made on site, the whole area now has sufficient soil to allow trees to establish and more especially, fruit and vegetables to grow; the site now produces enough food to supply the restaurant as well as feed on-site workers. Energy efficiency is the key word that crops up everywhere you turn. A timber framed self-build house certainly offers plenty of ideas of how to go about creating easy to build energy efficient houses. Whether our local planning authority would accept the concept of the straw-bale theatre is rather doubtful, but it was certainly snug even on a cold, damp, Welsh afternoon.

What did offer the best ideas was the Whole Home, a lesson in super efficient insulation. Surrounded by a typical suburban garden where the soil is all man-made, the house is the last word in comfort and energy efficiency. Layers of mineral wool 450mm thick insulate the roof, floors and external walls; heat loss is further reduced by quadruple glazing in all the windows. The net result is that, for an extra building cost of around 10%, only one fifth of the energy needed for heating a conventional house of the same size is used. Even in mid autumn the ground floor, the only section open to the public, was comfortably warmed by a single radiator.

The house also has a conservatory collecting further heat from the sun. The Whole Home’s garden stands on what was once quarry waste slate several metres deep; the soil created from a mixture of slate dust and compost made on site. As a result it is spongy and moisture retaining. Laid out in beds to conserve precious soil and also make work on them easy, an example of organic gardening has been created that would fit easily into the average domestic plot; there is even room for a small lawn. Along with a herbaceous border with plenty of flowers and a greenhouse, vegetables grown in rotation over a four-year cycle ensure that each variety is given the right soil conditions and also reduce disease. Flowers planted amongst the vegetables attract insects that control pests and also help pollination. No artificial fertilisers are used and the garden reaches the highest standards required by the Soil Association.

We enjoyed a warming bowl of soup made mostly from vegetables and herbs grown in this garden. Still on the theme of gardening, a nearby poly-tunnel was pleasantly warm and still growing weather sensitive plants despite the weather, but showing that large scale greenhouses can be made at a fraction of the cost of glass. Figs, grapes, peaches, peppers and squash flourished alongside winter salad. We could hear children squealing from the far end of the tunnel and moved to see what the noise was all about. It turned out they were happily scaring each other in an over-sized mole tunnel.

Mister Mole and his vicious teeth and long claws somewhat larger than life was poking his head out from a side run. The idea of the mole hole is not simply to entertain children, but to show how what goes on beneath the surface is as important, if not more so than on top. Sunshine was in short supply on our visit, but the exhibition of solar technology was still merrily producing electricity in a display that offers several ways of harnessing the sun’s rays.

A large photovoltaic solar roof extends over the restaurant and lecture buildings, one of the largest pitched roof arrays in the United Kingdom, generating 13.5 kilowatts. More than enough to supply the cluster of surrounding buildings, any surplus power it generates is diverted into the National Grid. Electricity generated on-site is also stored in batteries to cover night-time use, but this is unsuitable for general domestic use. Small scale demonstration models popular with youngsters who, by shading the sun can switch the solar power on and off at will, give an idea of the range of systems available using free energy. A booklet entitled ‘Choosing Solar Electricity’ covers a wide range of alternatives and can be bought on site.

Proposals to erect wind turbines up and down the countryside, even when proven to create ‘free’ power, can be guaranteed to generate heat of the wrong kind. Arguably a blot on the landscape, the system is one that should be considered without passion. The Wind Pavilion is devoted to the subject with cut-away triple blades of a decommissioned MS-2 showing how they operate, lying beside a spiral single bladed system and many other smaller ones. Seen close up the size of the MS-2 looks monstrous, but apparently it is considered very small by current standards. An older turbine pumps water through the energy created by a multi-bladed windmill, but it has been modified to create a ‘wind seat’ where visitors can feel the power of the wind. It also explains why water pumps required a greater number of blades than electricity generating turbines – apparently it is all to with torque (turning force) to pump water and high rotation forces to generate electricity.

Woodland management and bio-mass methods of growing fuel are another way of creating sustainable land use. Fast growing willow when coppiced can be used for hand tools as well as burning either when seasoned, or as charcoal. Bat boxes and bird feeders are in use all year round, while at ground level, geese and hens rummage amongst the dead leaves, keeping excess weeds under control and turning fat on worms. Even the humble lavatory has come under the scrutiny of CAT boffins. While they may look like ordinary toilets, those on the site are designed to recycle water.

Using rain water in a system known as an ‘Aquatron’, solids are first removed for composting and the water filtered away and then allowed to purify in reed beds. There is even a water-less loo that sits on top of a composting chamber; when it is full it is closed off and the ‘upper works’ moved over another box, leaving nature in the shape of friendly bacteria to do the rest. CAT, the Centre for Alternative Technology is open from April – October daily from 10am to 5pm and at variable times from November to March. The site is 3 miles north of Machynlleth on the A487. Nearest train station – Machynlleth. Buses 30, 34, T2 stop at the site entrance.

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