The Centre for Alternative Technology (CAT) teams up with Shambala festival to demonstrate sustainable buildings to festival goers.

For the last three years CAT and Shambala have been working together to make Shambala the greenest UK festival by producing the most detailed carbon audit of any UK event. This year, Shambala achieved the highest ever rating from the Industry Green assessment, and, alongside CAT, have been working with Julie’s Bicycle ( to make changes at Industry level.

“Shambala is 99% powered by wind, sun and waste vegetable oil and has been judged the greenest outdoor event by Industry Green and A Greener Festival ” Sidharth Sharma, Director & Creative Coordinator of Shambala festival

This year CAT is teaming up with Shambala to demonstrate sustainable building to festival goers. As part of a shared commitment to sustainable futures (and having fun), the CAT team will be on-site showing what can be constructed with natural raw materials.

“Houses out of hemp, Walls out of willow, Towers out of timber, Structures out of straw and Arches out of earth – Come and help us explore the new worlds of zero-carbon building!” said Peter Harper from CAT.


The Shambala Festival has blended music, art, creativity and participation all in into perfect bite size chunks of brilliance for well over a decade. It is now firmly established and respected as being one of the most innovative, creative and environmentally conscious festivals in the industry.

Set across 4 days on the August Bank Holiday weekend, the variety and quality of entertainment on offer is staggering for a festival of its size. With over 200 diverse musical acts across 12 live stages, world-class cabaret, stand-up comedy, inspirational talks and debates, jaw dropping circus and acrobatics, interactive theatre and nationally acclaimed poetry all housed in beautifully crafted venues.


Woodland management

At CAT we manage the woodlands to enhance their biodiversity and maintain a range of habitats for wildlife. We thin the trees to keep a continuous canopy, favouring certain species and removing others. This provides us with a range of sizes and species of trees that we can covert in to different products. Part of my job is developing the uses of our timber and trying to create marketable products such as rustic furniture, turnery and garden products, gaining a sustainable economic benefit along side the environmental and social functions of our lovely woodland.

When the trees are cut down, usually in the winter period when the sap is low, the wood is graded in to levels of usefulness. Small diameter straight stems for bean poles and plant supports and slightly larger stems for hedge stakes. Any other small diameter stems go to make charcoal in our retort. Medium diameter straight logs of ash, willow, beech, sycamore, lime and birch are kept for green woodworking and rustic furniture and large straight logs of oak, beech, douglas fir, western red cedar and larch for milling in to sawn timber or are split for fencing or construction. Any wood that can not be converted in to woodland products we leave for firewood. It is left in logs, or ‘in the round’, for a year then split, chopped and stacked for another year so it is very well seasoned. On site we have used a variety of different stacking methods including the rather attractive round German woodpile called a Holzhaufen.


Over the few months or so we have provided poles for some of the courses run on site, supplied Chloe and Roger with bean poles and pea sticks for the gardens and made some door knobs for the renovations in site community. I have also made a gate, a simple bench and a few items of turnery out of green wood on our pole lathe, including rounders bats, honey spoons and garden dibbers. The list of items to make is set to grow as long as I can keep escaping from the office to the bodger’s shelter!

Reedbeds and Sewage

The Eco cabins at CAT have their own reed bed systems which are used to treat sewage. Reed bed  sewage systems use a series of natural filtration systems to treat waste water. Discharging of raw wastewater has a negative impact on the environment such as eutrophication of receiving water bodies, pollution of groundwater and odor. What is more, wastewater contains pathogenic organisms which transmit disease to animals and human. For these reasons it is crucial to have an effective sewage management system and operate it in proper way. This is what our biology department does.


Continue reading “Reedbeds and Sewage”

A comparison of two methods of mushrooms cultivation

Today I would like to talk more specifically about how we cultivate our mushrooms here at CAT. Currently, we are testing out 2 different methods so as to compare the results. One method uses straw or cardboard while the other method uses sawdust. In both cases, the straw/cardboard or sawdust must be pasteurised in order to clear them from micro-organisms so that the mushrooms can proliferate easily. This is done by putting them in boiling water for about 2 hours.

In the first method, the straw/cardboard is put in layers in a box with a small mycelium culture (i.e. spore culture), closed in a plastic bag and left in a hot room for about 2 weeks until it is completely colonised by mycelium. The straw is then put into a fruiting room, which is much colder. The cold shock that the mycelia undergo at this stage, make them start fruiting, i.e. growing into mushrooms. This process should take about 2 weeks as well.


The second method uses sawdust, is easier but takes longer. In this case, the mycelium culture is put into the sawdust and in an incubator until the mycelium culture colonises the whole container. The saw dust is then taken out and packed into pre-drilled holes in logs that have been kept on the ground for 2 years (this is to replicate the natural decomposition process). The logs are then left for about 6 month and should, hopefully, grow oyster mushrooms.


Mushrooms propagation or how to grow valuable protein resources

My name is Ariana, I am a long term volunteer in the biology department and today I would like to tell you more about our recent forays in the realm of fungi, that special kingdom not quite plant not quite animal.

Mushrooms are divided into different categories according to the substrate they live on; saprophytic mushrooms that break down organic matter and replenish the soils, parasitic mushrooms that colonize living organisms and mycorrhizal mushrooms that form symbiotic associations with plant roots.

Aside from performing important functions in nature like decomposing and recycling nutrients, mushrooms have a wide range of applications very useful for humanity. In Europe they are most famous for their culinary use, whereas in the East they are most widely employed in medicinal use; in Japan most cancer treating drugs are derived from mushrooms, and in China a huge variety are sold dry as health tonics.

Mushrooms have also been successfully used as barriers for excess nutrient in a process known as mycofiltration, as cleaning agents for toxic pollutant contamination (mycoremediation), and as inhibitors of undesired plant growth (mycopesticides). Mushroom propagation is a low impact very accessible technology that can be adapted to a range of climates, skills, time and materials available.

To propagate mushrooms here at CAT we use, an incubator to keep a stable warm temperature so that the original culture becomes established, an autoclave for sterilization of cheap grains (which the culture can use as a food source to get stronger), and a variety of woody wastes from CAT as substrate for mushroom fruiting.

Hardwood logs plugged with mushroom spawn have been part of the displays of the biology department as an example of ways to grow valuable protein sources on a shady corner of a garden or a forest. This year however, we are conducting experiments to increase the viability of the crop, and hopefully establish a production system that might allow us to do some more research on other exciting applications of fungi. To start with we are collecting different waste products from the many activities that go on at CAT (glass bottles and coffe grounds from the restaurant, bits of straws and hemp from the graduate school, woodchip and sawdust from the building department, cardboards…) and testing them for their suitability as substrate for oyster mushroom production, a species that will be a welcome addition to the restaurant kitchen.

Stay tuned for fruiting developments!


Vole family in our gardens

Morning Everyone, Keeping Roger our gardener and his volunteers company in the garden is a family of voles which seem to have set up home under one of the tarpaulin sheets. They are probably Field Voles, although Bank Voles are very similar and to add to the confusion Field voles sometimes frequent hedgerows and Bank voles can be found in scrubland as well! The Field vole is slightly larger and less reddish and has a shorter tale but as a fleeting glimpse is usually all you get it is difficult to identify with any certainty.

Most of us have seen voles but sometimes you are not quite sure what you’ve see – if you spot something that looks a bit like a small sausage with tiny legs suddenly shoot across the path or lane in front of you it is probably a vole. They are in fact one of our commonest small mammals with a phenomonel breeding rate–a single female can have up to 6 or 7 litters a year and the young become sexually mature at a few weeks old. Mind you they have to reproduce so prolifically as the poor old vole is preyed on relentlessly and is the main food source for many predators–it is the staple diet of Barn Owls (some owl pellets I’m dissecting at the moment contain practically nothing else but vole bones) and foxes like nothing better than a couple of tasty vole snacks as an appetiser before their main course.

In fact it is likely that very few voles live their full lifespan–most of these inoffensive and rather cute little creatures end up as a food item for some hungry predator. The other species of vole found in this country is the much larger Water Vole (the Ratty of Wind in the Willows) which lives as the name suggests in and around inland rivers. You have to work quite hard to observe most of our native mammals but it is worth the effort – so make the most of any chance encounters you have.


From Bristol to CAT: Countryfile takes on Sustrans

On the 4th of May, the Countryfile Magazine editorial team and Rich from Sustrans are racing from Bristol to the Centre for Alternative Technolgy in Machynlleth, mid Wales using a variety of different travel methods. They aim to explore the trials and the triumphs of travelling in rural areas. Each person will take different routes and judge how efficient it is a way to travel based on time, cost, experience, environmental impact and the effort (calories/ energy/ stress)


Continue reading “From Bristol to CAT: Countryfile takes on Sustrans”

Plants are endlessly fascinating. In May I’m going to spend three days looking at how they grow, on our Botany for Gardening course

by Chloe Ward
When i was a kid i made a little promise to myself that i would never, ever be as boring as my Mum and Granny who would walk up and down their rows of vegetables discussing each one. It’s a promise I’m happy to break though. Plants are endlessly fascinating. In May I’m going to spend three days looking at how they grow, on our ‘Botany for Gardening’ course. We’ll be doing little experiments and stuff that was boring at school, but strangley is really fun now. There’s still spaces if you want to join in.

Thoughts on peat in response to questions and comments from twitter and facebook. I’d back a levy, but I’d prefer a ban

by Chloe Ward

I would back a levy, though of course i’d prefer a ban. It would be hard to sell bags of peat under the table in the pub, thought i guess it would happen. (trucks in the night?)

It astounds me on how slow the horticulture industry is to stop using peat. I’ve been a gardener for twenty years. I have never, ever used peat or felt the need to. At CAT we make up our own seed and potting mixes, but in other gardens i’ve used commercially sold organic mixes which also work fine. If you’re choosing a potting compost, they do vary in quality, so shop around until you find one which suits you. In 2010 ‘Which? Gardening’ awarded ‘Best Buys’ to three peat free potting composts – Vital Earth Tub and Basket Compost, New Horizon Mulit-Purpose Compost, and Vital Earth Multi-Purpose Compost.

Another big irritation on the peat-front is how sneaky the sellers are in their labelling. For example, recently i have seen a grow-bag labelled as “20% peat-free”. What does that mean, if not 80% peat? So, watch out for that – if in doubt, look for organic certification.

MSc Environmental Change and Practice

Environmental change will affect many aspects of society including the working practices and research agendas of the built environment professions.

Students in the sun at the Centre for Alternative Technology

Responding to this change, a new and innovative master’s degree is commencing at CAT in September 2011 in collaboration with the Cardiff School of Art and Design, University of Wales Institute Cardiff (UWIC).

The aim of the programme is to provide students with the theoretical knowledge and the research and practical skills to be able to operate effectively within their chosen field of the Built Environment, while responding to environmental change. The focus is on buildings and the built environment and is intended for architects, builders, planners, engineers, surveyors, researchers, academics and other built environment professionals and experienced individuals. Students may link coursework to their professional work projects, volunteering projects and/or current research projects running at CAT and at UWIC.

Heliodon pair

A portfolio of work is produced including practical work, case studies and reports. Intensive one week modules are held at CAT and at UWIC, and the programme is available Full Time (1 year) or Part Time (2 years).

Find out more.