Thursday podcast: Sir John Houghton. An introduction to climate science

This lecture was delivered by Sir John Houghton, former chair of the Intergovernmental Panel on Climate Change, as part of CAT’s Renewable Energy and the Built Environment postgraduate course.

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Quote from the podcast:

We are beginning to change [the planet] in ways that I, certainly as a young scientist, never imagined we would be able to change it. But we are making big changes on a global scale which are having big international impacts, especially on poor people.



Previous podcasts

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Are floating homes the answer? CAT student proposes a solution for housing on floodplains. Includes drawing and sketches for floating homes.


Amy Hamilton, one of CAT’s architecture students, has recently had success in a prestigious design competition aimed at encouraging designers to prioritise nature in the built environment.

First run in 2009, the competition brings together interdisciplinary teams to demonstrate the importance of nurturing natural habitats in towns and cities. While ecology and biodiversity frequently aren’t prioritised in the design process, the IHDC contest encourages participants to consider how we can regenerate our living environments.

Amy Hamilton’s entry was for floating houses to be situated in a flood plain in the Dyfi Valley. “I envisage…new green spaces which will enhance biodiversity networks,” Amy says. “I hope the wetlands and floating homes to be an environment that brings wildlife to the people and the people to the wildlife.”

Moreover, as flooding on the site is set to worsen with predicted changes in the climate, Amy’s design looks toward the future. Adaptable to the floods, the homes will “provide a continuous reminder of the effects of the erratic weather patterns on the river.”

Amy’s design was among eleven entries chosen by the IHDC judges, along with fellow Part II Architecture student Oliver Goddard. Oliver’s project was a proposal for a permaculture garden in Milton, Glasgow. While not selected as finalists, their work will likely go on display at the Museum of London.

Discussion event hosted by CAT – 4th November 2011: “Is energy security a toxic concept?”

Our current energy challenges are both unique and unprecedented; it is vital we explore how best to frame solutions to such important issues. Energy security¹ is becoming an increasingly used term, driven by a growing realisation that the days of cheap oil may be over. CAT is pleased to be hosting this workshop to explore the various ways this term is used by the different players and seeks to help move forward our understanding on how best we frame our proposed solutions.

Paul Allen External Relations director, Centre for Alternative Technology

Dulas Room, WISE Building, Centre for Alternative Technology, Machynlleth, SY20 9AZ
4 November 2011 10.00-17.00
To book email


5 blogs about domestic renewable energy you should be reading


YouGen Blog
A popular blog, with a useful filter enabling you to find posts by selecting the category you’re interested in. The host site is a mine of information about all aspects of renewable energy for the home.

Renewable Energy Law Blog
Detailed and technical blog about renewable energy development. A great place for information around the changing laws surrounding renewables, this blog keeps you informed about the debate.

Renewable Energy Blog
Though it also hawks free quotes, this frequently updated blog provides a lively and variable source of news about renewable energy.

Green Energy Net Blog
Packed with lengthy, well-researched articles, this blog provides interesting commentary on renewable energy. While not exactly light reading, it’s a great source of information and analysis.

The Green Energy Blog
While perhaps not everyone’s cup of tea with its preference for Top Ten lists and consumerist leanings, this blog nevertheless interesting information about environmentally friendly products and innovation from solar powered gadgets to clothes made from recycled plastic.

PV Roof

Everything you wanted to know about green roofs but were to afraid to ask


by Vicky Bhogal student on CAT’s Advanced Environmental and Energy Studies course

In February Blanche Cameron ran her module at CAT. One of the visiting lecturers was Dusty Gedge, who taught us about the benefits of green roofs.

Dusty has big plans to green London’s roofs: reducing the urban heat effect through transevaporation, helping to absorb water to prevent floods and replacing a building’s original green footprints with a living roof. As well as creating cool oases in the hot city.

Our flat roof extension in Brighton was on its last legs. Water was seeping through the cracked asphalt and beginning to stain the ceiling and walls. So it was time to do something about it. I went on a weekend course in practical green roof construction, run by Dusty. I came home with a sample corner section and an instruction manual.

I assembled my team: husband, good friends and volunteers from Brighton Permaculture Trust and ordered the butyl (pond) liner and thick felts. The construction took two weeks due to heavy rain, and cost about half the price of a conventional flat roof.

Help and advice on green roofs is available from CAT’s free information service. You can speak to someone about whether a green roof is right for you, download our fact sheets and find out where to get more information

We chose to replace the existing roof with a green roof because it looks delightful and we wanted to replace the grass removed when the extension was built We also wanted to encourage insect life into the garden. We used a substrate of varying depths and types, including lots of chalk, to recreate areas of local chalk downland, next to more compost rich, fertile areas. I transplanted lots of seedlings from our garden planted wildflower seeds.

At first, friends joked that we’d made an aerial weed patch, but during the summer the roof changed into a waist high poppy and wild flower field filled with bees and other insects. We have even been visited by the rare blue fritillary butterfly. Because it’s a living roof, it’s full of surprises; constantly changing and evolving. As we move into autumn, the wild flowers are dying back and there is a new growth of clover and snap dragons. I’m looking forward to watching the changes and seeing which plants grow over the next year.

I loved my time at CAT and feel blessed to have studied there. It has been a life changing experience. My formal training was in Art but the open access policy of the MSc meant that I was able to discover my hidden social scientist. I have developed strong friendships with students and we have also learnt a lot from each other. A group of us are working on setting up a local training and education centre in renewables and natural building techniques; with the goal of empowering and enabling others through sharing what we’ve learnt at CAT.

tea chest turf roof at centre for alternative technology.JPG
A turf roof at CAT

World Green Building week. Tour of CAT’s WISE building

by Caroline Alsop

According to a report by the European JRC PV Status Report 2011, Solar PV is now the fastest growing industry in the world.

With Solar PV production more than doubling in 2010 there’s significant evidence that green building techniques and methodologies are being used more widely in today’s building sector. In the next revision of building regulations in 2013 planning and development laws are expected to take a further positive step towards increased environmental sustainability and energy efficiency. From here on in, the demand for awareness in green building methodologies is likely to expand at a fast pace. However there is still plenty more to achieve.

The UKGBC (UK Green Building Council) have identified that ‘The Built Environment has a huge impact on our daily lives, our society and our natural world. Globally it accounts for 40-50% of natural resource use, 20% of water use, 30-40% or energy use and around a third of CO2 emissions.’ To address these worrying statistics, since 2007 the UKGBC have been on a mission to increase awareness about sustainability in our built environment. To help achieve this, each year they host ‘Green Building Week’ an event encouraging their members to talk about sustainability in their built environment.

This year, they’re using the event to ask the question ‘What does sustainability mean in relation to the built environment?’ Us folk at CAT thought the best way to answer this question was to host a tour of our 2011 RIBA awarded WISE building (Wales Institute of Sustainable Education), showcasing our unique vision of sustainability and the built environment. On Tuesday architect Pat Borer took a group of local architects and CAT visitors around WISE.

After the tour, CAT visitor, Simon Shelley commented ‘that was inspiring and fascinating. I have been told about building methods and materials I didn’t even know existed!’

For those who were unable to attend, here’s what sustainable design and construction means to our built environment.

Nestled in the scenic hills of Snowdonia WISE is the true embodiment of sustainable design and renewable technology. Sensitively constructed out of low embodied energy materials such as hemp and lime, rammed earth and sustainably sourced timber. It’s been thoughtfully designed for low energy consumption use. Contributions come from on-site renewable electricity sources such as solar PV, hydro and wind turbines, and an impressive array of solar thermal collectors contribute to the domestic hot water needs.

Green Building Week has been an excellent opportunity for us at CAT to raise awareness about our sustainable design and construction practices. Moving forward, with Green Building Week in mind, CAT will continue to provide the confidence, training and capabilities which will inspire individuals to construct their physical surroundings using local and natural resources in a thoughtful and realistic capacity.

WISE - Tim Soar photographs

Podcast: People, buildings, energy and sustainability. Nick Baker, Martin Centre, University of Cambridge

You can stream this podcast here or

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This lecture is part on the MSc Architecture: Advanced Environmental and Energy Studies course.

Nick Baker from The Martin Centre in Cambridge has spent most of his professional life working in building physics as a teacher, researcher, and consultant. He is also co-author of ‘Daylight Design of Buildings: A handbook for Architects and Engineers’

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Experience: Timber Frame Self-Build, an empowering journey in sustainable building skills

Last year I spent six-months volunteering in the CAT media department. Volunteers are invited to take part in two courses of their choice free of charge. Determined to build my own house one day, and to learn the skills I need to renovate my existing home, I chose Timber Frame Self-Build.

Attending the course were people from all walks of life, including self-builders and design & technology teachers wanting to improve their practical skills to pass on to their students. There was a nice mix of men and women, both younger and older, and plenty of people who hadn’t used a saw or drill before as well as those who had.

We started by discussing why we were all on the course. The tutors also introduced themselves and outlined self-build projects they had been involved in. It was great to learn that Pat Borer had designed WISE, the building we had our seminars and bedrooms in, and more that it was timber framed and built using locally sourced timber – local being only 500m down the road – and skills similar to those we were about to learn.

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Book on either Timber Frame Self-Build or Eco Building from New during Green Building Week and enter the chance to win a £50 voucher or free day course.
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From then on in it got more intense as the practicals began, making for a fast but fun learning experience. Tutors Duncan Roberts, Pat Borer and Geoff Stowe were great at making sure each team worked together effectively and gave everyone a chance to ‘have a go’. The diverse range of skills in the group meant that there was a lot of peer teaching too, great for overall team spirit and getting things done.

I was totally amazed at the outcome of the course. We constructed two timber frame structures – one using a post and beam method and the other using stud walls. It was amazing how much we could achieve in just five days.

During the evening seminars we also looked at self-build design principles, taking in the work of architect Walter Segal by looking at examples of his designs on the CAT site.

The course was exactly what I was looking for. I was so keen and motivated after the course that the following weekend I built a new wood shed for my garden, putting into practice the skills I had learnt on the course. Both teams worked so well together we stayed in touch after the course – we’re waiting for the first of us to embark on their own self-build project so we can all go and lend a hand.

Course participants lifting timber frame

The lost apples of Powys and how you can rediscover them

The Apple is considered to be the oldest cultivated fruit, with records of Alexander the Great finding the first recorded dwarf apples in 328 BC. The first apples to appear in the UK were brought over by the Romans and since then apple varieties have been adapted
and improved to the climatic and landscape conditions.

There are over 1200 native apples for eating and cooking, as well as for cider making and crab apples for pickling. They have enchanting names: Acklam Russets, Barnack Beauty, Nutmeg Pippin, Knobby Russet…and many more.

Despite this over the last few decades the arrival of cheap imported supermarket fruits has led to a rapid decline of many traditional orchards, with the loss of many old apple varieties. Not only do traditional orchards supply food but also they are also important for bio-diversity as the habitat structure is complex and supports a range of invertebrates, mosses and lichens, birds and bats.

There are however many groups across the UK who are working to save the traditional orchard and apple varieties. Chloe Ward, a gardener at CAT and member of Dyfi Valley Seed Savers, recently published a new book entitled Growing Fruit in Powys. As part of the project she surveyed 240 apple trees, and of the 105 varieties has identified four apple varieties in Powys that are “Star performers,” and another 5 that are reliable.

In my local area it is striking that many fruit trees produce well but the fruit is not commercially valuable because of the way it looks. In this study I wanted to find varieties that would thrive in our damp air and look beautiful in the shop.

Apples that thrive in the Powys area include Discovery, Laxton’s Fortune, Sunset and Charles Ross varieties; others that do well are the Egremont Russet, Ashmead’s Kernel, Blenheim Orange, Bramley’s seedling and Newton Wonder.

There is an aspiration for our Welsh landscape to blossom with fruit trees on sunny slopes, shops full of local fruits and pubs selling local cider – it’s an alluring idea.

Growing Fruit in Powys also explores sources of grants for fruits trees in Powys, training and information and other exciting projects in the local area such as the Apple Mach Cider project and the annual Apple Festival at CAT. It can be downloaded for free from
the Dyfi Valley Seed Savers website.

The Apple Mach cider project started when local lad Guy Shrubsole noticed that lots of fruit was not being picked from apple trees. With a penchant for cider he decided to approach the owners of the trees, collect the apples and turn it into cider. The result is the
Apple Mach project now in it’s second year and has around 20 people who participate in the group.

The Apple Festival at CAT is an annual event to celebrate that humble but wonderful fruit – the apple! Visitors can bring their own apples for identification and try their hand at pressing them, and there are kids’ activities, talks, music, locally made cider and a competition to see who can make “the longest apple peel”.