Monthly Archives: November 2010

Large Scale Solar Water Heating

In the UK we are used to solar water heating panels on our roofs, with an average size of about 2 square meters, just to contribute a part of the domestic hot water of a single household. Over the next couple of blogs I want to write about large scale solar hot water systems, from a few hundred to tens of thousands of square meters, now rapidly being deployed in Europe, with a few elsewhere in the world, but sadly none yet in the UK, despite the fact that they would work very well in our climate. These systems can be used to produce domestic hot water, central heating and even air conditioning in summer for groups of just a few households to towns with thousands of buildings. Hot water is fed into a district heat main with a central storage tank, which if of sufficient size and insulation can store the summer’s heat to meet a large part of the winter heating requirement of whole communities.
The photo above shows an apartment block, part of the 61 residential units that make up the Gneis Moos development in suburban Salzburg. These buildings are super-insulated to passive house standards, with plenty of south facing glass for passive solar gain, a 410m2 solar thermal roof feeding hot water into a 100,000 litre heat storage tank. Already ten years old this still represents cutting edge energy efficient architecture and just the sort of thing we should be doing in the UK. ( More about Gneis Moos see,
Christian Holter and his company SOLID Solar designed and built the solar roof at Gneis Moos and have since designed many more including the impressive swimming centre for the 2008 Chinese Olympics ( and retrofitting a huge bank in Lisbon for solar powered air conditioning, and about 200 other projects with solar collection areas greater than 100 m2, and are now increasingly designing solar roofs of over 1,000 m2!

Giving Talks

A couple of nights ago I gave a talk and slide show at the Talbot Hotel in Leominster, Herefordshire. It was organised by Leominster Civic Society and I was called in at the last minute because their planned speaker was suddenly unavailable. I put together a talk about the Herefordshire Local Development Framework document and how we could improve it by learning from some inspirational examples of global best practice in terms of Co2 reduction and a diverse range of other benefits. Throughout the document Herefordshire Council use the term “Sustainable Economic Growth” without ever properly defining it. Many of the places I have written about in this blog over the last year have made dramatic Co2 reductions while seeing rapid economic growth as they develop various forms of renewable energy. Gussing in Austria made a 93% Co2 reduction while creating a thousand new jobs; not bad for a small town of 4,000 people. There is much for Herefordshire to learn.
What I love about these evenings is the opportunity to present the examples that inspire me that a better, more ecologically sustainable and socially just future is possible, but also the many points that arise out of the discussion that always follow these talks. I hear about new ideas, projects, technologies and developments to use in future talks. I have had criticism that just talking doesn’t change anything. This week I heard otherwise: Last year I showed a slide and talked about carbon negative cements such as Novacem and Calera and someone in the group who’d not heard of this before was about to write a document where he now specified that the contractors were to source the lowest carbon cements available, which they have now done. Result!
Also after the Leominster talk there was a lot of networking going on about how some innovative and ecologically restorative land use ideas might be practically developed by a couple of members who owned land. Exciting stuff.
I’ve a few more talks in my diary, but am always open to giving more, so do contact me via this website if you’d like me come to talk to your group, be it a Council, Transition Town, Friends of the Earth group, school, college, Chamber of Trade etc

Fossil Fuels to Renewables

(350 LA says No to Coal and Oil)
A couple of weeks ago I wrote about the inspiring example set by the Austrian town of Gussing, where Co2 emissions have been cut by 93% in the last decade: a truly remarkable achievement. There are a number of other small towns making similar transitions. Frederikshavn, a city of 23, 000 people in Denmark is set to produce 100% of its electricity, heating and transport fuels from renewable sources by 2015.
Converting to renewables is easier in smaller locations where there is more space to capture the available energy, so for example each small town in mid Wales is surrounded by windy hilltops offering possible wind turbine sites, conifer forests for biomass and streams suitable for hydro: technically a relatively easy challenge. Converting the energy supply of big cities is a much harder challenge.
Seville, a city nearly one and half million inhabitants, is developing Concentrated Solar Power and is set to be producing all its electricity needs from solar within about 3 or 4 years; heating and transport will take longer.
It’s an interesting question, which of the really big mega-cities will be the first to go 100% renewable; which will see the sharpest reduction in Co2 emissions?
Strange as it may seem it could be Los Angeles, currently one with very high Co2 emissions and known for cars and conspicuous consumption. Over the last few years many planning applications were made for concentrating solar power stations in the deserts of Southern California but they all got bogged-down in a bureaucratic log-jam which suddenly is being cleared by the lure of federal loan guarantees conditional on work stating by the end of this year. If all the planned projects get built it could see Los Angeles’ carbon footprint plummet. That really would be something to celebrate!