This heat can affect the underground environment including the geochemistry of the aquifer and microbiological ecosystems.  When there are multiple systems in an area, they may interfere with each other, particularly if there is groundwater involved.  Therefore there are two main policy concerns here – protection of the underground environment, and equitable use of the heat storage resource.   With increasing numbers of these systems being installed in London(1), and their inclusion in the Renewable Heat Incentive, it seems important that someone be responsible for managing it all.  Sadly, noone is.

Earlier this week, I went to a meeting of the UK Groundwater Forum, a hydrogeology group, on ‘Groundwaters Role In Reducing Our Carbon Footprint’.   Among many interesting talks were two that touched on the subject of the way we manage the underground heat resource in our aquifers (2)

Richard Shennan of Mott MacDonald Fulcrum talked about the ground source heating and cooling project which is underway on the 1851 commission lands in Kensington, providing heating and cooling for the V&A, Imperial College and other sites in the area.  As part of the design for that project, maps of underground heat are being produced showing the heat flow through the aquifer as it changes through the seasons.  Of course, they’re restricted to that site only, and it was suggested that it would be useful to see similar maps for all installations.

Anna Hall of the Environment Agency discussed the regulatory environment, and in particular pointed out that the environment agency have no jurisdiction over heat because it is not a ’substance’ that can be released into the environment.  This means that while open loop systems need to have abstraction and discharge licences, closed loop systems do not.  The EA are apparently encouraging the Ground Source Heat Pump Association to set up a register of systems, but have neither the funding nor the power to do anything themselves.

This needs to change.  It seems that there are a few bodies which could reasonably administer ground source heating systems, given the funding and powers to do so.

The Environment Agency, who are already responsible for water, would be ideally placed.  They have the hydrogeological expertise, are already administering water consents and are charged with protecting the environment and contributing to sustainable development.

Local councils, are already responsible for planning, including the inclusion of renewable energy in new buildings under the Merton Rule which is the motivation for many GSHP installations.  Unfortunately, they probably lack the necessary technical expertise, but perhaps something could be done in specific areas, such as London, with the London Development Agency taking a role alongside its Decentralised Energy and Energy Masterplanning project.  That project, which is mapping heating demand in London, would seem to have a good synergy with managing and mapping heating supply.

Finally, the GSHP association could no doubt administer a register and at least have access to the technical expertise, but they are a trade body, who’s aim is to promote the industry in the UK.  Any regulatory role would give them an unreasonable conflict of interest.

Underground heat capacity will be an important resource in the near future if we are to reduce our carbon footprint and make our cities sustainable.  It needs to be managed for the good of the environment, and the fair use of the resource by those who need it.  The Environment Agency, or perhaps bodies such as the London Development Agency, are best placed to do this.

(1 ) Gropius, M., 2010. Numerical groundwater flow and heat transport modelling of open-loop ground source heat systems in the London Chalk. Quarterly Journal of Engineering Geology and Hydrogeology, 43(1), 23-32. Available at: http://qjegh.lyellcollection.org/cgi/content/abstract/43/1/23. 

(2) The talks aren’t available online yet, but should be soon at the conference site http://www.groundwateruk.org/Groundwaters_role_in_reducing_our_carbon_footprint.aspx

You can get a copy of the software at the QGIS website, and there are tutorials and introduction documents around the web.    This post is to pick up a few things that took me a while to figure out.  They’re notes for me, and they might be handy for someone else.

How can I add a new point symbol?

Point symbols are the icons you use to show a point on a map, like this wind turbine on a hill near Machynlleth.  By default, the software doesn’t come with a wind turbine symbol (incredible omission!), so I had to find one.

Point symbols are scaleable vector graphics (svg) files, and they’re kept in the  OSGeo4W\apps\qgis\svg directory whereever you installed the software.  To find a suitable one, I googled “windmill .svg”, and Google came up with one on Wikimedia Commons, which is available in the public domain, so no licencing issues.  Then I just copied it into one of the folders in that svg directory, and the next time I restarted Quantum GIS, it was available for me to choose.

My computer is grinding to a halt.  What can I do?

I had about a dozen layers, with lots of information from the Countryside Commission for Wales, who had kindly sent me data about all the restricted areas in Wales, and I’d loaded them up.  That was not smart.

There’s a little box on the bottom right hand side of the screen, with a label ‘Render’.  Turn it off, unless you want the system to redraw everything every time you move the view or make any change at all.  And if you must load dozens of layers, be prepared to spend a lot of time waiting.

I want to show a bufferzone around my feature

Working out where you can put turbines in a wind farm is all about figuring out what restrictions apply.  The Horse Riders Association don’t want one within 3 * the turbine tip height of a bridleway.  The Ramblers Assocation want them at least tip height +10% from a walking path.  There are other restrictions on roads, cables, microwave links and the rest.  What you really want to be able to do is draw all your features – paths, bridleways, roads, microwave lengths, and then push a button to show what areas of land this rules out.

To do this, you need to add the ftools plugin, which lets you do all sorts of analysis on your vector layer, and draws buffer zones.  It has a couple of dozen functions, and I’ve not had the chance to explore them yet, but it did make it much easier to draw my bridleway buffers.  If you set up the distance you need as a field when you draw the path, it can automatically use that to draw the right size buffer, allowing me to put my footpaths and bridleways in the same layer.

Doing my first degree back in (ahem..) the eighties, we had the miracle of fiche and, sometimes, computerised catalogues.  I photocopied everything in sight, and threw most of it away when I graduated.  Writing an essay meant piles of books, papers, notes, filing cards and little scraps of paper.

Now, it’s all on my wee laptop.  I search for papers online, through one of the databases provided by the University, or Google Scholar.   Wikipedia’s open in another tab to quickly explain phrases I don’t know, and the Engineering Toolbox is never far away.

All those printouts and filing cards have disappeared and in their place is the miracle that is Zotero.

Zotero is a free addon to Firefox which stores any sort of document, allows you to tag it, indexes,  keeps your notes, and produces a bibliograpy.  Inside MS Word, its a push of a button to insert a reference, and the bibliography is created automatically.

If I’ve got a book, I go straight to Amazon, find the book, click a button and my reference is created.  If the paper is in any one of a number of online databases, ScienceDirect, Wiley InterScience or whatever, I push a button and the reference is there with the paper downloaded.  If its an ordinary webpage, a youtube video, a newspaper article, Zotero will have a go.  At worst, I can type it in.

My entire degree is in Zotero.   It’s an extension of my brain.   In case you were wondering, yes,  it is backed up, automagically and constantly, to JungleDisk, an online backup service that costs me about $5 a month.

And those young people are looking great!

Per capita carbon emissions for domestic and road transport use in areas like this are low(1), because public transport is good and the cost of heating small apartments is much less than houses. If we’re to meet the energy challenges of this century, it will be by living in places like this.

And so, one of the reasons I’m doing this course is to find ways of bringing renewables into the inner city. I’ve started exploring this in the essays we do for each module, and will probably do my thesis on this subject.

It’s not an easy problem. Wind turbines on the tops of buildings don’t work well, with all the turbulence. Hydro power would get in the way of shipping on the Thames. Because we’re all so tightly packed in, with so many businesses and institutions, the energy density of inner urban areas is very high, making it all so much harder.

Clearly we need to reduce energy demand, and will have to bring a great deal in, from wind farms in the Channel and other sources but there are ways we can make our own. How about storing heat under roads, making use of the urban heat island effect and vertical boreholes with heat pumps, solar pv and thermal collectors, gas generated from organic wastes, growing microalgae for biomass in tanks on roofs and walls, hooking up all those treadmills in gyms to generators, harnessing the hot air in Westminster? Some of those have got to work! More blogs to come.

(1) Camden CO2 emissions per head were 7.3t in 2007, against a UK average of 8.0t. Domestic and road transport emissions per head were 2.48t, vs the UK average of 4.48t – ie when commercial emissions are not included. DECC National Indicators 185 and 186

Much to my surprise, coal burning is still possible. The Clean Air Act of 1993 makes it illegal to emit smoke in a designated Smoke Control Area, such as the London boroughs.  You’re only allowed to use authorised fuels which include gas, electricity and anthracite – ie. coal.

Anthracite coal

Anthracite is very hard, shiny coal and is over 90% carbon.  If you burn it, even at temperatures below its ignition point, it doesn’t emit smoke.  It’s not the greatest of fuels – heavy, hard to light, expensive and with a calorific content about half that of gas – but it is legal.

The Clean Air Act doesn’t concern itself with CO2 emissions, and because of its high carbon content anthracite has one of the highest emission rates of any solid fuel.  When you consider the carbon cost of mining, cleaning and transporting it, its obvious that using it in London would be a very bad idea indeed.  Make sure your flat is well insulated, and look to other types of heating first.

Typical Welsh countryside at Mynydd Gorddu wind farm – green hills, clear blue sky, sheep and turbines

There are 19 Nordtank* machines in the wind farm, 12 at 550kW and another 7 at 600kW. They’re the same machines, but the larger ones have short blade extenders at their hubs to increase the swept area slightly. When we were there, on a clear day with only a light breeze, they were still generating 2.3MW, powering a few hundred homes, or about a thousand kettles, all boiling at once.

*The link is probably for this 600kW machine, but I’m not 100% sure.

The archimedes screw is a type of water pump which has been known since ancient times, and may well have been used to water the hanging gardens of Babylon. It was certainly familiar to Roman engineers.

Archimedes Screw (c)Siberwolf at Wikipedia 2009 (click image to see original and licence)

To pump water from the bottom to the top, the pump needs to be twisted, either by hand, perhaps a windmill or someone running on the casing, as an ancient treadmill.

A few years ago, a genius engineer unknown to google or wikipedia, figured out that if you turn it upside down and let the water drive the turbine, you could stick a generator on top and make electricity, being careful not to let the generator get wet.

The big advantage of these turbines over others used for small hydro schemes is that they work well when there is a low head of water so can be used over an existing weir, or in outflow pipes.  That configuration means they don’t need much pipework either, making the civil engineering component of the scheme much smaller.  Debris in the river just passes through (at least up to a point), so there’s no need for trash screens

A 48kW scheme installed on the river Dart in Devon in 2008 consistently produces 35-48kW, enough to power visitor facilities, a conference centre and two bungalows in the River Dart Country Park.

Another in Osbaston, Wales provides 150kW, and powers 152 homes.  The environment agency cite it as an example of good sustainable practice in their guidelines for small hydro schemes.

Osbaston Hydro Scheme and Fish Pass

Most importantly, it doesn’t bother the fish.  Because its open to the air, and large, the fish just swim up it.  The water is going at the same speed as it would be over a weir, and so it makes little difference to them.  The one in the photo above is actually a fish pass as well as a hydro scheme.

Environmentally friendly, low maintenance and robust – it’s an ideal technology

The course is at the Centre for Alternative Technology in Machynlleth, Wales.  An old slate quarry has been turned into a research and education centre for all sorts of low-impact technologies – energy, waste, water, buildings.  Power comes from wind turbines on the hills, solar panels on the roofs and hydro-turbines drawing from the enormous amount of water which cascades down the slate hillsides.  The buildings are well-insulated and make use of experimental techniques – our lectures are held in a theater built of straw bales.  It’s a beautiful, tranquil place full of trees, water and interesting people.  Sometimes, a little too much water.

Centre for Alternative Technology, Machynlleth, September 2009

I’m up there once a month for an intensive week of lectures and practicals, then spend the rest of the time back home in London trying to figure out what I just learned, and writing essays and technical reports.