From IT Project Management to Renewable Energy
Renewable Energy
Who Manages the Heat?
May 28th
Vertical borehole ground source heat pumps use heat stored in the ground, and groundwater. That heat comes from the sun, and, to a far lesser extent, heat generated within the earth as well as human-generated heat from buildings, underground railways and other constructions. It may also come from a cooling system, where heat from a building is discharged through boreholes to be stored underground during the summer before being extracted the following winter.
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.
Solutions for the Inner City
Feb 4th
I’m passionate about Somers Town, the small corner of central London where I’ve chosen to make my home. Nestled in between the gothic splendour of St Pancras and the fifties austerity of Euston, its a tiny district of densely built low rise apartments, home to the British Library, the RMT and Unison, railway stations and about 8000 people from all over the world. I can walk to the West End, have Regents Park on my doorstep, and every amenity I could wish for a short stroll away. I’m not one of those ‘buy a small-holding in Wales’ Greens, and I’m sure Wales doesn’t want me and my 8000 neighbours to try.
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
Burning coal in central London
Jan 26th
The smoky coal fires of London were banished in the fifties and all that remains of that smog filled, grimy time are the blackened buildings of parts of Bloomsbury which haven’t been cleaned. Sunny days with blue skies are now common, but open fires very rare indeed.
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.
Walking to the Wind
Dec 16th
Last week we started the first practical module and in December, in Wales, the choice is between Biomass in a nice warm boiler room or Wind and walking on hills. The Welsh weather gods were in a kindly mood, and rewarded the hardy with crisp, clear days, perfect for a morning spent on the hillside at Mynydd Gorddu.
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.
Archimedes Screw Turbine
Nov 27th
What a fantastic piece of technology is the archimedes screw turbine. It’s simple, works in situations where other hydro power turbines aren’t much use, has a very low environmental impact and is even safe for fishes.
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
