Look at carbon, not energy
September 29, 2010 3 Comments
We urgently need a clear strategy for decarbonising the grid…and here’s why.
by thinkpanama, creative commons, flickr
The world is still awash with energy.
Peak oil may have passed but peak coal has not. Nor has peak gas, and nuclear and renewables are now a rising trend. In other words, the problem is not a shortage of energy it is too much carbon.
The trouble is, at the moment it’s hard to find a quick and easy way of taking carbon out of the primary fuel mix. So, the focus is on reducing loads, getting more out of each unit of carbon fuel, and using so-called renewables to substitute for fossil fuel.
We’re too used to having energy on tap, generated and piped from a distance. Community scale services challenge this view of life (we’ll be debating this at our briefing). Low-carbon communities attempt to use waste in order to distribute relatively low-grade heat rather than high-grade energy.
This heat is ‘free’ insofar as it recovers energy from electrical generation, household waste, or from geothermal sources. Of course, nothing is actually free. Pipe work, pumping, capital costs and so forth means that fixed costs can exceed the notional cost of the primary fuel burned to generate distributed heat.
Because of high capital costs and the long lifetime of systems (like water mains), financial planning for low-carbon communities needs to take the long view.
We don’t know what the carbon advantage of such systems will be in the future. If there is a significant and quick (economically speaking) rise in zero carbon wind and marine generation, and carbon sequestration in coal fired plants becomes the norm, then the carbon intensity of the grid will reduce to the point where the advantage of community based systems is lost. In short the carbon arguments for community heating systems depend crucially on the speed of decarbonisation of the grid.
This is a community-scale heating dilemma. We should have invested in CHP/DH a couple of decades ago when we had access to North sea gas – instead we face the prospect of digging up the roads yet again and forcing householders to abandon their cherished boilers. But, without a guaranteed connected load and the effective displacement of high carbon intensity grid supply it will be difficult to make community scale heating financially attractive to a commercial investor.
So, we should focus on decarbonising the grid or develop heat-sharing technologies through low-carbon communities? These are mega questions and need a national strategy where government must lead the way. What will be the role of the building services engineer and construction teams in planning and delivery whole-community solutions?
BSRIA
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Yussuf A
Interesting post Andrew, some questions I think we need to answer on district heating are:
At what point does CHP/district heating make more sense than extreme energy efficiency improvements? And does the business case for CHP/district heating disappear when these sort of improvements are carried out? How will the heat supply field be regulated to avoid fuel poverty for occupants connected to a scheme? Is there not scope for an existing building energy efficiency standard that must be reached before connection is made?
It is all about the marginal cost (or carbon content depending on your choice of metric) of the heat delivered. If the cost is very low, for example if there is waste process energy being chucked away, then why bother with energy reduction measures at all? I did once suggest that the very expensive flats being constructed almost opposite Harrods could usefully use the reject heat that is (very expensively) liberated on Harrods roof to keep the pigeons warm. I thought that the occupants of these flats might rather like the idea of buying their heating from Harrods, sort of fits. Reality is that doing something like that is in the all too difficult and messy catagory and that, in a nutshell, is why retrofitted CHP/DH is always going to be difficult
Andrew,
The ‘too hard’ is going to be an increasing part of the contruction landscape which the sector in general and building services professionals in particular will have to deal with as we drive towards zero carbon buildings. Your comments make sense on many levels, we need to reduce energy use, find low grade energy sources and learn how to successfully integrate these together to decarbonise the grid. Ignoring any aspect is likely to lead to the results starting to emerge which you describe. Another significant issue you touch on is of consumers acceptance of change and what will drive it. The role of government in setting this environment will unfortunately need to be addressed as few developments will be able to maximise the opportunities effectively. A framework within which everyone can work at planning, regulatory and standard level will therefore provide an adaptable but understood basis for this approach.