Making CHP ‘do-able’

November 10, 2010 by 3 Comments

Front view of a CHP unit

The Government’s set a target for the UK to generate 15.5 GWe from combined heat and power (CHP) by 2020. Today, only 5.5 GWe is generated from CHP. So, how do we deal with this target shortfall in CHP?

The planning department has, in recent years, relaxed their policy on approving CHP plant projects. On the other hand, they try to insist on new building design incorporating CHP.  Of course, nobody likes to be coerced like this. But what is more important is that arguably this approach is not effective. For example, design engineers sometimes find it difficult to justify using CHP instead of the traditional boiler. It is seen to be too costly to build the CHP where the return on carbon reduction will be so little.

There is nothing inherently wrong with CHP, but rather in how we apply it. This large kit, even with better efficiency, is not suitable for a building-by-building application. We need to think at a community scale. It works perfectly well in district heating, or even a small community with several buildings. The key is to have more buildings where the load profile requires a constant energy demand.

CHP is more costly than traditional boilers. When it comes in a larger scale, the capital investment will probably be rejected by your finance director. But, does that really have to be the end of the story?

A happy ending with Energy Supply Contracting?

Perhaps, if you haven’t already done so, you should consider Energy Supply Contracting (which is also called Contract Energy Management in the UK). The service providers (ESCOs) provide low carbon energy to the clients, and the advantage of this business model is that it can allow the end user to enjoy low carbon energy without any upfront cost.

More thoughts on this particular model to follow – but what do you think? Can you tell me about any good or bad experiences with this?

Filed under CHP, Communities, Energy, Heating

Look at carbon, not energy

September 29, 2010 by 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?

Filed under Carbon, Communities, Energy, Heating

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