Following the successful development of a fuel cell which not only works and achieves the highest electrical efficiency of any generation technology in existence, (not to mention the start of production at their Heinsberg plant in Germany last month), CFCL have now established a dealership with Neco, so you can actually go out and buy the Bluegen 2kWe fuel cell generator with a demonstrated efficiency of ~60% at the point of use. Of course, you also get to use the "waste" heat so it is really quite an amazing bit of kit. If only I had £20,000 or so to spare! Not cheap, but it actually exists, thus quashing the rumours that fuel cell technology is all vapourware!
At that price it would take over 10 years to pay back (based on UK energy prices), but if the UK government gets its act together and comes up with a sensible FiT, it would be nearer 5 years and, of course, that would help build production rates and bring down prices so that it would no longer need subsidy, probably in less than 5 years, unlike some other, more questionable micro-generation technologies.
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Modern gas fired stations are 60% efficient, we have a few in the Wales (United Kingdom) that run at that efficiency.
Plus at £20k a unit it would take nearly 100 years, yes 100 years, for it to pay back. Plus I’m sure you know that the unit doesn’t last that long and in fact needs a new stack every 5 years.
Also a feed in tariff will mean less government money elsewhere. Would you rather we cut teachers or policemen to pay for the feed in tariff?
I think @cells that you are being a little optimistic about CCGT. The very best units today may be able to achieve almost 60% at full rated load (i.e. running baseload)under ideal atmospheric conditions, but of course that is all they get. The remaining 40% is dumped into the atmsophere, whereas a micro CHP system can also make use of the "waste" heat. Plus, of course, that 60% is at the power plant; by the time it gets to the consumer the average losses are around 10% of the electricity generated.
However, you are absolutely right about the economics and I fully appreciate that SOFC has some way to go to becoming commercially competitive. This blog is intended to provide a view on what the opportunities are, not suggesting that micro CHP is a mature technology.
I also agree with your point about the Feed in Tariff which is an obscene waste of taxpayers money, incentivising the least cost-effective technologies in the most inappropriate locations; I have been trying to keep off the subject recently because I find it so frustrating that our dimwit government has been so roundly conned into thinking it will save the planet. However, inspired by your comment, I will indulge in an anti-FiT rant in the next day or so!
Generally speaking mCHP will have more transmission losses than conventional power plants. Say the blue gen unit. It produces 2kW and most of the time will be exporting that power. if your local grid is a net exporter as it will be if mCHP did take off then your power will be sent first though the low voltage high loss system, then through the high voltage system to a big user, say a steel plant. Overall your wastage is about 10%.
However a conventional power plant will pass that power over the high voltgage grid straight to the steel plant at only some 3% loss.
In low numbers the losses are better in mCHP, in any quantity they are WROSE!!
Plus your idea of 40% waste in a gas fired station is correct however a mCHP wont be 100% efficient, your looking at 85-90% tops. So the overall saving is not that big.
Plus the 60% efficient is indeed when not ramping, but even when ramping the efficiency tends to be >55%.
Modern gas fired plants are very very efficient!
I am afraid you misunderstand the way the system works! Any electricity I generate and use myself will incur insignficant losses (in the 2 metres of cable from the generator to my point of demand) compared to transporting power from the HV grid, down the distribution network to the LV network that supplies my house. What I generate, but am unable to use, will flow back through my consumer unit to the nearest available load, i.e. my neighbour, not some remote steelworks. The losses, even at 230 volts, in a 5 metre length of cable are quite negligible!
Your point about the local grid is an interesting one, and there has been quite a bit of work done in this area to understand the consequences of saturating the domestic network with micro CHP (or indeed any other microgeneration). The majority of micro CHP products emerging today are rated at 1kWe, although it is possible that some may have somewhat higher outputs up to 2kWe. The LV network is already designed to accomodate this level of power flow (albeit in the opposite direction). Depending on the type of micro CHP installed, the generation profile is likely to follow broadly in line with demand, bearing in mind that generation of electricity is a by-product of heating demand, so that micro CHP generation and domestic electrical demand align fairly well. Thus, even with 100% penetration, the majority of power will be consumed within the LV network where it is produced. Any surplus will then pass through the substation (with minor losses) to the next adjacent load. This is always going to be more efficient than the alternative of central generation distributing right through the system; I think you would agree that the losses in one 11kV transformer are lower than all the transformers and cables back to the power station!
I said in small numbers the losses would be low but in high numbers the losses will be greater than a power station.
You will not be using the full 2kW. Most of the time you will be exporting and some of the time you will be importing when you turn high demand things like power shower or the kettle on.
Now lets say in a crazy world every home has a BlueGen. That’s 25 million homes providing 50GWe of power.
Well nearly all the homes are exporting. But to who? Business and industrial users that’s who.
So not only will the power go through the high voltage system as it would do with a big plant, but first it needs to go through the most inefficient lines we have! The low voltage residential system.
In large numbers mCHP has a GREATER loss than a power station. It is the reason power stations are not connected to the low voltage grid but the high voltage one!
And you are wrong, something like 6-7% of the 10% transmission losses are from the low voltage grid not the high voltage power lines you see.
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