University of Edinburgh's CHP Plant

Today we toured one of the University of Edinburgh's three combined heat and power units - an incredibly efficient way to provide heat and power for the university. Most existing coal plants only turn about 30% of the energy stored in the coal into electricity, and the remaining energy is wasted - often in heat that goes into the air. You have to get coal or gas really hot to make electricity. CHP or co-generation plants capture that heat and use it to heat buildings. The university's system is 85% efficient. It's a really smart way to get much more bang for your buck and save carbon emissions by avoiding having to burn fossil fuels for both heat and electricity.

It's one of many projects David Somervell, the university's energetic and committed sustainability advisor, has developed over the past 20 years. David is a great change agent for this place - he thinks extremely long-term and puts a lot of energy into setting the fundamental principles that will drive changes over time. In this case, he's gotten the university leadership to buy-in to a very cost-effective principle that 5% of their annual energy fuel budget should go to energy efficiency projects. He's also successfully gotten the university to look at energy efficiency projects from a much longer term investment perspective than a typical for-profit business. Most private companies never consider energy infrastructure investments that don't pay for themselves within a year or two - the university has a general rule of looking at 4 year paybacks as do-able, and went for a 7-year payback to revolutionize their heat and power with 3 CHP units. It's a little easier for a 400-year-old university to think long term than a company trying to make payroll every month, but that's even more reason why institutions like universities and governments should lead the way on financing these projects. They'll be around for a long time and they will pay off in the long run. David's also been successful in getting the leaders of the University to think deeply about how they manage risk - not just financial risk, but energy price volatility risk over the next 50 years, as well as institutional and brand risk related to carbon footprints, etc. Change is slow, if you get these key drivers lined up, you can get a lot of really good things done over the long haul.

At the same time, money talks when it comes to these projects. The CHP units cost £12 million altogether - £5 million of which came from a UK government grant program, and the rest was financed by the University (through a private special purpose vehicle to avoid/delay some value-added-tax liabilities). CHP can often be quite expensive to install because it requires extensive piping infrastructure, but Edinburgh actually previously used steam engines to provide "district heating" - so replacing the relatively inefficient steam system with a modern CHP system was not that expensive.

I also like David's perspective on what's actually green and what's just "green jewelry." One of the greenest, most efficient buildings in the UK looks like any other tall tower on campus - but uses light and heat incredibly efficiently. On the other hand, another building with flashy building-integrated PV panels looks great symbolically (which has some value), but might was not the most cost-effective energy or carbon saving investment. (David also noted that he doesn't sell ROC's from his PV building because the registration processes are so complicated and the units produce so little electricity in the grand scheme of things that it's just not worth it.) In the same way, a super-efficient CHP unit like this one, even though it burns a fossil fuel (natural gas), might in some ways be a greener method of producing heat and electricity (and offsetting a lot of much less efficient coal fired electricity) than an expensive solar system.

Energy efficiency is really the most cost effective way to be green - you SAVE money and save emissions. I hope we consider projects like the CHP plants back home in Michigan - for example, it might be a really good option for Lansing, which needs to replace a coal-fired power plant and already has a steam-infrastructure for heat like the university did.

The visit also raised another difficult problem for me however - while I trust David and think the systems he's created are really efficient and great, I'm not an engineer and couldn't really critically analyze these units over any other. It's incredibly important to hire good engineers and consultants - but I'm not sure how a layperson knows who's good and who's not. Maybe it's like any specialty - you try to rely on good recommendations.




This CHP unit is actually a tri-generation unit - it produces electricity, heat, and cooling via an absortion chiller (heat is combined with a chemical to produce cooling).



David showing Rassul the control panel for the gas-fired electric engine - putting out about 1.3 MW of electricity.



Gas-fired engine - it's LOUD!



Waste heat from the engine is collected.



Heat can be stored in a giant tank of water when it's not needed and used later.



If need be, the unit has a couple of gas boilers to produce heat (they only run 10-15% of the time). The blue thing sticking out is a nitrous oxide scrubber - cleaner emissions.



The entire facility, because it serves a vet school animal shelter, is backed up by a diesel electricity generator (which can also be called into service by utilities during times of peak demand - in the US that would be hot summer days when air conditioners work over time. This is the MOST expensive time to produce powers, and partnerships like these are innovative win-wins. Another great possibility for Michigan that I know our utilities and manufacturers are working toward.).

David also showed us a video about CHP's use in Europe, and how it (and decentralized electricity generation generally) could be a great solution for the UK. It's produced by Greenpeace, and of course you always have to consider the source whenever taking in information, but I actually think it's a pretty balanced and unbiased statement of the facts (with a little hyperbole thrown in). Good explanations of the how electric systems work. Definitely worth the 18-minute watch if you have the time.