Guest post by Thomas Fuller
Although I’m a big fan of solar power and think it has a bright future, I must admit that our focus on the Big Three renewable energy sources–solar, wind and biofuels–has been a wasted opportunity, if not a waste of money.
The orientation of our policies to favor the adoption of The Big Three have led to our ignoring proven technologies that could have had an immediate impact and lessened not only our emissions, but reduced our gas bills as well.
The biggest example is with combined heat and power (CHP), also known as cogeneration. Amazingly, this technology that many people have never heard of produces 9% of the world’s primary energy. Here in the States it produces 7% of our energy. But in countries like Finland and Denmark, it produces up to 40% of all energy.
CHP is the simplest idea in the world. A typical power plant producing electricity wastes about 65% of the fuel it burns. CHP plants capture the heat released and put it to good work, heating buildings or even cooling them with the right configuration. It takes the efficiency of the plant from 35% up to as much as 80% in some cases. The very first power plant built in America was a CHP plant, built in New York. Continuing in that tradition, New York’s Con Edison heats 100,000 buildings with district heating powered by CHP.
CHP gets little attention from environmentalists, because it is powered (mostly) by fossil fuels. Most new facilities use natural gas for fuel, but CHP is pretty agnostic about fuel. I say mostly because there are new CHP plants being fueled by wood pellets, which (Ta-da!) makes it renewable.
But we produce less energy today from CHP than we did ten years ago. If we had focused on CHP instead of wind power (which is really starting to annoy me–and a lot of others, I think), and had built our capacity to the level of some Nordic countries, we would already today be close to the level of emission reductions President Obama promised the world we’d reach by 2020. And there’s a whole lot of money we wouldn’t have spent on fuel that we could have spent on other things.
CHP won’t solve all our problems. It is more economically viable in colder regions with expensive energy prices that make the capital investment more attractive, so unless we subsidized it the way we do solar and wind take-up would be slower than ideal. But in the U.S. it is not currently treated like other energy efficiency and renewable energy schemes, with tax breaks and feed-in tariffs and obligated purchases.
So the technology that we know works well, has done wonders in other parts of the world, and could make an immediate difference to our pocketbooks and our emissions is being neglected. While wind turbines are getting more expensive, taking more land and generally turning into a nuisance.
Where are our priorities?
Combined Heat and Power (CHP)stations are those that produce steam as well as electricity and thereby work at a much higher energy efficiency. The trouble for them is generally the difficulty of finding a market for the steam.
Co-generation as I understand it is something different and takes place when a station burns a fuel it was not specifically designed to burn (like e.g. a coal fired power station adding say wood or organic waste to the feed.
Co-generation used to be rare. The additives generally have less heating value so that there is a risk that it will cause the station to be de-rated (i.e. to produce less electricity than it was designed to). However it is becoming more popular since the additives can qualify as “renewables” and thereby attract subsidies and help meet the generating company’s “renewables obligation”.
To find a market for the heat the generating company might e.g. place the power plant near to a town and cooperate with the municipality to produce a district heating scheme, but this requires a lot of cooperation and can often wind up with the would be generator in a planning quagmire.
For all these difficulties, both of these technologies as well as combined cycle turbines in new power stations can provide huge increases in the amount of energy we get from a given amount of fuel. Unlike with wind or solar power, investment in these technologies will generally be profitable with little or no subsidy.
Unfortunately most governments (and NGO activists) look at it simplistically, concentrating on and where appropriate subsidising the fuel, while giving far too little attention to the effectiveness with which the fuel is being used.
So why do Finland and denmark produce so much wastage that they can get all that energy from it ? They should try to be less wasteful, and not make so much garbage.
First of all here in Germany the efficiency of a modern coal power plant is between 42 -45 % and for a gas power plant 53 % and even nuclear power plants have an effiency of 37 % and not of 35 %. I think modern american power plants have the same efficiency. But even if you take this higher effiency into account you are comparing apples with pears as we in Germany say, when you compare these efficiency with the efficiency of a power plant producing only electricity with that of chp. For your comparison you have to take into account the energy needed to produce the electricity a household needs and the heat a houshold needs produced by gas or oil fired central heating (efficiency around 90-95 %). So the overall efficiency of these two systems electricity produced by a coal fired power plant and a gas central heating is around 80 %. Normally chps are heat guided and the water transporting the heat has a temperature of 120 ° C, so there efficiency is cleary lower as the efficiency of a power plant producing only electricity. Even in the summer, when nobody needs heat and the chp will produce only electricity the chp efficiency is normally a little bit smaller as for a power plant producing only electricity. Also, nobody will lay out a chp for the maximum heat capacity for the 10 -20 day in winter, when it is really cold, you therefore need a plant producing only heat so that the people have a warm home. Taken this together the efficiency of a chp, working at the optimal point and this is only theoretical, the efficiency may 83 %. You have theoretical advantage of a chp against an oil fired power plant and an oil fired central heating of 3 %.
This system for home use changes the priorities (http://www.senertec.de/en/derdachs.html). Primarily it produces heat for the house. Electricity is a by-product that can be used or sold. An interesting system but a bit expensive. The main problem is to find a good balance between your needs for electricity an heating all over the year.
Another issue with CHP is the length of the heating season. In many areas of Texas, the winter season is so moderate that even just using purchased electricity is cost effective. I use natural gas and my monthly bill in Jan. – Feb. rarely exceeds $30 (US).
Don’t hear much about this either: http://pubs.acs.org/cen/science/88/8837sci1.html
More efficient nuclear reactors with waste with much shorter half life.
CHP does enjoy federal and state support in the USA:
http://www.powergenworldwide.com/index/display/articledisplay/357194/articles/cogeneration-and-on-site-power-production/volume-10/issue-1/policy-update/strong-prospects-for-chp-under-new-us-president.html
Also see California law AB 1613.
Cogeneration utilizes waste heat from electricity generation to heat buildings and or water. It saves money as long as you have a use for the waste heat. In the winter time we do, but in the summer we don’t. And summer is when we, in the USA, have maximim demand for electricity as everyone turns on the A/C.
Sadly the BBC still does not get it. Wind turbines are expensive and useless.
http://www.bbc.co.uk/news/science-environment-11418685
They also badly report, ignoring core issues, to bleat about manufacturing costs because the lovely little things have to be imported.
Roger,
Overall I’m a proponent of CHP. I think it should be a large part of our energy strategy. It’s not a cure-all, if the life cycle for specific applications pan out, it’s a great choice.
What baffles me is the carbon issue. A lot of these plants use natural gas (a fuel I also favor for many applications), but of course I end up with a carbon foot print when I run the load numbers. In addition, some plants use even more carbon heavy or non-environmentally friendly fuels. So who is going to decide where to balance these effective carbon systems vs. (sarc) sustainable systems?
Right, retrofitting large districtwide CHP schemes to existing houses will be very expensive and disruptive.
However, there are now systems coming onto the market designed to fit into existing homes where they replace the existing central heating/hot water systems. These will generate electricity as a “by product” of heating the home, and do so more cost-effectively than solar photovoltaic panels, for example. These systems can use natural gas or heating oil.
Admittedly, since the use of electricity in a home does not necessarily coincide with the time that heating is needed, there is the need either to grid-connect the home – and/or to provide an electricity storage system in the home (as is typically done for other off-grid solutions such as solar photovoltaic).
The aim is to use as high a percentage of the energy in the fuel as possible…
The story in smart energy is aligning the energy supply with the energy needed. So often, the energy needed is not electrical or chemical although when you need electricity or gasoline, they are hard to beat.
Storage can be batteries, or it can be whatever you want to do with energy. Could steam-chillers on a CHP be an economic basis for thermal stores as Ice Energy makes? Would this make a CHP an ideal load-shifting technology even in warm climates? We won’t know until we begin thinking about all energy sources, and final uses of energy, and make creative mappings between them.
Personally, I have long wondered why every data center is into incorporated into some sort of CHP system. They certainly reliably through off heat every day of the year. That heat can be re-used elsewhere.
Good post. Thanks.
A little late to game here but I designed and produced a natural gas powered cogen plant for use in California back in 2002. It used an internal combustion engine rated at 375Kw@900RPM. The exhaust went through a catalytic converter and then the heat was removed using a special heat exchanger. This heat and the motor cooling heat was then used in in an Ammonia absortion chiller to provide cooling or could be used directly as heat. The overall efficiency was about 80% and the idea was to prevent blackouts during periods of high utility strain. Since the unit could be brought on line very quickly it could reduce the peek demand at places like hospitals and hotels. It doesn’t solve all problems but is an efficient way to generate power and heat for reasonable periods of time.
It probably would not be very useful in areas with normally comfortable living conditions as the efficiency drops off dramatically if the waste heat is not used like days where ambient temps are 60 to 75 degrees F. On a 100 degree day in California at their energy rates it is actually cheap source of energy just not a silver bullet for everyone.
Barry C. Strayer
Toby,
I’ve designed HVAC systems for Data Centers, Telephony Switches and other elctronically dense facilities for over 25 years. Much of the problem with re-using the waste heat is collection and the temperature difference. Most of the gear is not rated for more than 104 F, and most sites are kept at considerably lower air temperatures. This usually on leaves a delta T of 15 – 20 F to play with. Collecting heat by hydronics is even more difficult; we can’t get it directly from the racks because of the fear of getting water or other fluids on the electronics. And most of these sites really don’t have a place to reject low grade heat. But keep optimistic; I keep seeing more and more investigations into methods of using this heat and hopefully it will soon be invented and part of standard practice.
Dzojar,
We built cogeneration systems by the dozens across the US Gulf Coast as the nuclear power plants were built, and utilities raised their electricity prices. No government assistance was needed.
At one large merchant chlorine plant near Houston (where I worked and have extensive knowledge), the new nuclear power plant and its high-priced electricity allowed us to build a large CCGT project (two large gas-turbines with waste heat steam generator and large steam turbine, three generators total). Natural gas is the fuel, and a large part of the steam is routed to the chemical plant so that previously-run boilers could be shut down. A win-win for the chemical plant.
Many other cogeneration (CHP in the modern parlance) were built, especially in Louisiana.
All it takes is another round of nuclear power plants to be built, and hundreds more CHP or cogeneration plants will be installed. We did it before. We’ll do it again.
http://energyguysmusings.blogspot.com/search?q=death+spiral
I agree Roger; we’re engineers, and the roads must roll! 😉
Grey Lensman,
You missed my “get rid of the subsidies” rant. Efficiency is determined not by some external calculation, but by the relevant parameters in each instance. Heat pumps are remarkably efficient, as long as the delta T is small – not exactly what one wants to hear in Phoenix, or in Anchorage.
I’m with you on the local power meme, distributed sources and sinks make for a very robust infrastructure for all concerned. I’m really gunshy about the huge grid, of which the E-companies are so proud. It’s failed before, and it will fail again. With or without external drivers.
If you are building a new town from scratch it makes sense to build it as a megastructure, with cogeneration. The hot water/hot air/steam pipes are all enclosed within the structure, so no heat is wasted.
However, for existing towns, the capital expense would be prohibitive, and the efficiency would be comparatively poor; a substantial and possibly excessive fraction of the heat would be lost in distribution. Since with cogeneration the “waste” heat has to be rejected at a temperature ~100K higher, significantly less electricity (~3/4) can be produced for the same primary energy. There might or might not be a net gain in overall energy efficiency.
Surprisingly, The size of the power plant and its distance from end users is not particularly important for cogeneration. This is somewhat counter-intuitive. The reason is that nearly all the heat loss happens close to the consumer; loss is proportional to linear length but almost independent of pipe diameter (~logarithmic), so the lowest levels of the network dominate the loss (and also the cost). What matters is the density of users; loss is proportional to the typical distance between users. So city centres are good, sprawling suburbs bad.
New ideas:
‘Blue energy’ seems feasible and offers considerable benefits
http://www.physorg.com/news176125611.html
Osmotic power – Statkraft
http://www.statkraft.com/energy-sources/osmotic-power/
Most modern successful CCGT schemes do not involve distribution of heat to domestic consumers – because the capital costs are prohibitive and the legal problems associated with wayleaves normally insurmountable in any western economy. New capital programs typically focus on the provision of excess heat to one (or a small number of) commercial or industrial consumer with a high baseload requirement, which often includes the coincidental new-build of the industrial development at the same time as the CCGT generation. This is a win-win for everybody in terms of costs and efficiency.
People are supporting TIDAL POWER? Do you not care about the environmental implications? How are the newly-hatched little baby sea turtles supposed to survive when the waves are not strong enough to wash them out to sea and safety? Are you PREJUDICED against sea turtles because they are not cute enough, not soft and fluffy like panda and polar bear cubs? Must the sea turtles DIE so you can have your big plasma flat-screen HDTV? Have You No Shame?!
(Who doesn’t see this “line of reasoning” getting used by deep-green activists?)
😉
Dave, posting above, mentions ground source heat pumps, geothermal space heating and cooling.
I’ve installed a 2 Ton (24,000 btu) unit in my house, and it is truly amazing.
54 degree ground water in New Jersey makes for air conditioning which is three times as efficient as conventional split unit systems. For heating, it is twice as efficient as electric heat. Overall, 2.5 times the efficiency.
My 2 Ton unit draws 4 Amps at 220V when air conditioning.
An equivalent non-geothermal unit would draw around 12 Amps.
This is an inexpensive, well understood technology which beats the crap out of solar power and wind power as a solution to reducing energy consumption while maintaining a comfortable “Western” lifestyle.
Meanwhile, California goes further down the drain with the state’s Air Resources Board now requiring 33 percent of all electric power sales to be from renewables, by 2020.
The primary claim is cleaner air, plus more jobs will be created in the state. There is also a claim of insulating the state’s consumers from future natural gas price increases. The words “dirty fossil fueled generation” are used, yet California has no coal-fired power plants.
Apparently no one told the ARB that these renewable power plants require gas-fired power plants as back-up. Also, it is laughable that any manufacturing jobs for such plants will be in California, given the very high labor costs, real estate costs, tax rates, and regulatory burdens.
http://www.arb.ca.gov/newsrel/newsrelease.php?id=155
j.pickens,
Ground source heat pumps are great energy savers. Like all systems it does have some limitations, primarily the local soil conditions. However, many ot the residences in this country could use this technol0gy with fairly rapid payback on investment.
It’s tougher with large dormitory type facilities; I doubt you have more than two vertical bores; I recently did a barracks requiring over 120 bores.
– some soil conditions don’t provide an adequate heat sink without large bore drilling costs.
And they can be small…
My kids high school put in a CHP gas turbine from Capstone Turbine CPST of about 30 kW size. Consumes the same fuel that they used to use to heat the pool, but now cuts their electric bill by 30 kW -hr / hr… The whole thing fits in a small garden shed sized enclosure. They also use their micro turbines to power busses, so the package will fit i a bus engine bay…
These things are small enough you could put one on your block and share it between a dozen houses and tell the utility to go stuff it… AND they run on gobar gas (cow poo fermentation gas…) and ‘sour’ well gas as well as land fill gas and you name it.
Yeah, I wish they had a 3-6 kW version. I’d be replacing my furnace with it…