As we shift our energy system away from a few very large power plants and toward more localized and efficient clean energy resources, one opportunity has yet to truly take off in Minnesota: combined heat and power. Combined heat and power (CHP) takes much of the heat that is wasted during traditional power generation and uses it to heat a building or a water system. This efficiency creates big time energy and financial savings – so why hasn’t it been more widely embraced?
Despite our leadership on energy policy more broadly, Minnesota hasn’t yet developed a robust public policy to encourage and implement efficient CHP systems economy-wide. Fresh Energy is working to change that.
Using local resources while cutting waste
One reason CHP makes sense for Minnesota is our local, natural resources – more specifically, our wood. If sustainably harvested wood can be used to fuel a combined heat and power system, you can utilize a local resource while cutting waste from your energy bill. To dive a little deeper, we brought together two leading experts in combined heat and power and forestry to see what that might look like.
Ken Smith is the head of Ever-Green Energy and St. Paul District Heating and Cooling, a successful CHP project that’s utilized tree trimmings and other residual wood products for decades. The key point, from Smith’s perspective, lies in creating systems that use local resources and use them more efficiently.
“Nationwide, we waste about 60 percent of our energy,” Smith said. “We’re a little better in Minnesota, but we’re still wasting about 58 percent of the energy we generate because it’s simply given off as heat when the energy is generated.” A closed loop system, however, can utilize much of that heat for other uses, such as heating an entire district of buildings.
Katie Fernholz is the head of Dovetail Partners and a forestry expert. When it comes to CHP, Fernholz wants to ensure we’re valuing our forests for the long term by creating market demand for sustainably harvested wood: “If the world needs renewable energy, I want forests to play a part in that. We can find the right fuel sources and the right scenarios to use wood for sustainable combined heat and power.”
Impact on forests
Fernholz hopes that creating a market demand for wood could help reverse a growing trend of forests being sold off, clear cut, and used for farming, in particular potato farming across north central Minnesota. The question comes down to how those forests are managed and what carbon impacts come from burning the wood they produce. Essentially, the carbon impact of burning one type of tree can be much different from another.
As we move forward, policies we pursue should take those elements into consideration and target the solution that provides the greatest carbon benefit. With the right policies in place, communities across Minnesota may be able to replace aging power plants with efficient combined heat and power systems that run almost entirely on local, sustainably harvested wood – simultaneously cutting waste, lowering emissions, and supporting our forests.
Will Nissen is a senior policy associate at Fresh Energy.
Want to add your voice?
If you’re interested in joining the discussion, add your voice to the Comment section below — or consider writing a letter or a longer-form Community Voices commentary. (For more information about Community Voices, email Susan Albright at salbright@minnpost.com.)
Burn more wood????
Just because something can be done, doesn’t mean it should be.
Or: what am I missing here???
Is there some new process for wood burning that is not being explained here?
The trees are the’ lungs’ of the world. Thanks to deforestation efforts worldwide, there are too few of them now, which puts the planet & its inhabitants at increased risk for both health, and life. True hardwoods also take years to grow, so it’s not like we’re talking about quick growing bamboo (often used for flooring now).
Additionally, wood smoke ‘particulates’ are tiny but extremely dangerous & spread far & fast & permeate everything! They kill many thousands in the USA alone every year. As an asthmatic, I know firsthand how quickly wood smoke can change my asthma from under control, to life threatening.
I am all for being as efficient as possible. But better methods exist, or can exist, that are far cleaner & safer, and more sustainable. This wood burning idea sounds like a huge step backwards.
I Second Your Concern
There’s something about the lay of the land and the wind patterns it creates that means,…
whenever one of my neighbors (I’m not quite sure which one) decides to take the chill off their living room (generally in mid fall and mid spring), by lighting a cozy fire in their fireplace,…
the smoke drops to ground level and the whole neighborhood fills up with enough smoke to make my eyes burn, my sinuses swell, and my lung efficiency drop by a substantial percentage.
The truth is, I used to love a cozy fire (when I was inside the room where the fireplace was burning), and it doesn’t happen all that often so I haven’t tracked down the source and complained.
I suspect that, in areas of the state which are close to forests, ideas such as the one described here could be implemented,…
though I’m not aware of any district-sized or building sized systems that have the pollution controls necessary to remove particulates from exhaust,…
nor am I aware of what the chemical composition of the combustion products of such a system would be,…
though I doubt they’d be any less heavy on CO2 than coal.
Depending on the wood being burned, there are a whole collection of volatile compounds that could also be a problem, especially if pine is being burned.
I can appreciate the need to find alternative uses for trees being planted and harvested by companies in the northern regions of Minnesota,…
especially now that paper product use is in serious decline,…
and, at the same time, the continuing sluggish economy keeps building construction suppressed.
Perhaps solutions such as this would be useful up North or in other rural areas, where the population is a good deal less concentrated and neighbors are spread out,…
but I highly doubt this could ever be a viable solution in moderate to larger cities or urban areas.
I also doubt that it would reduce overall air pollution and fear it would like increase it.
Back in the early 70’s when loggers were done with an area the burn piles of branches and trimmings were huge. Even back then I felt torching off those piles after the first snow was a waste and hated doing it. I grew up in a family that heated our house with wood. If the EPA doesn’t ban wood burning (they will try) I believe using wood, which is a renewable and sustainable, could help both the logging business and lower costs of heating. I have always wondered why the Forest Department goes along with a ban on logging on Federal land when they know that trees grow, they mature, they die, they fall down and finally burn to clear the forest floor for regeneration. If you cut them once they reach maturity you can use them and that also clears the forest floor and regenerates the forest without the fires which we pay big money to put out. Never has made sense to me??
Disappointed in Fresh Energy here…
I’m disappointed that Fresh Energy would be advocating for wood burning, though I’m glad to see I’m not alone in this concern. Wood burning creates a substantial amount of air pollution. What sort of technology would we need in order to create a facility that sends both power and steam into a closed network dense enough to support such a technology? Folks who live by the HERC aren’t enamored with it just because it’s CHP — in fact, people have been organizing to close it since it opened due to localized air pollution!
A few months ago, I went to a forum on air quality and asthma. Most of the attendees were older folks who experienced repeated issues with neighbors’ wood burning stoves. I don’t see how this proposal is feasible/desirable when we already have the technology to create a sustainable grid — one that generates power without generating heat, which allows us to decide when we actually need the heat.
How about those raging forest fires on Federal land where logging is not allowed, do they create air pollution? Trees grow, then die and fall down to the forest floor, Mother Nature for thousands and thousands of years has started fires to burn those fallen trees & regenerate the new growth that sustains the forest. Logging regenerates the forest without the fire. You not only save money by lumber being cheaper, you can use the trimmings for fuel. I guess there must be less pollution in a 10,000 acres burn than in a fire place or furnace. How do think, in nature, trees replenish themselves and new growth begins in a forest?
If the Hennepin Energy Recovery Center were burning wood instead of garbage, I’d feel much better about them. We could be better served by wood burning facilities more efficient than HERC.
They still burn a lot of coal in winter as well as wood in St. Paul’s heating and cooling district as far as I know, and I don’t feel good about that either.
I’d feel better with more advanced utilization of wood fuel through gasification, i.e., the wood can be broken down by heat and reformed into cleaner burning gases to better address the particulate problems. Much better than burning coal and garbage. The University of Minnesota Morris campus has been working with a gasifier (see: https://wcroc.cfans.umn.edu/research-programs/renewable-energy/biomass ) and other commercial plants have been using them as well.
I think we’ve mostly all experienced our neighbors burning stuff even when we’re stuck in an inversion layer that holds all the combustion products close to the ground for us to breath in. You don’t need to have asthma to hurt under conditions like this. Better to let the pros burn most of the wood in advanced facilities or get ourselves cleaner stoves and fireplaces too.
Burning wood
If you are worried about global warming (i’m not) then burning wood has the benefit of being closer to carbon neutral.
Other than that, it is going to be VERY difficult to get wood to burn anywhere NEAR as clean (smoke and particulates) as does coal or natgas.
More Than Just Energy and Carbon
Using woody biomass for energy positively impacts many values important to Minnesotans. There is much more to forestry than energy and carbon.
1) As to carbon, burning wood recycles ambient carbon and does not add fossil carbon to the atmosphere. In addition, a cut-over forest area sequestrates a huge volume of carbon in the underground root structure, and then a new forest grows on top to add its roots to further add to carbon sequestration.
2) As to efficiency, burning technology is in place and being used right now from home-size hot water boilers to industrial sized boilers that achieve 98-99% burn efficiency. Admittedly, these are not 100% particulate pollution free and might not be suitable for all areas of the state, but I welcome anyone interested to visit and see my home-sized 140,000 btuH wood gasification boiler which has been in place since 2006 and talk to any of my neighbors if they have any concern over the non-existent smoke (particulates). Similarly, Deep Portage, an environmental learning center near Hackensack which has about 10,000 visitors per year, has in place three wood gasification boilers with combined output in excess of one million btuH and which provide space heating and domestic hot water for a 60,000+ square foot facility, all within about 200 feet of classrooms and dormitory style sleeping rooms, and there have been no issues related to particulates that have arisen from visitors or residential guests.
3) Wood harvested in Minnesota “fuels” the local wood cutters, loggers, truckers, and firewood processors, with nearly 100% “recycling” multiple times in the rural economies of the cash generated from their sales. The “recycling” is the spending of that money in local grocery, hardware, clothing, building supply, etc. stores, supporting not only the jobs and families of the wood-based workers but also other jobs and families in the area communities.
4) Wildlife habitat, from birds, to deer and other four-legged forest critters, to bugs, to fungi and bacteria and other organisms, depends strongly on diversity on the landscape for a healthy environment, as do us humans. Sustainable forestry helps to provide that diversity. New growth, early growth, mid-growth and old growth forests all play a vital role in healthy ecosystems.
5) Harvesting of wood in sustainable forestry provides huge value in recreational opportunities for hunters, birders, ATV riders, hikers, campers, etc., along with the value which those enjoying these opportunities provide to local economies. The economies of much of the forested regions of the state are driven in large part from tourism and recreation.
6) Keeping land forested and helping to make retaining that land as forest land through the economic benefits of sustainable forest management help ensure clean water to meet the needs both of local communities and all those benefiting from the Mississippi River watershed. It is well known that a major factor contributing to the clean water which exists in Minnesota is the ancient forest cover which continues through new growth to thrive yet today. Forest cover traps, filters, and then delivers clean water to ground aquifers, streams, rivers and lakes, and then that water is “freely” available for healthy support of all life, and importantly water for us to drink.
7) The consequence of discouraging working, sustainable forests is the clearing of forests, or more dramatically “deforestation,” and using that land for non-forest development. We easily complain about deforestation in other parts of the world, but Minnesota also experiences deforestation every day. Sustainable forestry provides economic incentives to prevent our home-grown deforestation.
Woody biomass is an important energy resource in Minnesota. Responsible, sustainable use of woody biomass supports many important values we all share. Wood is far more than just energy and carbon.