Innovative Heating And Cooling Projects Prove The Benefits Of Geothermal

by Chris Williams

A few months ago, I reported on the largest geothermal heat pump project in the United States currently under construction at Ball State University in Indiana. The project is a breakthrough for the geothermal heat pump industry for a couple reasons. First, its massive size. Second, it is extremely economical and shows that geothermal heat pumps are ready for district heating and cooling applications.

To give you a sense of the size, the project is a 10,000 ton system, which is equivalent to 35 megawatts of power. That’s large enough to heat and cool 47 buildings — replacing four old, dirty coal-fired boilers. The project will also help create 2,300 direct and indirect jobs throughout the construction period.

The project will cost $60 million dollars, which equals $1.71 per watt of power, beating the cost of utility-scale solar projects. Utility-scale solar PV projects have an average installed cost of $4.69 according to the Open PV Project in November 2012; although this number if falling.

Geothermal is a great technology because it’s cheap and because it’s extremely energy dense, meaning it produces a large amount of valuable energy in a small amount of space.

A 35 MW solar PV project would generate roughly $3.8 million worth of electricity every year in Indiana and would likely cost around $105 million dollars to build. In contrast, the 35 MW geothermal project will generate $2 million dollars worth energy per year. The project is also being installed under parking lots and and sports fields, so it will take no additional room on campus. An equivalent 35MW solar PV facility would take up about 140 acres.

Those are some of the very clear benefits to geothermal that don’t get a lot of attention.

I want to follow up on the Ball State project with a quick snapshot of two other great geothermal projects that are helping drive adoption of this valuable and under-appreciated technology.

The first is a community-scale geothermal project in Massachusetts. We’ve heard a lot about community-scale solar PV projects, but community geothermal is also starting to emerge. New England Renewable Energy Systems has installed a community geothermal project in Provincetown, Massachusetts that uses a single loop field to heat and cool ten homes. The system has 19 vertical bores that supply 44 tons of geothermal heat pumps, or about 154 kilowatts of capacity. The challenge for community-scale geothermal, like community-scale renewables generally, is coordinating the investment among homeowners. But the benefit is clear: Homeowners participating in the program can pool their resources with others and save about $2,000 per year in heating costs from avoiding burning oil.

The second notable geothermal project is at Missouri University of Science and Technology which was designed by MEP Associates, the same firm that designed the Ball State project. Missouri S&T is currently constructing a 6,000 ton geothermal system that will heat and cool 2.17 million square feet. That is a huge project equivalent to about 21 MW of power capacity. Like Ball State, the project is extremely economical; the system costs $32.4 million dollars, or about $1.54 per watt.

The project has other notable benefits: it will reduce the whole campus’s energy spend by 50 percent, it will save $1 million dollars per year annually, it will eliminate $26 million dollars in deferred maintenance costs for the aging power plants it is replacing, and it will save the university’s water consumption 8 million gallons per year.

Here’s a video about the project:

Geothermal for district heating and cooling is a great investment for large commercial entities and public institutions. As these projects show, it has clear benefits that some other technologies can’t provide. It’s time to give geothermal heat pumps some due credit.

Chris Williams is the Chief Marketing Officer for HeatSpring Learning Institute a national renewable energy training company, Chairman of the Government Relations Committee forNEGPA and an advisor to Ground Energy Support, a provider of real time geothermal heat pump monitoring technology.

31 Responses to Innovative Heating And Cooling Projects Prove The Benefits Of Geothermal

  1. David W. Potter says:

    Why do you insist on mistakenly referring to this as ‘geothermal’? The term means ‘heat from the earth’. If there was a significant output of HEAT from seismic or other source in the earth, this would be accurate. USE THE TERM ‘EARTH-COUPLED’ OR ‘GROUND-COUPLED’ to show that this technique uses the soil rock and earth underground as a medium to exchange heat or cold. This is what you are doing with this technique.

  2. Photon says:

    The $4.69/Watt figure from NREL that was quoted for the price of PV capacity is highly misleading. The Open PV figures include all capacity built to date, with many of the projects dating back over 4 years. New utility-scale capacity installed in 2012 is significantly less costly, typically under $3.00/Watt.

    In places like Germany that have more experience with solar, ground mounted arrays are going in at $1.70/Watt

  3. Adam R. says:

    The statement “…the 35 MW geothermal project will generate $2 million dollars worth [of] energy per year.” is somewhat misleading. Better to say that the project will SAVE $2 million dollars worth of energy per year.

    The system will replace fuel burning boilers and conventional electric water chillers with heat pumps whose efficiency is enhanced by ground water source heat absorption/rejection technology. It will still be a net user of electrical power for the ground water pumps and heat pump compressors.

    This is a most ambitious project because of the extensive network of ground water extraction and injection wells required. A smaller project of this nature for the U. S. military with which I was associated five years ago was initially successful but ultimately failed due to well fouling problems. I hope technology has advanced to cope with such issues, because the basic idea offers large efficiency gains over conventional boiler/chiller systems.

  4. Mark Shapiro says:

    How was the following estimated?:

    “A 35 MW solar PV project would generate roughly $380,000 worth of electricity every year in Indiana and would likely cost around $105 million dollars to build.”

    Wouldn’t a 35 MW PV array generate about 35,000 MWh in Indiana, worth about $3 million?

    That would be roughly a 3% tax-free annual return.

  5. AA says:

    You can’t really compare geothermal cost/capacity to electricity generation costs.

    1$/Watt of electricity would be about $.25-.40/Watt of heating and cooling when you take the COP of the heat pump into account.

  6. Photon says:

    I think someone misplaced a zero somewhere. A 35 MW array in Indiana would generate about 40,000 – 45,000 MWh per year. If valued at $90 per MWh ($0.09/kWh), that equals about $4 million dollars. That’s a a whole order of magnitude greater than the ~$380,000 figure from the article.

    So, yeah. Scrounge up another zero there TP.

  7. David,

    Sure. This is all semantics that only the industry cares about. Figuring out exactly what to call it is something engineers can argue about, but property owners could care less.


  8. Photon,

    Agreed. I noted that the price is falling. Yes, typically around $3/watt +/- 20%, depending on the market and the site.


  9. Mark and Photon,

    Yes, just missed a zero in there. It will get changed shortly. I used 1kW to 1kWh as a general of thumb. It could be a lot larger if it was a tracker as well, but the point was not to get into details talking about pv power production.


  10. Adam,

    I 100% disagree with you about the wording on this. A solar pv project can also be seen as “saving energy” in Indiana because it’s displacing coal used for power general. However, we commonly refer to it as “producing energy”.

    A ground loop is no different for heating. We’re extracting BTUs out of the ground. This is production.


  11. Mulga Mumblebrain says:

    Fair enough Photon, but we need every possible renewable, non-carbon energy source, so power to them both I say.

  12. AA,

    You can absolutely compare them. It’s simple math to convert watts, to BTUs, to tons, etc, etc.

    I agree with you that each have to take into account derate (DC to AC) or parasitic loads used to move energy, but again, simple math.

    Putting technologies into the same units is beneficial because it allows us to compare apples to apples more easily.



  13. Martin Orio says:

    Chris – Great work on identifying non-bias comparisons and related IRR with geo/groundsource technology!
    As long as application respects design used to attain published efficiency then geo is unbeatable, and a vital tool for reducing/eliminating fossil, and the carbon it comes with! To say nothing of it being a smart investment!

  14. Adam R. says:


    Suppose you install a common residential heat pump at your home. In that case, you are extracting BTUs from the outside air to heat your home. Would you say your home heat pump is “producing energy”?

    The “producing energy” usage fails in the cooling mode anyway, because in that case, you are moving BTU’s out to the outside air to cool your home. Would you say then that you are throwing energy away?

    A heat pump is an energy user, just a smarter, greener one than an oil-fired boiler. Let us please not confuse energy conserving technology with energy producing technology.

  15. Thank you, David!

    The term we use for these systems at ArchitectureWeek is “ground-source heat pump.”

  16. Language inflation and hype don’t help anyone. Education is central to making better energy choices, and we look for accuracy on these things here at Climate Progress!

  17. It sounds like there’s some basic confusion here about the thermodynamics of heat pump systems.

  18. Kevin,

    Nope. No confusion here.


  19. Kevin,

    Agreed. Ground source heat pump is the most technically correct term, but again, what’s technically correct doesn’t necessarily have anything to do with the best way to communicate the technology to property owners, policy makers, and the public.


  20. AA says:

    Can I plug a 2.4 ton mini split into a 230V/20amp power supply?

    If you don’t see what I’m getting at, I have a resistance heater in Brooklyn to sell you.

  21. Adam R. says:


    More like a re-branding of energy efficiency. That’s where confusion is being added.

  22. Ed Malloy says:

    I understand the goals of this article and it’s greatly appreciated.

    It seems it’s quite possible we’re making correct statements in different contexts.

    Although I understand Brooklyn could have used a few heat pumps with back-up generators most recently.

    There’s a broad range misconceptions and misinterpretations due to overlapping concepts (e.g. geothermal heat is from radioactive decay of earth’s core … vs. GSHP – extracting energy from a constant temperature – those in the industry, manufacturers included do refer to their equipment as part of a geothermal system)

    Actually you can connect a 2.5ton ductless into a 25A breaker – 80% @ 20A.
    And are we talking about system starting or running? Or neither?
    Are we refering to the cost of generation? Loss of energy from centralized generation? Cost of centralized generation, distribution, system control, maintenance, … end user true cost.

    In any case, appreciate the exchange.

  23. Dave Bradley says:

    This is a really awesome project, and it is good that this is being discusses. But the mis-information and ignorance about ground-sourced heat pumps as heating and cooloing systems is also pretty big. So, in hopes of correcting this ignorance……

    A heat pump uses electricity, steam turbines or a fuel fired motor to power a compressor which pumps heat via a working fluid such as R-134a, ammonia or R-245fa. For a large system like this, one energy unit of electricity should deliver 6 units of heat, or extract something like 5 to 20 units of heat in cooling mode. in this case, it probably uses electricity, which in Indiana is either coal (most likely), nuke or wind sourced. Electricity is really cheap in Indiana; generators are usually paid less than 3 c/kw-hr these days, and sometimes less. Bulk delivered electricity probably costs less than 5 c/kw-hr.

    A coal fired boiler system might deliver 5 units of heat from 6 units of heat liberated by burning coal.

    A 35 MW (capacity) PV system in Indiana might make 35,000 MW-hr/yr. This has a value of about $1 million/yr if generated elsewhere, or about $1.75 million/yr if made on thew site it is used. And it would probably cost around $140 million installed. You can buy a lot of heat pump systems for $140 million..

    At 10,000 tons, this is 120 million Btu/hr, or 35 MW of delivered heat. This would probably use around 6 MW of delivered electricity, though for some parts of the year, no where near that rate. 20 MW of Indiana wind farm capacity could power this up.

    Indiana has an awesome wind resource – see for the one based on old-fashioned wind turbines like the GE 1.5 MW x 77 meter rotor. At 225 GW of capacity * 0.25 = 56 GW delivered, this is around 4 times the present consumption rate. Using modern Low Wind Speed Turbines, you could up this to around 80 GW delivered, but again, you only need what is consumed.

    Indiana’s present capacity is around 1343 MW (see, or close to 400 MW delivered. This Ball State project could use 1.6% of Indiana’s wind turbine delivered output to replace a lot of coal that was made for steam or to make electricity to power air cooled chillers. So this heat pump set-up is awesome, even if it uses coal fired electricity. But it would be really nice if it used only wind too power it up…

  24. Adam,

    I agree, we should not confuse these things. To be clear, no energy can be created, only moved. This is true for solar pv, solar thermal, oil, biomass and heat pumps.

    To your point. Yes, for an air source heat pump in heating model, the energy that is extracted from the air is produced. The air is an energy source. Why? It has BTUS in it. BTUs = energy. The same for a ground source heat pump. If the heat pump delivers 63MM BTU at an average COP of 3.75, then 13.5MWh of power will be produced (extracted) from the ground loop.

    Things about heat pumps in this way is key to understand the renewable thermal production based incentives that are being created. For example, the $29/MWh production based incentives in New Hampshire can be gathered on a geothermal heat pump system.

    For cooling, I agree with you it makes the most sense to call it efficiency.


  25. AA says:

    2.4 Tons is 28.8kbtu/hr or about 8.4 kW

    The circuit described can deliver 4.6 kW (3.6 kW in continuous operation)

    So the mini-split delivers more energy than the circuit can provide… how is it possible?

    The answer lies of course in the fact that the mini-split is a heat pump moving energy from a different source: air or ground heat or a water loop. The compressor doing the work can probably move 3 or more units of heat with one unit of electrical input.

    To bring this back to the article, a 35 MW capacity heat pump doesn’t use 35 MW of electrical power; 1 Wh of electricity is a lot more useful than 1 Wh of space heat.

    GSHP systems are neat, but their advantages are often oversold. In fact, it’s possible to design a system that “produces energy” from the ground but emits more greenhouse gasses than a pretty average natural gas boiler delivering the same amount of heat.

  26. AA says:

    You write really long, substantial comments. Even if I’m not 100% in agreement with your positions (on FIT for example), you always make a good argument.

    You should put together a guest post and ask Joe to run it.

    It’d be a lot better than some of the other things that have run recently.

  27. Mike Swift says:

    Chris, and Photon. Both of you are talking about $/Watt, and the numbers look about right for these described systems, however I would think you should be talking about Watt/hours, W/h. As an analogy if you compared a $0.50 flash bulb with a light output of 10,000 lumens to a $2 flashlight with an output of 300 lumens, and said the flashbulb was a better deal to light your way across a dark room because it gave much more light per dollar that would be a false premise. If we use Wh/day the solar system puts out 4-6 Wh/day, or about $3.00/6, or$0.50 per Wh/day, and the ground-coupled system produces 24 Wh/day for a cost of $1.54/24, or $0.0642. GSHP is vastly more economical.

  28. Hi Dave,

    Thanks for providing some technical details, I decided not to go into technical details because it was just a basic post. Also, you can tell my simple conversion from tons to MWth (megawatts thermal) to relate the huge size of the ball state project, confused a lot of people.

    Furthermore, everyone seems to be genius about ground source heat pumps, and things everyone else knows nothing about them. That’s funny.

    I agree with you, it would be super cool to run the heat pumps off of wind power.

  29. Hi Mark and Photon,

    I just did some research into Indiana net metering rules. 35MWh produced from a PV around will only be worth about ~$1.5 million because it will be sold at wholesale rates. This is because Indiana doesn’t have net metering that will allow for large project to sell their power at retail rates. Also, it doesn’t have virtual net metering so it can’t be sold it another site. This could be changed with legislation, but currently, that power would be worth around ~1.5 million per year.


  30. Ed Malloy says:

    Got it – thanks guys – appreciate the thoughtful comments. Ultimate goal being that we move toward large scale clean power generation and distribution … as we develop these technologies at a rate that mirrors microelectronics. And capital markets coupled with social policy can/will/shall shift investment.