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How New England Can Eliminate Oil Use For Single Family Homes for Less Than We're Spending on Solar PV

Chris Williams, HeatSpring
November 08, 2012  |  56 Comments

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We can use simple, effective, and proven policies that have been used to supercharge the New England solar PV industry to incentivize renewable thermal technologies and eliminate oil use for single family homes. Here's the best part, the policies will be cheaper than solar PV, they will create more local jobs per kW installed and displace more expensive fuel. 

At Renewable Energy Vermont 2012, I delivered a presentation on how a production-based incentive for renewable thermal technologies, like the $29/MWh incentive in New Hampshire, would be cheaper than the current solar PV incentive in Vermont and could have a larger impact. The current incentive for solar PV in Vermont is $271/MWh for 25 years, but we could eliminate oil use for single family homes with a policy for renewable thermal technologies of $100/MWh guaranteed for five years. This policy would be much cheaper than the solar PV incentive and would drastically increase the adoption of biomass, air source heat pumps and ground source heat pumps. It would put a huge dent in oil consumption for single family homes, save money and create local jobs. If you're new or curious about thermal incentives, Renewable Energy World has done some great reporting on it.

As I started to run the numbers when I was creating the presentation, I was blown away by how much energy renewable thermal technologies produced, and how valuable that energy is when displacing oil, propane and electricity. Many attendees at the talk had never seen the numbers broken out in a way that easily compares apples to apples. However, as any engineer knows, converting kWs to tons to BTUs is relatively simple. When we compare these technologies in the same terms, it starts to provide a very clear picture of the results that can be achieved by investing in proven renewable energy thermal technologies. These technologies include solar thermal systems, geothermal/ground source heat pumps, air source heat pumps, and biomass.

For the purpose of this article, I'm going to compare solar thermal and ground source heat pumps to a standard solar PV project in a baseline home. I'm using these technologies because I'm the most familiar with them. However, further analysis should absolutely include air source heat pumps and biomass technology.

Background: Why look at renewable thermal technologies?

We waste a lot of money on oil for space heating. Yes, oil industry, my goal is to put you out of business. But don't worry, we'll train you to install these new technologies. In addition to building and retrofitting buildings to have tighter shells, there are only three technologies, yes three, that can eliminate on-site fossil fuel use: biomass (pellets and cord wood), air source heat pumps, and ground source heat pumps. Here are a few pieces of data on why a focus on oil usage is so important for New England.

The EIA separates the US into five energy regions.

The Northeast uses the most oil for space heating, which also happens to be an extremely expensive fuel source. Six million homes use oil for heat, and the average home uses 800 gallons of oil per year, which equals roughly 4.8 billion gallons per year.

If we assume that the average residential price is $4 per gallon or slightly higher, home oil-heat spending is roughly $20 billion dollars per year. 

These are huge industry trends, so let's break the data down into something more tangible. U.S. census data reveals the number of single family homes in each specific state, this is the "total homes" column. I then broke down the heating fuel mix for each state, provided by the EIA, and found the number of single family homes in each state that use a high-cost fuel (oil, propane). You can see that the numbers are sizable. I then took the total number of homes and divided it by the number of homes using an expensive fuel source, which you can see on the far right. This means that nine out of 10 homes in Maine are using a very expensive fuel source. In Massachusetts, 54 percent, or five in 10 homes, use these sources.   However, Massachusetts-specific data reveals that some communities use natural gas (that's green). However, there are a large number of communities where 60+ percent of single family homes use an expensive fuel source.

Solar PV is a great investment but doesn't address oil use — how can we address this problem?

The goal of this post is to show how we can use policies and incentives that have already been successfully implemented in the solar PV industry to address fossil fuel use for space heating in New England. I'll provide a basic comparison of how solar pv and renewable thermal technologies compare when looking at fuel savings for property owners, direct job creation, and the cost of the incentive.

With that said, let me be clear: solar PV is a great investment. The purpose of this post is to be a "yes...AND"conversation. Solar PV will do nothing to address direct fossil fuel use. Additionally, the solar PV industry is large enough to be a great comparison tool because many people are familiar with the economics of solar PV. Thus, using solar pv as a baseline will make it easier to communicate the value of other technologies.

I'm also looking to address a question I recieve often: If geothermal heat pumps are so great, why aren't more people using them?

How do we look at renewable energy policies?

When trying to understand renewable thermal technologies and the impact of different policies, a small number of variables seem to be critical for policy makers.

  1. Reduction in utility bills for property owners and reduction in fossil fuel use that is imported
  2. Local job creation
  3. Amount that said incentive costs for the state or utility
  4. Water quality and air quality issues
I could be missing something here, so let me know if I am. 

Let's create a baseline home for comparison purposes.
 
This is the home we'll be dealing with. If you're not into the technical part of things, please feel free to skim over this, I just want to be extremely clear with my methodology and calculations. If anything is unclear, please let me know; I'll be happy to address any questions.
  • 2,000 square feet
  • 180 degrees
  • 10 pitch roof (40 degrees) — enough space for a 5-kW system.
  • Requires 63MM BTU for heating (read average shell)
  • Existing heating system is oil furnace with AC that must be replaced within two years. Replacing the existing oil furnace and AC unit with the same technology will cost $10,000.
  • Electric rate is $.17kWh inflating at 3 percent per year
  • Oil prices are at $4.00/gallon inflating at 5 percent per year
Let's create a baseline with diferent technologies based on current installed costs, incentives and energy costs for an average home. 
 
1. Solar PV
  • $5.50 per watt times 5 kW = $27,500
  • For those of you who think this is high. Think again. Read more on residential prices in Massachusetts at The Open PV project and the MA CEC's website. Also, I have no reason to make solar PV seem high, I love the technology am a huge supporter of it. 
  • Produces 1,000 kWh per kW installed = 5,000 kWh or 5 MWh
  • Value of energy is $850
  • Local jobs created: 15 man hours per kW installed --> 75 man hours (does not include sales, support and supply chain jobs, just direct construction jobs)
  • Percent of year installed costs driven by rebates: 44 percent
  • Gross installed costs to value of energy: $32
  • Net installed cost to value of energy: $19
  • 20 Year IRR, not considering equipment lifetime or O+M: 9 percent

2. Solar Thermal

  • $110 per square foot gross installed costs
  • 80 square foot system (2 modules @ 40 square feet per module)
  • Gross installed costs = $8,800
  • Net energy production per year: 4,100 kWh (140 therms)
  • Value of energy production displacing #2 heating oil = $443 (140 therms is approximately 110 gallons of fuel oil)
  • Local Jobs Created: 20 man hours per module (this is based on anecdotalle experience not an industry study, because they don't exist) = 40 man hours.
  • Incentives in Massachusetts: ITC, Personal Tax Credit, MA CEC Cash Rebate
  • Percent of year one installed costs driven by rebates: 62 percent
  • Gross Installed Costs to value of energy: $20
  • Net installed costs to value of energy: $7.50
  • 20 Year IRR: 12 percent

3. Geothermal

  • Oil and AC replacement costs = $10,000
  • Geothermal costs = $9,000 per ton X 4 tons = $36,000
  • 4 ton = 14-kW system
  • Geothermal premium = $26,000
  • Oil heating costs = $3,000
  • Geothermal heat costs = $1,000
  • Geothermal Fuel Savings = $2,000
  • Net geothermal energy production from the ground loop = 13,500 kWh
  • Incentives: 30 percent ITC from $36,000 = $10,800
  • 90 man hours per ton = 360 man hours for the job (25 percent of installed costs is labor: $36,000 X .25 = $9,000, and $1,000 is a week's wage for 40 hours, so nine weeks work * 40 hours = 360 man hours / 4 tons)
  • Percent of year 1 installed costs driven by rebates: 41 percent
  • Gross installed costs / value of energy: $13
  • Net installed costs / value of energy: $7.6
  • 20 Year IRR: 14 percent

For those of you that love tables, I've put the data on a table as well.

  

Conclusions

There's a lot of information in the above graph, so I made a few simple graphs that display and answer some specific questions.

Installed Cost per Watt

Geothermal costs roughly $2.57 per watt, while solar thermal costs $3.96 and solar PV is around $5.50. Yes, a lot of residential solar pv projects still cost $5.50 per watt. You may be able to reduce this to $4.00 per watt on new construction, but this trend is decreasing.

Energy Production per Installed kW

Solar PV generally produces 1 kWh per year for every 1 kW installed. A geothermal system will produce 13,500 kWh net energy from the ground loop, backing out the electric use for the pumps and compressor. A 4-ton system is 14 kW, so it produces slightly less then 1 kWh of net energy for every 1 kW installed. The solar thermal system is only a 2.22-kW system, but will produce 4,100 kWh of energy in one year.

Gross Invested Cost per Dollar of Energy Output

This metric is simple. Without considering any incentives (using just gross installed costs), how many dollars need to be invested to get $1 in fuel savings? Geothermal and solar thermal are clearly the winner here when displacing fuel oil. If they were displacing propane or electric they would be higher.

Gross Installed Cost to Net Installed Cost: How much do incentives drive returns?

This metric looks at how much incentives decrease installed costs by taking the gross installed costs and dividing them by all available incentives. What we see is that in Massachusetts, solar thermal is the most heavily subsidized technology, followed by solar pv and geothermal.

Net Invested Cost per Dollar of Energy Output:

After incentives are considered, we can look at the net energy investment required to get $1 in energy savings. Solar thermal and geothermal become more equal at $7.60 and solar PV is around $19. This means that to replace oil with a geothermal project in Massachusetts, you need to invest $7 to get $1 in fuel savings in year one.

Total Man Hours Needed per Job

This is looking at the total direct construction jobs to install a project. This is not based on any reports (because they don't exist for solar thermal and geothermal), but anecdotal evidence. A typical 4-ton geothermal system will require 360 direct man hours in construction, and a solar thermal system will take 40 hours, and a solar PV project takes around 75 hours.

Direct Jobs Created per kW Installed

When we look at direct man hours per kW installed, geothermal and solar thermal create the most jobs, followed by solar PV. The reason for this has to do with the type of equipment being used. For geothermal and solar thermal technology, commodity equipment is used and repackaged in a different way. Components for these technologies aren't industry specific, except for the actual solar thermal modules and geothermal heat pump, but these are easy to manufacture and thus there are many manufacturers. For the solar PV industry, all main components are specialized: modules, inverters and racking. Thus, equipment costs tend to make up a larger percentage of the installed costs. However, this is declining as economies of scale are reached on the manufacturing side of the business.

20-Year IRR with Current Incentives and Assumptions

This graph shows what the 20-year IRR of these different projects is with our given assumptions. Yes, the IRR of solar PV is getting much lower as installed costs drop and property owners see it as low risk, but also because Massachusetts SREC prices are declining. Geothermal is around 13 percent and solar thermal is around 12 percent.

20-Year IRR of All Technologies Received SRECs

This graph is answering a question I frequently hear: If geothermal is so amazing how come more people aren't doing it? My answer is simple: If geothermal received the same REC prices as solar PV, no one would be using oil, geothermal would just be cheaper. So, if we assume that geothermal and solar thermal get paid $200/MWh for 10 years based on their output, their IRRs skyrocket to 30 percent.

 

Lessons earned and what implication does this have for policy in New England?

There are a few lessons we can learn from this analysis.

First, renewable thermal technologies can provide as good or better returns than solar PV technologies for property owners.

Second, renewable thermal technologies need more policy support, but they do not need as much support as solar PV. As you can see, a 30 percent IRR is too high. This is good for policy makers because it means that the cost of deploying renewable thermal technology will be CHEAPER than deploying solar PV. Renewable thermal technologies are cheaper and produce more valuable energy per kW installed, so more of the returns can come from displacing fuel than from a subsidy.

Third, renewable thermal technologies create more construction jobs per kW installed than solar PV.

Fourth, if we're serious about incentives for renewable thermal technologies, we must use production-based incentives. Production-based incentives maintain quality control throughout the entire process: manufacturing, design and installation. A huge lesson learned in the solar PV industry is that incentives based on installed costs have huge flaws (installing solar PV projects in the shade is one example). Those modules on the left in the photo below will still receive a rebate even though they won't produce must power.

Fifth, if any policy makers reading this happen to live in New England, my message to you is simple:  If you're bullish on the solar PV industry and believe that it's a wise investment in terms of job creation, reducing emissions and saving property owners money, you should look into renewable thermal technologies as the next area of rapid growth. If you're looking for the next technology that is going to create a huge number of jobs in your state and save a massive amount of money, you must look at renewable thermal technologies.

If you want to chat, I'd be happy to. Here's my contact information: cwilliams@heatspring.com, 800-393-2044 ex. 33.


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

The information and views expressed in this blog post are solely those of the author and not necessarily those of RenewableEnergyWorld.com or the companies that advertise on this Web site and other publications. This blog was posted directly by the author and was not reviewed for accuracy, spelling or grammar.

56 Comments

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Marvin Hamon, P.E.
Marvin Hamon, P.E.
November 14, 2012
Chris,

I don't see PACE as being too complex for a homeowner. It's a loan that is paid back through an increase in the property tax and like a loan it has an interest rate. This is all really straight forward, much easier than trying to explain third party ownership and those make up 75% of residential PV installs here in CA.

The quality control comes in the same way as any residential project. Hire good licensed contractors, check references, get multiple bids, and know enough about what you are buying to have an intelligent conversation with the people trying to sell you something.

In the end the best solution is system prices low enough that no incentives are needed to get people to buy. Until then the best incentives to drive installations are the ones that reduce the upfront cost.
Martin Orio
Martin Orio
November 13, 2012
Chris - The PACE comment was not mine.

I left the conversation when 80% became 100%...
Best to all, and any thoughtful efficiency that reduces waste or carbon is a good move in my book!
Great to see such passionate conversation regardless!
Chris Williams, HeatSpring
Chris Williams, HeatSpring
November 13, 2012
Martin,

PACE is too complex to explain to the homeowner and doesn't provide quality control on the design and installation.

Production based incentives are a better. FITs are the best.

Chris
V. Bruce Stenswick
V. Bruce Stenswick
November 13, 2012
@Chris

Fine by me. With regards to GSHP's, I suggest a PACE mechanism to fund the loop field with a modified 1000 month payback. Suppose the loop field cost $6000, the homeowner would pay $6 per month, but when he/she sold the house and moved, he/she would owe the balance of 1/3 of the cost of the loop field, and the next two owners of that home would finish off paying for the loop field. At worst it would take 1000 months to pay off the loop field. Also, we need more trained installers and well-drillers so there is a bit more competition. When I put my system in, vertical boreholes were $1000 each, 11 years later they were $2500 each. This may become moot with GeoColumn which may make the loop field considerably less expensive. The lawyers will have to figure out how to get around the problems with PACE. I also get all of my electricity for my heat pump from our local "WindSource" program, which makes it close to carbon neutral. A house like mine with the best furnace would use 80 - 90 million btu of natural gas to heat. In terms of CO2, 1 million btu of natural gas is equivalent to about 6 gallons of gasoline, so by using a heat pump with green electricity I do not put the equivalent of 480 - 540 gallons of gasoline into the atmosphere (burned of course).
Chris Williams, HeatSpring
Chris Williams, HeatSpring
November 13, 2012
Hey Guys,

Just a quick thought. We should stop wasting time talking about the technology and start talking about implementing policy so we can stop wasting so much money on oil. That's the purpose of the article, not to discuss the finest points of technology efficiency, etc, etc.

Chris
lawrence elliott
lawrence elliott
November 13, 2012
@forrest-jones

"Let me clarify why I believe that Radiant Ceiling Panels (RCP) are the best choice."

"BEST" requires quite a bit of qualifying to deserve the word.
So far you fall far short of the mark

There is no way that a resistance ceiling heating system can in any way compete on any level when installed in a thermal envelope that is not 'extreme'

When you can get 2 or even 5 or more units of heat for each unit consumed it's pretty much a 'no-brainer'.

Also when using this system,again when installed in anything but extreme envelope where latent cooling is not required you then need to install a cooling system anyway.

Also an HRV has no function in the heating and cooling

Only fresh air
V. Bruce Stenswick
V. Bruce Stenswick
November 13, 2012
I have a "right sized system", it still should have been one size smaller. If I did not burn any wood, I would use about 7500 kwh of electricity to run my heat pump during the winter. The next smaller size would have maxxed out at about 1 above zero. About 1.5% of the heating load is below that temperature. 1.5% of 7500 is about 113 kwh. If that were obtained with electric resistance heat rather than the GSHP, it would have require 113 x 3.3 = 373 kwh. Our flat electric rate is about $0.08/kwh, or 373 x $0.08 = $29.84. It would really be considerably less than that on a time of day rate since the coldest temperatures are at night, but let's use $29.84. It costs me an extra $29.84 per year to run the system and the savings on installation costs are $3000 or $4000, or maybe $5000. That seems pretty reasonable to me, especially since it is probably less than half that (less than $15 per winter extra).
Martin Orio
Martin Orio
November 13, 2012
@v. bruce stenswick - Repectfully, 80% is 80%...
You and I just spoke on the phone and you said that in 11 yrs. your electric resistance heat has only come on once. This is confusing to me.
That is what I would refer to as a 100% system that does not rely at all on resistance heat as a second stage device.
Your argument against OVERSIZING is valid. Oversizing geo is worse than undersizing, and is also a waste of money. I am glad you have a "right-sized" system that provides 100% of your heating and cooling with geo!
lawrence elliott
lawrence elliott
November 13, 2012
You would have found a system done for a law office a few years ago far more efficient and with every advantage of ceiling heat plus air conditioning.

Essentially we placed very attractive decorator level valance (now function as lighting also using LED's) around the rooms. Using finned copper tubing behind the valance zone valves fed either heated fluid delivered from an air to water heat pump or chilled. When in heat mode they heated the ceilings and then heated the rooms. When cooling they pulled heat from the upper levels and chilled it where a very gentle convection current was set up passively without the silly blowers used in the 19th century forced air (dust and smell distribution)systems America uses in spite of all its very obvious limitations.

Copper 'scuppers' under the tubes removed the condensate.
*Note copper used to avoid mold

Even having everything custom made it was very cost effective and has been working with rave reviews now for over 8 years.
I'm quite certain that produced in volume it would be extremely cost competitive with any other option.

Totally silent,very efficient and delivering heat as well as latent and sensible cooling and all running off of PV.
Forrest Jones
Forrest Jones
November 13, 2012
Let me clarify why I believe that Radiant Ceiling Panels (RCP) are the best choice. True, an HRV should be used with any type of heating/Air Conditioning system to recycle the heat and provide code required ventilation. So the real comparison should be on the type of heating used. The key to the whole RCP system is that the individual Ceiling Panels are controlled separately with a "thermostat in each room," and that the system has "Instant on/off capabilities." Those 2 features make all of the difference. No other system even comes close to having these. That level of control is what makes them use less energy. Most non-RCP systems that are currently installed have a single thermostat that covers the whole house. People do not need to heat the whole house, Basement or other rooms that are not being used, and they usually only use a couple of rooms at a time. This zonal approach is where one of the real savings occur. The other real benefit is the way that overhead Radiant Ceiling Panels work. The Radiant effect heats the object and rather than the air. You feel warm with a lower air temperature. It is like stepping out into the sunshine. RCP heating should not be confused with the Radiant Slab heating. Radiant slabs take 6 hours to heat up, and then have to radiate through the concrete slab, the flooring, and then through the bed, chair or couch to warm the bottom side of a person. Slabs realistically can only "directly" heat your bare feet, but people do use it to "indirectly" heat their homes by leaving it on all the time at a fixed setting (thereby heating the air as well). Even with underslab insulation, half of the heat that is produced is trying to go below the slab and into the ground. In a study done by the DOE (http://www.sshcinc.com/PDF/EnerjoyCaseStudy.pdf), it was determined that RCP heating was: 33% more cost effective than air-to-air heat pumps , 52% better than electric baseboards and that the users preferred RCPs to forced air.
V. Bruce Stenswick
V. Bruce Stenswick
November 13, 2012
@ Martin Orio

Mr. Orio's calculations are incorrect. He is assuming an 80% system means 80% of the heat over the course of the winter comes from a ground source heat pump. In the Minneapolis area, a GSHP that maxxed out at 10 above zero, which is about 2/3 of maximum load, would give you about 97% of your heat. I have it graphed on my website which you may have to try a few times since it crashes and I have not gotten around to fixing it.
Warren McKenna
Warren McKenna
November 13, 2012
Great arguments here! I'm not against GSHP's, its the electric resistance elements, and the electric water heaters that get installed with these units that create the additional electrical infrastructure requiremnets. Like looking the other way when a solar installer sells and installs solar that is 50% shaded. There are other more cost effective and efficient options as provided in these comments.

Throw on a 10 cent/kWhr tax and kill all incentives and let the best resource win. On my recent visit to Germany I was amazed at the efficiency in residential energy use that a kwhr priced at .24 to .27 cents can produce.

Thanks all
lawrence elliott
lawrence elliott
November 13, 2012
@forrest-jones

I seriously hope your levity at the start of you post was intentionally kept in the same theme as you progressed.

"The real Northern championship bout should be between GSHP's team in one corner and HRV/RCP's team in the other."

Your less than serious theme was crowned with this statement.

I once rented a home with resistance radiant ceiling 'heat' and found it to be the worse heating system I have ever observed.

Secondly why would you ever use resistance electric heating when air source heat pumps work almost as well as a GSHP in %80 of the climates and at a fraction of the cost and deliver at least a 2x COP in most cases and can operate as low as 0 f?

And just what does an HRV have to do with any heating of a home. Ventilation yes, with at least a %15 energy penalty.
Martin Orio
Martin Orio
November 13, 2012
Well Chris, it WAS a thoughtful forum...
Great work identifying a real metric for groundsource heat pumps alongside other renewables!
Forrest Jones
Forrest Jones
November 13, 2012
This thread is taking us in an interesting direction of trying to determine what the Ultimate Heating system is. For those of you that follow the Ultimate Fighting Championships, we may have a similar type of matchup going here. It started out with talk of GSHP as a NE contender. All of us do know that he is a good fighter farther South where AC is also used, but he is weaker on the road up North. Others have put Air Source Heat Pumps (electric heat pumps) into the ring, but he did not fare too well and he got beat up relatively quick. The fans are again looking around, waiting for the next matchup and are wondering who the next contender is going to be. Let me step forward and recommend my champion Fighters (actually a team) into the ring. GSHP is really a tag-team also since he is joined by Backup Electric Resistance heating. I believe that my Heat Recovery Ventilation (HRV) system with a record of 80% heat recovery, is able to defeat GSHP. For the tag-team match, I would like for my champion to team up with the invincible Electric Radiant Ceiling Panels (RCP) (http://www.sshcinc.com/) with thermostats in each room. The match will have to start with the Radiant Ceiling Panels being the first of my champions to enter the ring, since HRV can not recover any heat that does not already exist. Note that RCP is 'instant-on/off,' as needed, controlled on a room by room basis and has a Thermostat in every room (separate, controllable, thermostats are comparable to heating on steroids). RCP is silent, has no moving parts, longer warranty, does not take up any floor or wall space and shines like the Sun. His secret weapon and real advantage is the thermostat/zone control in every room. 'No other contender has that.' Although RCP will start the match, it is really HRV that will be spending most of the time in the ring and generating 80% of the punch. The real Northern championship bout should be between GSHP's team in one corner and HRV/RCP's team in the other.
Chris Williams, HeatSpring
Chris Williams, HeatSpring
November 12, 2012
@Marvin,

Thank you for the comment. To be blunt, no, that's not the point of the post! I don't think PV incentives should be stopped, reduced, or put into another source. I think they are a wise investment and make a lot of sense. The purpose of the article is to show that 1) if we agree that PV incentives make sense in the northeast then 2) thermal incentives make even more sense and should be invested in. Most of the debate around this has stopped because no one has put specific numbers to anything. This post is the first attempt to do that, and I'll be working on more in the future.

Again, this is a yes and conversation, not a solar PV bashing conversation. I sell solar PV projects for a living, and I own systems too. They're great.

I felt that I made this message clear in the article, sorry if I did not.
Chris
Geoff McBride
Geoff McBride
November 12, 2012
Cont. post: Take the temperature of the blade. Then waive that hot blade in the air for 5 minutes and check the it again for temperature. Then do the same exact thing and this time put the blade in a small bucket of water. Check the temp again. Guess which blade is colder after 5 minutes? Though not a perfect analogy, it is a pretty decent one when comparing air source to GSHP that use fluid in the ground. That fluid and ground have a much higher capacity to absorb that heat than does the air. Air source is a good technology for mild climates. When the air outside is either to hot or cold, it has much less capacity to 'absorb' what you are putting back into it. When you are cooling, you are taking hot air from your home and putting it back into the outside air. Air which is already hot or you wouldn't be cooling. Great technology in N. CA or climates that are relatively mild in temp year round. The efficiencies are decent but still don't touch GSHP. I find it laughable that you think utilities are in favor of GSHP because they use electricity. And what do air source use, that you seem to advocate for? Less? See my argument above and I can prove it further if necessary. Utilities are starting to finally look at GSHP but for another reason completely. Those FEW that are interested and looking to 'subsidize' are interested because they are looking at ways to reduce the size or not have to build their next electric power plant. GSHP technology helps reduce their peak demand. The time they are concerned with most is when folks come home from school/work in the summer months and turn up the AC. When are air source hp least efficient? Yep, exactly at peak demand when the temperature is high and the air has less capacity to absorb your home's heat. The ground doesn't suffer those same issues so when you compare air source to GSHP efficiency, it is WAY worse for air source at exactly the time and condition you need it to be most efficient.
Geoff McBride
Geoff McBride
November 12, 2012
Hi Warren,

Not sure you read the article or just the subject line but the author CLEARLY points out his affinity for Solar PV. Perhaps you think he is being deceptive in his motives? Interesting how this subject quickly became a battle. Strange because both technologies have a place together and in fact can work together rather nicely (PV produces electricity, GSHP uses it).

Please do explain how an air source heat pump uses less electricity than a GSHP? I'd like to hear this. If your ONLY argument is that the GSHP system comes with an electric resistance strip that is hardly an argument in your favor. GSHP generally come with the 'option' to have a back up electric coil to be used as an emergency. An emergency would be when the outside temperature is well below the design temperature of the system for an amount of time that the GSHP can't keep up with the set point. Obviously you don't want a 6 ton system when 3 tons will do the trick 95% of the time. Consumers feel better about having that back up heat there if it became necessary. It is a different technology than fuel burning appliances. You can't just burn more fuel....Is it efficient if the strip has to come on? Obviously not but again it will hardly ever come on if the system is designed correctly (not to big, not to small).

GSHP system are not designed to set back. If you do so you will bring on the emergency heat. That is because the T-stat will start the system in 1st, then 2nd and when it can't get up to temperature quick enough--it will bring on 3rd stage emergency. A lot of people don't know that or ignore it. People just need to understand that fact with GSHP and they won't have this issue. Still, the amount of electricity used by GSHP even with back up coming on at 10% of the time (which should never happen for reasons I've already outlined) would be lower than the best air source. Here is an analogy. Heat up a sword blade so hot it turns red. Cont. next post.
Michael DiPaolo
Michael DiPaolo
November 12, 2012
Chris, Great article but the results in favor of solar thermal would have been even better if your design used evacuated tube panels instead of flat plates. I did a solar simulation based in Portland Maine using Ritter panels and their Aqua set point control. Assuming 90 gallon day DHW demand, two panels (73 ft2 gross area)and 119 gallon tank fuel offset is 180 gallons of oil.
Martin Orio
Martin Orio
November 12, 2012
@ V. Stennswick -
OK, yes, first cost is important to consider. As is the rate you pay for kw and the # of run hours you should expect in the "federally approved" winter.
Re: an 80% system...
figure 3000 hrs. of winter heating in New England.
So...
2400 hrs at a COP of 4.
That leaves 600 hours (if by electric resistance) at a COP of 1, which is the same as 2400 hrs. at a COP of 4...
So 20% resistance heat will cut annual heating efficiency in half!

Resistance heaters are a cheap "insurance" measure in case of compressor or well pump/loop pack failure, but they do not make sense for New England.
20% electric resistance will double the length of simple payback AND makes a spike to the grid during winter design days...

I agree geo is expensive and we want to avoid ANY unnecessary costs, but not at the expense of destroying the incredible annual efficiency profile a 100% system represents.
Martin Orio
Martin Orio
November 12, 2012
@mckenna - I do not suggest that PV incentives be removed in favor of geo. In fact using the kw you make with PV to run your geo will pay back your PV 4 to 5Xs faster!
I don't even want to see anyone buy or install more geo than they need.
My only point is that resistance heat - though cheap to install, as an active "second stage" device is NOT a part of a thoughtful geo system in the northeast where we experience 2500 to 3500 hours of heating/yr. at 18 to 20 cents a kw.
Using resistance heat AT ALL is like using oil to heat up your solar array!!!
When you heat and cool using geo as it is designed and scientifically proven, it is 2 to 3Xs more efficient annually then the best air source heat pump. This is a PROVEN SCIENTIFIC FACT.
Folks who install and use resistance as a second stage are shooting their geo investment in the foot, and are creating a grid spike for the winter.
Neither are wise.
If you want to undersize your geo for the dominant load, have at it, but just DON'T use electric resistance to make up the undersized geo.
If you do, don't blame your annual bill on the geo. Blame it on the LEAST EFFICIENT/COST EFFECTIVE form of heating - resistance heat.

Geo is not like horse shoes or hand grenades... follow ISO-13256 install parameters and you will achieve ALL the operating efficiency the units are proven to provide.
lawrence elliott
lawrence elliott
November 12, 2012
Spreaking of incentives

Our local utility offered incentives through the Bonneville Power Authority that paid a portion of the cost of air source heat pump mini splits

Problem was the local dealers inflated the cost plus installation to such levels that most folks still found the cost to be prohibitive.

Some who took the time to do some research found that most average skilled folks could purchase the same heat pump off of the internet for a fration of the cost and then on a weekend install it in a few hours.

The majority of our local heating is electric resistance

Those who installed these mini splits report dramatic reductions in their electric bills

I think they should be as ubiquitous now as a TV or Microwave all across the country.

BTW a complete system costs less than one bore hole for a geo loop
Marvin Hamon, P.E.
Marvin Hamon, P.E.
November 12, 2012
A good analysis of thermal systems Chris, but it is pretty clearly trying to convince us that PV incentives should be redirected to thermal systems. I don't think in the renewable energy industry we need to be trying to fight for incentive funds by saying that one kind of renewable is "better" than another. I know there is a lot of bad feelings among solar thermal folks that PV gets more of the press and is getting a much greater proportion of incentives but still, let's all work together on getting more incentives for thermal and not work on trying to get other renewable incentives changed to thermal. It's not a zero sum game, incentives should be available for all types of renewables.
V. Bruce Stenswick
V. Bruce Stenswick
November 12, 2012
The reason is cost. See my latest comment. I have a 45,000 btu/hr system with 17,000 btu/hr electric resistance. I have only needed the electric resistance once in 11 years. The next size smaller would have saved at least $3000 on the installation costs at today's prices. Since the electric resistance heat is needed at night when rates are low, a "right sized" system that handles 100% of load is not justified. For most houses in the Minneapolis area, a GSHP that maxxed out between zero and 15 degrees F above zero would be appropriate. See my website, www.vbrucestenswick.com for details. Admittedly, calculating heat loss on a house may not be accurate, but the contractor should aim for 60%-70% of maximum load. This usually means one tom less, or one vertical borehole less.
Warren McKenna
Warren McKenna
November 12, 2012
@Martin, I agree with you that GSHP might be a great technology, especially if you are selling it. However if residential GSHP's are so great then why intall the resistance elements at all? Every residential system that I have ever seen has enough resistance elements to heat the entire house. I don't believe you can tell me with certainty that these are all "undersized". The manufactures seek a trade off between price and performance because their desire is to sell more systems and they can't do that if they oversize the system for the heating season. These are the facts or the electric heat wouldn't be a part of the system....and for that reason they still require more utility infrastructure to feed this potential.

When the argument is made to pull incentives away from PV in favor of GSHP technology then someone needs to step in and call a spade a spade. This has recently happen here in Iowa when a new state tax credit got split between PV and GSHPs. One technology relieves electric capacity and one doesn't at all! The GSHP manufactures have a 30+ year head start so why are they still getting incentives at all?

Electric Utilities love them because they are a load growth technology.
V. Bruce Stenswick
V. Bruce Stenswick
November 12, 2012
I disagree with Mr. Orio. I have a ground source heat pump that handles 100% of my load. It very well could have been one size smaller. My system is 45,000 btu/hr. At the time I installed mine, the next size smaller from that manufacturer would have been 34,800 btu/hr. At that time, my house lost about 500 btu/deg-hr, so the smaller system would have provided 69 degrees of heating capacity, so if I set my thermostat at 70, the heat pump would max out at one degree above zero. There is not enough heating load below one degree zero in the Minneapolis area to justify the additional expense. It is certainly not anywhere neat 20%. I have a website, www.vbrucestenswick.com that displays the heating load for four different locales. When my system was installed, vertical boreholes were $1000 each, today they are $2500 each. The smaller system requires one less borehole. Electric resistance heat would be needed for under 2% of the load.
Martin Orio
Martin Orio
November 12, 2012
Chris - Great article. Nice to see a responsible "kw - to- kw" comparison.
@Mr. McKenna and some of the other naysayers on groundsource (geo) HVAC systems.
To those who identify a so-called "oversized" geo system that does not use electric resistance heat... Resistance heat is 4 to 5X LESS efficient than geo. Running resistance heat for just 20% of the winter to supplement an undersized geo system will cut your annual efficiency opportunity by 50%, and WILL tax the grid during design days.
Properly installed geo (100% of the dominant load) is MORE THAN TWICE THE EFFICIENCY OF THE BEST AIR SOURCE IN HEATING AND COOLING! This is a proven scientific fact - see ISO-13256 efficiencies - including pumping penalty.
NO RESISTANCE HEAT IS NEEDED!!!!!
Those that suggest that geo is NOT this efficient are doing it wrong or are trying to sell you something else!

Keep up the good work Chris!
Also, any who would like to challenge the facts I have listed are encouraged to call me directly.
I'd appreciate the opportunity to provide more information on the subject.

Sincerely,
Martin Orio
508-904-5815
bob freeston
bob freeston
November 11, 2012
Reply to #22--Deep Geothermal has three sub types--Hot spot ie related to volcanic activity-- doable in limited areas. EGS Engineered or also called Enhanced Geothermal Systems can be done almost anywhere. Around 15,000 feet earth temp is above boiling and low temp steam generators (organic rankine cycle) can create electricity. The exiting heated water can be used for large scale district heating. The Germans are doing a lot with this. At 5,000 feet almost anywhere earth heat is sufficient to heat a school or hospital. The Brits are working with this. Regarding GSHPs, they don't need extra back up in the winter. With mediocre insulation, as I mentioned above, you do want elec resistance back up built into the system, an option available on most units. It is integrated to the thermostat and will be used infrequently in most circumstances. Here in upstate NY heat is by far the dominant load and the heating season is eight months with 5 being shoulder and 3 being deeper. The AC load is light. The GSHP is doing a large per cent of my hot water load via a desuperheater. Warm water goes to an elec resistance tank at around 100 degrees F and the resistance takes it to 120 degrees. The ground source heat availability discussed in #22 isn't accurate. Rock probably requires vertical bores, which is more expensive. The water table isn't relevant in many systems. Earth constant is at about eight feet, so horizontal closed loops are often around that depth. Actual temperature varies with latitude.
Phil Manke
Phil Manke
November 11, 2012
Good to hear of solar energy in often rainy (I'm told) western OR! If it works there, it surely works!
lawrence elliott
lawrence elliott
November 11, 2012
@phil-menke79191

"Power companies push heat pumps because they rely on electric power for their conversions of heat grade, but one PV panel could operate a sola thermal system to heat either DWH or home heating independant of the grid."

Really could care less who pushes what technology or for what reason.
I'm only concerned with what works and what does not

My house and shop are both heated with an air source heat pump and I live in Western Oregon climate.

On most days I have no problem powering both systems on PV and without batteries or the grid.

As far as using solar thermal for heating of a building in most climates it's a really lousy method unless you first tighten up the envelope as much as possible within current technology,remove as quickly as possible any forced air system (19th century technology) now installed,replace the heat delivery system with radiant floor or ceiling or some hybrid with a very large surface area to volume ratio to allow low supply temperatures and then add the solar thermal in combination with the heat pump (air source works in majority of applications but add geo loop if needed).

I have developed a hybrid (DIY desinged) heat pump system where any thermal source not matter the temperature is blended with heat pump using coaxial heat exchanger that allows me to exceed the COP that can be achieved at low ambient outdoor temperatures.

This hybrid nature of the system also allows me to heat my home at night on both the stored thermal energy as well as the electrical in a very small bank of batteries charged during the day off the grid tied inverter power.
If I run short I can always tap off the battery in my EV without a complicated and expensive V2G (vehicle to grid) system installed.

Phil I might add that in tests I've conducted on solar thermal vs PV to heat pump water heating?

In spite of the thermal's higher efficiency the overall efficiency of both is nearly equal. My own design PVT panels? Excellent!
Warren McKenna
Warren McKenna
November 11, 2012
Larry,I totally agree your solution is right on the mark!

I also agree with Kenneth that the heat-pump waterheaters are great.
They operate at about 500 watts and cool and dehumidify at the same time. Here again maybe we could use a solar-thermal/heat-pump hybrid system, to backup the solar thermal.

One can easily cut water heating demand by 1/2 to 1/3rd (10%-15% of home energy use), which in most homes is this study is probably more than they spend on cooling (10%-15% of home energy use).
Phil Manke
Phil Manke
November 11, 2012
The last photo shows the need for production tied incentives. I prefer SRECs for this, because they do not impact government coffers negatively while offering the real possibility of covering the cost of money for the solar part of an installation. The need to transition from oil heating calls to engage the petroleum industry in contributing to the carbon costing of polution of our common atmosphere. Typically, coal is the CO2 contributor recognized in the carbon balance of SRECS, but oil is an equal contributor. All the graphs and numbers seem to be allot of 'confuse-a-cat' distractions that will convince no one. Solar thermal offers the highest ROI altho larger systems for home heating will cost more to install, but will lay off a greater load and diminish cash out flow for fuels or electricity. Power companies push heat pumps because they rely on electric power for their conversions of heat grade, but one PV panel could operate a sola thermal system to heat either DWH or home heating independant of the grid. That independence it the fear of a money investor dominated economy, while inteligent investing in solar hardware pays dividends that, with fair SRECs, would allow covering of the cost of loans for these conversions. My local bank is offering home improvement loans to include solar eneregy devices below 3.5%, which would easily fit into a 300 dollar SREC program with incentive to spare. I call on you to petition the President and your state Governor to move on adopting a well intended 'solar carve-out' with adequate 'SACP' over the next four years to allow the learning curve to become established. This will benefit everyone except perhaps investment brokers, who may find difficulty tapping the stream of solar produced energy. If we dally long enough, they may find more ways of doing that. Be assured they are aware of it and pushing inroads for it........................... Including Petro in the carbon costing may allow electric autos to flourish with PV.
lawrence elliott
lawrence elliott
November 10, 2012
I'm always somewhat amused and also disappointed each time I review articles like this one. Articles that are written by folks who are 'in the trenches' so to speak in regard to this entire energy conservation and renewable production issue.

In almost every case the primary emphasis is on producing more energy and not conserving what is already used.

I have lived in the New England area.

I also have friends who still live there.

Nothing unusual about their climate,both summer and winter in regard to energy use patterns.

If I had not personally accomplished what many so called experts flat out told me could not be done with an older home I have here in Oregon I would be reluctant to make this statement but "I know for a fact I can take any existing old home in Connecticut,Vermont,Maine etc and for a relatively modest expenditure of time and money reduce their heating and electric needs to a fraction of what it current is.

One example:
Total elimination of all incandescent bulbs or CFL's
Replace with very cost effective LED lighting

Substitution of oil fired boilers and furnaces with air to water or air to air heat pumps as either 'boiler' or mini split.

NOTE*
For all the skeptics: Yes I have sources of air source heat pumps that operate down to as low as 0f and some even lower while still maintaining a COP of at least 2x.

Next would be an entire revamp of the thermal envelop whereby all exterior inner wall covering is removed and fir'd out to increase cavity depth and then installing at least 1" minimum foam and then BIB insulation. Same treatment for ceilings and floors.
And no this is not a giant undertaking and does not need to cost a fortune. Lathe and plaster can be a 'bugger' but not impossible.

Now replace all windows and doors with .023 U or lower.

Send the existing tank water heater to the dump or use for solar thermal.

Now add PV as needed.

Without doing the changes the PV is 'peeing in the ocean'
KENNETH JUDD
KENNETH JUDD
November 10, 2012
I can only talk to what I have done in CT. I have installed a 9KwH ground based solar array via a lease program using Ct clean energy fund to off set some costs (best thing I have done). I have oil furnace for heating and i did have oil for hot water, but replaced it with hot water heat pump next best thing I did. now I'm looking into infrared space heaters. I did just recently come across Bloom Energy and they have fuel cell tech that blows me away when they are ready for home use I will jump on board. Everyone should take good look at this tech especially if you have solar and/or wind
Forrest Jones
Forrest Jones
November 10, 2012
I also would like to compliment the author in writing a brief article on a subject that has so many variables. Let me just add a couple of rules of thumb to help put all of these Alternative Energy sources into their proper perspective. First: we have to agree that no single technology (or even several technologies) is going to solve our energy problems. We will have to attack the issue of energy supply from many different directions. Second: Savings, ROI, Payback are all directly related to the cost of electricity in your vicinity. What works in California or Hawaii (expensive electricity) may not pencil out in other areas. Third: GeoThermal is totally different than Ground Source Heat Pumps (GSHP). Geothermal will only be realistic over a hot spot, and would have so much government red tape attached, that it can not be distributed on a per home or per building basis. Fourth: GSHPs pencil out when you "both" heat in the Winter and Air Condition in the Summer. If you do not Air Condition, it will not be used for half of the year. And GSHP systems should be considered to be a pre-heat and a pre-cooling system. You would still need a furnace for the coldest nights, and would still need an Air Conditioner when it gets over 100 degrees. I am not saying that it is bad, but rather that you will still need your furnace to go with it. Fifth: GSHP systems want to be deep into a water table or area where the heat can dissipate or be absorbed with consistency. Best is when it goes below the water table. The theory is that the ground maintains a consistent 50ish degrees when you get down far enough. If you have a clay soil, no water, are in a rocky or bedrock soil, then it would not be realistic. Depth is critical to get the consistent temperatures. Sixth: The reason that people are not using Solar Thermal (hot water) systems is that they produce way too much heat in the Summer, and the heat that is produced is in the afternoon. It is hard to store hot water.
bob freeston
bob freeston
November 9, 2012
Re comment #9 "loop saturation at end of winter" This indicates an improperly sized closed loop. An open loop doesn't have this type of problem. Re electric backup on a GSHP which I have, as others have stated it is only used on a few extremely cold and or windy days. Last winter was so warm here in upstate NY that it hardly went on at all. This is in a building with mediocre insulation (upgraded from poor). Grid capacity and peaking issues here are strictly a Summer issue. Electric sources for me include on site PV (small) and wind bought off the grid. My ground source is my previously existing water well dumping to a very large dry well.
Gerry Wootton
Gerry Wootton
November 9, 2012
So geothermal is a proxy for electric HVAC but a very efficient one. The net advantage depends on the GHG intensity of the electrical supply. For some parts of the US, natural gas is GHG negative relative to geothermal as a heating fuel because they produce the majority of their electricity from fossil fuels. In any case, geothermal has a lower GHG potential than oil or coal as a heating fuel. The case is better if you consider that geothermal achieves a CoP for air conditioning that is superior to conventional air-cooled HVAC. On the other hand, NG only looks good if you use its 100 year GWP but not so good if you use a shorter timeline. In New England, primary sources are NG and nuclear, so it's possible that geothermal is a step up over any fossil fuel option (unless you hate nukes and/or wind turbines). The title could be improved: it's true that geothermal as an alternative to oil would reduce GHGs and reduce HVAC costs; if it has a fair ROI, then it costs nothing. If the implication is that people need incentives to save themselves money, that may be true; otherwise, if the implication is that individuals are not motivated to reduce their GHG footprint, that would be true.
Warren McKenna
Warren McKenna
November 9, 2012
Chris, I reviewed the WF study and the focus again is on summer peak savings. Therefore it totally misses the mark!

"GEO has requested that the U.S. Department of Energy further study this issue and test specific equipment at 100-dgree ambient temperature," he concluded, "and more utilities should embrace GHPs as a cost-effective way to reduce the cost and scope of future power needs."

Current GSHP technology will not reduce future power needs!!!
Warren McKenna
Warren McKenna
November 9, 2012
doggydogworld,
Try installing a GSHP system on an off-grid home and you'll soon see why gas isn't so absurd. We have trucks that deliver gas here. How do you suppose oil gets delivered to the home in MA?

Shifting from oil to resistance heat doesn't make any more sense than using PV and resistance heat. The cost to build a new nuclear plant at $7,000-$10,000/kW plus the added cost for transmission and distribution systems to feed a 10-20 kW electric resitance strip heater in every GSHP system is what's absurd. PV releases kW capacity so killing it to justify GSHPs in this analysis is not a fair comparison.

Move away from oil for sure but don't move to another technology that's just as bad if not worse.
DoggyDog World
DoggyDog World
November 9, 2012
Warren, your air-source heat pump over gas 'solution' is absurd. Did you even read the article? It's about legacy northeasterner homes who are stuck using $35/mmBTU heating oil. If they had access to $3/mmBTU gas, believe me they'd already be using it.
Gerry Wootton
Gerry Wootton
November 9, 2012
Thanks, good article. Geothermal and solar thermal are certainly important technologies. You sort of glossed over the land area needed for geothermal ground loops. I live on a 1/2 acre lot - not enough area, but my farming neighbors have no problem making geothermal work. On the other hand, solar thermal is more efficient than PV making it more practical for rooftop installation - perhaps the biggest technical problem is that it's easy to produce too much heat in summer. Something that can be considered for solar thermal is back radiation i.e. modules can be used to dump heat at night. I was shocked and surprised that people still use oil heat. Haven't seen a furnace oil truck in my area in years. This seems to be a local flavor of the day.
Ed Sears
Ed Sears
November 9, 2012
Tim Gulden asked me to break down the PV costs further. Okay, I will talk about a straightforward 4kW system (i.e easy to scaffold with normal roof tiles) because the figures are in my head - current UK fully-installed price would be $10,400. This includes Tier 1 panels and good quality inverter plus mounting, electrics, installation, scaffolding and VAT (sales tax). There is lots of competition in the UK PV market, but that price is for a proper job by qualified people with proper margins.

This has changed A LOT, as I said in my previous post. For the same system, we were quoting $19,000 in December 2011 and more like $27,500 in 2010. As I also said, panel prices (retail - we pay less for trade) are $1/w currently. So the system budget currently splits: panels 35%, inverter and other parts 25%, scaffolding 7.5%, labour 27.5%, sales tax 5%.

I will take the time to read through the article in more detail - thanks for all the numbers even if we are disagreeing with some of them. It sures beats people simply throwing vague assertions at each other. We are definitely interested in adding heat pumps to our existing PV, solar hot water and biomass installations.
Chris Williams, HeatSpring
Chris Williams, HeatSpring
November 9, 2012
Hey Warren,

Give me a call to discuss 800 393 2044 ex. 33.

There are a few data points I have that are in direct contradiction to what you're saying.

1 - GSHP do not have high failure rates. This is a myth.
2 - The power coil in GSHP has less impact then you think, it will run less in electrical resistance than ASHP. If you wanted, you can also run GSHP with Gas, if you have gas.
3 - Regarding demand side reduction for utilities, GSHP wins hands down. Here's a well done study by Western Electric Coop that found ASHP feel short on their EERs and didn't reduce peak demand for cooling as much as promised: http://www.geoexchange.org/index.php?option=com_content&view=article&id=6315:seer-vs-eer-for-utility-dsm&catid=376&Itemid=33

Not trying to have an argument. There is simply a substantial amount of misinformation about geothermal that is myth and not based on fact, "high failure rates" being one of them.

Chris
Warren McKenna
Warren McKenna
November 9, 2012
Chris,
I didn't have time or the space here to expand on my research, but I too monitor over 30 GSHP systems and have done so for over 10+ years. I did like your careful analysis and think every GSHP should be monitored because of their high failure rate. I heat with wood pellets, heat our water with a heat pump, have a solar clothes dryer, drive a prius, have two solar arrays in my yard. As close to net zero as i want to get and still enjoy life.

Residential GSHP because of their resistance coils do little to relieve power capacity requirments. The better more cost effective solution would be an air-source heat pump over gas for the peak heating part of the season. The electricity demand/capacity component is substantially reduced when compared to the current GSHP technology. These units are selling because they are half the price of a GSHP system and they save both gas, electricity, and electrical capacity requirements (capacity from the generator to the distribution transformer to the size of service to house). These are the facts. If there was a GSHP over gas, and couple this with a gas water heater or a heat-pump water heater, then and only then would i agree with some of your analysis, but this would drive the system cost substantially higher.
ANONYMOUS
November 9, 2012
This article is filled with inaccuracies that, not surprisingly, benefit solar thermal is every respect--the very product the author sells.
"renewable thermal technologies" is a JOKE--purely a marketing message--this article STINKS and is an example of conflict of interest.
Tim Gulden
Tim Gulden
November 9, 2012
Hi T4, can you break down and show your total complete turn-key costs as it appears it may not be all inclusive as I frequently see the following UK disclaimer 'The above prices do include installation, scaffolding and VAT'. Here you can find UK total installed costs to be 4 to 5 Euro per watt which is about $4.80 to $6/watt US. (www.solarinsiders.co.uk/cPages/view/16/Solar+PV+Calculator#calc) Here is another UK site: (www.spssolar.co.uk/ReturnOnInvestment/PriceExamples.asp) And another UK site: (www.thegreenhome.co.uk/green-living/ask-the-experts/solar-pv/185-what-is-the-payback-period-of-a-solar-pv-panel-system) Using your pricing system reveals our company to offer a 5kW system for $2.54/watt (that's using the much more expensive micro inverter which has a $.30/watt premium).
Chris Williams, HeatSpring
Chris Williams, HeatSpring
November 9, 2012
Warren,

Thank you for your comment. I have to disagree for New England. Look at the citations for solar pv costs, $5.50/watt is reasonable.

Regarding geothermal, the yearly COP of 3.75 is taking into account the small amount of time operating at COP of 1 for electric resistance. The analysis is assuming the heat pumps delivers 63MM BTU over a heating season, typically for the Northeast, at an average COP of 3.75. I have data on this from Ground Energy Support which monitors system in real time: http://groundenergysupport.com/.

I assure you, the numbers and my basic analysis are solid for it's purpose.

I agree, air source and biomass will be part of the mix. To say that they're the only real choice is nonsense.

Chris
Warren McKenna
Warren McKenna
November 9, 2012
I agree with cutting oil use, but justifing incentives using PV as a comparison, not a good analysis. We are installing PV here in Iowa for less than $3/watt before incentives. Residential Geothermal Heat Pumps utilize electric resistance backup heat and therefore they don't release electric generation capacity requirements at all. Typically they are also installed with an electric water heater and thats not good. Wood pellets, and high efficiency air source heat-pumps with gas backup are the only real choice when it comes to really making an impact on our carbon footprints at the residential level. This assumes there isn't a GSHP with gas backup/assist (support heat is needed due to loop saturation at the tail end of winter). Increase the efficiency of the home and then size everything to run off a battery system and you'll soon find out the importance of capacity in this analysis.
Chris Williams, HeatSpring
Chris Williams, HeatSpring
November 9, 2012
Hi T4,

Thank you for your comments. However, please do research before making comments. I'm talking about the massachusetts market. You can download the whole list of every solar pv installation in the state of MA here and I assure you 5.50/watt is not a high price (http://www.masscec.com/index.cfm/pk/download/id/13416/pid/11163). Yes, UK prices are much lower.

Paul D,

Again, thank you for your comment. All of these calculations were made in the calculation of the baseline building. Feel free to send me an email at cwilliams@heatspring.com and I can share them with you.
tony penachio
tony penachio
November 9, 2012
Chris, excellent article! It is through the hard work such as yours that geothermal heating and cooling systems is gaining the recognition as the energy problem solver it is and a methodology to get us away from fossil fuel dependence. I also wanted to make your readers aware that there is a brand new type of ground source hx, a hybrid, low-impact, direct-exchange heat exchanger know as the GeoColumn coming onto the market in nearby Long Island. It is a dx coil housed inside an HDPE containment that is filled with 100% tap water. The entire unit is a factory manufactured, off-the-shelf product and is simply inserted in a 30" wide X 23' deep borehole that can be quickly installed by excavation type equipment in granular soils. As the caps of these GeoColumns reside only 3'-4' beneath the surface they can be repaired, removed or replaced (should the need ever arise). One of the primary intents of the GeoColumn technology is to allow retro-fit or new installs in urban or suburban settings as only 16' long by 10' wide of ground surface area is required per ton of capacity. As the GeoColumn can be installed by almost anyone with strong A/C or heat pump experience and background it is seen that the GeoColumn technology can aid in reducing the complexity, increasing the market share and lowering the costs thereto for "Going Geo" which in turn will aid in enabling both more dealer/installers and end users to participate in the benefits of geothermal HVAC.
Paul Dennis
Paul Dennis
November 9, 2012
This is completely flawed. in addition to the comment by T4 where you have inflated the solar PV installation cost You need a proper calculation methodology which calculates the uvalues of the property to get the heat loss, the degree days available depending on the location to calculate the amount of solar available and the coefficient performance of the heat pump, that's just the start. the weather in New England is probably the same as Old England. We have something called SAP the specification is 160 pages to calculate the heat loss from a house. I have software available for the calculation if the author would like to download a copy.

The UK is introducing something called the renewable-heat initiative which goes some way towards a comparative approach between renewable generation and renewable-heat.

Regards
Paul
http://www.completepicture.co.uk/mcs-sap-calculator/microgeneration-features
Peter Bradshaw
Peter Bradshaw
November 9, 2012
The name "geothermal" has been used for decades for systems that get high heat from local areas with volcanic-type activities, such as the Geysers in CA, Rotorua in New Zealand, etc., where (typically) steam heated by the very hot rock is used to generate electricity, and/or provide direct heating. I think it would be better to use a term such as "geo-exchange" or "geo-storage" to describe the kind of system you are advocating, where a heat pump is used to provide heating/cooling from a local heat storage system in the ground, which can be done anywhere. This would reduce potential confusion between the very different technologies involved, both of which are very important for a renewable energy future, and avoid the "we can't do that here, there aren't any geysers" reaction.
Ed Sears
Ed Sears
November 9, 2012
Your solar PV prices don't look right. I write quotations for PV systems in the UK and a 5kW system should be maximum $12,000. That's about 60% less than your figure. $5.50 per watt is way too high. In the UK the panels are around $1/watt, with installation costs and balance of system making it up to something like $2.50/watt. The point is: PV panel costs have come down A LOT very recently - its happening month by month. Although of course the US is putting tariffs on Chinese PV panels just as they did on cheap Brazilian ethanol.
V. Bruce Stenswick
V. Bruce Stenswick
November 8, 2012
Geothermal heat pumps should be considerably less expensive. There is generally a shortage of installers and well drillers, so they can charge a premium. Also, they tend to put them in too large. If a home needs 60,000 btu/hr on the coldest day, then you only need to put in 35,000 to 40,000 btu/hr of geothermal, the remainder could be electric resistance heat which would only be used infrequently. Estimating heat loss for a house is not exact, but the installers should aim for the geothermal system to be 60%-70% of maximum. If they aim for that and miss and the system is too small, then pick one or two exterior walls, rip off the sheet rock, pull out the insulation, and spray foam it with closed cell polyurethane.
Chris Williams, HeatSpring
Chris Williams, HeatSpring
November 8, 2012
Christof,

Thanks for the comment. I agree, it's not true in the absolute sense just for the mass market customer, for the average homeowner with a grid tied solar PV project, it's not directly displacing oil, but may be displaying nuclear, coal, hydro, etc depending on where it is.

Agreed on all your points. Especially for #3, there's a strong case for all electric homes with passive homes and using PV to supply the electricity to power a air source pump which double the output of the electricity. Because the load in these homes is so low, ground source and biomass tend to be too large.

Chris
Christof Demont-Heinrich
Christof Demont-Heinrich
November 8, 2012
This is a thorough analysis and I think you make important points. But it's simply not true that solar PV can't be used to displace oil, at least in some cases:

-->Case No. 1: Using solar PV to charge an electric car which replaces a gasoline powered car (http://solarchargeddriving.com/editors-blog/on-going-solar/394-solar-can-replace-oil-and-eliminate-your-gas-costs.html)

-->Case No. 2: Using solar PV to produce electricity to power an electric heat pump(s).

-->Case No. 3 (admittedly somewhat inefficient): Using solar PV to produce electricity to power resistance heaters. In fact, this case describes our own case, which you can read about here -->'Heating our home with solar electricity' http://solarchargeddriving.com/editors-blog/on-going-solar/1082-heating-our-home-with-solar-electricity.html

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Chris Williams, HeatSpring

Chris Williams, HeatSpring

Chris works with HeatSpring developing new products and managing online content. He combines his business education, technical training and hands on experience to help contractors grow their companies.
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