Solar May Be Hot, But Geothermal is Cooler

Photovoltaic solar cells capture the public imagination as a renewable energy source for homeowners, but nothing beats geothermal heating/cooling for proven efficiency and reliability. My dad installed a geothermal system when he built a house in Norfolk some two decades ago. As far as I know, it has worked trouble-free all those years, quietly racking up savings on his heating and air conditioning bills.

Geothermal units function as heat pumps: They run water through underground tubes, absorb the constant 57- to 58-degree temperature found underground, recirculate the water into the house, and exchange the heat again. Although circulating the water does requires electricity, the system is three to four times more cost-effective than electric resistance heat.

From an electric-grid perspective, geothermal offers advantages over solar. Solar generates electricity intermittently — during the daytime only, and when clouds aren’t blocking the sun. When homeowners are generating more electricity than they need, they can sell it into the electric grid. The inherent unpredictability poses problems for power companies whose job it is to manage a stable grid. That’s why Dominion and other electric utilities want to restrict the contribution of solar energy to one percent of system capacity.

By contrast, geothermal is totally predictable. It runs evenly round the clock, and by its nature, it makes the biggest contribution when outdoor temperatures — and the demands on the electric grid — are at their extremes of heat and cold. Geothermal systems create a more stable and easily managed grid.

Geothermal isn’t high-tech, cool or glamorous in any way. You don’t even know it’s there. Which is another one of its selling points — geothermal systems are unobtrusive. They don’t violate homeowner covenants for unsightliness. The neighbors won’t complain. As Virginia investigates strategies to promote conservation and renewable fuels, it should take a good, hard look at geothermal.

As a practical matter, what can Virginia do?

  1. Work out electric billing rates that reward homeowners for reducing peak electric loads. Right now, power companies charge the same for every kilowatt hour, regardless of the time of day. Charging higher rates during periods of peak load and lower rates for off-peak consumption will provide a strong financial incentive for homeowners to invest in systems, like geothermal, that moderate system demand.
  2. Get some clarity, reflected in local ordinances, on when less expensive “open loop” systems are permissible. Clarke County recently denied a homeowner request to install an open loop system, which draws water from one well and discharges it into another, on the grounds that “they use more water and cause what they called ‘ponding and excessive runoff’ when no body of water was available to receive discharge,” reports the Clarke Times-Courier.

Here’s what not to do: Give homeowners a tax credit for installing the systems, as the state has already done with energy-efficient appliances. The state tax code already looks like it’s been peppered with buckshot. Tax credits of various kinds cost the state well over $1 billion a year in lost income tax revenue alone. The goal of public policy should not be to encourage geothermal regardless of the cost — it should be to encourage geothermal where it makes rational economic sense. The best way to do that is to create a rational tariff for electricity consumption and to clear away encumbrances from local ordinances.

(Image credit: Renewable Energy UK.)

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23 responses to “Solar May Be Hot, But Geothermal is Cooler”

  1. Anonymous Avatar

    I put one in my house in 1989.

    It works well, and it is much quieter than air cooled heat pumps. It sounds like a refrigerator running inthe basement.

    My biggest problem was the grief the county gave me over the installation.


  2. Anonymous Avatar

    Open loop systems may be less expensive to install, but closed loop is more reliable. Sediment and minerals from the open loop system will clog your heat exchanger, and that is an expensive repair.


  3. Anonymous Avatar

    If you really want something cool, and you have enough land, you could consider a solar pond. This is a small pond which is saturated with salt. then you float a thin layer of fresh water on the top. the dendity gradient keeps the layers apart. Sunlight goes though the thin top layer and is absorbed in the salty layer which can actually boil.

    Unlike a normal pond the heat cannot escape to the atmosphere, because of the covering layer. You then use a heat exchnager to capture the heat for whateve use you need.

    Ore-Ida uses a system like this to boil oil to cook potato chips.


  4. Larry Gross Avatar
    Larry Gross

    these are what I call environmental widgets.

    They save energy, save money and create jobs and reduce damage to the environment.

    It would seem to be something that the US could make and market worldwide also…

  5. John Witherspoon Avatar
    John Witherspoon

    Who in Richmond is good at working on these systems. We bought a house a year ago that at one time had the a geothermal up and running. According to the realtor, they had it taken off line and went back a “regular” heating and cooling scenario for resale purposes. We still have the giant water pressure tanks in the basement and all the other equipment seems to be there too. We would like to use it in conjuction with the new HVAC system. So does anyone have a good recommendation on who can come and look at it? And let us know what we need to do to get it back up and running.

  6. Jim Bacon Avatar

    John, I wish I could help you, but I can’t. I don’t know diddly about the local market.

    It sounds, though, like you’ve identified another barrier to the propagation of this technology: the resistance of Realtors and the lack of a well-established service infrastructure. Obviously, those issues need to be addressed.

    Good luck in finding someone to help you.

  7. Anonymous Avatar

    “and reduce damage to the environment.”

    You wouldn’t think so, considering the grief the county handed me. To hear them talk I was endangering th ground water and sewer system of the entire county.


  8. Anonymous Avatar

    These things are still kind of rare. There are contractors around with experience, but check them out carefully.

    Water pressure tanks? I don’t have any tanks. Just a reefer looking thing in the basement with two water pipes, one in and one out.


  9. Anonymous Avatar

    Thermal solar has far more economic potential (right now) than photovoltaic power. Pacific Gas and Electric has just annnouned a one square mile thermal solar 177 MW plant, to be built in California.

    I agree that the goal of public policy should not be to encourage geothermal regardless of the cost – it should not be the goal of public policy to encourage ANYTHING regardless of cost – but there are times when a swift kick in the pants can do much good.

    The trick is to prevent it from becoming an entitlement, as Larry Gross seems to think his priorities are. The way you do that is to keep a sharp eye on benefits vs costs.

    In the case of Geothermal, the equipment costs pretty much the same as a conventional heat pump, but that half million dollar drilling truck and five guys to run it are not cheap. But, once drilled that is a long term investment. And, because the heat sink is a limiting factor on the heating and cooling available, it acts as an effective deterrent to radically upsizing the home. There may be some value in finding some kind of help, not for the system itself, but for drilling the geothermal wells, and maybe that is an area where the state could help: provide the incentive not to the homeowners, but to localities that make it easy, as opposed to what happened to me.

    By the way, I bought energy efficient appliances, wher do I go to get my tax credit?


  10. Darrell -- Chesapeake Avatar
    Darrell — Chesapeake

    Here is an idea they came up with in Oregon. Too bad anyone who can afford to buy one of these units will probably work in Portland, 60 miles away.

  11. Anonymous Avatar

    60 miles away….
    That’s pretty funny.

    Interesting, they have both photovltaic and solar thermal.

    When I have solar panels, they are not going on the roof. I have enough roof problems as it is.


  12. Larry Gross Avatar
    Larry Gross

    The trick is to prevent it from becoming an entitlement, as Larry Gross seems to think his priorities are. The way you do that is to keep a sharp eye on benefits vs costs.

    By the way, I bought energy efficient appliances, where do I go to get my tax credit?

    The “entitlement” is the way we currently create and sell electricity.

    I think on small change would change everything, spur new market offerings and get everything thinking about how to make their home more energy efficient – without having to subsidize anyone or bribe them with incentives.

    Just put a Smart Meter on every structure and charge a market price for electricity. If there is a big demand for electricity that day or week – the price will be just like the price of hamburger or peppers at the food market.

    Then let people decide how they want to reduce their costs – short term and long term.

    Right now, we’re all locked into a hugely expensive and wasteful system that encourages consumption.

    Dominion has absolutely no incentive to encourage efficiency and conservation for it’s customers.

    In fact, every time someone does something to conserve electricity – it, in effect means, they are evading their share of the capital costs for new power plants and ultimately Dominion seeks rate increases to pay for more plants and more power lines.

    Smart Meters would change almost overnight people’s patterns of electricity usage but more importantly they would start looking at their own capital costs of buying more efficient appliances and cooling/heating.

    we have a system where “big daddy” is more than happy to provide us with as much power as we want no matter how inefficient and wasteful it is because – he is ENTITLED to a profit – no matter what he does.

    plan and implement a more efficient and effective energy paradigm.

  13. Darrell -- Chesapeake Avatar
    Darrell — Chesapeake

    “60 miles away….
    That’s pretty funny.”

    What I found interesting was how they did the financing deal on the solar. It looks like something that could be done here, with Virginia’s priority on commercial vs residential energy proposals.

    I could see how these units could be built in an urban environment, with a housing association being a commercial co-op for solar energy inside the development. Such operations are already occurring in Calif. and Arizona. The cash flow could possibly be used to replace or reduce association dues and special assessments to fund the amenities/maintenance of modern urban life.

    I didn’t run any numbers, but my initial gut feeling is that this would give a low cost incentive to state energy policies, while meeting acceptance by homeowners.

  14. Anonymous Avatar

    Pacific gas and electric is building a 177Mw solar thermal facility in the California Desert. It will occupy one square mile of land.

  15. Anonymous Avatar

    Power companies say the technology to install smart meters in England will cost, estimated to cost between £5bn and £8bn to implement, and is unworkable without agreed technical standards.

    Electricity uppliers will have to overhaul their IT systems to cope with the huge increases in data generated by the meters, and this information will have to be cross-referenced with existing systems and stored for up to three years to meet data regulations.

    British Energy IT director Ian Campbell says that without agreed rules or common functions a meter installed by one firm could not be read by a rival should the homeowner or business decide to change supplier.

    But smart meter suppliers say the government must do more, and only a mandatory system will solve the problems.

    Individual smart meters cost up to £180 each.

  16. Larry Gross Avatar
    Larry Gross

    lots of issues. No fundamental reason to not do them.

    I have a hard time understanding how someone could “read” a power company’s meters…

    and even more trouble understanding why that would be a valid reason to not do it.

    put encryption on the data if that is a problem.

    all in all.. the reasons given sound pretty lame as reasons to NOT save energy.

  17. Anonymous Avatar

    Actually, there are a number of cometing ways to read the meters. One uses short distance radio waves, but that still means someone has to drive around and get close enough to pick up the signal.

    One uses the electic lines to carry a signal, but that needs a repeater at every transformer.

    One uses the internent, but then every home has to have internet, and one uses the phone system, but not every home has phones, and there is the issue of sharing service, which the phone companies won’t do for free.

    There is no present system of handling the data that will provide all the touted benefits of smart meters. If the meters are only read periodically then whatever readouts you have in your house will provide a guesstimate of what your costs are, because your unit will have no way of knowing the gross load on the sytem that drives costs.

    Sothern California electric did their cost benefit study and concluded that smart meters at present would not pay. They have started their own systems level program to go invent the things they need to make it work.

    One of those things is the ability for the power company to turn on and off your appliances selectively. Your heat pump, pool circulator, and water heater, for example might be turned off for 15 minutes and then back on. That is a whole other level of technology over and above smart meters. Southern California electric figures that is the only way to break even on the technology, and as much as half the benefit comes from being able to turn off your water heater.

    Some experts estimate that Smart meters will save between 5 and 15% at best. That is still not chicken feed but it is low enough that you wouldn’t want to spend a huge fortune just to get it. Southr California electric doesn;t think you even get that much, without their new (probably proprietary) system.

    The most intersting one is from Edison Electric Institute. They point out that the big savings is in reducing capital costs of meeting peak demand. But, in order to make it work, the rate structure has to be set so that users who do shift time of use see a savings over the present system.

    This is a case where the winner, (the Power company, in capital costs) has to pay the loser (the consumer, in time of use inconveneience, and possibly loss of control) and still manage to arrange things to come out ahead.

    Notice the similarity in EEI’s cost benefit analysis and my previous statements : we all have to come out ahead, and fairly, or it isn’t worth doing.

    And there is one other downside. Smart metering will affect net metering adversely. If you are using solar cells you will be selling back at the lowest rates and buying at the highest. As EEI puts it, it will reduce the amount the power company subsidizes net metering customers. It might be a bad thing is smart metering kills distributed generation or co-generation.

    This smart metering thing has way too much print for what it seems to be worth. It looks to me like a case of regulatory capture, wherein the makers of the meters get policy passed to make the use of their products mandatory.


  18. Larry Gross Avatar
    Larry Gross

    right now – as we speak… Rappahannock Electric “reads” my meter from their central office.

    Right now, REC can stop my water heater from getting power (during peak hour).

    Right now, REC could, if they wished, offer me Internet via my electric wire.

    A “smart” meter is nothing more than having a electronic “widget” showing me the same info that REC is seeing.

    This is OLD technology not yet adopted by Dominion – not because it’s not doable and not because it is “too expensive”.

    The reason is – that they really don’t want you to cut back on your usage because they want to sell you as much electricity as you’re willing to use.

    This is a standard business philosophy… but not in the best interests of consumers. As Jim Neigbors would say on Gomer Pyle – surprise surprise.

    Smart Meters would be a disaster to Dominions Shareholders and so, not only will the cows will not come home but we’re gonna die of old age before we see Smart Meters in Virginia.

  19. Anonymous Avatar

    REC reads your meter via your internet connection, no? or is it via electric power carrier?

    Either way, what works for you won’t work for everyone without substantial expense.

    That expense cuts into the savings.
    Just because we know how to do it in theory, doesn’t mean we know how to do it well in bulk.

    Actually REC does not see the same info that REC is seeing. All they see, absent your widget, is bulk demand, and maybe some variations on regional circuits. Absent your widget, they have no idea what is going on in your house.

    But tell me, how is it they can shut off your water heater? Has it got a programmable switch installed? Yet another expense to be managed, and another widget to be repaired.

    What happens if that switch fails and burns down your house? Is it your switch, or theirs? Who installed it, your electrician, or theirs?


  20. Anonymous Avatar

    What is your take on how smart metering could affect net metering?


  21. Larry Gross Avatar
    Larry Gross

    I”m not familiar with the term net metering..

  22. Larry Gross Avatar
    Larry Gross

    …But tell me, how is it they can shut off your water heater?

    it’s a black box with a red light.

    The light is stays on or it blinks.

    when it blinks.. the power to the water heater is off.

    they installed it and they are responsible for damage.

    further, in exchange for me agreeing to install it, they repair my water heater is an element burns out.

    In fact, they send out a technician to diagnose .. and if the water heater is dead.. they’ll replace it for a market priced unit.

    They also sell whole house surge protectors – and once installed, if your house takes a hit and you lose equipment – they pay for it.

    They have looked into Internet over power lines and are partnering with WI-FI companies to co-locate on their towers.

    These are ALL things that Dominion could also do…

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