A year in green tech: GeoExchange

Throughout 2014, I will take a look each week at a technology or strategy that holds promise to help us eliminate the need for chemical fuels (also known as fossil fuels) that have the dual drawbacks of finite resources and damaging transformation into useful form.  I will strive to maintain a balance between presenting the science behind the technology, and maintaining some readability.  I look forward to a dialogue on the subject, and welcome comments and feedback that will further our collective understanding of the topic.

Week One:  GeoExchange and Thermal Batteries

On a simplistic level, we use energy in its various forms nearly equally to power our buildings, our transportation, and our industrial activities.  In our building systems, over half of all the energy use (or approximately one-sixth of the total) provides us thermal comfort, what we generally refer to as heating and air-conditioning.  Especially when it comes to heating, shifting away from fossil fuels meets great resistance because of the built-up infrastructure of distribution networks for natural gas and heating oil, the proliferation of equipment to convert the fuels into heat, and the high reliability of these networks of energy transfer.  In order to supplant this significant portion of damaging, but most necessary - at least in the case of building heat - energy use, we need a technology that provides an equal level of reliability and efficacy without relying on the use of a limited resource.  Thankfully, for over half a century, we have had that technology: geoexchange.

Geoexchange, also known as geothermal* or ground-source, systems work on a couple of basic scientific principles.  Before getting into some more detail, I want to introduce geoexchange with an analogy, that of the rechargeable battery.  We all understand that a battery holds onto a set amount of electricity for us to use to power some electronic device, and many of us have seen the battery packs that we can take out of a device and plug into a wall to recharge.  Our phones and computers have rechargeable batteries, and although over time the constant charging and recharging can wear a battery out, for the normal life of an electronic device, it gets the job done.  Geoexchange works on a similar principle, except that instead of energy in the form of electricity, we move energy in the form of heat, and instead of using a chemical solution to store the charge carrying the energy, we use the earth to absorb and store the heat.

US Department of Energy

Before going much further, I should mention a couple of the scientific properties that will help describe what happens in a geoexchange system:

First, one of the fundamental principles of nature states that thermal energy moves from a hot area to a cold area, but never the reverse.  Although we may feel a wave of cold "moving toward us", the movement of thermal energy always moves hot to cold.  This is especially important to understand as we think about things like refrigerators, where we do not "add cold", but rather try to take heat away from a cold area and move it to a hotter one.  In order to do that - essentially violate a law of nature - we have to add significant amounts of energy (although refrigerators have become much more efficient at moving heat over the last twenty years).  Our homes have window air conditioners or equipment that sits on the ground outside the house (called condensing units) that reject heat from our house to the outside.  This law of nature, and the methods we use to violate it, play significant roles in the technology.

Second, some materials do a poor job of holding onto heat and get hot very quickly, then cool off equally as quickly.  These materials have a low specific heat, which is a measure of how quickly the temperature of a material changes for each unit of thermal energy added to it.  For example, in the liquid state, water changes temperature rapidly when heated, and once we remove the source of heat, it reaches the temperature of the surrounding room relatively rapidly.  On the other hand, for a material like stone, it takes a significant amount of heat to change the temperature of the material, but once heated, it can give off heat while slowly dropping in temperature.

Lastly, it helps to understand the concept of evaporation.  We all have seen steam rising from a boiling kettle, but some liquids do not need that level of heat to evaporate, and in fact will evaporate at room temperature or lower.  Some may know of an extreme case of this with dry ice, solid carbon dioxide, which changes from solid to gas at room temperature in a process called sublimation.  This process of evaporation at low temperatures holds the key, especially when we talk about heating with geoexchange.

So how does geoexchange allow us to heat and cool a building with a minimum of fossil fuels?  The basic operation uses the relatively fixed temperature of the ground (below around four to five feet beneath the surface) of anywhere from 45 to 75 degrees depending on where one lives.  In the summer, when we like a space temperature of between 74 and 78 degrees, we can run cool fluid (usually water or a water-antifreeze mixture) from the ground at nearly the temperature of the earth, and either bring it directly in contact with air from the building or use a heat pump to draw heat from the space and add that energy to the fluid.  We then return the fluid, using a fluid pump, to the earth.  With the added heat, the fluid now has a higher temperature than the earth, and will flow from the pipe to the earth.  We help this process by surrounding the pipe with a grout that has high thermal conductivity (meaning it allows heat to quickly pass through it), and since the earth has a high specific heat, we can add significant amounts of heat without changing the temperature.  The cycle then starts over with the lower temperature water returning to the building.

In the winter, when we need heat, we cannot rely simply on the temperature difference, since the earth still sits at 45 to 55 (in the areas that need heat, we get to 75 in areas where air temperatures do not drop to the point where we need heat) and we want space temperatures of 68 to 72 degrees.  In this case we do need a heat pump, which uses that evaporative property in a material called a refrigerant.  The refrigerant in this case will evaporate at the temperature of the earth, pulling heat from the fluid and sending it back down slightly cooler than the ground temperature, then reject that heat into the space to maintain the temperature.  This still requires an input of electrical energy, but a significantly lower input than the chemical energy needed to provide conventional heating.  The fluid returns to the earth to pick up more heat and the cycle continues.

The geoexchange system has some drawbacks.  The system requires that we bury a series of plastic pipes either deep underground (in the case of a vertical system, sometimes as deep as 500 feet) or throughout a large area (a horizontal system, and depending on the building size, this could mean almost an acre).  This requires a significant capital investment, although over the life of the system (which lasts a minimum of fifty years before anyone would have to think of digging up the pipes and starting over) that cost requires much less investment than the annual cost of paying for fuel to heat and cool a building.  Also, the system still requires a source of electricity, and if that electricity does not come from a reliable, renewable source (more on that in the coming weeks), we have not eliminated all of the potential damage caused by our need for heating and air-conditioning.

The greatest impediments to widespread implementation of geoexchange systems fall under three main headings: logistic, application, and economic.  Some buildings do not have the requisite land area or underground access to install the pipes necessary for the system to work.  Innovators have begun looking into phase change materials that can provide the thermal battery storage nearly equivalent to the earth, but without the need to dig, but that will take some time to reach the market.  Geoexchange systems work best when the amount of heat needed in winter nearly matches the amount available in summer, or when the amount removed or added matches the rate at which the earth can rebalance its temperature.  When we cannot achieve that balance, the application of geoexchange requires either a supplemental heat source (further reducing the benefit) or the addition of solar collectors to increase the summer thermal storage (which increases the cost), since over time drawing heat or adding it faster than the earth can tolerate will greatly reduce the performance of the system...even to the point where the building systems will no longer work. Lastly, our energy delivery market currently centers around the selling of electrons and molecules, not the movement of heat.  Since we have nothing to sell after the initial installation, investors and financial markets have not yet found a way to value a system that relies on such little input energy.  This last challenge faces all green technologies: how do we price something that is ubiquitous and readily available?

Over the coming weeks, I will look at other strategies and technologies that work in concert with each other and geoexchange, forming a palate of solutions from which homeowners, designers, and builders can choose today and in the near future to create a "fuel-less" economy.  Some of these, like hyper-insulation, solar photovoltaic, and battery storage, work hand-in-hand with geoexchange, while others, such as earth tubes and energy recovery, can work in place of it.  If you hear of a technology about which you would like to learn more, please let me know and I will try to include it in the series.

* Although geothermal has more popularity in the building industry, another more appropriate application of the term geothermal applies to underground hot springs that can be tapped to produce electricity.  Because they both relate to the energy industry, geoexchange more appropriately describes the process used in buildings.

Flashes: January 8, 2013

• Wind turbines that can be taller because of innovative construction methods
• Electricity production from low temperature waste heat

• Change in Pacific nitrogen content tied to climate change

• Commercial Building Analysis Tool for Energy-Efficient Retrofits
  
• Distributed Energy Resources Customer Adoption Model
  
• Energy and Water Use Analysis
  

• A new material for solar panels could make them cheaper, more efficient

Hoax or no hoax, climate action is in our best interest

John Stewart had a great rant on it.  CNN and Fox have beaten it worse than bowl opponents beat the SEC.  Facebook had meme after meme on both side of the issue.  Being stuck inside most of the last couple of days, most could not ignore the story of the year thus far...

Global warming is a hoax because it's so cold in part of the country.

I can discuss (and have discussed...as have many others) how this extreme weather may actually follow from arctic warming, or how Australia finds itself in an intense heatwave, or how climate has to do with long term weather patterns, not short term ones.  But none of that really means anything anymore because all of the actions required to address human-caused climate change are in our best interest economically and socially.

On the economic front, renewable energy sources prove a better investment than new fossil fuel or nuclear sources on the utility scale.  This stands true even in the Midwest where especially solar has had a rough ride.  Both carry some risks, but the risks associated with the cost of commodity in fossil fuel plants greatly outweigh the risks of availability of solar and wind.  Energy efficiency (including the alternative use of renewable sources such as using sunlight for daylight in buildings or providing heating and cooling using geo-exchange thermal storage) trumps them all economically, providing a perpetual return on investment.

Socially, the inequity surrounding the availability and environmental damage associated with energy use exacerbates the gap between the haves and have nots.  Power plants, mines, and wells site near poor communities because the demand for this property gets driven down by the presence of these assets.  This puts only those who cannot afford to live elsewhere at risk.  Especially with assets like coal fired electricity plants, coal mines, and natural gas/oil fracking wells, the local environmental damage placed an extra burden both socially and economically on the communities.  Moving away from these technologies would remove this additional burden, and provide those most at risk with the opportunity to lift themselves out of poverty.

There is no downside to investing in renewable energy and energy efficiency.  To those who scoff at the potential level of investment, we can show how similar levels of investment in the digital economy paid dividends.  To those who fear the loss of jobs in the industries affected, we can show how the renewable energy and energy efficiency industries have higher jobs per dollar than any of the non-renewable industries.  To those who decry the subsidies that would be required for some of these technologies, we can show the higher level of direct and indirect subsidies that the supposedly mature industries in fossil fuels enjoy.

Switching to an all-renewable energy economy requires the solving of many problems, but none of them insurmountable.  We can continue the development of storage technologies to address intermittency, and adjust load timing to improve the matching of source availability to load.  The only issue we really need to overcome is social: we need to stop finding reasons to argue and start to look at the plain numbers if we act or we do not act.  If we act, and all of this was just hype, we have a more resilient economy with little to no risk of pollution.  If we do not act, and the worst of this becomes real, it will not matter that we were right.  We might be dead right as a species.

Digital expectations in an analog world

Almost every weekday morning I wake up and take the commuter rail to work.  Normally, this routine takes up about half an hour of my time, and if any expected delays occur, I can track them on my mobile device and adjust my plans accordingly.  I have refined the operation to minimize my time spent waiting, and maximize the time I get to spend doing the things I want to do in the morning...namely sleep and spend time with my family.

And then today happens...-12 degrees F after a foot of snowfall over the weekend, and everything devolves.

Today's commute included two cancelled trains, slow travel through the route, and a delay entering the station.  My normally reliable half-hour travel ended up taking almost two hours.  The conversations at our neighborhood station and on the train chided the rail agency for not being prepared, for not getting information out better, and for generally not meeting the expectation for timeliness that commuters expect every day.

Although I do not apologize for any negligence or poor planning, in general I think we have absolved ourselves of understanding what really goes into something as simple as commuting to work - whether by train, bus or car - and in this case took that out on the commuter rail agency.  The act of getting twelve to fifteen trains in and out of one station in a given morning requires not only that the engines and brakes work, but that the switches and signals along the track work.  These devices include digital technology to a point, but at the end require moving parts.  Some of these parts can get jammed, and require a person to thaw, unjam, or otherwise repair.  No matter how smart, connected, or integrated the electronics of a system are, at some point, it comes down to a piece of equipment that has to work.

This all leads back to some fundamental concepts in our economy.  First, that labor costs represent an inefficiency that we must minimize or eliminate, and second, that people need to "work hard" to earn participation in our economy.  By relentlessly pursuing the former, we not only jeopardize the ability to ensure opportunities for the latter, but we also force institutional knowledge (in the form of people) out of the economy.  If we automate everything, that makes sense under normal operation, but we lose the ability to quickly respond when things go wrong.  No one wants to pay for resilience when times are good, and everything moves well.  But when things go wrong, we need to have people who can understand, assess, and address issues, and we need to make sure that they are valued all the time and not just when our commute is a little longer than normal.

Friday Five: January 3, 2013

On the twelfth day of Christmas, my environment gave to me: 
Nine politicians dancing around regulation to protect our health...
EPA fails to deliver coal ash rules 5 years after catastrophic spill
"Miraculously, nobody was injured when 5.4 million cubic yards of piled, sodden ash broke loose on Dec. 22, 2008. But the slide, which destroyed three homes, damaged dozens of others, and poured into two tributaries of the Tennessee River, has required a $1 billion cleanup, with $200 million more to go. That bill will be paid by the 9 million residents of the Tennessee Valley — including more than a quarter of a million households in Central and Western Kentucky — at the rate of 69 cents per month per person through 2024."

Eight maids a milking in an area where we couldn't milk before...
Climate change works wonders in Leh
"If the farmers are thrilled, climate scientists strike a somber note. They say the eruption of vegetables and fruits at an altitude of 11,000 feet is a clear indication that global warming is catching up in the Himalayas, its long-term consequences unclear but one which could spell trouble for the region. The farmers are however, having none of it. As far as they are concerned, it is a boon and are determined to make hay, while the sun shines literally. They have started cultivating vegetables and fruits in earnest including cucumber, pumpkin, watermelon, bottle gourd, tomato and capsicum."

Ten lords a leapin' over themselves to jump on the renewable bandwagon now that...
Why Michigan's Republican governor supports clean energy - or does he?
"More than half of the electricity in Michigan is generated by burning coal. Michigan doesn’t have coal. But anyone who has been there in winter knows that it has plenty of wind. Why send your money elsewhere to buy coal, when you can generate energy with the resources you do have? In a rare confluence, both the Sierra Club and the Michigan Conservative Energy Forum cite with dismay the same statistic: that Michigan spends $1.2 billion per year on out-of-state coal. And they even use it to make the same point: that Michigan should instead develop its own natural resources. As wind power keeps getting cheaper, they argue that it will both save Michiganders money and put them back to work."

Five gold rings - well, actually, only one: the sun, that is now besting even natural gas in value to the consumer...AND...
Massive solar plan for Minnesota wills bid over gas
"In an unprecedented ruling, a judge reviewing whether Xcel Energy should invest in new natural gas generators vs. large solar power arrays concluded Tuesday that solar is a better deal. If the finding by Administrative Law Judge Eric Lipman is upheld by the state Public Utilities Commission (PUC), Edina-based Geronimo Energy plans to build about 20 large solar power arrays on sites across Xcel’s service area at a cost of $250 million."

A partridge in a pear tree that can travel most of its trips without having to plug in, fill up, or make a refueling stop of any kind!
Ford to show solar-powered car at electronics show
"Rather than recharging through an electrical outlet, the C-Max Solar Energi harnesses the power of the sun by using a concentrator that acts like a magnifying glass to direct rays to solar panels on the roof. Ford research shows that the sun could provide enough power to cover up to 75% of all trips taken by an average driver. It also could provide a viable alternative for electric vehicles in regions where there is bountiful sun and a scarcity of recharging stations."

Happy Friday!

What will climate change take from you?

By the time the dust settles on the impacts of human-driven climate change, I will be elderly, and the direct impact on my day-to-day life will be relatively insignificant.  If predictions are true, I will worry for my children and grandchildren, worry that they will experience life in a far rougher way than I would have planned for them.  All-in-all, climate change will likely take only one thing from me...

Skiing.

I have already seen it each of the past four years.  Areas that had snow November through March and even into April are lucky to get a full January and February.  Changing climate will not prevent snow in these skiing-rich areas, but it will change the snow pattern enough to make owning ski resorts or sustaining ski towns economically unviable.  The death will come as generations grow up without skiing every week throughout the winter.  It will arrive as young people find other hobbies.  

Although it seems a decidedly elitist thing to worry about, there are countless small towns that rely on skiing to survive.  Skiing's blue-collar cousin, snowmobiling, affects a large segment of the population.  The effects ripple throughout the economy.  It may feel comfortable for us to sit back and judge a change in another's way of life, but invariably, it affects us in some way shape or form.

I hope we figure out how to eliminate our impact soon.  I do not hold out hope that we will reverse it, but holding a front will be a good start.  That way, climate change does not damage my quality of life in this small way sooner rather than later.  If that happens, I fear more changes will happen sooner than we can handle.

Five innovations to watch in 2014

Wikipedia

As well bid farewell to 2013, and look forward to 2014 with anticipation, we hope - as every generation that has preceded us - that we can leave the world a little better than we found it.  Continued development, especially in  countries containing most of the world's  population, combined with economic forces will continue to challenge our ability to deliver on our desire.  Thankfully, we do have reason to hope.  The following summarizes the five great opportunities we have right at our fingertips.  These may not become everyday solutions in 2014, but they have the potential to make great strides in the next twelve months, and who knows...maybe at this time next year we could be talking about 2014 as "the Year of...."

Driverless cars
The evolution of the automobile (back) to all-electric fleet has begun already, and with more manufacturers joining the competition every year, we have great hope that the Western capitalist economy (combined with a strong focus on battery technology from the federal government) will deliver cost-effective vehicles.  Electric cars will not change much about our lives, but driverless cars will.  This will not only improve the safety and efficiency of the vehicles, but it will solve one of the great problems with the current mode of car ownership: the significant unused capacity that takes up land and resources.  Now, we spread car ownership around, use our cars far less often than we leave them stationary, and take up huge amounts of real estate with parking spots and garages.  The driverless car will allow us to share vehicle usage much more readily, which in turn will allow us to free-up real-estate and road infrastructure for much more efficient movement of resources. As a result, they will save us significant amounts of wasted time.

Evolution of the "sharing economy"

Cynics like to remind us that the "sharing economy" is just another word for "renting", and that there is nothing new about that.  I could not agree more.  The innovation will come in using advances in communications technology to tap into unused capacity within our personal capital (everything from our cars to our homes to our power drills) both for financial gain as well as for the betterment of our personal relationships.  Many like to lament the good old days when we could sit out on the front stoop with our neighbors, and borrow a cup of sugar or the lawn mower.  Although we have lost the social capital to make these relationships work, the advances in mobile technology will allow each of us to turn our assets into retable commodities. This will open us up to new ideas in what we consider a "rentable" service or item.  The revolution in the sharing economy will not come in thinking it some major innovation, but simply in opening our minds to a new balance of what we own and what we rent.

Geo-exchange energy and thermal batteries

We may look back on 2014 generally as the year of the battery, but in this case, I mean thermal battery - those that store hear energy instead of electricity.  For the better part of a century, we have known how to store heat energy in the earth when we do not need it, and recover it when we do.  This form of thermal storage (commonly known as geothermal energy, but to distinguish it from hot springs and other forms of true geothermal energy we now more accurately call geo-exchange) will allow us to drastically reduce the need for fossil fuel energy in temperate climates - those that require heating part of the year and cooling part of the year.  Advances in phase-change materials and improved building efficiencies will also mean that we may not need the earth to be our thermal battery, saving time and money while maintaining the reduction in operating costs.

Placing value on air
As the one political issue on this list, we have seen over twenty years of debate on how we as a country want to deal with carbon pollution, and almost forty years of serious discussion on other forms of pollution.  The past ten have focused on carbon, completely overshadowing the notion that we protect the air we breathe when we avoid pollution.  The next year will - if we want success - will shift the balance back toward a combination of climate change and breatheability.  Air stands as the only life requirement on which we do not place a monetary value, and as such, does not have priority over economic development or job creation - ideas that polluters throw into the discussion to sway politicians.  This year, grassroots and established environmental groups need to move from the idea of "carbon taxes" to a broader, more personal concept of "air valuation".  If you ask a person what value they place on their child or grandchild having more oxygen and nitrogen than carbon dioxide and monoxide (plus particulates and heavy metals), that will have greater sway against the arguments of industry than talking about implementing a sin tax.

Solar energy

The most under-reported story of 2013 has to be the meteoric change in the cost of renewable sources on energy compared with fossil fuels (including nuclear).  The next year will see a change in that ignorance.  Grid parity - the phrase used to describe the economic point when renewable energy costs to generate match those of traditional sources of electricity generation - will reach an even wider swath of the nation, changing the conversation in some of the more populated urban centers.  This will have a significant influence on the debate; as more people see a future of solar (including wind) energy, the less they will accept polluting alternatives, and the faster the market for those resources will collapse.  Contrary to popular thinking, it is not high prices of fossil fuels that will sound their death knell, but rather low demand, and therefore low prices, starving the fossil energy beast of the capital it needs.

Check back with me over the course of the next year and see if I am right.

Enjoy the journey, and have a safe and prosperous 2014!