Geothermal plant, Brady, Nevada. Photo copyright 2006 ORMAT

Around the world, geothermal plants provide energy to about 60 million people, but only about 4 million of them live in the United States. And most of those live in the West.

Although the U.S. is the world’s largestproducer of geothermal electricity, generating an average of 16 billion kilowatt hours of energy per year—more than wind and solar combined—it’s still just a fraction of the known potential and geothermal power plants provide less than 1% of the nation’s electricity.

Today, roughly 60 new geothermal energy projects are under development in over a dozen states that will double current geothermal power production.  With effective federal and state support, recent reports indicate that as much as 20% of power needs in the U.S. could be met by geothermal energy sources by 2030.

The Bush Administration recently extended production tax credits for geothermal power plants through 2008, although it is still attempting to eliminate geothermal research funding for the second year in a row, at a time when its advocates say research is desperately needed.

Drilling for geothermal mirrors that done for oil and gas. Going down sometimes as deep as 30,000 feet, water is then pumped under pressure into fractures to break apart underground rock formation and free up reservoirs.

Geothermal has its problems

Although geothermal is a considered a source of ‘clean’ energy, it has its problems. The plants, wells and pipelines are expensive to build and operate. A 50-megawatt plant that serves 50,000 people can cost $110 million to build. Corrosive water can foul turbines, reservoirs must be managed, and sludge has to be disposed. More research is needed to make the process profitable.

Geothermal power plants are typically built where there is access to a geothermal reservoir. Doing her research in El Salvador, hydrogeochemist Dina Lopez of Ohio University recently completed a study of silica scaling, one of the biggest problems plaguing the geothermal industry. After the heat or hot water is pumped up from the underground geothermal reservoirs and wells, it spins the turbine generators that produce electricity. After that water cools, silica precipitates.

A common element found in water, silica is released from dissolving rock. The silica forms a hard, glassy deposit that clogs pipelines and injection drill holes at geothermal plants. Removing the silica buildup is costly and difficult due to the high volumes of water involved. Lopez hopes the model she and her co-authors created (www.geothermal.org) will help scientists better understand the impact of silica scaling and the rate at which it occurs, and that, in turn, will help guide efforts to control silica scaling at geothermal power plants.

Nevada a hotbed for geothermal

One of the Western states high on geothermal is Nevada, where Nevada Power Company is required to meet Nevada’s Renewable Portfolio Standard of 20% renewable energy to supply their customers by 2015.

Currently Nevada has 14 geothermal power plants capable of producing 277 megawatts of power.

Among the players in Nevada are Nevada Geothermal Power Inc., Ormat, and Raser. Just in the last month the Nevada Power Company, a subsidiary of Sierra Pacific Resources, announced Power Purchase Agreements with NGP and Ormat and power generation leases with Raser.

Raser claims binary system produces zero emissions

A Provo, Utah, company, Raser operates in two business segments, transportation and industrial technology, and power systems. The company’s power systems segment is seeking to develop new geothermal electric power plants and bottom-cycling operations, incorporating licensed heat transfer technology and Raser’s Symetron™ technology.

Raser has just signed leases on two parcels in the U.S. Geological Survey’s Known Geothermal Resource Area (KGRA). The first lease is for 155 acres for 50 years, providing the company with the right to develop and construct geothermal power plants. The other takes over an existing geothermal lease of 240 acres with the Bureau of Land Management. Both are in central Nevada and are part of a series of geothermal lease arrangements Raser has made. (www.rasertech.com)

An independent study done for Raser by Dr. Carl F. Austin and Richard R. Austin identified five target drilling areas on Raser’s leased properties in Nevada. The geologists identified shallow resources at depths of approximately 1,500 feet with water temperature ranging from 225 degrees F to 275 degrees F. The report also identified deeper resources at approximately 5,000 feet with higher temperatures. In the regions encompassed by the study, there are over 46 known hot springs, warm springs, seeps and wells.

The technology that Raser intends to use in the development of geothermal power plants uses water-based geothermal resources of generally lower temperature, ranging from approximately 200 to 360 degrees F. In the advanced binary cycle system, warm geothermal fluid is pumped to the surface and channeled into a heat exchanger. The geothermal water is then used as a source to heat another ‘working fluid,’ which then vaporizes to turn a turbine generator. After the heat transfer process is complete, the cooler water is returned to the reservoir in the Earth. Raser claims the advanced binary method efficiently converts more commonly found low temperature water resources into power through the use of working fluids that have a low boiling point. The company also claims the binary method produces zero emissions, making a properly managed geothermal resource sustainable and renewable.

Nevada Geothermal Power signs 20-year PPA

Renewable energy company Nevada Geothermal Power Inc. is exploring and developing geothermal projects in the U.S., and its flagship project, Blue Mountain, covers 9,637 acres in Humboldt County in northern Nevada. NGP owns 100% leasehold interest in the Blue Mountain, Pumpernickel and Black Warrior projects in Nevada. (www.nevadageothermal.com)

Potential reduction in U.S. carbon emissions (click for larger view)

NGP recently signed a 20-year Power Purchase Agreement with Nevada Power for up to 35 megawatts of geothermal power at Blue Mountain. Development drilling is currently underway, and production test data from the wells will be used to complete a feasibility study.

The power plant is projected to begin generating power in 2009. In the initial program, four 13-inch diameter production wells will be drilled to 4,000 feet into the moderate temperature of 300 to 330 degrees F. A water well rig will be used to drill the top 800 feet of each well and to set surface casing. A production drilling rig with a substructure to accommodate blow-out-prevention-equipment will then complete the holes.

Blue Mountain is located 20 miles west of the Winnemucca, and the project will connect to Sierra Pacific’s 120kV-transmission line north of Mill City.

In Pumpernickel Valley NGP has leased 10.5 square miles of geothermal lands. Sierra Geothermal Power Corp., a TSX Venture listed company, has an option to earn a 50% joint venture interest in the land. Sierra Geothermal is required to make certain cash payments and to issue common shares to NGP as well as to undertake $5 million (Canadian) in project expenditures over a five-year period.

Ormat announces two 20-year PPAs in Nevada

In February Ormat Technologies, Inc. announced two 20-year Power Purchase Agreements with Nevada Power, a subsidiary of Sierra Pacific Resources, and two of its subsidiaries received the approval of the Public Utilities Commission of Nevada. Under these PPAs, Ormat’s Buffalo Valley Project in Lander County and Carson lake Project in Churchill County will produce between 18 MW and 30 MW each for Nevada Power.

The two new power plants are expected to begin commercial production by the end of 2009 and will produce between 18 MW and 30 MW each for Nevada Power. Sierra Pacific Power will receive the energy from these two power plants until a transmission line between Sierra Pacific Power and Nevada Power is completed in 2011.

Ormat currently operates geothermal plants in the U.S. at Brady, Heber, Mammoth, Ormesa, Puna and Steamboat, and in the Philippines, Guatemala, Kenya, and Nicaragua.

By Terry Laudal

What it takes to become “green” are design and construction practices that significantly reduce or eliminate the negative impact of commercial buildings on the environment and its occupants in five key areas: sustainable site planning; safeguarding water and water efficiency; energy efficiency and renewable energy; conservation of materials and resources; and indoor environmental quality.

SAP Americas, Newtown Square, Pa.

SAP Americas, in expanding its headquarters in Newtown, Pa., is committed to making a positive contribution to the environment while providing an innovative, state-of-the-art “green” facility for its workforce. It will be the first corporate-owned building in the mid-Atlantic region to achieve the USGBC’s Leadership in Energy and Environmental Design (LEED) Platinum level, the highest in the organization’s green building rating system. The LEED ratings also serve as a benchmark for the design, construction, and operation of high-performance green buildings.

Among the special features of the building will be sophisticated, automated control systems and sensors to maximize energy conservation such as:

• Geothermal wells that will use the constant ground temperature to both heat and cool.
• An ice storage plant that will produce ice during overnight hours when electric rates are lower. The chilled water will then cool the building during the day.
• An underfloor air distribution system that will allow lower velocity air movement to save energy and also will give employees full control at each individual workstation and office.
• Green roofs with no exposed mechanical systems that will not only weave the old into the landscape, but also reduce rain water runoff. Rain water will be collected in cisterns and used in the existing cooling towers and as irrigation water for the site and green roofs.
• Rolling daylight or lighting systems that will be controlled by daylight sensors which will both dim lighting levels and rise or lower window shades based on the light provided through a floor-to-ceiling glass exterior wall.

All of these “green design” features not only will improve the building’s energy performance and reduce any detrimental impact on the environment, but they also will improve the comfort of its employees, and as a result, improve the health of SAP’s workforce and help retain our highly engaged and productive work force.

According to a study conducted by the Lawrence Berkeley National Laboratory in Berkeley, California, in the United States alone, the estimated potential annual savings and productivity gains from better indoor environments are $6 billion to $14 billion from reduced respiratory disease, $1 billion to $4 billion from reduced allergies and asthma, $10 billion to $30 billion from reduced “sick building” syndrome symptoms, and $20 billion to $160 billion from direct improvements in worker performance unrelated to health.

The Canada Green Building Council, in its reports, states that other North American studies completed in the last several years concluded that good day lighting increases productivity by 13%, can increase retail sales by 40%, and can increase school test scores by five percent. In addition, the studies found that increased ventilation spiked productivity up to 17%, better quality ventilation reduced sickness by up to 50%, and increased ventilation control increased productivity up to 11%.

For example, in a USGBC white paper prepared for the U.S. Senate Committee on Environment and Public Works, Verifone, a division of Hewlett-Packard in Southern California, renovated its global distribution headquarters and reduced energy consumption by 59%, decreased employee absenteeism by 47%, and increased employee productivity by 5%.

The paper also cited that even a modest investment in soft features, such as access to pleasant view, increased daylight, fresh air, and personal environment controls, can quickly translate into significant bottom-line savings. Case in point is Lockheed’s engineering development and design facility in Sunnyvale, California, which reported a 15% drop in employee absenteeism–a savings that paid for the incremental costs of the company’s new high-performance facility in the first years alone.

And a simple lighting retrofit at the Postal Sorting Facility in Reno, Nevada, enhanced visibility for workers and, as a result, the number of mail pieces sorted per hour increased 6%–a productivity gain worth more than the cost of the project.

Therefore, according to the USGBC, “going green” has a triple ripple effect to the bottom line–environment, economics, and people. Better buildings not only add up to an improved effect on the surrounding environment, but also lower operating costs and enhance employee productivity in terms of higher attendance and recruitment rates, lower turnover, and a 7% increase in overall productivity.

But it is not corporate America’s responsibility alone. We must each do our part and be proactive about curtailing waste and saving the Earth’s resources. For example, if we rode a bike to work or drove a hybrid car; if we used multi-function machines to fax, copy, print, and scan; if we increased home office and desk-sharing; if we transformed to a paperless work environment; or if we simply turned off the lights, we would be making a difference. Consider this, for example: If we turned off all office equipment on standby power, it would save enough energy for one nuclear power plant!

One by one, the effects would be astounding. In our work and home lives, we at SAP believe that it is best to be part of the solution and not part of the problem in making this a better world for our children and grandchildren–the workers of today and those of tomorrow.

Terry Laudal is Senior Vice President, Human Resources, SAP Americas, headquartered in Newtown Square, Pa.

Originally published January 2008

By Fred L. Walls, Ph.D.
and Kay Turnbaugh

As his house was being built in Lafayette, Colorado, Fred Walls installed the loop field for a ground-based heat pump (GBHP) five feet under the basement. His research on GBHPs indicated they were the most energy-efficient means of heating and cooling, so he asked the developer of his neighborhood to dig a little deeper and allow him to install the necessary pipe work before pouring the foundation for his new house.

The Walls’ house in Lafayette, Colorado, is heated and cooled by a geothermal heat pump system. The system is so efficient that the Walls spent $456 to heat their 3,000-square-foot house in 2007. Photo by Fred Walls

Walls, a physicist and Fellow of the American Physical Society and IEEE, documented his energy savings during the first year he and his wife lived in their new house.

During the first year his GBHP was on line, 2007, the energy usage for heating his home was only 21% of comparable homes with gas heat. His total energy usage is less than 50% of comparable homes. His average heating costs in 2007 were $38 per month, which included 100% wind adjustment for electricity.

Heating/cooling consumes roughly 45% to 70% of the energy in a typical home. GBHPs have efficiencies of 350% to 500% compared to a fuel-based furnace, which is typically 65% to 92% efficient. “Replacing an old 65% gas furnace with a new GBHP would reduce energy consumption for heating by an astounding 85%,” Walls says.

“GBHPs also provide very efficient summer cooling and can provide pre-heat for the hot water.”

Walls also points out that the gas that is saved by using a ground-source heat pump (GHP) can then be used to displace coal used in the generation of electricity. “This is important because gas generators produce 45% less CO2 and much less heavy metal pollutants than coal, and electrical output of gas generators can easily be controlled to accommodate changes in load and/or generating capacity of intermittent renewables such as wind or sunlight.”

The pipes for the Walls’ geothermal heat pump system are buried five feet below the basement and thirteen feet below ground level. The house itself acts as insulation for the system below it. Photo by Fred Walls

“It’s a value-added system,” Walls says. “Investments in selected energy conservation projects show a savings in utility costs of roughly 5% of investment. The expected increase in energy costs should create an additional return of roughly 3% to 10% per year due to appreciation in the value of the energy conserving projects. Total rates of return could easily approach 8% to 15%. These factors make it feasible, in most cases, to reduce energy consumption, reduce the average monthly cost of ownership, and at the same time increase the value of your home.” Walls expects the value of his house to increase faster than the rate of inflation because of its energy-saving GHP system.

According to the National Renewable Energy Laboratory (NREL) and Colorado’s Xcel Energy, geothermal heat pumps, also known as ground-source heat pumps or GeoExchange systems, are the most energy efficient way to heat and cool a home and provide hot water. The Environmental Protection Agency (EPA) says that GeoExchange systems are the most energy-efficient, environmentally clean, and cost-effective space conditioning systems available.

Ground-source heat pump systems typically show a savings in utility costs of roughly 5% and add value to the home of about $20 for every $1 reduction in yearly home energy costs. (See The Appraisal Journal; “More Evidence of Rational Market Valuation for home Energy Efficienty,” October 1999.)

There are federal tax rebates for some energy conservation projects, including ground-based heat pump systems, and many utility companies offer large rebates for the installation of a GHP system. More than 1 million GHP systems have been installed in the United States, including over 1,000 at colleges and universities, according to NREL.

HOW IT WORKS

A GHP system moves the heat from the earth, or a groundwater source, into the home through a heat pump/exchanger in winter and pulls the heat out of the house and discharges it into the ground in the summer. Underground piping loops serve as a heat source in the winter and a heat sink in the summer. A pump circulates temperature-sensitive fluid through the ground loop.

Walls’ system is installed under his house, which makes it more efficient than a system that is detached from the structure. Of course, if you’re retrofitting a system to an existing structure, the pipes have to be buried in the yard or a field. An alternative approach when there is not much space is to drill several wells approximately 200 feet deep in a narrow strip of land or beneath the driveway.

A few feet below the earth’s surface, the ground temperature remains at a relatively constant temperature. Depending on latitude, ground temperatures usually range from 45 degrees F to 75 degrees F (7 degrees C to 21 degrees C), even when temperatures outside can range from sub-zero in winter to scorching highs in summer. A GHP system can take advantage of this constant temperature by exchanging heat with the earth through a ground heat exchanger.

Walls has plotted the inside temperature and the outside temperature over the course of a year. As the first year of using his system progressed, it got more efficient. At left is a graph of Wall’s data for a day during the GBHP’s first month of operation.

COST AND SAVINGS

Fred Walls used a system of sensors to record the temperature in the underground pipes and on the walls of his house for this case study. Photo by Kay Turnbaugh

A geothermal heat pump system averages about $5,000 per ton of capacity. A three-ton unit, at a cost of roughly $15,000, works for a typical residence. Xcel Energy estimates that other systems would cost about $4,000 with air conditioning. “When the cost is included in the mortgage, the homeowner has a positive cash flow from the beginning. For example, say that the extra $11,000 will add roughly $95 per month to each mortgage payment. But the energy cost savings will easily exceed that added mortgage amount over the course of a year. The savings of roughly $800 to $1,000 a year in utility costs adds about $16,000 to $20,000 to the value of the house. Therefore, the homeowner can typically reduce total monthly costs, increase the value of the home, and reduce total energy consumption with its associated CO2 production.”

The graph below shows details on Walls’ utility bills and energy usage.

Here are Walls’ conclusions for his 3,000-square-foot home with a 3.5-ton ground-based heat pump for its first 12 months:

1. Use of the ground-based heat pump reduced energy usage for heating by approximately 79% per square foot versus a conventional 80% efficient furnace.
2. Total energy usage was reduced approximately 55% per square foot when compared to a conventional home.
3. Cost savings were approximately $800 to $1,175 ($67/mo to $100/mo depending on rate structure). This is roughly $19/mo to $29/mo per ton of heating/cooling.
4. Cost savings typically are enough to finance loan and still save on total monthly costs.
5. The cost of the system added to the value of the house.
6. The cost to install a system is very roughly $5000/ton.
7. The size needed is roughly 1 ton to 1.5 ton per 1,000 square feet.
8. Ground loop lifetime is 50 years guaranteed; expected lifetime is 200 years.
   

Above is a graph for Walls’ home in Lafayette, Colorado, for the 12 months from December 19, 2006, to December 18, 2007. Heating costs were about $1.25/day when all service charges, including 100% offset with wind energy, are included. Note that the heating energy consumption is only 21% of the comparison house when adjusted to the same square footage. Note that the comparison house energy usage was measured from January 1, 2007, to January 1, 2008. The Degree days are similar for December 6 (1028) and December 7 (1181) so the comparison should be valid to within 5% of December usage or a few dollars.

One of the reasons Walls’ system is so cost-effective is that he installed it under his house. He can’t allow the ground under the house to freeze, because then the house would heave, so he installed enough pipes in the ground to keep it from freezing. The pipes are buried five feet below the basement, which is 13 feet below ground level, and, on the advice of a friend in Alaska, Walls took the extra precaution of adding two inches of Styrofoam insulation between the pipes and the house.

The house itself is insulated with R38 blown-in cellulous insulation in the attic and R19 bats in the walls. The foundation walls are insulated to R11, and under the slab is R10. The attached two-car garage has R11 insulation in the walls, an insulated steel garage door, and an insulated ceiling. Windows are Amsco double-pane vinyl VLS low-E, U factor 0.24, solar gain 0.31.

Walls hired an EPA-certified inspector to evaluate his home. He gave it a 5 Star Plus rating, which certifies that expected energy usage was less than 50% of comparable homes. Based on this rating, above, Walls qualified for a $2,000 tax refund.

MAINTENANCE

Photo by Kay Turnbaugh

Xcel Energy says that geothermal heat pump systems have fewer maintenance requirements than most other systems. The underground components are virtually worry free. Walls’ says the only maintenance he has to do for his system is to clean the filter every couple of months. Unlike regular furnace filters, his GBHP filter can be washed.

LIFESTYLE

Walls and his wife have not had to change the way they live to accommodate the geothermal heating system. “We can save 70% to 80% on gas consumption and not change our lifestyle,” Walls says. They maintain their house at 73 degrees F in the winter and 76 degrees F in the summer.

When they leave the house for a few days or for a vacation, they enable the back-up electric strip heater within the geothermal system in the remote chance there is a failure in the loop field or compressor.

Some geothermal systems use radiant floor heating rather than a forced air system. The Walls’ master bathroom floor is heated in the winter by electrical radiant heat.

Walls’ data shows that the payback for a geothermal heat pump system is approximately twice as fast as a photovoltaic system, even with the rebates usually associated with a PV system. In 2007, the cost for heating Walls’ house was $456.

LINKS

Information on Energy Efficient Mortgages

Energy Efficiency & Building Technology

International Ground Source Heat Pump Association

Geothermal Resources Council

Tennessee Valley Authority

Geothermal Heat Pump Consortium (includes information about incentives by state)

DOE web site with residential energy consumption data