Drill, Baby, Drill! Geothermal Energy

Did you know that the U.S spends between 30 and 50 billion dollars every month on foreign oil?  I find that number to be HUGE and think that we need to reduce that amount if we want to remain competitive, independent, and environmentally friendly. It doesn’t make long-term economic sense to spend so many of our resources on an environmentally toxic substance that also needs to be transported half way around the world.

If the goals are energy independence, environmentally friendlier and local jobs, some say the U.S should drill for domestic oil and other fossil fuel resources that are within U.S. borders.

In a recent interview I had with T.Boone Pickens, he mentioned that if we switched large trucks to natural gas instead of diesel we could reduce foreign oil dependency by 50%. I agree with him, but also think we should focus more on geothermal energy and call for a “drill baby drill” campaign that all political parties can endorse as it will save money and help our environment, while creating domestic jobs that would be difficult to outsource to other countries. To accomplish this requires a slight change in policy to remove some unfair barriers, but let me first explain the benefits of geothermal.

Geothermal Quick Facts
Geothermal energy is the only commercially available renewable energy that offers 100% uptime reliability. It uses extremely simple technology low operating maintenance costs and results in far fewer emissions by using the earth’s thermal energy instead of fossil fuels. Geothermal energy represents a broad spectrum of applications, including utility scale power as well as solutions for buildings and homes.

For example, utilities use hot spots in the earth’s crust to make steam and then drive a turbine to make electricity. In addition to using our U.S.-based resources to make kWhs, utility-scale geothermal steam generation plants are also eligible for Renewable Energy Credits (RECs), just like solar and wind energy projects.

Where I want to focus your attention is on another example of geothermal energy- the Ground Source Heat Pump (GSHP) which uses the ground as a moderate temperature heat source during the winter and a heat sink during the summer. Basically, during the summer, it is easier to reject heat from the building to the ground (~60^oF) versus the outside air (~80^oF). The same concept is true in the winter- easier to recover heat from the ground (~60^oF) versus the outside air (~40^oF).

GSHPs are an example of renewable energy technology that is also distributed, which reduces the strain on our electrical grid. According to the Department of Energy, the U.S. had over 600,000 GSHPs installed and operating by 2008, so the technology is proven and GSHPs are being installed by countries all over the world.

The Economics of Ground Source Heat Pumps
I am surprised Ground Source Heat Pumps are not more popular.GSHPs reduce the kWhs required for air conditioning. When you also consider that when a utility promotes GSHP applications (for example as a Demand-Side Management method), the utility will have reduced demand during peak periods, requiring less generation plants and less pollution.

As our world’s overall energy consumption increases, we should be promoting GSHPs to help us satisfy our needs because a GSHP only costs about $.8 million/MW to build, as opposed to a new fossil-fueled power plant ~$2 million/MW.

I acknowledge that GSHPs do have higher installation costs to the building owner than a traditional air conditioner (air to air heat pump). The main reason is due to the infrastructure cost of drilling the GSHP boreholes and installing the ground heat exchanger.

However, the ground loop will last more than 50 years, so perhaps utilities should treat this as “infrastructure” the same way that they evaluate transmission lines. In addition, because these systems last 50+ years and we pay the operating costs every year, the life-cycle costs should be compared. When this is done in combination with the economic benefits to the utility, GSHPs are a no brainer and offer the lowest life cycle cost.

They have shorter payback periods than other renewable technologies and do not require back-up infrastructure, wind and solar energy generators need back-up generation when it is cloudy or calm.). GSHPs provide 100% uptime. Because the ground loop has a long life and is hidden and quiet, it is an asset to the building/home that should add value the same way that a solar array on the roof does.

Let’s look at some sample numbers using these equations relating to Energy Efficiency Ratio “EER” and Coefficient of Performance “COP”.

EER = (COP * 3.412) = (BTU per hour_moved/watts_in).

Example: If you had a 5-ton air-to-air heat pump, we would be moving 5 x 12,000 BTU/hour, which equals 60,000 BTUs per hour. If the air-air Seasonal Energy Efficiency Ratio (SEER) is 10, that means we use ~6 kW every hour we run the air-air heat pump.

In contrast, a GSHP would have a SEER of 20 during the summer, which means you would only need ~3 kW. Thus, the GSHP reduces demand by ~3 kW, reducing emissions and helping the utility shave peak demand during the summer. In the winter, the SEER of the GSHP drops from 20 to 13.65 (COP = 4), meaning that the unit will draw 4.4 kW to move 60,000 BTU/hour. 4.4 kW equals about 15,000 BTU/hr of input energy, with the remaining 45,000 BTU/hr coming from the earth.

The total fuel/energy usage is still less than conventional sources (fossil fuels) because the GSHP gets ~75% of the energy from the earth (~45,000 BTU/hr), which avoids fuel that could be going into a natural gas fired heater/boiler. In addition, most utilities are not hitting their kW peak load during the winter, thus GSHPs do help the utility level their kW load throughout the year, which is an effective demand side management function.

Conclusion and Call to Action
Although GSHPs leverage a renewable energy resource, it does not currently allow the user to obtain RECs. I think we should change that.