The grant is one of 32 research and design projects for geothermal power production funded through a $38-million initiative by the DOE's Office of Energy Efficiency and Renewable Energy. These projects are designed to meet President Obama’s challenge to generate 80 percent of U.S. electricity from clean energy sources by 2035.
Sandia, Atlas CopcoRon Boyd, the Atlas Copco Secoroc project manager for deep-hole drilling applications, says that the project is a result of Atlas Copco’s current work with Sandia National Laboratories. Known foremost for its work developing science-based technologies for U.S. national security, Sandia also partners with government, industry and academic institutions to address scientific challenges on a broad range of national issues, including energy security.
Sandia engineer and senior staff member for geothermal research David Raymond, whom Boyd is partnering with on a current project, sought out Boyd when this research and development opportunity arose. Boyd, with the support of TJ Plunkett, then formed a project team with Atlas Copco engineers Paul Campbell and Dale Wolfer, who devised and submitted their proposal for developing a high temperature hammer for the DOE initiative.
Geothermal Power“If you mention geothermal drilling, people may think of water well rigs making holes on residential and commercial properties. People are more familiar with that use of the word,” Boyd says. He adds that even within the mining and drilling industry, most people are not likely to understand the challenges that geothermal-based electricity generation presents to the industry.
“Depending on the location of the heat source, they have successfully drilled over 10,000 feet down. The deeper you drill, the hotter and more expensive it is,” Boyd explains. To date, this has excluded current down-the-hole (DTH) hammer designs because the hammers have heat-vulnerable parts, including rubber and plastic. “They are drilling at 300 degrees Fahrenheit and higher.”
Hot AirWhile companies have managed high-temperature drilling with other techniques at these depths, those methods do not offer the benefits of air, also known as percussive, deep-hole drilling. Percussive drilling’s greater penetration rates can cut time in the hole by half, which greatly reduces the cost of boring a deep hole.
Boyd is confident Atlas Copco Secoroc will be successful due to their experience with deep oil and gas exploration and production drilling, along with the research and design that exist already from their current lines of deep-hole tools.
Hard, Dry RockBoyd says that most of those currently familiar with state-of-the-art geothermal energy production are in a limited number of countries, but these advancements will have worldwide applications. Geothermal power no longer is dependent upon isolated spots of high-pressure, high temperature steam, which had held back its viability as an alternative to fossil fuels because of its relative unavailability.
Advanced techniques to stimulate and develop enhanced geothermal systems (EGS) mean that thermal energy can now be harvested even from what specialists refer to as hard dry rock sources, or HDR.
Lower Boiling PointRecent successes with “binary cycle” generating stations have vastly increased the number of geographic locations where geothermal production is feasible. These binary plants use hot water pumped from underground to heat liquids that have boiling points much lower than water, such as liquid butane. The vapor from these liquids drives the generating turbines in place of steam.
Lowering CostAtlas Copco was awarded one of the two largest contracts involved in the DOE initiative. Other projects by universities and research institutions will pursue solutions to such technical challenges as aerial identification of geothermal reservoirs, more precise methods for predicting reservoir capabilities, and other cost-reducing techniques for creating and sustaining enhanced geothermal systems.
The overall DOE goal is to increase the feasibility of geothermal energy production by lowering the cost and financial risk associated with this environmentally friendly means of power generation. Therefore, recipients are required to perform feasibility studies before advancing to prototyping and validation. Evidence is to come from vigorous laboratory and field testing.