Transitioning to Renewable Energy

Landfill gas, for example, must be cleaned before it can be burned and developers, such as the University of New Hampshire, are using the same oil and gas industry method of pressure swing adsorption to remove hydrogen sulfide, volatile organic compounds and CO2 to clean it. "The processes to remove sulfides, etc., are well established in oil and gas and industrial gas refining," says Bob Harrison, vice president for construction at Norwalk, CT-based Emcor Energy Services, which built and operates the UNH plant. "Pressure swing adsorption is essentially a sponge with specific sized holes. You force methane and CO2, which have different-sized molecules, through the sponge, and it separates gases of different molecular weights."

Another place where technology crossovers exist is in geothermal energy. Drilling geothermal wells in both high and low-temperature, water-dominated reservoirs also uses the same drilling equipment for oil and water wells.

Nonetheless, the high costs associated with drilling have made it difficult for geothermal projects to get off the ground, making the use of abandoned or declining oil and gas wells particularly attractive. Estimates say there are more than one million abandoned oil and gas wells around the world, and Emcor's Harrison notes that the number of out-of-service gas wells is on the rise.

Historically, however, the water in those wells, at between 170-250 degrees, has not been hot enough for conventional geothermal applications, says Doug Tennyson, director of technical services at the Department of Energy's Rocky Mountain Oil Test Center (RMOTC) in Casper, WY. But since last summer. RMOTC has been running a pilot low-temperature geothermal installation from Ormat Technologies Inc. that provides enough electricity to run 2 or 3 oil well pumps.

"We have a lot of oil fields producing not much oil, but a lot of water," says Tennyson. "Companies like Ormat, ElectraTherm and UTC, are taking existing technology to convert the low-quality geothermal source into electricity. Since water is being produced as a byproduct, we can use the electricity to offset the cost to produce the oil. But the cost to produce the electricity can't be more than cost of buying electricity. That's what we're trying to validate now."

Should the costs pencil out, Tennyson says President Obama's Reinvestment Act contains money for low-temperature geothermal projects, and RMOTC would likely expand the project, potentially producing enough electricity to put back on the grid. It has been estimated that oil fields in the U.S. could provide an additional 5,000 MW of electricity with low-temperature geothermal technology.

In the meantime, the University of New Hampshire's biogas facility is well on its way to providing the majority of the university's electrical needs, with a Siemens natural gas turbine modified to burn processed landfill gas. "It was modified because landfill gas has a lower energy content," says Paul Chamberlin, UNH's assistant vice president of energy and campus development. "Natural gas is 96% methane and has higher energy hydrocarbons. Our landfill gas will be plus or minus 85% methane."

Emcor's Harrison says the turbine modification required depends on the machine's level of sophistication. "If it was not designed specifically for that gas, the changes can be substantial," he said. He adds that UNH is not only adapting its existing Siemens turbine, but is installing a Solar Turbines Inc. (Caterpillar) turbine already adapted to run exclusively on processed landfill gas.

Solar Turbines had been collaborating with Lawrence Berkeley National Labs (LBL) to commercialize a fuel-flexible, near-zero emissions combustion technology, but the firm will not use the technology until it resolves intellectual property differences with LBL, says Ram Srinivasan, head of Solar Turbines' advanced combustion program in San Diego. Robert Cheng, LBL advanced energy technology scientist and inventor of the low-swirl injection technology, says LBL continues to develop the "total fuel flex" version of LSI, which would allow gas turbine operators to choose among natural gas, propane, waste gases, biogases and petroleum refinery gases.

Vastly expanding the production of photovoltaic manufacturing equipment posed no such problem for semiconductor manufacturing equipment behemoth Applied Materials when it jumped into the solar industry in 2007, given the significant overlap between its LCD display expertise and solar cell manufacture. "It's a straightforward thing to convert a system for manufacturing an LCD panel to a solar panel, and the glass in a solar panel is actually thicker, so it's easier to handle. A lot of the know-how for making wafer-based solar modules is related to IC (integrated circuits)," says Charlie Gay, a solar industry pioneer and president of Applied Materials' Applied Solar.

Gay notes that the glass must have a semiconductor layer "traffic cop," a transparent conductor (+) and back metal (-). "You need a glass sputtering system used for architectural glass manufacture to deposit the conducting layers, but the semiconductor layer is the same as for the display industry," he said. To produce its first thin-film PV product, Applied Materials modified its display manufacturing equipment and combined it with glass coating technology it acquired with thin-film deposition equipment manufacturer Applied Films.

Neither was it much of a leap for Marine Innovation and Technology, a firm comprised of former oil and gas platform engineers, to morph offshore drilling platform technology into WindFloat, a semi-submersible floating wind generation system. WindFloat is intended for use in waters greater than 50 meters deep and ten miles or more from shore, providing physical stability for wind turbines so that existing offshore wind turbines can be used with very few modifications, says Marine Innovation's Dominique Roddier.

Whereas oil and gas offshore drilling platforms are engineered to minimize vertical motion, with less attention paid to angular motions, a platform for a wind turbine must minimize pitch and roll in order for the turbine to function optimally.

So Marine Innovation and Technology created a three-columned triangular design for WindFloat, placing the turbine on top of one of the columns, and giving more ballast to the other two columns to stabilize the entire platform. The ballast from the other two columns stabilizes the weight distribution and allows the turbine to stand upright.

Like oil and gas platforms, WindFloat has multiple mooring lines (six), although four of them are connected to the column stabilizing the turbine, creating an asymmetric design that supports the additional forces placed on the turbine's column. At the base of each column, water entrapment plates resist the water around them, effectively making the platform move less in waves. A "truss spar" type of oil and gas platform, by contrast, stacks similar water entrapment plates vertically, rather than spreading them horizontally.

As already reported in REW.com, Principle Power, a developer of offshore wind projects, has licensed WindFloat technology.

Although commercial licensees for its kinetic generator have dried up, Boise, ID-based M2E Power expects to go into production in 2010 for specialized military applications that would have "immediate crossover" into commercial markets, such as for charging wireless sensor nodes in logistics tracking or industrial uses like monitoring heavy equipment, says operations manager Jim Gutierrez.

M2E's technology integrates energy/battery management electronics and a unique generator capability, based on translation of kinetic energy into electric current via magnetic induction that uses abundant rare earth magnets. It has shown increases in power output of between 300-700% over existing kinetic-motion configurations.

The advantages to using cleaner, renewable versions of traditional technologies or to using them for renewable energy are too numerous to deny. Thus, the move toward them is inexorable and inevitable as the U.S. and other countries being to transition away from the traditional sources of energy and into renewables. As further indication, one need only look at the increasing deployment of renewable energy technology, notably solar, at fossil fuel plants to reduce the intensity of those plants' carbon production.

To learn more about a solar / fossil fuel plant combination, check out RenewableEnergyWorld.com's video tour of the 10-MW El Dorado Thin-film solar plant that resides next to Sempra's existing 480-MW El Dorado Energy power plant.