Geothermal industry leaders say they are losing a popularity contest with wind and solar power, but claim they are offering a better product. Are they right?
Geothermal industry leaders say they are losing a popularity contest with wind and solar power, but claim they are offering a better product.
“We dressed up to go to the prom, but the car is not showing up,” Dennis Gilles, CEO of U.S. Geothermal of Boise, Idaho, told attendees at the Geothermal Resources Council (GRC) Annual Meeting and theGeothermal Energy Association (GEA) Geothermal Expo last week in Las Vegas.
For comparison, solar photovoltaic power installations in the United States rocketed 61 percent during the 12 months ending in June 2013 to 9,370 MW, according to the Solar Energy Industries Association (SEIA). And the American Wind Energy Association (AWEA) reported that U.S. wind power installations jumped by 28 percent in 2012 to 60,000 MW. In contrast, geothermal power capacity rose by 5 percent, or 145 MW, over the last year, according to the GEA.
“We’re slow right now, but we have a product or commodity that is going to have real value, and we’ll be back,” said GEA executive director Karl Gawell.
The Renewables Dilemma
California, which intends to get 33 percent of its electricity from renewable energy by 2021 through its renewable portfolio standard, has favored solar and wind projects.
Stephen Berberich, CEO of the California Independent System Operator, said that geothermal could become more important in California as the state seeks to reduce greenhouse gases and increase reliance on renewable energy. Berberich told geothermal industry professionals that California is likely to either increase the 33 percent RPS or boost renewables to reduce carbon dioxide emissions.
However, it is challenging for Cal ISO to manage the big swings in solar and wind power due to intermittency, Berberich said. Solar power spikes when the sun rises in the morning and throughout the afternoon, but drops at night, while cloud cover and other variables can also affect it. California’s wind resources climb in the evening but fall in the morning, he said.
Cal ISO has been increasingly forced to ramp up power — on Sept. 30, 2013, for example, it spiked power by 6,500 MW in a three-hour period , Berberich said. By 2020, the ramps will more than double to 13,500 MW, he predicted.
“In the past, we’ve used natural gas to help manage that ramp, but natural gas is not popular with environmentalists,” he said, referring to carbon dioxide emissions. This is where geothermal comes in; Gawell predicted that California will inevitably start focusing on the overlooked benefits of geothermal energy.
Proving Geothermal Value
California will be replacing aging power plants in the coming years and a large portion of the replacement power will come from renewables. The question is whether geothermal can be flexible enough to ramp up to fill power needs when solar and wind power dwindles, Berberich said.
Geothermal energy can ramp up quickly to back up wind and solar when the intermittent resources stop generating, Gawell confirmed. In addition, geothermal is a baseload resource, which can replace coal-fired power plants that California is slowly shedding to meet carbon reduction goals.
A study by Aspen Environmental Group in February 2013 showed that binary geothermal plants with new technology can ramp up power generation quickly. Binary geothermal plants use a fluid, such as isobutene, which boils at a lower temperature than water, allowing developers to produce power at geothermal temperatures below 302 degrees Fahrenheit.
Berberich suggested that geothermal plant owners reserve a portion of their power production capacity to offset declines in variable power sources. California is studying ways to pay power suppliers who quickly ramp up to balance the state’s energy supply, he said.
“Geothermal has the potential to grow exponentially,” said Kewen Li, senior engineer and research manager at Stanford University and also professor at the China University of Geosciences, Beijing.
For geothermal, the biggest hurdle is the need to risk $4 million to $5 million to drill an exploratory hole which may reveal no geothermal resources. It also takes an average of 5.7 years to complete a geothermal project, Li said.
The geothermal industry, meanwhile, is innovating.
ElectraTherm, a Reno, Nev.-based company, has developed and installed 21 units that convert geothermal heat and waste heat from solar thermal units and biogas power plants into 200 kW or less of electricity. ElectraTherm said it has also demonstrated the ability to use hot water from oil and gas wells to generate electric power.
Hot water often comes out of the ground with oil and gas, but the water is separated and discarded, said John Fox, CEO of ElectraTherm. The water’s heat could be extracted through a binary geothermal process to produce electricity.
Geothermal companies would like to use the hot waste water to generate electricity for use on the well or well field, but oil companies typically consider energy efficiency a lower priority, Fox said.
ENEL Green Power of Italy in 2012 installed a 22-MW solar photovoltaic facility to complement its Stillwater 2 geothermal plant near Fallon, Nev. Solar generation is used during mid-day peak demand to avoid the need for natural gas-fired generation while using the same transmission interconnection.
And enhanced geothermal system (EGS) technology scored a win in April 2013 when ORMAT Technologies announced the operation of a new well at its Desert Peak project in Nevada. EGS technology was used to stimulate a previously unproductive well to add 1.7 additional MW of capacity at the site.
“In the early days, all (geothermal developers) looked for were prime resources,” the hottest underground water and steam, explained Louis Capuano Jr., president of the Geothermal Resources Council.
Most of the hottest and best geothermal resources in the United States, however, have been tapped. So geothermal developers today seek to either reach higher temperatures deeper in the earth or find ways to produce power from lower temperature geothermal resources, he and Fox said.