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Hats off to The Gas City’s solar project
Medicine Hat, Alberta, dubbed "The Gas City" because of its huge natural gas reserves, is looking to the sun for some of its own energy needs. Unique for a Canadian municipality, Medicine Hat is in the gas production business. A vertically integrated energy utility, the city has approximately 4,000 natural gas wells in its area and neighbouring southwestern Saskatchewan, distributes natural gas in the region and also uses natural gas to run its municipal power plant.
December 9, 2009 By Ricki Normandin
“Basically, we’re energy self-sufficient,” says Russell Smith, Medicine Hat’s environment manager. “Of course, at this point in time the challenge is that natural gas is not renewable. That’s why we’re looking at other options available to allow us to be more sustainable as a community.”
Medicine Hat has set a target to provide 25 percent of its residential energy from renewable sources by 2025. The city of about 61,000 people gets more sunlight hours than almost anywhere else in Canada, which translates into some of the highest solar radiation. That’s the basis for developing a solar thermal power pilot project.
“We’re trying to understand, given the solar radiation we get in this area, how much we can rely on the sun’s energy for our heating, cooling and electricity needs,” Smith explains. “We know solar is going to be part of our solution but we’re just not sure how big a part and the first step is to understand how this technology will work at this latitude.”
North of 50
“The technology the project will use is proven but not in a northern climate,” says Smith. “In California and Nevada they’ve run technology like this for the last 15 years. We’re proposing a 1 MW project and that would be about enough electricity for about 175 homes.”
The HAT Smart Solar Steam project consists of a 1000 square meter field with rows of concave solar mirrors that bounce the sun up to a transfer tube running across the top of the mirrors. The transfer tube is filled with high-temperature oil. The sun bouncing off the mirrors heats the oil to about 700 F and the oil circulates back to the steam generator to create steam. That steam is sent through pipes to the power plant and is tied into a steam cycle, which runs a turbine to generate electricity.
In Medicine Hat’s existing combined cycle power plant, natural gas is used to run a gas turbine to make electricity. Excess heat is generated from the burning of the natural gas and the turbine’s rotation and that heat is captured and used to boil water and create steam. The steam is used in a second stage steam turbine to produce more electricity. The solar steam project would come in at that second stage and replace any extra natural gas fed into the process.
In addition to generating electricity, solar steam technology could also be used a renewable energy steam generator for food processing or other industrial processes, Smith notes. “It could be used to heat a subdivision or to replace natural gas hot water in a variety of ways.”
Economics
The solar steam project will cost $9 million CDN. The city of Medicine Hat has approved one-third of that amount and is looking for funding for the remainder from provincial and federal sources.
“We’re hoping to cost share in this project and provide lots of learning, not just locally but provincially and federally, to understand the use of this technology,” Smith notes.
Part of the learning curve will be the economic comparison with natural gas.
“This technology tends not to make pure economic sense until we’re dealing with substantially higher natural gas prices,” says Smith. “But the second and equally important part of the puzzle is the cost of carbon. At some point there is likely going to be a burden that’s going to fall on those who are burning fossil fuels, a level for every MW of electricity you produce. With natural gas you produce about ½ ton.”
“The other thing happening over time is that renewable technology is being refined and prices are coming down as more people install it. If there were a graph of rising natural gas prices and decreasing capital costs for renewable energy, at some point those lines will cross. When they do we want to be in a position to be able to install the technology and supply our citizens with more sustainable energy sources.”
A solution with many parts
The city is also looking at wind power as part of its renewable energy portfolio, with an 18 MW wind project now in the application for permission stage. It would use eight large 2 MW windmills and cost about $40 million.
But renewable energy technology is only part of the long term solution. Smith talks about “our fossil fuel addictions” as a society and stresses that “the hardest thing is to get hold of our per capita energy consumption.” Public information and programs and incentives to reduce consumption are a critical part of the solution, in his community and elsewhere.
Happily, the citizens of Medicine Hat have responded, with participation rates in federal energy saving programs that are double the Alberta-wide rates.
“We like to think we’re on the right track but it’s a long process,” says Smith. “Society has to be interested in changing as well.”
Ricki Normandin is editor of forest industry websites and western correspondent for CLB Media. She is based in Victoria, B.C.
10 top solar thermal energy projects worldwide
Location: Mojave Desert, USA.
Megawatts: 500 MW, with plans to expand to 900 MW.
Solar Company & Electric Utility: BrightSource Energy and Pacific Gas & Electric.
Status: Will begin operating as early as 2011.
Location: Mojave Desert, USA.
Megawatts: 500 MW, with possible expansion to 850 MW.
Solar Company & Electric Utility: Stirling Energy Systems and San Diego Gas & Electric.
Status: Will begin operating in 2011.
Location: Mojave Desert, USA.
Megawatts: 553 MW.
Solar Company & Electric Utility: Solel and Pacific Gas & Electric.
Status: Will begin operating in 2011.
Location: California, USA.
Megawatts: 400 MW.
Solar Company: Solar Partners
Status: Scheduled to begin operating in 2012.
Location: Mojave Desert, USA.
Megawatts: 310 MW.
Solar Company & Electric Utility: Florida Power & Light and Southern California Edison.
Status: Operating.
Location: Seville, Spain.
Megawatts: 11 MW currently, planned increase to 300 MW.
Solar Company and Electric Utility: Mirrors by Abengoa and power tower by ALTAC.
Status: Operating. Scheduled 300 MW production by 2013.
Location: Florida, USA
Megawatts: 300 MW.
Solar Company & Electric Utility: Florida Power & Light.
Status: Scheduled to begin operating in 2011.
Location: Arizona, USA.
Megawatts: 280 MW.
Solar Company & Electric Utility: Abengoa Solar and Arizona Public Service Co.
Status: Scheduled to begin operating in 2011.
Location: Mojave Desert, USA.
Megawatts: 250 MW.
Solar Company & Electric Utility: Florida Power & Light.
Status: Scheduled to begin operating in 2011.
Location: California, USA.
Megawatts: 177 MW.
Solar Company & Electric Utility: Ausra and Pacific Gas & Electric.
Status: Scheduled to begin operating in 2010.
Source: ecoworldly.com
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