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Cities Aim for 100 Percent Renewables

But are the results achieveable?


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In 1984, the Rawhide coal-fired power plant was born on the prairie north of Fort Collins. Back then, it was expected to live a useful life until 2047. Nowadays, its future isn’t as clear.

Rawhide, a major power source for Fort Collins as well as three other Northern Colorado cities, produces electricity with relative efficiency, thus emitting less carbon dioxide. But as Fort Collins works to achieve ambitious greenhouse gas reductions by 2030, Rawhide’s future will be under close scrutiny.

Coal-fired power plants have been closing in droves across the U.S., partly to reduce smog but also because of competition from now-plentiful natural gas and ever-more affordable renewable energy. At the same time, dozens of cities — including Boulder, Pueblo and Fort Collins — have adopted resolutions calling for 100 percent renewables in power supplies. Denver Mayor Michael Hancock wants an 80 percent reduction in emissions by 2050 from all energy sources, including heating and transportation.

Fort Collins, a city of 167,500, has been taking many small steps to reduce greenhouse gas emissions since 1999. But in 2015, the city gained national attention for its ambitions: a modest decline in carbon by 2020, then a giant 80 percent reduction by 2030. The final goal, to be achieved by mid-century, is carbon neutrality across all sectors, including home heating and transportation.

This poses a question about the longevity of the 280-megawatt Rawhide plant, operated by the Platte River Power Authority, a generation and transmission association made up of Fort Collins, Loveland, Estes Park and Longmont. Platte River began embracing wind energy in the late 1990s, the first utility in the region to do so. Non-carbon resources now comprise nearly one-third of Platte River’s electricity. Directors of Platte River envision nearly 40 percent of the electricity being carbon-free by 2020. But for now, 67 percent of electricity comes from Rawhide’s coal plant, supplemented by two other coal-fired power plants in Craig.

Can Platte River achieve deeper cuts? Directors recently commissioned a study, to be released later this year, investigating whether 100 percent net carbon-free electricity can be achieved by 2030. One option: closing Rawhide and divesting from the two plants in Craig. One of the plants already is scheduled to be retired in 2025 and the second in 2042. The four members of Platte River, including Fort Collins, which represents 47 percent of the load or demand, will be deciding the future of Rawhide and divestment from Craig.

Planners in the trenches of this energy transition see no simple solutions. Both society and individuals will need to think differently about how we use energy, says Tim McCollough, manager for Fort Collins Utilities’ Light & Power. Today, we expect lights, the dishwasher, and every other appliance to perform at the flip of a switch. “In the future, if you are relying heavily on renewables, you will need some flexibility,” he says.

Expanded energy storage, for those cloudy, windless days, is another possibility. Prices have been generally considered prohibitive, but an Arizona utility in May turned heads with a solar-plus-storage power-purchase agreement at the relatively low price of 4.5 cents a kilowatt-hour. Whether prices of energy storage continue to dive, as they have with solar, remains an open question.

Major businesses operating in Fort Collins and elsewhere have been stepping in the same direction with their own goals. Anheuser-Busch, which has a major brewery along I-25, aims to get 100 percent of its energy from renewable sources by 2025. It recently contracted for a major purchase of wind in Oklahoma. Hewlett-Packard, a major presence in Fort Collins, has a similar goal. Wal-Mart wants to secure half its electricity from renewable sources by 2025.

Cost remains a concern, but rapid reductions in both wind and solar costs have made them competitive. Big wind farms on the Great Plains deliver electricity at 2 cents a kilowatt-hour, cheapest of all sources. Solar prices have also tumbled. The Solar Energy Industries of America says solar energy prices have declined 65 percent in the last five years. A study released in September by researchers from the National Renewable Energy Laboratory found utility-scale solar could be delivered for as low as 4.4 cents per kilowatt-hour, without subsidies.

Federal tax credits — set to expire in 2020 for wind and 2021 for solar — make renewables even more affordable. With those deadlines in mind, Xcel Energy in August proposed to close two aging coal-fired units at Pueblo’s Comanche complex by 2025 or earlier. That’s early retirement by about 10 years. The plants are still being paid down, but the cost savings are just that great. David Eves, the president of Public Service Co. of Colorado, an Xcel subsidiary, called it a “unique point in time.” He predicted that ratepayers may even save money, because the fuel is free, unlike the coal hauled through Denver on trains, while reducing CO2 emissions by up to 60 percent below 2005 levels. Together, the two aging Comanche plants (one plant that went on line in 2010 will remain) can generate 660 megawatts of electricity. Xcel expects to replace that generation with 1,000 megawatts of wind generation capacity, up to 70 megawatts of solar, and about 70 megawatts of natural gas. When it’s all done, 55 percent of Xcel’s energy in Colorado will be from renewables.

Can Xcel go even higher, as both Boulder and Denver want? Yes, but give the company time to get to 55 percent first, says Drake Bartlett, Xcel’s senior trading analyst. He’s responsible for helping Xcel deliver electricity reliably and economically. Xcel curtails electricity from wind farms as a last resort. After all, it’s the cheapest electricity available.

A decade ago, doubts were pervasive whether substantial renewables could be absorbed into the grid without impairing system reliability. Those doubts have dissipated. One reason, Bartlett explains, is that wind and solar sources can be ramped up and down more rapidly than coal or even natural gas. Think of coal plants as lumbering ocean liners, say the Titanic, and renewables more like speed boats, Bartlett says.

Utility-scale solar plants also provide flexibility. At Comanche Solar, a giant farm adjacent to the coal plants at Pueblo, the panels shift during the day, tracking the sun as it moves cross the sky. This produces 50 percent more electricity than standard roof-top solar and at half the cost.

For even higher renewable penetration, utility planners see need for a regional market for electrons, also called a balancing authority, which exists in other parts of the country. Colorado energy providers — and most of those across the West — have been more Balkanized, each utility drawing from its own resources to meet its own demands. But what if electrons could be moved around the grid in broad geographic areas to match supplies with demands? That would allow utilities to better use renewables instead of curtailing them.

Baby steps have been taken, and a giant step is being launched. The Front Range Joint Dispatch — made up of the Platte River Power Authority, Black Hills Energy and Xcel, among others — began pooling resources to meet demand. In September, the Mountain West Transmission Group announced plans to begin negotiations to join the Southwest Power Pool by late 2019. This would allow electricity supplies from Rapid City, South Dakota to Phoenix — including all of Colorado — to be moved around with greater flexibility to meet demands.

Goals of 100 percent renewables can be achieved, but at very high cost, Bartlett believes. “Batteries are incredibly expensive,” he says. They also lose capacity with repeated use. He believes we need carbon-free nuclear plants, as does climate scientist Jim Hansen.

By definition, greenhouse gas emissions are a global issue. But in efforts to tamp down those emissions, Colorado is among the planet’s hotbeds of innovation.

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Allen Best

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