|Solar energy & the future of the San Luis Valley
by Nicholas Chambers
On Saturday January 17, the San Luis Valley Ecosystem Council (SLVEC) and Water Protection Coalition (SLVWPC) co-sponsored a standing-room only presentation and panel discussion in Alamosa regarding the coming boom of solar energy in the Valley. Concerns about mega-scale concentrated solar power (CSP) and what impacts that may have on agricultural water seemed to be the impetus for the well-attended meeting. The national push for ways to reduce greenhouse gas emissions were also considered as a driver for large solar development. While it was apparent the multinational solar industry is coming to the Valley, it was presented as a mixed blessing and something to keep an eye on.
As stated by Ceal Smith, Acting Director of the SLVWPC, “Water is the lifeblood of the Valley.” President Obama’s campaign for climate change really brings in what Colorado Governor Bill Ritter coined as the New Energy Economy. As a nationally mainstream initiative, this means the southwestern sunspots of the nation are prime candidates for big solar. Colorado is 5th in the nation for its solar resource, and the San Luis Valley is none other than number one in the state. This means the Valley’s sun, land, and perhaps water, are under the eye of a budding industry to be the electrical generator for the Front Range and northern New Mexico.
Bill Brown of Sage West Consultants: Energy Science, Law, Architecture, also a member of Al Gore’s Climate project, delivered a comprehensive tour of the current state of affairs in the solar industry, the fossil-fuel powered electric grid, and the changing “megapolitan west.” The sunny Southwest is poised with the challenge to either “lead the transition or be overwhelmed” by the new policies, new technologies, and new economics that are evolving out of an era of cheap coal and unbridled expansion.
While this region is experiencing tremendous growth, the population and government alike are suggesting limiting the growth of coal-fired power plants. This is at the same time when traditional fossil fuels (coal, oil, and natural gas) are becoming more difficult and expensive to find, develop, and bring to market. When you compare this to the 100 mile x 100 mile “black box” of land area (yes, the math has been checked) needed in photovoltaics to power the entire nation against the map of ubiquitous natural gas and oil wells around the west, it was clear that solar power is a viable approach to multifaceted energy security. The convergence point in the trajectories of the declining cost of solar energy technologies and the rising cost of fossil fuels will be sometime around 2020, however depending upon technological growth and economic policy decisions, the crossover point could be much earlier, explained Brown.
Parabolic trough Concentrated Solar Power system.
Source: Department of Energy
A key point Brown made was the difference between distributed generation (DG) and that of utility-scale CSP power plants. The vision of distributed generation is that there can be a multiple of photovoltaic installations interspersed within communities. These can be built into parking structures, in brown fields, or on medians of highway corridors: i.e. local power. Examples of this are the 1-megawatt facility at the Denver Federal Center off of 6th Avenue, the 2-megawatt installation at Denver International Airport, as well as the numerous grid-tied household systems throughout the nation.
These smaller installations provide a decentralized power source close to the place where it is used and do not require expensive, high-voltage power transmission lines, and their associated efficiency losses, to carry the power great distances from the place of generation to the place of use. The era of electric cars being able to feed the grid at night is also becoming a reality.
Note the black box 100 miles on a side needed in
photovoltaics to power the entire nation.
Source: Sage West Consultants
Replacing coal with concentrated solar
While the arguments in favor of distributed generation are strong, there needs to be utility-scale solar if the nation wants to replace coal-fired electricity, stated Brown. In contrast to the distributed generation of photovoltaics that require no water and have no moving parts, utility-scale solar is usually based on the CSP type where the sun’s rays are concentrated on a pipe using parabolic mirrors, or similar, to super heat a working fluid like mineral oil or molten salt. The super-heated fluid then travels to a heat exchanger where it creates steam from water to spin turbines and electrical generators, much like a coal-fired power plant.
The storage capability currently associated with CSPs is usually more for being able to warm the turbines first thing in the morning so they can have earlier start up, rather than being able to produce electricity through the night, noted panelist and Tri-State Representative Lee Boughey.
Concentrated Solar Power plants require hundreds of acres of land, as opposed to tens of thousands of acres required for the mining of coal. Like big coal-fired plants, though, they rely on high-voltage transmission lines to transfer the electrical energy from the plant. They take significant capital to build, but also have the benefit in the economy of scale, for example, so that their costs can be recouped in electricity sales within 3 years. There are even projects combing traditional coal-fired plants with CSP because they both produce high temperature steam that can be used on the same turbines for electricity.
The AWDI veterans’ concern that these plants would be using enormous amounts of water seemed to be quenched by statements by Tri-State’s Boughey. Tri-State’s recent Request for Proposals (RFPs) solicited only those projects that have a closed loop cooling circuit and thus do not consume water. Panelist and Valley native Ralph Curtis also indicated that even if a solar company could buy any water, it would be agricultural, and they would have to go through water court to change the use. This is but a legal issue steeped in complicated Colorado water law. So, at the present only closed loop CSP technologies that do not consume water are being considered for the Valley. These CSPs operate “much like a car’s cooling system,” said Boughey, using air instead of evaporating steam as the way to dump excess heat. Closed cooling systems, or dry cooling, are about 10 percent more expensive than wet cooling.
There are also other concentrated solar approaches that do not need water, such as the solar stirling engine. In this approach, sun -light is focused on a heat differential engine to cause reciprocation of pistons that turn a generator. This system can operate at high temperatures and needs no cooling.
The final point that Brown offered was that although the Southwest has great solar power potential, it doesn’t mean that the rest of the nation is devoid of any solar opportunity. By extension, there could be distributed generation solar development closer to the load centers of the Midwest and eastern regions of the nation.
New transmission line
This is another type of tracking solar concentrator that is photovoltaic
and not thermal. They perform very well in the valley because of our
“cool” sunshine and do not need active cooling. This picture was taken
at the 8.2 megawatt facility near Mosca. Photo by author.
The electric grid, especially in the Valley, is relatively outdated and running at sometimes over-capacity. The Valley begins to have problems with the grid when Xcel and San Luis Valley Rural Electric Cooperative (SLVREC) are providing about 65 megawatts each. When the farmers are irrigating in the summer with frequent 24/7 duty cycles, there is a threshold of reliability at about 125 total megawatts. This is all coming down from Poncha Pass on the single main transmission line that comes into the Valley.
Panelists Boughey and SLVREC representative James Clare both spoke of the importance of needing to provide reliability for their customers. The planned transmission line coming over from Walsenberg to Mosca is not only important for present operations and new customers, but also to get the solar electricity that is generated here to the markets that need it.
While some attendees spoke of just generating enough electricity to serve the Valley’s needs, and that perhaps the new transmission line was not necessary, many in the room shook their heads in disagreement. Farmers with a multi-hundred thousand-dollar crop in the ground cannot afford to have their irrigation shut off because of voltage collapse, and many are seeing the opportunity to farm the sun as a great way to utilize their land. The principle of redundant feeds into the Valley was noted as being important.
Colorado’s electric provider
Just about two years after the Valley saw its first commercial 8.2 megawatt photovoltaic solar power plant near Mosca go into operation, the floodgates are open to further solar development, transmission line pending. The report of Colorado Senate Bill 07-091 states that there are roughly 2.75 gigawatts, or a quarter of the state’s peak demand, in total solar electricity potential within the San Luis Valley. This would cover a land area of 27,500 acres and could provide power for about 400,000 homes.
Panelist Mike Wisdom was in meetings at the state capitol last August when he heard the business interests of five multi-national corporations. They were all in the solar industry, they are all choosing America to develop their business, they are all coming to Colorado, and they are all looking at coming to the Valley. Even though a gold-rush phenomena might be happening, “that sunshine has a zip code on it,” says Wisdom.
His SLV Development Resources Group has been working on a Valley Power Authority to help organize the dialogue between Valley communities and the now multinational interest the Valley’s power production potential. He believes that Valley communities should be able to derive some benefit from having its resources tapped for a national and state service.
This 20 megawatt photovoltaic (PV) solar park in Beneixama, Spain is elegantly
incorporated into the rural countryside of sprawling orchards. It is currently the largest PV
plant in the world. Source: www.city-solar-ag.com
Valley Power Authority, contact the SLVDRG at 589-6099.
SLV Water Protection Coalition: www.slvwater.org or firstname.lastname@example.org.
SLV Ecosystem Council www.slvec.org, email@example.com
Bill Brown: http://www.billbrownclimatesolutions.blogspot.com
Tri-State Generation and Transmission: www.tristategt.org