I have been reading about solar and wind electric generation and the problems of getting the power from the places that can generate it to the places that need it. Many of the areas that can generate the power do not have capacity on high voltage transmission lines in the area to move the power out of the region. New high voltage transmission lines from these areas to the places where the power is used will cost billions and take years to get approved and built.
I was looking at satellite views of the western US and noticed the wide-open spaces on Native American lands. I figured that they could generate Gigawatts of solar and wind power on just a small fraction of their land, but, how do you get that power out to the big cities that use it?
The Navajo Nation has the most land. I looked at Arizona wind maps and saw a few locations on Navajo land that could probably generate a Gigawatt or so of wind power. Square miles of land could produce Gigawatts of solar power with lots of land available for battery storage. They could be a great generator and storage facility for renewable energy.
The leases and other income from the wind and solar farms could potentially bring some good, steady, long term income to the Navajo people as well as good paying jobs. From what I have read, farmers in the Midwest are getting $10-12K per year to lease about 1 acre of land for a wind turbine. A farmer near my town leased out 40 acres of a larger parcel located next to a major distribution substation for a solar farm (yet to be built). It is more profitable than growing corn or soybeans on the land.
At 4-5 MW per wind turbine, a 100 MW wind farm can produce $250-$300K in income for the Navajo people per year in leases. 1 GW of wind turbines about $2.5 – $3 million per year. Solar land leases could bring in similar numbers. Energy storage facilities too. Good jobs would be created in construction, maintenance, operations and administration of the batteries, solar and wind farms, boosting their economy.
If they had the transmission facilities, there should be no problem finding people willing to develop wind, solar and battery farms on Navajo land. If they parceled sites out into 50 MW or 100 MW parcels, then they could have a diversity of developers and would not be reliant on one or two large corporations, or one large source of money for development.
On the Navajo Nation, one large coal plant was closed earlier than planned in 2019 along with the associated coal mine. Two more coal plants are scheduled to close. One in a couple of years (or possibly sooner) and the other in 2031. In addition, the Cholla Power Plant (1 GW, coal) south of the Navajo Nation is scheduled to close in 2025. There will be an abundance of transmission capacity to replace these coal plants. Transmission is one of the biggest hurdles that wind and solar projects must overcome.
Arizona Public Service has committed to eliminate carbon emissions by 2050. APS will be looking to replace this lost coal generation over the next decade. With high voltage transmission lines running from these closed plants and mines, this gives the Navajo Nation a great opportunity to become leaders in state of the art renewable electric generation, storage and transmission.
Let’s take a look at what can be done.
APS will eliminate carbon emissions by 2050 and close coal plant ahead of schedule, CEO says
Jeff Guldner, the new CEO of Arizona’s biggest utility, said the plan is ambitious and will require technology not currently available. But by setting the goal, the company will move in the right direction, he said.
“Nobody today actually knows how you get to 100% carbon free,” Guldner said. “I take some comfort from the fact that there are others who also believe we can get here to 100% by 2050 even if we don’t know what the answers are.”
In addition to the energy it gets from coal today, APS gets just over one-fourth of its power from natural gas, meaning it will have to replace nearly half its energy supply by the midpoint of this century to meet the new goal.
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How will APS get to zero carbon?
APS will achieve the new goals largely through increasing use of solar, including large-scale power plants with batteries.
Guldner said advancing energy storage will be key. That includes storing power on the grid with technologies like lithium-ion batteries and storing energy from season to season. Renewable energy from solar and wind is ample in spring, but power demand from customers is highest in summer.
He said the company will work with the state's public universities to solve problems on the path to 100% clean energy, and that Arizona State University will be a key collaborator.
The grid’s big looming problem: Getting power to where it’s needed
The Biden administration is counting on solar and wind generators to replace fossil-fuel-burning power plants. But they require a considerable amount of real estate, and the right weather, and as a result they’re typically located far from the cities they would serve. This is why the congestion of transmission lines that stems from inadequate capacity to meet demand is looming as an ever bigger problem.
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A consequence of congestion is that wind and solar equipment is sometimes unable to operate because there is no room on the lines to carry their electricity. (This is called “curtailment” in energy lingo, and it also occurs when demand falters.) In New York state last year, 62 gigawatt-hours of wind power was curtailed; it was a small but not insignificant fraction of total wind production.
A larger problem is that wind, solar and other projects can wait for years before they get the green light to connect to transmission lines. Developers have to demonstrate, among other things, that the cost to upgrade those lines to carry their output is justifiable. A new study of five regions by the Lawrence Berkeley National Laboratory found that fewer than a quarter of all proposed projects actually make it to commercial operation because of transmission hurdles. The rest are withdrawn.
Currently, the waiting list includes proposed renewable power plants capable of turning out 680 gigawatts, “backed up for a grid that doesn’t exist yet,” Granholm told the Senate Energy and Natural Resources Committee on June 15. Given that transmission companies are careful not to take on more than they are sure they can handle, she said, “we have to absorb some of that risk in order to get the level of build-out that is necessary for our needs.”
But even then, it can take seven to 10 years for a new transmission line to be planned, permitted and built.
Since the utilities have 3 coal plants closed or closing in the next 10 years on Navajo land, they have over 4 GW of electric power (5 GW if you include the nearby Cholla coal plant) coming from Navajo Nation to replace (or else abandon the high voltage lines which would make no sense). The Navajo have lots of sun and land and some wind. Perfect match.
TRANSMISSION LINES, COAL MINES and COAL PLANTS
I traced out some transmission lines running thru Navajo lands using Google My Maps (link). I found a few of the high voltage transmission lines running thru Navajo land. I figured there maybe some capacity where 50 or 100 MW could be added along the way. Similar to this Wind project at Perrin Ranch near Williams, AZ, built in 2012, that was connected to a nearby 500 kV transmission line.
There are two 345 kV circuits running from the Glen Canyon Dam to the Pinnacle Peak Substation near Scottsdale. These lines are most likely fully utilized sending power from the dam to the Phoenix area. It may be possible to add a small 50 or 100MW wind or solar farm to them though.
From Pg 3-68:
A 230 kV transmission line runs from Glen Canyon Dam near Page, AZ to the Shiprock (NM) substation near the San Juan Generating Station (900MW, Coal). The San Juan Generating Station may be closing in 2022 or within a few years.
From Pg 3-68:
The Shiprock-Kayenta portion of this 230 kV line has a Nominal Rating of 442 MVA and as of 2015 was at about 1/3 capacity. Although this report says this line connects to the Navajo substation, satellite photos do not show any connection into this substation from this line, however, it does pass nearby.
The 345 kV and 230 kV transmission lines coming from Glen Canyon dam are owned by the Western Area Power Administration, part of the U.S. Department of Energy. The WAPA would probably be willing to help the Navajo use the 230 kV line for renewable energy if/when the San Juan plant is shut down. The DOE is sponsoring 2021 Tribal Energy Webinar Series to educate tribal leaders on using their land for renewable projects.
The 230 kV line also passes by (or possibly connects to) a substation at the now closed Navajo Generating Station (2.25 GW, coal) located near the Glen Canyon Dam in Page.
The closed Navajo Generating Station has three 500 kV lines that sent power out. One heads west to the NV Energy Crystal Substation near Las Vegas and onto southern California.
The other two head south through Navajo land. One goes to the Arizona Public Service owned Moenkopi 500-kV Switchyard on Navajo land near Cameron, AZ and the other to the Westwing Substation near Phoenix. The lines share right of way from the Navajo plant to the Moenkopi switchyard.
This would be a prime corridor to add large solar farms tapped onto one of the 500 kV lines. This line could feed power to both the Moenkopi switchyard and the Navajo substation, which could put the power onto the 500 kV line to Las Vegas/SoCal.
The Moenkopi 500-kV Switchyard takes power in from one of the 500kV lines coming from the old Navajo plant and another 500 kV line from the Four Corners Generating Station (1.5 GW, Coal) and sends power out on two 500 kV lines, one to the Westwing Substation near Phoenix and the other to the Southern California Edison Eldorado Substation near Las Vegas. The 345 kV lines from the Glen Canyon Dam pass nearby as does the second 500 kV line from the Navajo plant.
A 500 kV line, owned by Arizona Public Service, runs from their Moenkopi 500-kV Switchyard near Cameron to the Four Corners Generating Station near Shiprock, NM. The entire 180 mile length of this line runs through Navajo and Hopi land. The Four Corners Generating Station is scheduled to close in 2031.
There is also a 345 kV transmission line between the Shiprock substation and the Four Corners plant. This 8 mile line has a Nominal Rating of 1200 MVA and as of 2015 was at about 9% capacity.
With the San Juan (900MW), Navajo (2.25 GW) and Four Corners (1.5GW) coal plants closed or closing by 2031, it leaves an abundance of transmission capacity running through the Navajo Nation.
With the closure of the Navajo plant in 2019, the three 500 kV lines coming from the old Navajo plant now have nothing to do. They carried most of the 2.25 GW the coal plant produced.
WHAT CAN BE DONE TO USE THIS TRANSMISSION CAPACITY?
The land around the old Navajo Plant is a prime location for a very large solar and battery farm. For example, a 1 GW solar and battery farm could be created that uses a combination of solar and batteries that outputs a consistent 400-500MW 24 hours a day. The area outlined below is about 13 sq miles. Not all land would be used/ Small 50 or 100 MW farms could be built within this region with the property of the old coal plant densely developed with batteries and solar panels.
Another similar solar and battery farm could be sited ½ way along the 500 kV power line ROW. At this point on the line, a new 500 kV substation would need to be constructed. The 500 kV line from the Navajo plant to the Moenkopi 500 kV switch would be connected to the new substation. This new substation would collect the power from the nearby solar/battery farms and be able to send it to both the Navajo and Moenkopi substations where it can be sent out other high voltage lines at both substations to where it is needed.
The new 500 kV substation and the 500 kV substation at the old Navajo plant would act as power plants. They would distribute the power from all the wind/solar/batteries farms connected to them and regulate power output onto the 500 kV transmission lines, similar to how the coal and gas plants operate.
If the 500 kV line has a capacity of 1 GW from the old Navajo plant to Moenkopi, then solar farms around the new substation midway on the line could generate up to 2 GW of power and transmit 1 GW in each direction. But in reality, you would not want to generate more than 1 GW so you could transmit all the power in case of a line outage on one of the paths.
Two large solar and battery farms such as these would still not take up all the capacity of that one 500 kV line. There seems to be plenty of land available to generate even more. It’s probably not a good idea to build several 500 KV substations on a short section of lines, but over time several other large solar/battery farms could be built near these areas and transmission lines ran to connect them to one of these two substations.
These large solar farms don’t need to be concentrated in one location, you could spread them out in small 100 MW farms within a 20 or 30 mile radius of the 500 KV substations, but the further away, the more expensive it will be to build the remote farms. However, spreading them out would probably be easier when acquiring the land needed.
There does not seem to be much wind potential along this path, so it would have to be an all solar and battery powered line.
The capacity of these 500 kV lines seems to be available now since the Navajo plant is closed. These 500 kV lines are most likely owned by Arizona Public Service.
With solar only, the lines would not be used at all at night. At this time, utility scale batteries are just now starting to become ready for prime time. In 3-5 years, it could be possible to use the output from a 1GW solar farm to provide a consistent 400 MW 24 hr stream of power.
The 230 kV transmission line that runs from Glen Canyon Dam near Page, AZ to the Shiprock (NM) substation near the San Juan Generating Station has spare capacity now. The San Juan Generating Station may be closing in 2022 or within a few years. The Shiprock-Kayenta portion of this 230 kV line has a Nominal Rating of 442 MVA and as of 2015 was at about 1/3 capacity.
This line can get power from both ends, from Glen Canyon Dam and the San Juan or Four Corners coal plants. It is owned by the US Government’s Western Area Power Administration.
When the San Juan plant closes, this line can send 400 MW of power from Kayenta to the Shiprock substation, and from there to other locations that had been receiving power from the San Juan plant.
If the Navajo substation is upgraded at the old Navajo plant and the portion of the 230 kV line in front of the plant is connected, power from both Glen Canyon Dam and Kayenta can be sent out the old Navajo plants 500 kV lines.
There are two sections on this line, from Glen Canyon Dam to the Kayenta substation (with a substation at Long House Valley about 20 miles west of Kayenta). The other section runs from the Kayenta substation to the Shiprock substation.
The Navajo Tribal Utility Authority built the 55 MW Kayenta Solar Project at the Kayenta substation in two phases. Phase I in 2017 and Phase II in 2019.
This solar farm can be significantly expanded at this location or nearby with room to add battery storage as well.
According to Wind maps I have seen, the ridge lines along Black Mesa and to the west near the Kayenta substation has some great potential wind farm locations.
There are three 115 kV lines that run to two now closed coal mines on Black Mesa (one closed in 2005 and the other in 2019 when the Navajo coal plant closed). These lines are still used to power small clusters of homes. One of them also brings power to Pinon.
One line runs to the Long House Valley Substation about 20 miles southwest of Kayenta, then to the Kayenta Substation. The other two lines run directly to the Kayenta Substation.
Now that these mines are closed, these lines are vastly under used and could be used to bring power from the wind farms along the ridge line on Black Mesa and solar/battery farms on land strip mined by the coal mines.
A 200-250 MW wind farm could be built along the ridge line to the east of Black Mesa and another along the ridge line west of Kayenta. Similar to the Oso Grande Wind Project in New Mexico. That 247 MW project has sixty 4.5 MW turbines made by Siemens Gamesa on 24,000 acres. It cost $300 million.
The wind farm along the ridge line west of Kayenta would need transmission lines built to the Long House Valley Substation and/or the Kayenta Substation.
The wind farm along the ridges of Black Mesa could reuse the 115 kV transmission lines that were used by the coal mines.
Two new Substations would need to be built to collect the power from 34.5 kV lines running to the wind farms on the ridge and step it up to 115 kV for transmission to Kayenta and the 230 kV line. An 8 mile 115 kV transmission line would eventually be needed between the two substations for redundancy.
At the base of the ridge line, are the two closed strip mines with a combined 35 square miles of strip mined land. This area is perfect for the two new substations and very large solar/battery farms.
It would be great to turn these old coal mines into one giant solar and battery farm. You could most likely get these wind, solar and battery farms to output 500MW of power continuously, with some additional capacity to output at peak times. The three existing 115 kV lines to Kayenta could handle that load. By way of either the Long House Valley or Kayenta substations, the power could be sent to the Shiprock or Navajo substations.
As these wind as solar farms grow to capacity and the Four Corners plant gets shut down freeing up capacity on the 500 kV line that runs south of Pinon, another outlet could be constructed using the 115 kV line that runs to Pinon. A new 500 kV substation would be needed on the 500kV line that runs south of Pinon to connect the 115 kV line (similar to the Perrin Ranch wind farm, but at 115 kV to 500 kV).
Another Solar battery farm could be constructed on land around this new 500 kV substation.
Once this new substation is constructed, the extended 115 kV line from the new substation at the coal mine to the new 500 kV substation can be used to send power from the wind and solar farms near Kayenta as well as power from additional wind farms along the ridge lines from Chilchinbito down to south of Blue Gap and the new solar/battery farm.
The northern most wind farm near Chilchinbito can send power to the 115 kV substation at the coal mine while the wind farms from Rough Rock south would send power directly to the new 500 kV substation. This could create another 400-500 MW of wind power that could be sent on the 500 kV line.
After they are shutdown, the sites of the old San Juan and Four Corners coal plants can be used for large solar/battery farms.
The ridge line to the west of Cameron near the Moenkopi 500-kV Switchyard is another potential wind farm location. There is potentially 600-750 MW of potential wind sites in this 107 sq mile area. Transmission lines could be built from wind farms in this location to a new substation next to the Moenkopi 500-kV Switchyard.
Another large solar/battery farm can be built around the Moenkopi 500-kV Switchyard as well.
After Four Corners closes, power from this wind farm could be sent on the 500 kV line to the Four Corners substation and from there onto other lines the closed Four Corners plant had powered. Or it could be sent down the 500 kV lines to Eldorado or Pinnacle Peak 500 kV substations.
Another potential spot for solar generation would be near Burnside at the send of a 115 kV line that runs thru a substation near Window Rock and on to Gallup.
Eventually, a 115 kV line could be built connecting this solar farm with the 500 kV substation built for wind power on Black Mesa. Additional Solar farms could be added along this route as well, sending power to the 500 kV line and to Window Rock/Gallup.
Each of the connection points onto the 230 kV or 500 kV high voltage lines would act as independent power plants. Many small and large independent solar and wind farms would connect into the transmission substations.
The transmission substations would manage a consistent output onto the grid from a variety of sources. Any power generated by wind and solar beyond the set output limit gets diverted to the batteries. When generation falls below the output limit, power gets drawn from the batteries. Batteries would be located at each solar farm and also at each transmission substation.
In order to keep a consistent output at all times, it would be necessary to have far more generation capacity than the consistent output figure. For instance, a collection of wind farms and solar farms may only be able to produce enough power to consistently output 40% of their rated power 24x7, 60% would need to be stored for transmission at night and even more when the wind is blowing lightly.
It will take some research and development to get the mix of solar/wind generation to battery storage/transmission right. I don’t think this has been done before. New equipment and software will be needed to manage the power being transmitted, stored or drawn from batteries.
Beyond the high voltage transmission lines, extra capacity on subtransmission 115 kV or 69 kV substation distribution lines could also be used by building smaller solar battery farms scattered throughout the area. This would power the local substation distribution grid with power generated locally while sending extra power into batteries so it could be used at peak times or at night. Very little power would need to be drawn from the high voltage lines on the larger grid.
SOLAR AND WIND FARM DEVELOPMENT
I have outlined very large areas, measured in square miles, for potential wind or solar/battery farms. This is not to mean that every acre in the enclosed area would be fenced off and developed for the wind or solar farms.
For the wind farms, each turbine requires about an acre of land. For example, 60 turbines producing 250 MW would use 60 acres that would be spread out over 20-30 sq miles.
For the solar/battery farms around the closed coal plants and the old coal mines, every acre possible should be used on the old coal plant property and on formerly strip mined land. The old coal plant buildings can be turned into giant batteries.
Solar/battery farms around the new or expanded high voltage transmission substations and near the retired coal plants and mine, could be divided into 50 or 100 acre parcels scattered across a 10 – 20 sq mile area. They could also be grouped in larger clusters depending on current land usage in the outlined areas or if large “agrivoltaic” farms are feasible.
Solar farms don’t need to be parking lots barren of vegetation and could even be used for grazing or farming.
Pilot projects in Massachusetts, Arizona, Germany, China, Croatia, Italy, Japan and France look encouraging for mixing crops with solar panels, referred to as “dual use” farms because they offer both agricultural and electrical production. “So far, the pilots have been extremely successful in showing that you can grow crops and make electricity at the same time,” Macknick says.
A dual-use farm operated by the University of Massachusetts–Amherst grows a variety of plants — peppers, beans, cilantro, tomatoes, swiss chard, kale — below solar panels elevated roughly 7.5 to 9 feet (3 meters) or more above ground to allow for easier harvesting mainly by hand. Project researchers have found that 1- to 1.2-meter (3- to 4-foot) gaps between panel clusters led to crop yields almost the same as what they would have been in full sun sites.
One of the first concepts for mixing solar and agriculture, dubbed “agrophotovoltaics” (APV), was developed more than three decades ago by physicist Adolf Goetzberger. The research institute Goetzberger created — the Fraunhofer Institute for Solar Energy Systems — finally got around to building its own dual-use farm on one-third of a hectare (just over three-quarters of an acre) at an existing farm cooperative a few years ago. The institute elevated 720 solar panels high enough for farm machinery to harvest plants underneath and nearby, according to a 2017 press release.
The researchers planted wheat, potatoes, celeriac and clover grass in the open and under the panels and compared the yields. Solar shading decreased production 5.3 percent to 19 percent. Yet electricity from the panels, which capture both indirect and direct light, was used to power a crop processing plant and electric farm machinery, offsetting those costs and increasing land use efficiency by 60 percent.
It could be possible to build solar farms with irrigation systems built into the structures that elevate the panels 10-12 ft off the ground. Native vegetation or strips of farmland could be planted under the panel structures. The irrigation and shade would make the desert land far more productive, and has many other benefits.
Similarly, agriculture faculty members at the Josip Juraj Strossmayer University of Osijek in Croatia grow shade-happy organic vegetables beneath solar canopies on a local farm operated partly by faculty members. The energy generated goes to power the farm’s irrigation system and farm machinery. In Austria, an entrepreneur created a system similar to APV but using fewer stationary poles by placing panels on a cable infrastructure in an effort to reduce costs and potential accidents involving farm machinery. APV systems are being tested in another part of Germany and in several other countries.
Greg Barron-Gafford, associate professor in the School of Geography and Development at the University of Arizona, has worked on a solar “agrivoltaic” pilot project — basically, the American version of APV — for two years. Tucson public schools with existing solar canopies are being used, as well as the university’s Biosphere 2 research and public education center. Focused initially on reducing the heat island effect of solar panels, the project morphed into one testing crop yields under panels.
A first run at a salsa garden of cilantro, pepper and tomato “was awesome,” Barron-Gafford says. Crops grown underneath the panels required only half the water of those growing out in the open and grew well in the microclimate beneath the panels. “The plants seem to love the modulated temperatures,” he says.
Panels protect the plants from frost, allowing a longer season for avocados, cilantro, peppers, tomatoes and mangos. In late spring researchers began harvesting a winter crop of carrots, kale, chard and lemongrass. “It’s really been something to watch,” he says.
The experiment found other advantages to the panels as well. The skin temperature of people harvesting crops underneath the panels was 25 degrees cooler than those working out in in the sun, no small matter in a state with scorching summers. And some claim the shade-grown produce tastes better than conventionally grown crops.
Barron-Gafford would like to try the dual-use concept out in collaboration with a community-supported agriculture (CSA) farm that would involve at least 10 acres of cropland under solar panels, he says. The extra cost of adding a solar canopy over crops could be paid for by the 5 percent gain in power production seen in panels in Arizona, reduced maintenance and premium pricing for solar-grown produce.
I see no reason why land under the solar panels couldn’t be used for grazing livestock as well as farming. The livestock would love the shade. Irrigation systems built into the solar structures would provide more grazing food per acre than open land. Some sections would need to be fenced off from livestock for electrical transformers and batteries, but large areas under the panels could remain open for grazing land.
The company where I used to work had acres of open parking lot around their campus. They put solar panels across every back to back row of parking spaces a couple of years ago. Those canopies, similar to the ones in the picture, are at least 10 ft tall. If they let people drive cars around them, cattle or sheep should be no problem at all.
Obviously, this kind of structure over a parking lot would not work over farm land. But it does provide nice shade for the cars on hot summer days! For panels constructed over farmland, the panels would need to be spaced apart and open air under them (no solid canpoy roof).
Research is still ongoing, but I can see this being a thing as time goes on and designs get developed. For example, you maybe able to graze 100 sheep on 100 acres on natural arid desert land. Or, you may be able to generate 100MW of solar power if you packed solar panels tightly across the acreage.
But, if you spaced out the solar panels and only produced 50 MW on the same 100 acres, and included efficient irrigation systems in the structures holding up the solar panels, you could grow more vegetation on the land and graze 200 sheep. If solar farms can help turn desert land into productive farm or grazing land, I’d expect alot of people to sign up to have irrigated solar farms installed on their desert grazing or farmland across Navajo Nation and elsewhere.
BATTERIES
I mention solar/battery farms, not just solar farms. To make the most effective use of the transmission lines, they need to be used 24 hours a day. Large utility scale batteries are now starting to come online. Within the next 3 – 5 years, they will probably be required onsite for any large-scale renewable projects intended to replace retiring coal plants. Even wind power will need batteries to even out the power sent out on the transmission lines as wind speeds constantly fluctuate.
In the near future, the scale of the batteries serving U.S. power grids is set to explode, increasing from about 1.5 gigawatts today to tens or hundreds of gigawatts by 2030. These batteries will play a vital role in shifting intermittent wind and solar power from when it’s produced to when it’s needed and serving broader grid services needs on an increasingly decarbonizing grid.
But as a resource that can both absorb and discharge energy at a moment’s notice, batteries are very different from both dispatchable generators and intermittent wind and solar farms. That requires new technical and economic systems for managing and valuing them — and the grid operators that run wholesale electricity markets serving about two-thirds of the country are struggling to make those changes to keep up with the pace of growth.
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At the same time, “renewable energy generators see storage as a very important partner,” he said, as wind and solar projects add batteries to firm and shift their power output to meet grid demands. These hybrid resources now make up about two-thirds of all solar projects in the interconnection queue of California grid operator CAISO and constitute a rising share of clean energy projects across other markets. Developers including EDF Renewables, Enel, NextEra Energy, LS Power and many others are increasingly combining renewables and batteries in multiple states.
As the battery technology improves, the costs are coming down. By the time any construction could start on any part of this “plan”, it would be 3 to 5 years out, battery technology will be far more advanced and they will be much cheaper.
A promising battery technology that would work well with solar and wind farms is now becoming more widely used. Flow batteries.
Small flow batteries have been in use for a while now. Flow batteries seem to be a good fit for renewable energy. A very large utility scale 200MW/800MWh vanadium flow battery in Dalian, China, opened in 2017
China started building battery storage in 2017 and continues to develop the technology while building more capacity. They are starting to combine smaller units with solar farms.
Large-scale Vanadium redox flow battery (VRFB) technology looks set to be deployed at a 100MW solar energy power plant in China, two years after a smaller-scale demonstration project was commissioned in the region.
Canada-headquartered vertically-integrated technology provider VRB Energy said that the solar PV power station will be integrated with a 100MW / 500MWh (five-hour duration) battery that the company is developing in Xiangyang, in China’s Hubei Province.
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Since the September 2017 publication of the country’s first high-level strategy and policy document on energy storage, China has been keen on getting several huge vanadium flow battery projects deployed. The 100MW / 500MWh project for VRB Energy was among those
With 30 year lifespans with no degradation over that lifespan and ability to ramp up or down with no degradation they are a good fit with solar and wind that has fluctuating power output.
In the utility space, flow batteries are best suited for longer discharge durations (six hours or more) in megawatt-scale power increments. Certain use cases favor flow batteries over other storage types. For applications where multiple charge/discharge cycles are required each day, flow batteries are available within milliseconds as loads dictate and they can quickly recharge from a variety of available power sources. In fact, depending on tank configurations, flow batteries can discharge and recharge simultaneously, providing power capacity or voltage support almost indefinitely. Attributes of flow batteries include:
- Demonstrated 10,000-plus battery cycles with little or no loss of storage capacity.
- Ramp rates ranging from milliseconds for discharge if pumps are running, to a few seconds if pumps are not.
- Recharge rates for flow batteries also are reasonably fast.
- Wide temperature ranges for operation and standby modes compared to lithium-ion options.
- Little or no fire hazard.
- Chemistries that pose limited human health risk due to exposures.
- Easy scale-up of capacity by adding electrolyte volume (although that may involve more tanks and piping).
Though there are dozens of different types of flow batteries, only about 10 to 12 specific chemistries appear ready for commercial applications.
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In a redox flow battery, catholyte and anolyte are stored in separate tanks, and pumps are used to circulate the fluids into a stack with electrodes separated by a thin membrane. This membrane permits ion exchange between the anolyte and catholyte to produce electricity. The power produced is dependent on the surface area of the electrodes, while the storage duration is a function of the electrolyte volume. For some technologies, the power and energy can be scaled independently, allowing for an easily customizable battery.
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Flow batteries can be configured as both a single tank, usually for smaller applications, or as a dual tank, usually on a larger footprint. The single-tank systems typically feature zinc or other metal batteries, while dual-tank systems require electrolyte comprised of saltwater, iron, vanadium, or other minerals.
Flow battery system designs change depending on the application and project size. Behind-the-meter commercial systems are commonly kilowatt-scale packaged units that can fit into a typical utility room. For distribution applications in the 1-MW to 5-MW range, containerized and/or modular solutions exist with varying levels of scalability depending on the storage duration requirements. Utility-scale designs in development may have millions of gallons of electrolyte storage, so the industry is trending toward large quantities of stack modules headered together and piped to large, field-erected tanks.
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Lithium-ion systems designed for deep discharge will exhibit greater performance degradation (with potential warranty implications) if they are cycled multiple times per day or used for different applications such as frequency response.
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By blending the favorable characteristics of both lithium-ion and flow batteries, utilities can reduce risk across their entire portfolio of energy storage options.
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With today’s technology, flow battery capital costs are nearly double the cost of a similarly sized lithium-ion system. With longer storage durations and longer lifespans, the economics improve, but it is not expected to achieve parity with lithium-ion at today’s pricing. Decommissioning and recycling costs may favor flow batteries because the electrolyte is more easily recyclable or disposable (depending on technology type), but these costs are still developing. As flow OEMs improve manufacturing scale and supply chain efficiencies, and as EPC contractors gain field experience, costs will continue to plummet. Still, flow batteries are chasing a moving target with falling lithium-ion costs.
The primary barrier to full market penetration of flow battery technologies today is simply the lack of commercialization compared to the heavy installation base of competing lithium-ion technology. In the near term, it is likely that more relatively small flow battery facilities will be installed until a widespread commercial track record is established and use cases, costs, and returns on investment are proven.
Other battery technologies are being pursued. Aluminum-ion batteries seem to be a very promising technology using more widely available aluminum instead of Lithium.
“Testing showed rechargeable graphene aluminum ion batteries had a battery life of up to three times that of current leading lithium-ion batteries,” said AIBN Director Professor Alan Rowan. “And higher power density meant they charged up to 70 times faster.”
AIBN has been working hard on the technology for several years, and the research team is excited to be shifting into a commercial prototype development stage, especially as the promise on the cards is more efficient and greener batteries.
“The batteries are rechargeable for a larger number of cycles without deteriorating performance and are easier to recycle, reducing potential for harmful metals to leak into the environment,” said Rowan.
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GMG CEO Craig Nicol agrees, noting that the possibility for the energy storage market included far-reaching benefits in safety, efficiency, sustainability. He points to the ability of aluminum ion batteries “to use local raw materials to manufacture battery cells at a competitive cost to replace imported lithium-ion cells is a massive opportunity for GMG and Australia to reduce supply chain risks and create local jobs.”
Aluminum-Ion batteries are probably 5 years out before they are ready for utility scale Aluminum-Ion batteries, but it will take 3-5 years out due to the time it takes for planning and permits before any construction would begin on anything that is just starting the planning process.
It seems that a mix of flow batteries and lithium-ion batteries at each solar farm would be the best bet for storage. As Aluminum-Ion batteries become available, they could be used instead of the Lithium-Ion batteries (or any other battery technology we don’t know about yet), then used to replace the Lithium-Ion batteries as those reach end of life.
The power plant buildings would be a great place to house large battery farms. Similar to what was done at the Moss Landing power plant in California.
Vistra Energy, the nation’s largest competitive generator, has begun operating a 300-MW/1,200-MWh lithium-ion battery storage system on its 1,020-MW combined cycle gas turbine Moss Landing power plant site in Monterey County, California. The battery storage system is the largest of its type in the world in terms of size and scale, and it towers over similar systems that have been installed to date.
Brought online on Dec. 11 [2020], the 300-MW/1,200-MWh Moss Landing Energy Storage Facility Phase 1 project is housed inside a “completely refurbished former turbine building” at the two-unit Moss Landing site, and it spans “the length of nearly three football fields,” Vistra said last week.
The system comprises more than 4,500 stacked battery racks or cabinets, each containing 22 individual battery modules. Phase II, which Vistra plans to complete by August 2021, will add an additional 100 MW/400 MWh, bringing the Moss Landing Energy Storage Facility’s total capacity to 400 MW/1,600 MWh.
However, Vistra may consider expanding the project if supported by the right “market and economic conditions.” The site’s existing infrastructure and physical space can support up to 1,500 MW/6,000 MWh of storage capacity, the company said. “With the development permit already in place and the site in condition for expansion, Vistra will be able to move quickly when that time comes,” it said.
For efficiency, it would be best to have some battery storage near the solar panels since they produce DC power and batteries save DC power. The panels could feed the batteries DC power. To feed offsite batteries, the power is converted to AC for transmission and back to DC to feed the batteries.
Wind turbines produce AC power, so the batteries located at the major substations could save any power from wind as well as solar.
With batteries included, 1 GW or wind farms + solar farms may only output about 40% or their generating capacity, but would output that amount continuously, like a gas or coal fired plant. And like a gas or coal plant, output can be ramped up or down as needed. A consistent output will be necessary rather than outputting 1GW on a windy and sunny day and nothing on a windless night.
PLANNING AND FUNDING
Just by using Google Satellite, streetview and search, I have demonstrated that it could be possible to generate Gigawatts of solar and wind power and provide battery storage as well to utilize the 230 kV and 500 kV transmission lines that will or are no longer used by closed or closing coal plants.
Hopefully the Navajo Tribal Utility Authority and Navajo Nation government are working on developing a master plan, similar to zoning and planning for new residential developments before Big Money and their stooges at the Bureau of Indian Affairs do it for them.
Instead of subdividing large parcels for residential and commercial development, then building streets, water and sewer lines to support them, they would be zoning and planning for new solar and wind sites, subdividing parcels, preapring the terms of land leases and setting up right of ways for transmission lines and access roads and siting and building transmission lines and substations to support the new solar and wind developments.
As was learned back in the 70s and 80s by the mistakes made by lack of zoning for residential developments in the rush during the 50s and 60s to build suburban subdivsions, it made for a mismash of streets that all run into each other. Developing a master plan will help prevent that from happening with what I think will become a mad rush to build on the Navako Nation in the coming years.
Navajo leaders and the NTUA could get people together who know what they are doing to study wind turbine locations as well as the existing transmission system (APS and the WATA) that runs thru the Navajo Nation to find ways to send the power out of the region and sites for potential substations and solar/battery farms.
Once a master plan is conceived, it could be built out in sections. Instead of trying to find one entity to provide the billions of dollars needed, the solar and wind sites could be divided up into 100 MW parcels and several smaller developers sought out to develop pieces of it.
Any new substations or 34.5 kV, 69 kV or 115 kV transmission lines needed to get power to the major transmission substations at the high voltage transmission lines should be built by the NTUA, but the wind and solar farms could be built by private companies on leased land. They would pay fees to the NTUA for use of their transmission facilities and could possibly help towards costs of those facilities by upfront fees paid when leases are signed (similar to sewer tap in fees charged to developers for each house in a new subdivision). The NTUA could also issue bonds to pay for the transmission infrastructure needed as well as obtaining grants and other possible funding from the Federal Government.
The WAPA and Arizona Public Service could be sources of funding for some of the solar, battery and wind farms, especially the battery farms since they will be the ones responsible for transmission of the power to the places that need it, when they need it. Besides, they would probably want to build and control the big substations on the transmission lines that will dispatch the power out on the transmission lines. APS will be looking to replace the coal and gas plants they are taking offline over the next decade or two. However, if the transmission facilities are in place, private investors could develop most of the wind and solar farms.
Efficient Grid Interconnection Act of 2021
“This bill addresses a key barrier keeping new resources off the grid—the full assignment of shared network costs to individual generators,” said Rob Gramlich, Executive Director, Americans for a Clean Energy Grid. “Homeowners should pay for driveways, not the whole road into town or the highway lane expansion. This bill bans the most egregious form of that type of cost allocation with respect to electric transmission.”
“In order to meaningfully address the climate crisis, we must add hundreds of gigawatts of solar and storage to our electricity mix over the next decade, and it’s critical that these projects are fairly evaluated and able connect to the grid in a timely and cost-effective manner,” said Abigail Ross Hopper, President and CEO, Solar Energy Industries Association (SEIA). “The backlog of solar projects waiting to connect to the grid will only grow as the industry continues to experience record-breaking growth. We must create a smoother runway to a vibrant clean energy economy and appreciate the leadership of Chairwoman Castor and the Select Committee on the Climate Crisis on this important issue.”
All of this is very cutting edge today, but the opportunity is there over the next 10 to 20 years. It needs to be planned out now tho.
IF I HAD THE MONEY…
If Jeff Bezos had divorced me and I had a bazillion dollars to try to give away before I died, I’d be down there tomorrow to start building out my “plan”. Here is how I’d do it.
First, I’d have a feasibility study done of my “plan” above. Assuming my “plan” is perfect...
I’d immediately get started on expanding the Kayenta Solar Farm and work on the solar farms around the closed Navajo coal plant and along the 500 kV line from there to the Moenkopi substation. For now, I’d make plans for batteries, but would hold off until the technology improves and some generation comes online at the new solar and wind farms. Some Lithium-Ion batteries could be included at first with flow batteries added later.
While that work was underway, I’d connect the 200 kV line from the Glen Canyon Dam to the 500 KV switch at the closed Navajo coal plant (if it is not already connected). This would allow power from the dam to be sent to the Moenkopi, Pinnacle Peak and Kayenta substations.
While all that work is going on, I’d get started on the two new substations and the 115 kV transmission line that connects the two substations at the closed Black Mesa coal mines, work on the Long House Valley and Kayenta substations and any other work necessary to reuse the 115 kV lines to the old coal mines to send power from the Black Mesa solar/battery and wind farms. Batteries would be done later, similar to the solar farm around the Navajo plant.
While construction of the new substations was underway, the new solar/battery farms and the wind farms on Black Mesa could be developed. Additionally, work could get underway on the wind farm in the ridges west of Kayenta and transmission lines from there to Kayenta.
By the time the work around Kayenta could be completed, the San Juan coal plant would be closed freeing up capacity on the 230 kV line. The new wind and solar/battery farm would then be the primary power source on this line sending power in both directions to Page and Shiprock. Power from Glen Canyon dam would serve the line as a backup. Power from Glen Canyon Dam along with power from Kayenta would be sent out the two 500 kV lines from the old Navajo plant to the Nevada Energy, Pinnacle Peak and Moenkopi substations.
By the time we get this done, we’d be about 5 years in and the flow battery technology should be affordable and can start being installed at the solar farms and old coal plants.
3-4 years before the Four Corners coal plant shuts down, work can get underway to use the 500 kV line from Moenkopi to Four Corners.
Development of the wind farms west of Cameron and the rest of Black Mesa, building the substations at the Moenkpopi 500 kV switch and on the 500 kV line south of Pinon, connecting the 115 kV line that runs thru Black Mesa to the 500 kV line and building out the solar/battery farms around the two new 500 kV substations.
The new 115 kV line from the Pinon 500 kV substation to the 115 kV line at Burnside along with the associated solar/battery farms could also get started.
The goal would be to have all the infrastructure and wind/solar/batteries in place and ready to go the day the Four Corners plant goes offline for good in 2031.
At this point, we are at 10 years into the plan. Once Four Corners is shutdown and decommissioned, the land around it could be developed for solar/batteries and the building itself used to house a huge battery farm.
Over the next 10 years, exsting solar/battery farms could be expanded, other locations near 115 kV and 69 kV power lines could also be used and additional solar/battery farms could be built all over Navajo Nation using new transmission lines running to one of the big transmission substations until the capacity of these and other transmission lines are in use 24 hours a day.