I was at Rose Acre Farms in Hyde County last week, wearing a hard hat, standing next to solar panels, a couple hundred yards from 3.5 million hens. If you had eggs this morning, there’s a good chance they came from one of them.
Rose Acre is the second-largest egg producer in the country. It has partnered with Tideland Electric Membership Corp. to create a “microgrid.” This looks like one of the larger solar farms you pass on rural roads, but much more complex, and the complexity is the story.
If you subtract folks who live on the Outer Banks in Ocracoke, the mainland part of Hyde has around 3,800 residents, around six per square mile. If you are looking for a place to fish and hunt and not be bothered, this is it.
Rose Acre is headquartered in Seymour, Indiana, with 15 laying facilities in seven states. More than 20 years ago, the company began working on a major new facility in Hyde County, and put the first chickens there in 2006. The location had a couple of advantages. The hen business, like all livestock enterprises, is a feed business.
“There’s a four- or five-county area there that grows a lot of corn,” said Tony Wesner, Rose Acre’s chief operating officer. “They’ve got to haul that stuff a pretty good distance to markets, and we’re right in the middle of it. So we help raise the grain basis, which the farmer benefits from. So it’s a good partnership and it works.” Rose Acre makes its feed at a mill on site.
The other plus was the local electric co-op, Tideland, which ran a power line directly from its substation in Ponzer. “It’s one of our most reliable circuits,” said Paul Spruill, Tideland’s CEO.
Tideland, based in Pantego next door in Beaufort County, is one of the 26 electric co-ops that serve 2.5 million North Carolinians in 93 of the state’s 100 counties. Tideland serves six of them: Beaufort, Craven, Dare, Hyde, Martin and Pamlico.
North Carolina is a vast state with a few big cities and a lot of rural counties. Around 45% of the state’s land area is served by the co-ops, who mostly get their power through the North Carolina Electric Membership Corp. You can think of NCEMC as the wholesaler, and the co-ops as the retailers, with local power lines to homes and businesses like Rose Acre.
Like a lot of big companies, Rose Acre has been interested in renewable energy, such as solar. “We had been looking at it for some time,” said Wesner. “I would get approached two or three times a month with somebody wanting to do a system.” But he wasn’t comfortable that the folks pitching him knew what they were doing. And he was uncertain about their motives. “I always felt like it was people chasing government grant dollars. I wanted a partnership with somebody for the long term.”
“About that time, Tideland, because we had a relationship with them, said, ‘Would you guys ever consider looking at a solar field?’ And it was like, ‘As a matter of fact, yeah, we probably would,’” said Wesner. “And it just kind of went from there.”
What Tideland wanted to build was a microgrid, which is a very smart and versatile solar field. It had some experience building these, including one on Ocracoke – which can lose power when storms rake the Outer Banks. Building one at Rose Acres required 6,300 solar panels – a 2 megawatt array. It required a 2.5 MW battery energy storage system – basically stacks of Tesla batteries – and backup diesel generation. And, critically, it required a lot of hardware and software to be the brains of the operation. It knows when to send the electricity generated by the solar panels off the farm to the Tideland grid for its customers. It knows when to send the power to the egg farm. It knows when to charge the batteries. And it is able, within milliseconds, to know if power from the outside grid had been interrupted and can switch the whole egg-laying operation to run off the microgrid as an electricity island.
This last part was perhaps the most important and challenging. It couldn’t be a three- or six- or 30-second delay. That might be OK for a home generator if you lose power. A big egg-laying operation has continuous processes that need constant power.
“You want it to be seamless,” said Spruill. “We’ve had solar for a while. We’ve had diesel for a long while. We’ve had battery energy storage systems for a while.” But to be able to switch the farm from the outside power line to the microgrid in three cycles – there are 60 cycles in one second – that meant lots of very fast communication in a controller box filled with fiber optic cables and processors.
“Even if you only waited three minutes, you’d be like ‘What harm is three minutes?’ But it’s their processing, their value-added stuff that gets interrupted by that delay,” said Spruill. “We couldn’t have that happen. They wouldn’t want it. They would look at us and say, ‘Well, look, man, that ain’t no different than an automatic transfer switch. We’ve already got those. They’re on diesel engines back there. So what are you really doing for us?’ We had to get it right and we finally got it right.”
Unlike a typical backup generator or other uninterruptible power supply, the microgrid is able to generate power basically all the time, meeting up to a third of the farm’s needs, in addition to charging up the batteries and keeping the farm going during a power outage.
But there’s another layer of complexity. In Raleigh, NCEMC is able to peer into Tideland’s system and into the microgrid itself. Around five years ago, NCEMC installed a Distributed Energy Resource Management System. The larger electrical grid is getting more complex. A lot of solar and wind farms are connecting to it and want to sell power to utilities. A lot of companies have solar next door or on the roof; sometimes they want to buy power from the grid and sometimes they want to sell power.
At the same time, large, multi-state confederations of electric utilities want to be able to move around power on very cold and very hot days. They may need to raise or lower thermostats. To do all this, big electrical grid managers like NCEMC have to be able to see all the generating resources on the edge of its system and manage loads as needed. DERMS makes this possible. For example, from Raleigh, around 145 miles away, it can see the batteries at the farm and tap into them if needed.
That is what happened a year ago, said Lee Ragsdale, NCEMC’s senior vice president, energy delivery. Winter Storm Elliott hit most of the country just before Christmas, straining electric resources. The batteries of the Rose Acre Farms microgrid were feeding power into the larger grid at 6 a.m. Christmas Eve morning, before the sun was up. “We had charged the batteries the previous day, and we dispatched them for the benefit of the portfolio,” said Ragsdale, meaning the power was going out to help supply regional needs. “And that is a profound impact. It helped avert larger issues on the grid. It was still not a great day, but it could have been a lot worse. We were in Raleigh controlling the battery at Rose Acre Farms from our DERM system.”
Ragsdale anticipates more microgrids being developed by the co-ops. “The challenge is that they are individually unique solutions for issues where they are, and so each opportunity presents itself, newly. Thinking through what those solutions look like and how they can work for our members is key.”
These aren’t easy projects. “It’s definitely getting easier, but they’re still complicated. It’s a pretty complicated system, and it’s supplementing a very complicated electric grid.” But computers are getting more powerful and smaller; battery costs are coming down and storage capacity is increasing. There’s a massive installation of fiber optic cable in rural areas, which is where the co-ops operate.
“All of those technology curves are moving at different speeds, but they are all improving,” said Ragsdale. “And collectively they are making it easier and more affordable to bring solutions like this.”
