Houweling’s Hot House

New Plant Design Program helps greenhouse to unexpected yields

Nina Winham
For bchydro.com

Efficient lighting makes a difference whether you’re illuminating offices or a production floor. But when your product won’t grow properly without it, getting the light right is critical.

That’s why, when Houweling’s Hot House planned to add lighting to nine of their 50 acres of greenhouses in Delta, they decided to talk to BC Hydro first. That led to efficient lighting, and some surprising results.

Houweling’s produces tomatoes and some cucumbers from its hydroponic greenhouses. It also grows seedlings for its own and other hothouse operations. The greenhouse compartment in question was used for growing tomatoes using natural light, but with demand for propagated seedlings on the rise, Houweling’s wanted the flexibility to produce tomatoes or seedlings as needed. That meant adding lights.

“Since the last time we installed supplemental lighting, a new technology became available – electronic ballasts,” says Ruben Houweling, the company’s propagation manager. “This compartment was an opportunity to try out these new electronic ballasts, which have much greater efficiencies than the conventional ballasts can offer.”

Houweling decided to approach BC Hydro because of a Power Smart business success story   he’d seen about another BC grower, Glenwood Valley Farms, and their work on energy efficiency. “That’s what inspired us to call Hydro before we started the project to see if there was something we could do here.”

Talking to BC Hydro before starting the lighting installation meant Houweling’s was able to work with the New Plant Design Program,  which provides incentives and expertise to help industrial customers plan energy efficiency into their expansions from the outset. The program helped Houweling’s chart a path towards efficiency – and productivity – that would have been hard to achieve later on, even with a retrofit.

Quality light, quality production

“The difference with the electronic ballasts is that we get 100% of the output – whatever it is that’s going into the ballast is the same power coming out, whereas with a conventional ballast, every year you may lose up to 1% or more of the power,” says Al Ram, Houweling’s energy manager. Ram explains that what is lost is the “PAR level” – the specific range of the light spectrum known as photoactive radiation, which is required by plants to grow.

“As you lose your light you can’t see it visibly. Your greenhouse may still look nice and bright, but it is not giving what the plant will absorb. So after 10 years, you’ve lost 10% of your power supply which means you’ve actually lost at least 10% of production.”

Ram says testing conventional ballasts to check if they’re losing their colour spectrum has to be done in a lab off-site, a costly and time-consuming process. Without testing, a grower relies on guesswork to determine when conventional lights must be replaced.

“With the electronic ballasts, it’s a constant power supply,” he continues. “So [the quality of light] will never change five or 10 years from now.”

Ram says electronic ballasts also remove the guesswork. “The old ones lasted 80,000 hours, but after 40,000 you’re only getting 40-50% of the light you want. The electronic ballasts last 50,000 hours, and the entire time you’re getting 100% of what you need for your plants. The electronic ballasts either work or they don’t.”

Efficiency from the outset

Having BC Hydro on board “helped us significantly,” says Houweling. Choosing electronic ballasts will help the greenhouse operation save an impressive 2.2 GWh of electricity per year as compared with conventional ballasts (in addition to improved growing conditions) – but the upfront costs were higher.

“The electronic ballasts did not work on the conventional power supply of 347 volts, so we had to put in a 400 volt power supply system and transformers to accommodate them,” says Houweling. He says designing for efficiency from the start was important, because the different power supply required for each type of lighting would have made it prohibitive to upgrade later. The project also included a sophisticated control system.

“It looks at the outside light levels and it turns on or off based on outside light intensity. There’s a timer, plus the system tracks cumulative light as well, so if you reach a certain amount of cumulative light over the day or period, you can adjust,” he says. The project was also designed to light sub-compartments of the nine-acre area only when needed, allowing efficiency and flexibility (seedlings have different lighting needs than full plants).

“Typically when you’re lighting a tomato crop, you would put lights over the whole greenhouse surface area and turn the nine acres on or off. To light particular sub-compartments we needed a lot of hardware and we needed the computer control program. We estimated that controls and compartmentalization will save 15-30% of wasted electricity.”

Due to its efficiency, the project qualified for an incentive of $469,000 under the New Plant Design Program.

“We were double the install price of a conventional program,” says Houweling. “Over the long term we’ll save on the power, but having help on those capital costs did allow us to justify this a little bit easier.”

Surprising results: bigger, faster

The new lighting project was completed in November last year, and an initial seedling crop was grown. Then Houweling’s tested the new lighting on a tomato crop.
“We came up with some remarkable findings,” says Houweling. “It [the new lighting] will probably increase the yield of that crop by about 3% over the whole year – that’s for a crop that is 9% younger than a conventional crop. So basically a four-week younger crop has 3% more production.”

Houweling says the electronic ballasts are cooler than conventional ones, allowing them to be safely mounted closer to the greenhouse ceiling and further from the plants, which is better for growing mature plants. 

“You can imagine that when we’re using [the lights] to raise seedlings, it delays the planting of our conventional tomato crop. The light has been able to make up for that lost time and produce more tomatoes than the existing conventional plants with no light. We didn’t think it would be so significant on production.”

The productivity gain is an unexpected bonus on a project that continues Houweling’s overall efforts at efficiency, including those being made at its 128-acre facility in California.

“We’re undertaking a lot of simultaneous updates to our facilities to reuse water better, collect our rainwater, use solar energy and do effective heat management,” says Houweling. (See the details in the video on Houweling’s home page.)  “Electricity, water, fertilizer, natural gas – for the future, it’s going to be absolutely important that we’re conserving everything.”

To learn more about the New Plant Design Program or other Power Smart industrial programs,  contact your Key Account Manager. Or reach Customer Care by email or phone 604 453 6400 in the Lower Mainland, 1 866 453 6400 elsewhere in B.C.

Nina Winham is a Vancouver-based sustainablity consultant and regular contributor to bchydro.com.