Calculating Energy Savings

There’s a new energy in town and it comes from saving energy. And not just saving, but knowing exactly how much you’re saving, where and what pays off when.

Greenhouse businesses have long been focused on reducing fuel and other energy costs. Far before sustainability became the moment’s hottest buzzword, growers knew energy was their highest cost besides labor. Saving energy would benefit not only their businesses, but their customers and, eventually, consumers.

Knowing how and where to start saving is quite another story. And knowing whether investments like energy curtains make sense in your specific greenhouse – not a generic average operation – is difficult to determine. But with a quick and simple payback calculator, growers can assess how quickly investments like energy curtains pay off.

Getting Started

For many growers, knowing where to start saving is as difficult as actually making the changes to save. So what do you look at first? Think of a pyramid. Start at the bottom and work your way to the top to determine the best way to manage and save energy at your operation. At the bottom of the pyramid are items that require little investment but generate quick payback. As you work your way to the top, time and investment increase and payback stretches out.

The first step is a simple Energy Audit. For a very small fee, an engineer will analyze an operation’s energy use, then provide a detailed report outlining specific ways to save and conserve. Some recommendations are as simple as tightening a loose vent. Others are more involved, like upgrading fans. Either way, you’ll have a blueprint for exactly how and where energy is being used at your greenhouse.

Next, modify your behavior for energy conservation. This is where change really starts to impact. For example, consolidate or co-locate early crops with warmer temperature needs to avoid heating or overheating more space than is necessary. Grow the same plants in a different way. It may cost a little more upfront, but the payback will far exceed it.
Then, really focus on increasing your energy efficiency. Grow at the same temperatures in the greenhouse with more efficiency, such as upgrading to more efficient motors or lamps, setting computers to control temperatures at set targets and installing energy curtains.

When you’ve got the equipment online for energy savings, take a look at time of use management. Can you adjust by taking advantage of energy savings opportunities? For example, many power companies offer vast savings for off-peak versus peak-time electrical power. Or, warm hot water off peak and store in insulated tanks to use at night. Take advantage of variable rates and reap the rewards.

One of the last steps will be examining major infrastructure changes, for several reasons. Changes like these – incorporating renewable energy like wind, solar or biofuels – take a major investment, so you’ll want to have all of your other energy conservation efforts in place before you move on them. Know exactly what your energy use is so you don’t invest too heavily or overcompensate.

Save Heat, Save Energy

Heat escapes from a greenhouse in every corner and any way it can. How fast it escapes depends on a host of different factors, including temperature fluctuation, wind speed, greenhouse sealing, radiation and conduction properties, cloud cover and greenhouse construction.

That’s why it’s essential you identify and block every possible opportunity for heat loss. For example, creating a greenhouse attic with an energy curtain is a good heat loss barrier but makes a well-sealed perimeter critical for energy efficiency.
Screens work by doing just that, slowing the heat loss rate by blocking outgoing radiation and trapping the insulating cold air layer above the screen in the attic. By separating the warm, moist air of the growing space from the cool, dry air in the roof space, you minimize heat loss and maximize energy efficiency. But exactly how much do curtains save?

Extensive testing in two greenhouses with artificial crops reveals these energy savings numbers. One has a horizontal screen; one does not. We count heat loss only through the roof and maintain identical temperature control to within +/- 1°C. We select a percentage relevant for all glazing types and test for all heat transfer, using computer-generated mathematical models for validation.

Then we look at approximate installation costs. The base cost for flat, sliding, cable-driven Firebreak curtains installed on a 1-acre range is $1.25-1.50 per square foot. Prices increase 12 to 14 percent for slope-flat-slope, 10 to 12 percent for suspended, 10 cents per square foot for push-pull, and 20 cents per square foot for blackout systems. Smaller, multiple zone, occupied or busy greenhouses cost more. Replacement costs run about two-thirds the cost of the original.

Knowing that information, we can calculate the typical energy savings with different types of screens:

• An all-clear curtain, such as the XLS10 Firebreak with no aluminum, functions just like glass or poly, allowing a great deal of light in (85 percent direct light transmission), and provides 47 percent energy savings.

• A screen made with 50 percent aluminum, such as the XLS15 Firebreak, increases the energy savings to 57 percent by blocking more light (46 percent direct transmission).

• Using a curtain with open space between the fibers, like the XLS15 F Firebreak, allows 50 percent direct transmission and provides 20 percent energy savings.

• And putting in a two-layer blackout curtain, such as the XLS Obscura A & B, offers a whopping 75 percent energy savings. The combination is at the same time reflective to prevent overheating and nearly opaque with less than 0.1 percent direct transmission to intercept any light that leaks through.

The bottom line is energy savings pay back; you just need to figure out which options, from energy curtains to renewable energy, make the most sense for your business.

Leave a Reply

More From Finance/Operations...

April 11, 2017

Jerry Halamuda of Color Spot Nurseries Retires

The co-founder of Color Spot Nurseries has retired, effective immediately, and has named a replacement.

Read More
Socius Webinar

March 30, 2017

Webinar to Offer Tips on Properly Managing Your Business for Growth

“How to Survive and Thrive: New Revenue Building Tools for Growers,” presented by Socius, takes place on April 6.

Read More

March 21, 2017

How Greenhouse Vegetable Growers Can Prepare for a Product Recall

The United Fresh Produce Association is holding a Recall Ready Workshop in April that is designed to help growers properly manage a recall, from liability to communications.

Read More
Latest Stories

April 11, 2017

Jerry Halamuda of Color Spot Nurseries Retires

The co-founder of Color Spot Nurseries has retired, effective immediately, and has named a replacement.

Read More
Socius Webinar

March 30, 2017

Webinar to Offer Tips on Properly Managing Your Busines…

“How to Survive and Thrive: New Revenue Building Tools for Growers,” presented by Socius, takes place on April 6.

Read More

March 21, 2017

How Greenhouse Vegetable Growers Can Prepare for a Prod…

The United Fresh Produce Association is holding a Recall Ready Workshop in April that is designed to help growers properly manage a recall, from liability to communications.

Read More

March 14, 2017

Expanded Customer Footprint, E-Commerce, Succession Key…

Costa Farms' acquisition of indoor foliage producer Delray Plants rocked the industry, but the story behind Delray Plants' sale is the same as for many growers struggling with succession planning. For Costa Farms, the strategic purchase expands its customer footprint and also fast tracks its foray into e-commerce.

Read More

March 10, 2017

Costa Farms Expands With Purchase of Indoor Houseplant …

Costa Farms annnounced March 10 that it has acquired Delray Plants, one of the leaders in the indoor houseplant industry. The two operations are committed to the same values, principles, and goals to grow the industry, and will fit well together to accomplish this, say Randy Gilde, CEO of Delray Plants, and Joche Smith, CEO of Costa Farms.

Read More
Ken and Deena Altman

March 7, 2017

Altman Plants in Escrow to Purchase EuroAmerican Propag…

Ken Altman, a co-owner of Altman Plants based in Vista, CA, has confirmed that the operation is currently in escrow to purchase EuroAmerican Propagators, the Bonsall, CA-based young plant and finished plant grower that filed Chapter 7 Bankruptcy on Jan. 23, 2017. Ken and Deena Altman are co-owners of Altman Plants and The Plug Connection, along with their son Matthew, who has recently bought into the family business. The 55 acres of land and all of the facilities on it, which were previously owned by Jerry Church, a partner in EuroAmerican Propagators, are part of the purchase agreement currently in escrow, Altman says. However, it would not be absorbed by Altman Plants, which in 2016 was number 3 on Greenhouse Grower’s Top 100 Growers list with more than 11 million square feet of environmentally controlled greenhouse production, 62 acres of shade production, and 400 acres of outdoor field production. Altman Plants’ property […]

Read More
EuroAmerican Propagators Greenhouses

February 14, 2017

Suppliers Comment on Plant Genetics’ Fate After EuroAme…

Since the operation’s bankruptcy filing on January 23, 2017, suppliers associated with EuroAmerican Propagators have updated Greenhouse Grower on what the operation’s bankruptcy means for them – and how it will impact grower customers.

Read More
Stephanie Whitehouse

January 17, 2017

Stephanie Whitehouse Takes Her Passion for Plants to Di…

Stephanie Whitehouse, who has spent the last seven years as the Sales and Marketing Director for Peace Tree Farm in Kintnersville, PA, recently joined Dickman Farms Greenhouse and Garden Center in Auburn, NY, as the company’s new Retail General Manager.

Read More
Laura Drotleff

December 6, 2016

Are You Driving Young Growers Away? [Opinion]

In a time when the industry is facing a critical shortage of both labor and skilled, educated growers, it's important that grower operations don't unwittingly turn candidates off to a career at their business or in the industry in general. Take a closer look at your hiring practices to ensure you are being inclusive and not breaking any laws.

Read More
Trays move on an overhead conveyor to the end of the production line, where workers carefully pack the cleaned, sized, graded, counted and sorted Calla tubers

November 29, 2016

Texas Judge Halts Overtime Rule; Here’s What It Means F…

According to Craig Regelbrugge at AmericanHort, the injunction against the overtime rule is welcome news for horticulture.

Read More
Craig Regelbrugge, senior vice president of AmericanHort - Feature image

October 25, 2016

Contribute To HRI To Help Honor Industry Advocate Craig…

In honor of Craig Regelbrugge's extraordinary contributions to the horticultural industry, AmericanHort and the Horticultural Research Initiative created a special HRI endowment fund in his name: "The Craig Regelbrugge - Advocates for Horticulture Fund."

Read More
Lucas Greenhouses Shipping

October 6, 2016

Greenhouse Shipping Costs Down, But Concerns Remain

Lower gas prices have led to lower shipping costs for some growers, but many continue to seek out ways to become more efficient.

Read More
Pansy ‘Cool Wave Blue Skies’ (Wave)

September 20, 2016

PanAmerican Seed Settles Alleged Trade Sanction Violati…

PanAmerican Seed, a division of Ball Horticultural Co., has been charged with violating trade sanctions to Iran over a number of years. According to a release from the U.S. Treasury department, PanAmerican Seed made 48 indirect sales of seeds to two Iranian distributors. The company shipped the seed to consignees based in countries in Europe and the Middle East. PanAmerican Seed’s customers then arranged for the re-exportation of the seeds to Iran. The release states that the Office of Foreign Assets Control (OFAC) determined PanAmerican Seed did not voluntarily self-disclose the alleged violations to OFAC, constituting an egregious case. “We believe that the settlement was extreme; however the alternative was to litigate with the U.S. government, which would take months, if not years,” says Todd Billings, Chief Financial Officer for Ball Horticultural Co. When asked what Ball Horticultural Co. has done to ensure that violations to trade sanctions do not […]

Read More
young-plants

September 20, 2016

The Top Young Plant Growers, And Four Critical Challeng…

In Greenhouse Grower’s 2016 Top Young Plant Growers Survey, growers discuss the latest challenges and opportunities in fulfillment, shipping, labor, and crop protection.

Read More
Cavicchio Greenhouses

September 6, 2016

Cavicchio Greenhouses Wins Inaugural Sustainability Awa…

The Sudbury, MA, growing operation sustains more than 250 acres of annuals, perennials, and nursery stock, with a number of practices to mitigate its impact on the environment.

Read More
Charlie Hall Feature Image

September 6, 2016

10 Insights From Charlie Hall’s Green Industry Economic…

With the uncertain current economic climate, Texas A&M economist Charlie Hall says now may be the perfect time to invest — as long as you do it smartly.

Read More
Penn State Plant Bud

August 23, 2016

AmericanHort Is Helping Plant Importers Adjust To New R…

A report from Craig Regelbrugge at AmericanHort says the government is implementing a streamlined system for imports, in which all required data will be submitted electronically through a single window.

Read More
Plug Connection Assortment

August 9, 2016

AmericanHort’s Plug And Cutting Conference Will Feature…

This year’s conference, which takes place Sept. 19-21 in Carlsbad, CA, features discussions on water, pest and disease control, and production inputs, as well as a biocontrols workshop and tour of local cuttings facilities.

Read More