A local energy group plans to build three special greenhouses this year that will be powered by little more than the sun.
About 80 people gathered at Grant MacEwan University Wednesday night to hear about the Solar Energy Society of Alberta’s cold climate greenhouse project. In development for two years, the project aims to show Albertans how to grow vegetables year round with little to no fossil fuel power.
Most food in our stores travels some 2,400 kilometres before it reaches our plate, says Rob Harlan, executive director of the society, giving it a large carbon footprint.
“We have a system that’s very dependent on fossil fuels for transportation as well as heating,” he says, which makes food prices and greenhouse operators vulnerable to fuel price spikes. “These supply chains are not necessarily totally reliable.”
His group has investigated solar greenhouses throughout North America, Europe and China, the latter of which has about 263,045 hectares of them — an area about the size of Edmonton plus Sturgeon County.
These long, quarter-cylinder-shaped buildings use thick walls and thermal blankets to trap the sun’s heat for use at night, Harlan says, allowing them to grow vegetables in weather as cold as -20 C. “Many of these solar greenhouses don’t use auxiliary heat. They’re totally dependent on solar for their heat and lighting.”
Harlan’s group thinks a similar setup could work here. We can already heat homes with very little fossil fuel using the sun and clever insulation, Harlan notes, citing Edmonton’s many net-zero homes as evidence. The tricky bit in Alberta is light: plants need about 16 hours of it a day, and we only get seven here in the winter.
The group plans to build three experimental solar greenhouses in the Two Hills region this year — one based on the Chinese model, and two using vertical glass walls, shutters and/or curtain-walls. Each will test technologies like ground heat storage, LED lights and heat recovery ventilators to find the best way to save energy in a greenhouse. Each will have supplementary light, but only one, the Chinese model, will have a supplementary heat.
Light and heat are two of the biggest costs for most greenhouses in Alberta, says Jim Hole, co-owner of Hole’s Greenhouses & Gardens, and the industry is very interested in ways to cut back on both. “If they’re going down that path, I think it’ll really showcase what can be done here.”
Call 780-378-6178 for details.
If you ever wanted to see the guts of a net-zero home, you’ll have your chance to see three of them this weekend.
Les Wold of Effect Home Builders Ltd. has organized a tour of his group’s three new net-zero homes in Edmonton’s Belgravia region. The homes, currently under construction, use advanced insulation and solar power to produce as much or close to the amount of energy they consume over the course of a year.
One of the homes will be net-zero at the start, Wold says, while the other two will need more solar panels added later. The homes have 30- to 40-centimetre thick walls insulated with cellulose or polystyrene foam that trap two to three times more heat than a typical wall.
Each home demonstrates a different package of technology, says Gordon Howell, the engineer who worked on the solar systems for the homes. One of technologies they hope to test is an air-source heat pump, which is like an air-conditioner that runs in reverse in the winter, sucking in heat from the outside. “It’s a system you’d never think of trying here,” he says, but they think it could save homeowners money on their heating bills.
The tour runs from noon to 4 p.m. April 30 and May 1. Call 780-450-1399 for details.
