Solar-Powered Greenhouse Solutions

More productive agriculture with less water and fossil fuel

“Over the past several decades, climate change has increased the severity of wildfires, heatwaves, droughts, and floods … [and] combined with slower moving impacts like sea level rise, ocean acidification, and the loss of mountain snowpack. has presented risks and challenges to communities, infrastructure, and natural and working lands”—Washington State Climate Resilience Strategy.

According to the 2024 United Nations Convention to Prevent Desertification (UNCCD), “Up to 40% of the world’s land is degraded, affecting over 3.2 billion people … compounded by the sharp rise in droughts—up by 29% since 2000—
with projections showing that by 2050, three in four people worldwide could be affected.”[1] The intensity and frequency of heatwaves is rising with a resultant annual decline in agricultural productivity.[2]

With large-scale agribusinesses, 1% of the world’s farms control more than 70% of agricultural land. In contrast, worldwide, 80% of farms comprise less than two hectares, totaling just 12% of the total. However, family farms are “key sources of the diverse diets that provide food and nutrition security for local communities.”[3]

Extreme temperatures, droughts, floods, and storms due to climate change are the leading potential causes of agricultural loss across the world.[4] The next decade will present significant challenges for agricultural land worldwide and pose substantial threats to global food security.[5] The projected loss of millions of hectares of fertile land will have profound implications for global food production and security.[6][7]

Moreover, extensive use of chemicals, agricultural and industrial, is polluting the food supply and can be deleterious to our health.[8]

“The growing concern for sustainability is driving up demand for environmentally friendly farming methods. An effective answer is provided by solar greenhouses, which employ renewable energy to keep growing conditions ideal all year round. Furthermore, solar panels are now more affordable and efficient thanks to technological improvements, increasing their accessibility for farmers. Furthermore, the growing preference among consumers for locally sourced produce is propelling the development of solar greenhouses. The solar greenhouse market is expected to increase significantly in the upcoming years due to favorable government policies and rising environmental awareness.

Several factors are fueling the growth of the solar greenhouse market. Firstly, rising concerns about climate change have prompted governments to incentivize renewable energy solutions, including solar-powered agriculture. Secondly, the desire for food security and self-sufficiency has led farmers to seek sustainable methods like solar greenhouses to ensure consistent yields. Thirdly, advancements in greenhouse technology, such as improved insulation and ventilation systems, are enhancing the efficiency of solar greenhouses, making them more attractive to growers. Additionally, the growing consumer preference for organic, locally grown produce is bolstering the demand for solar greenhouse-grown crops, further propelling market expansion.”—Market Research Intellect

What is solar greenhouse farming?

Solar greenhouse farming involves the use of specially constructed greenhouses that create an optimal environment for plant growth and/or fish farming by harnessing solar energy to regulate temperature, humidity, and light conditions. Solar greenhouses can combine aquaculture (fish farming) and hydroponics (soilless plant farming) to form symbiotic life support for fish and plants.

Traditional greenhouses heavily rely on the grid or fossil fuels for heating and cooling. Solar greenhouses leverage renewable energy sources, and in so doing, reduce the reliance on fossil fuels and reduce the carbon footprint and operational costs.

Benefits of Solar Greenhouse Farming

Environmental Sustainability

Solar greenhouses significantly reduce the reliance on non-renewable energy sources, thereby minimizing greenhouse gas emissions. For some grow zones, a solar greenhouse could be independent of non-renewable energy sources year-round. By utilizing solar panels and other renewable energy systems, solar greenhouses contribute to the global effort to combat climate change.

Cost Efficiency

Although the initial investment in solar greenhouse technology can be substantial, the long-term savings on energy costs are considerable. The reduction in utility bills and potential government incentives for renewable energy adoption make solar greenhouse farming financially viable and attractive.

Extended to Year-Round Production

One of the most notable advantages of solar greenhouse farming is the ability to extend the production of crops by months or even year-round in many locales (grow zones) at a lower cost of energy use than conventional greenhouses. The controlled environment within the greenhouse allows for the cultivation of various crops regardless of external weather conditions, ensuring a consistent supply of fresh produce. For many northern latitude growing zones, achieving year-round farming could require grid-power or propane for heating. In these cases, there would be a net reduction in annual energy costs while extending the growing season by months.

Enhanced Crop Quality and Yield

Compensation for environmental factors such as temperature, light, and humidity leads to improved crop quality and higher yields. Farmers can optimize growing conditions to meet the specific needs of different plant species, resulting in healthier and more nutritious produce.

Key Components of a Solar Greenhouse

Solar Panels

Solar panels are essential for converting sunlight into electricity, which powers the various systems within the greenhouse. The placement and orientation of the panels can provide shade for plants during intense summer months and admit more light during winter months when the sun is at low elevation.

Thermal Mass

Thermal mass materials, such as water barrels, concrete walls, concrete slabs, or a thermal battery or combination thereof, are used to store heat generated during the day and release it during the night. This helps maintain a stable temperature within the greenhouse, reducing the need for additional heating.

Ventilation Systems

Proper ventilation is vital to prevent overheating, ensure adequate air circulation, and support pollination. Automated vents and fans help regulate temperature and humidity levels, promoting optimal plant growth conditions.

Insulation

High-quality insulation materials are used to minimize heat loss and maintain higher internal temperatures in winter months. Insulated walls, roofs, and flooring are essential components of an efficient solar greenhouse.

Challenges of Solar Greenhouse Farming

Initial Investment

The cost of constructing and equipping a solar greenhouse can be high. Farmers need to consider expenses related to solar panels, thermal mass materials, insulation, and automated systems. However, the long-term savings on energy costs can offset these initial expenditures.

Maintenance and Technical Knowledge

Operating a solar greenhouse requires a certain level of technical expertise. Farmers must be familiar with the maintenance of solar panels, inverters, batteries, ventilation systems, and other components to ensure optimal performance. Regular inspections and upkeep are necessary to ensure operating efficiency and to prevent system failures, especially in below-zero temperatures. Fortunately, there are readily available instruction materials and videos that expedite the learning process.

Solar Access

Because solar greenhouses are designed to harness solar energy, effective operation is dependent on site location. The location must have excellent sun exposure, especially in winter months when the sun’s elevation is lowest. At this time of year, the sun’s elevation could be below the tree line, even though it’s above the same tree line in summer.

Weather Dependence

While solar greenhouses are designed to operate in various climates, extreme weather conditions can pose challenges. Prolonged periods of cloud cover or severe storms may impact the greenhouse's ability to generate sufficient solar energy, necessitating backup energy sources in the form of grid power or propane. In the summer, abnormally high outdoor temperatures can cause high greenhouse temperatures that need to be exhausted quickly.

Incentives and Subsidies

Both Canada and the United States offer various incentives and subsidies to encourage the adoption of renewable energy technologies. Farmers should explore available programs that provide financial support for the installation of solar panels and other energy-efficient systems.