What is meant by solar energy? Is it the energy we have on a sunny morning to get out of bed? Most of us feel more energy on a sunny morning than we do on a cloudy or rainy one, but I don’t think this is what most would consider solar energy.
Solar energy is radiant light and heat from the sun and is harnessed using a range of ever-evolving technologies such as solar heating, solar photovoltaics, solar thermal electricity, solar architecture and artificial photosynthesis.
Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the sun, selecting materials with favourable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.
Photovoltaic (PV) cells, which the name implies (photo meaning “light” and voltaic meaning “electricity”) convert sunlight directly into electricity. They are made of special materials called semiconductors such as silicon, which is currently used most commonly. Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material. This means that the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, allowing them to flow freely. You’ve probably seen calculators with solar cells — devices that never need batteries and in some cases, don’t even have an off button. As long as there is enough light, they seem to work forever.
A solar thermal collector collects heat by absorbing sunlight. The term “solar collector” commonly refers to solar hot water panels. Solar power plants usually use the more complex collectors to generate electricity by heating a fluid to drive a turbine connected to an electric generator. Simple collectors are typically used in residential and commercial buildings for space heating.
Solar architecture is the integration of solar panel technology with modern building techniques. For example, big windows placed on the sunny side of a building allow sunlight to be stored in heat-absorbent materials on the floor and walls. These surfaces then release the heat at night to keep the building warm. Similarly, absorbent plates on a roof can heat liquid in tubes that supply a house with hot water.
Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. But solar energy doesn’t work at night without a storage device such as a battery, and cloudy weather can make the technology unreliable during the day. Solar technologies have been very expensive and require a lot of land area to collect the sun’s energy at rates useful to lots of people.
Despite the drawbacks, solar energy use has surged at about 20 percent a year over the past 15 years. The growth in solar energy capacity in 2013 was up 26% over 2012. The average cost of solar energy installations has declined by 60% since 2011, and is set fall even further as new, less costly technologies are now coming into production.
Solar energy is a renewable and clean energy source that in most cases simply saves money for the consumer. The dropping cost of solar panels and improvements in technology have positioned solar energy as a relevant mainstream option for consumers.
The Province of New Brunswick offers a number of energy efficiency incentives that may pertain to solar energy installations, including residential, commercial, industrial, and community projects. N.B Power has created a Net Metering Program that allows distributed renewable energy projects to connect to the electrical grid system.
Net metering allows you to send electricity you generate from renewable sources to the distribution system for a credit toward the cost of electricity that you otherwise may need to purchase. In essence, it’s a “trade” of electricity you supply against electricity you consume. For more information go to the NB Power website and put “net metering” in the “Search” box. Or put “NB Power net metering” into Google directly.
Peter Caverhill is a member of the Woodstock Sustainable Energy Group.