As nonrenewable energy sources become depleted, proponents of investing in solar energy say the sun’s daily presence justifies its development as an energy source. Questions about solar energy include economic arguments that it are not always cost-effective, and that location restrictions, such as the amount of sunlight in the North versus the South, impedes its use.
II. Solar Energy Basics
III. Passive Solar Heating
IV. Environmental Requirements
V. Property Rights and the Sun
VI. Turning Solar Energy into Chemicals
A tenet of U.S. environmentalism is conservation of natural resources. When electricity comes from burning gas, coal, or other materials, the cost of electricity can increase dramatically in a short time because many of these resources cannot be renewed. Fossil fuels and other power sources such as nuclear fission greatly affect environment in ways that range from damage during resource extraction to pollution and dangerous byproducts, including nuclear waste. The Deepwater Horizon oil rig disaster in the Gulf of Mexico in 2010 is an example.
Many developing nations adopt solar power because that is the only electricity available. Many countries have limited hours of electricity, if any at all. Power sources can be unreliable, with frequent brownouts. Solar power combined with low-power LED lights is currently bringing light to the night in villages in developing nations. Instead of relying on a complicated grid of wires to carry electricity from distant generating stations, solar power can be produced on site. This also greatly reduces its ecological footprint.
Discussion of alternative energy sources triggers debate about cost-effectiveness. These can be complex matters including utility rate structures; bond recovery rates; local, state, and federal regulatory accommodations, and safety. Most measures of cost-effectiveness compare the new source with petrochemical sources. Because petrochemical depletion is contested, it remains an unknown factor in cost-effectiveness computations. Another debated assumption in these measures is the provider of the power. Solar energy can be home-generated, which is called “off the grid” power generation. In some areas the power company is required to buy back the excess power generated provided the correct monitoring mechanisms are in place.
Another tenet of environmentalism is saving power. Using less power is considered to reduce human effects on the environment. Frugal homeowners also find it a convenient way to save money.
Solar Energy Basics
The sun is our major source of energy. The conversion of sunlight to electricity or heat uses solar energy. There are many technologies and technological variations for this process. The most basic way is the use of photovoltaic systems to convert sunlight directly into electricity. Photovoltaic (PV) arrays commonly are used to generate electricity for a single residential or commercial building. Large PV arrays covering many acres can be combined to create a solar power plant, and large mirror arrays can be used to generate heat. In the latter, sunlight is focused with mirrors to create a high-intensity heat source. This heat then produces steam to run a generator, which creates electricity.
Solar water-heating systems for most residential and commercial buildings usually have two main sections. The first is a solar collector that is aimed so that it faces the sun as much as possible. Generally the longer and more direct the sunlight, the more power is created. The second section, which is connected to the solar collector, is a storage tank of liquid, generally water. It retains the heat generated by the solar collector. This heated water can then be used for heating, washing, cleaning, and other daily tasks.
Solar power can be used for anything that requires electricity. For the most part, it is used to heat water, which uses a lot of energy. Many residential and commercial buildings can use solar collectors to do more. Solar energy systems can heat buildings. A solar ventilation system can be used in cold climates to preheat air before it enters a building. Other than for buildings, solar power supplies energy to space missions, remote viewing and sensing outposts in wilderness areas, home motion-detector lights, and many other applications.
Passive Solar Heating
When architects design a building, they can develop an energy plan for it that incorporates using the sun. To use the sun efficiently requires strict compliance with the rules of nature at the particular site. If a design does this, it is considered to be using passive solar energy; once the building is built, the solar energy system demands little maintenance.
In the Northern Hemisphere, buildings designed to use solar energy require features such as large south-facing windows, building materials that absorb and slowly release the sun’s heat, and a structure that can support tanks that might be holding water heated by the sun. Passive solar designs should include natural ventilation for cooling.
The way a building sits on a lot can have a large effect on the efficiency of passive solar energy. Many municipal zoning and land-use laws restrict how buildings, especially for residential structures, sit on a lot. Buildings often must be set back from the front, back, and side, creating an envelope around them. On a small lot, this will greatly constrain the direction the building can face, which can limit passive solar efficiency. This is one of many land-use issues related to solar power.
The environmental requirements for solar power differ based on power usage. Often they are site-specific and not always readily available to a home buyer or builder. Essential environmental information is how much solar energy is available to a particular solar collector. The availability of or access to unobstructed sunlight for use both in passive solar designs and active systems is protected by zoning laws and ordinances in some communities.
Property Rights and the Sun
Access to the sun in cities has been controversial, whereas access to light and air is part of U.S. private property law. Solar access means having unobstructed, direct sunlight. Solar access issues emerged in the United States when commercial property owners sought to ensure that their investment in solar power was not obscured by shadows from a later nearby development. This can be contentious because solar access needs can clash with development rights of nearby property owners. Solar energy advocates say that communitywide solar access can greatly increase the efficiency of the solar collectors and lower the cost of energy.
Several communities in the United States have developed solar access land-use guidelines or ordinances; most have not done so. Many communities are entangled in debates over other issues, such as the erection of cellular telephone towers and ways of economic development. Powerful interests—such as real estate, banking, and mortgage-lending institutions—prefer traditional private property approaches, and many private property owners see mandatory solar access as an infringement on their rights. As a result, mandatory solar access can encounter community resistance. Environmentalists would like to see more protection for investment in solar energy. Many states now offer tax incentives for the development of alternative energy sources.
In the absence of access laws, landowners using solar power can avoid shadows by buying surrounding development rights, but that is a costly alternative. Governmental entities can also exercise their power of eminent domain to achieve public purposes related to solar energy development.
Traditional zoning ordinances and building codes can create problems for solar access. Most pertain to the zoning envelope mentioned previously:
- Setback from the property line
- Exterior design restrictions
- Yard projection
- Lot orientation
- Lot coverage requirements
The most important solar access rule is making sure an installation faces the sun in a predominantly east–west direction. Common problems that landowners or developers who want to install solar power have encountered with building codes include the following:
- Exceeding roof load
- Unacceptable heat exchangers
- Improper wiring
- Unlawful tampering with potable water supplies.
Potential zoning issues include the following:
- Obstructing side yards
- Erecting unlawful protrusions on roofs
- Siting the system too close to streets or lot boundaries.
Special area regulations such as local community, subdivision, or homeowners’ association covenants also demand compliance. These covenants, historic district regulations, and floodplain provisions can easily be overlooked.
Turning Solar Energy into Chemicals
How to store energy derived from the sun has been a central drawback to its use. In April 2010, microbial scientist Derek Lovley of the University of Massachusetts at Amherst found a way that turns 90 percent of carbon dioxide, a greenhouse gas, and some bacteria into fuel without further processing. His method, called “microbial electrosynthesis,” is carbon-neutral—which means that it does not add greenhouse gases to the atmosphere. In addition, it is believed to use solar energy more efficiently than is done by plants. As such, it provides a solution to the storage problem because it immediately turns solar power directly into chemicals, which are then readily stored with existing infrastructure and distributed on demand.
Excitement over this innovation stems in part from the fact that no biomass or feedstock or arable land is required for the process. Similarly, far less water is required of the process than, say, energy generated by nuclear means. And, no elaborate postproduction fermentation is required. Consequently this process does not produce any known toxic waste.
Voluntary consumer decisions to purchase electricity supplied by renewable energy sources are a powerful market-support mechanism for renewable energy development. Beginning in the early 1990s, a small number of U.S. utilities began offering green power options to their customers. Since then, these products have become more available, both from utilities and in states that have introduced competition into their retail electricity markets. Today, more than 50 percent of all U.S. consumers have an option to purchase some type of green power product from a retail electricity provider. Currently, about 600 utilities offer green power programs to customers in 34 states.
This burgeoning economic growth will push at the current constraints on the use of solar energy. As more information emerges about the environmental costs of petrochemical production, the amount of oil left, and the record-breaking profits made by multinational petrochemical corporations, communities and residents seeking more self-sufficiency will pursue solar power.
Robert William Collin and Scott M. Fincher
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