PV Gap

Ricardo Said:

Are there any environmental and social costs associated with solar energy?

We Answered:

Of course it takes energy to make solar collectors, to smelt the steel, or refine the aluminum, glass, silicon, whatever. But as far as net environmental cost, I'd say the cost is negative, as the collectors return more in energy than it cost to make them.

The social costs depend on the local culture. Some communities find them ugly. I find them beautiful. If you're the only house in the neighborhood with panels, it might flag you as a showoff, or rich, or the panels might be a target for thieves. Other social costs are hard to quantify. Less smoking means less jobs for tobacco workers, but also means healthier people. Similarly, if the air or water is incrementally cleaner because of solar energy, that might have a positive or negative social cost.

Mary Said:

Are there hidden environmental and social costs for solar energy?

We Answered:

Solar energy can be captured in several ways and we have hardly begun to tap its potential.

One of the hidden environmental costs also applies to other forms of energy capture and generation - the resources required to build the equipment. The materials (metals etc) need to be mined, transported and subjected to the manufacturing process and there will be environmental costs and resource depletion consequences. This is one of the reasons we need to reduce our energy demands as well as switch to sustainable sources.

Solar energy also has the disadvantage of not being entirely reliable because of cloudy days. This means that there is a need for backup energy generation capacity or energy storage. Again providing the backup or storage will have environmental consequences.

Turning to social costs - switching from one form of energy to another may require social change. People may loose their jobs in fossil fuelled energy generation and have to re-train in the new technology. Scrapping old energy plants and building solar capacity will also impact on the price of energy for consumers. But both of these costs are short term problems and the sooner they are faced the less they will cost.

Overall the conclusion is that we need to reduce our energy demands and switch to a mix of sustainable energy sources in which solar will make an important contribution.

Raul Said:

what are the environmental, social, and economic costs of solar energy?

We Answered:

Each method of capturing solar energy has its own costs. Most can be traced to the basic understanding that solar energy is diffuse, nature best handles environmental costs that are diffuse and over longer periods of time and higher population densities strain natural systems.

Solar energy has been with us since the formation of the Earth. It comes to us in the forms of heat and light. Man has seen passive solar "systems" in nature and by design has attempted to copy them. We have improved them with active systems to capture the sun's heat and with photovoltaic systems that give us a way to transmit solar power over longer distances.

Passive solar system use only natural convection, conduction and radiation to transfer heat. Solar passive systems are arguably the most natural with the least environmental costs. Pueblo Indians in the US used Passive Solar design when they located their dwellings under the northern overhangs to catch the southern sun in the winter and avoid sumer sun.

Energy is just one element of existence. Food, shelter, water and ways to obtain them are all important. As a society we have skew our cost allocations when we isolate our energy costs from our environmental, social, food, water, shelter and transportation costs.

Unlike other energy systems solar energy is diffuse and passive systems require space. High value spaces will have water, sun, and other resources nearby. Unfortunately we have more people than high value spaces.

The answer is social organization. We can put a solar thermal power plant in one location (where there is lots of sun) and a town in another location (where there may be lots of water or other resources like transportation) but this specialization imposes other environmental, social and economic costs. Environmentally more land must be used for power transmission. The specialization of use also creates a concentration of environmental impacts. Instead of small garbage piles spread around a town, it creates an industrial landfill. Instead of one solar collector preventing rainwater from reaching the ground a massive area may be made arid while a nearby area is overwhelmed with the occasional flash flooding.

Some environmental costs are easier to deal with on a large scale. We can treat sewage of a town but this takes human effort and economic costs which nature would have assumed in a more rural setting.

Photovoltaics are not the most common nor the most efficient, but they get the most press. Photovoltaic attempts to transform the visible light aspects including some ultra violet and infra red energy into electricity. The very best photovoltaic cells in the lab are about 42% efficient while the commercial models are around 24% efficient. By comparison Solar concentrators and solar thermal panels are 60% to 80% efficient.

After passive solar systems active solar thermal systems have the least environmental impact. With more efficiency they create less waste in material and energy. By offsetting electrical usage with thermal systems (solar hot water, solar heat, solar air conditioning all from solar thermal) we reduce our electrical demand. By using solar thermal to make electricity we presently have a technological advantage. The most efficient method of making electricity is with solar thermal concentrators in the form of a parabolic dish and a stirling engine.

All active and to a lessor extent passive systems require a larger investment in equipment than in operation. The sun is free but capturing and using the energy is not. Making equipment creates pollution and solid wastes. But just as the costs of solar energy have to be put in perspective with our other needs as a society they have to be compared to alternatives. The advantage of solar energy is that when including our environment solar is cheaper than alternatives.