A Word about Carbon

Costa Rica is one of the few countries in the world where conventional grid power is generated from nearly 100% renewable sources. Less than 10% of the nation’s power is generated from oil-burning. So, the grid power that Costa Rica uses is relatively environmentally friendly. In comparison, China obtains 95% of its electrical power from coal, which is the dirtiest fossil fuel in industrial use today.

The relatively high cost of solar power systems encourages homeowners to consider alternate fuels (read: propane and natural gas) for such energy intensive activities as hot water heating, cooking, and clothes drying. For instance, an electric hot water heater that is on three hours a day requires SIX 280-watt panels ($5600) to provide the charge necessary and FOUR inverters to provide the 4000 watts of 240V power needed just to operate the heater. Adding the additional batteries needed and throwing in labor, this represents around $24,000 in capital costs to heat water by solar power versus no capital costs for gas hot water heating (we assume that the price of the hot water heaters cancel themselves out). Even if we assume a generous $75 a month in propane costs, it would still take 27 years to pay for the solar system. This is not economically sensible for anybody.

However, if one compares the actual carbon footprint between the various options, it can be shown that the payback period when comparing propane to solar hot water heating is closer to fifteen years. In order to compare the carbon footprint of grid electrical hot water heating (as an example) to operating an electrical hot water heater using solar panels and equipment (to distinguish between this and solar hot water heating as described earlier), this comparison depends completely on how the local power grid obtains its electricity. For nations like Costa Rica, there is relatively little advantage in carbon footprint suppression since grid power in Costa Rica is mostly environmentally sustainable already. But for nations like China with a dirty power system, the carbon footprint suppression advantage of powering high wattage appliances with costly solar power is orders of magnitude higher.

For those interested in suppressing or eliminating carbon footprint altogether, then a much larger solar system with considerably greater costs is required, and the cost/benefits of such a system simply do not provide a favorable comparison in pure economic terms. A proper economic evaluation must take into account the relative importance to the consumer of carbon footprint suppression and is accessible as a practical alternative essentially only to the affluent.