Solar advantages and disadvantages

Solar powered systems are a source of clean electricity, hot water and space heating. And they are already cost-competitive in solar water heating or about to be in solar photovoltaic (that's, at least, what manufacturers like GE are predicting for the next few years).

Photovoltaic will be more advantageous and cost competitive in the next few years Anyway, beyond these advantages there are also some solar disadvantages and limitations that can't be ignored.

Current prices of PV solar electricity aren't cost-competitive with those of fuel and nuclear generated electricity. Without state incentives solar electricity is far from cost-competitive.

Besides, its dependence on solar resources and local weather conditions - solar PV systems do not work at night and can have a very poor performance in adverse weather conditions - are also good examples of solar limitations.

Below, we summarize the main solar advantages and disadvantages.

Solar Advantages

- Heating our homes with gas, oil or power coming from fossil fuels is a major cause of global warming and climate disruption. Solar energy, on the contrary, is basically clean and environmentally-friendly. Concerns over visual impacts, or land disturbance, or the the use of potentially hazardous materials in some of the components of solar systems are concerns that should be addressed but are minor when compared with the solar environmental benefits.

- solar hot-water heaters require little maintenance, have proven their worth even at subzero temperatures, and their initial investment can be recovered within a relatively short time. Energy savings and lower energy bills are an important solar advantage. See: Solar Costs and Payback.

- solar hot water systems can work in almost any climate, even in very cold ones. You just have to choose the right system for your climate: drainback, thermosyphon, etc. Low sunlight levels can reduce the efficiency of solar systems, but new solar panels largely overcome this limitation. See: Solar designs.

- Maintenance costs of solar powered systems are minimal compared to other systems, and the warranties large. A large lifespan - of over 20 years - for panels and other parts of solar systems is an important solar advantage.

- Financial incentives (in USA, Canada, European states…) can reduce the cost of the initial investment in solar technologies. The U.S. government, for instance, offers tax credits for solar systems certified by SRCC (Solar Rating and Certification Corporation), that may amount to 30% of the initial cost of the system (2009-2016 period). These incentives help the sector become commercially competitive in the long run. See: Solar incentives

Solar Disadvantages

- The initial investment in solar water heaters or in solar photovoltaic is higher than that required by conventional electric and gas heaters systems.

- The payback period is high without tax incentives and grants; only the solar hot water heating payback is short or relatively short. The competitiveness of solar electricity is only possible with state incentives. See: Solar incentives

- Solar water heating demands a back-up gas (or electric) water heater or a boiler. See: Solar Backup and Solar Upgrade

- Some solar technologies (solar space heating, solar cooling) are uncompetitive and too immature or untested (solar cooling).

- The efficiency of solar powered systems is rather dependent on sunlight resources. It's in colder climates, where heating or electricity needs are higher, that the efficiency is smaller.

- At a macro level, intermittency and reliability are huge solar disadvantages, namely in what concerns solar electricity. We can't store industrial amounts of electricity; we have to transport and use electricity as it is generated, no matter its source; it can't exist - at least for now and in the foreseen future - substantial stocks of electricity, unlike with oil, gasoline or uranium.

And that poses a major problem to solar electricity during nighttime, even in future scenarios of competitive solar electricity. In fact, in such scenarios, we may well need nuclear or fossil-fueled electricity during periods of lack of sunlight.