Recent research from the University of Texas at Austin suggests that the greatest environmental and economic benefits from solar power come from sending excess solar power to the utility grid instead of storing it on-site for later use.
The paper examines the costs and benefits of adding energy storage to homes with existing solar panel systems. While the number of American households with rooftop solar panel installations has rapidly reached the level of 1 million, many fewer homes have a means for storing any excess solar power that is produced. However, there is a growing interest in the on-site storage of excess solar energy, and this study sheds some light on the factors involved in this decision.
Solar Power Still Effective Without Storage
The main thrust of the paper’s findings is that there is no need to have a storage system in place to benefit from the installation of solar panels. One of the most common negative myths about solar energy is that it requires the installation of an additional storage system for when the sun is not providing adequate electricity. However, it is actually more efficient to merely switch to grid energy during times when solar is inadequate rather than storing excess solar power.
The researchers found that the storage of solar power for nighttime use will actually increase a household’s energy consumption, compared to the use of solar panels without any form of storage, due to the consumption of additional energy caused by the charging and discharging of the storage unit. While an increase in energy consumption as a result of storage is not surprising, the level, from 8% to 14% over the span of one year, was much higher than anticipated.
Storage of Solar Power Leads to Greater Environmental Impact
The study discovered that the addition of storage indirectly increased overall emissions of carbon dioxide, nitrogen dioxide and sulfur dioxide. The increased emissions are due to the increased energy consumption that is required to compensate for the inefficiency of household storage. However, since storage will affect the time of day that a household will draw electricity from the grid, it will also reduce emissions in that way.
The benefit for utility companies is more clear. The storage of solar energy reduced peak grid demand by 8% to 32%, as well as the magnitude of solar power fed into the grid by 5% to 42%, which is beneficial for the utility as it will reduce the amount of required capacity.
Overall the analysis demonstrated that the storage of solar power now offers less environmental benefits than sending it into the grid, since the energy that is lost to inefficient storage will ultimately be covered by electricity from the grid that is produced using a high proportion of fossil-fuels.
See also: Solar In, Coal Out, In Texas Electricity Grid