It’s a marriage made in heaven: Solar PV and Geothermal Heat Pumps
Part 1 of a 6-Part Series
Solar, the Fair-Haired Boy
Solar photovoltaic (PV) is a light-based technology well known and embraced throughout the world. Its popularity is pretty obvious: install these modern marvels and generate your own electricity.
The US and New York State governments, among others, offer income tax credits to offset the installation costs and electric utilities or power authorities often provide rebates to encourage their use, provided they are tied into the electric grid. As a result, more and more people are going solar, whether via outright purchasing or through financing plans, leasing or power purchase agreements (PPA).
When PV systems are grid-tied, these on-site power systems become distributed generation (DG) sources, which reduce the strain on distribution systems and add resiliency to the grid. Electricity produced but not used is exported to the grid and used as a credit against future electric use. This ensures customers are charged only for their net energy use at the end of the monthly billing cycle. Most often net metering allows credits to be rolled over from month to month with any residual credits being settled annually. Some states’ utilities settle the credits on a retail basis, others on an avoided cost basis.
Net-metering is a great innovation, since PV systems, when in operation, often produce more than a home can use at a given time, particularly during midday hours. Without storage and net-metering, this energy would be lost. When the system is not in operation, such as nighttime, the home can draw power from the grid as needed. On average, 20-40% of a solar energy system’s output is exported (SEIA). The Solar Energy Industries Association (SEIA) points out “…net metering policies create a smoother demand curve for electricity and allow utilities to better manage their peak electricity loads.” (SEIA)
There are other, less obvious community-wide benefits. When the unused electricity is sent out over the electric grid it goes to the utility’s local power distribution system, which redirects this electricity to nearby customers’ homes. This means the entire community can gain from some members’ solar PV system’s output.
The electricity from these DG sources is stored by a variety of small, grid-connected devices called distributed energy resources (DER). A smart grid can manage and coordinate DERs within it. This is one of the reasons DERs are playing an increasingly important role for the grid, even though their capacities are tiny in comparison with centralized commercial power plants.
Having many small, modular local power stations are more flexible than conventional power plants, while long-distance transmission from them can cause about a 10% energy loss (SEIA).
Localized power generation and storage allows the collection of energy from many sources resulting in greater the security of the energy supply. This diversity may also lower the environmental impacts of our way of living.
Going solar has become more a question of when not why. There is no way our society can survive and thrive without generating electricity with renewables. It is the way of the future in powering all our appliances in home, office, factory and school.
But solar is only one half of the renewable energy equation… Solar may power our appliances, but how do we heat without fire? Can we efficiently heat indoor spaces with technologies that use electricity?
Next Blog: Prevailing Heating Technologies