Not all solar energy systems are alike. The public may read about three different sizes and shapes of systems. Here is a look in broad terms.
Utility scale solar: These are large systems. A utility owns the solar and sells the power to customers. The solar field is just another large energy generation source in this case. Improved solar economics and corporate power buyers bode well for utility-scale solar. (Source) Companies like to be able to show they are using low-to-no-carbon power.
Some utility-scale solar fields also install energy storage to capture the power and use it when needed most. (The power may not be needed as much when the sun is out than when it isn’t.) That gives the utility more flexibility.
The U.S. has more than 2,500 utility-scale solar photovoltaic electricity generating facilities. Most are small and account for under three percent of utility-scale electric generating capacity and under two percent of annual electricity generation (Nov. 2018 figure).
“The growth in small utility-scale facilities is driven by several factors, many of which are tied to state-level policies and practices. For example, North Carolina used the Public Utilities Regulatory Policies Act of 1978 to allow utilities to set long-term purchase agreements with solar facilities, enabling solar developers to secure project funding more easily and spurring growth.” At the end of 2018, North Carolina had 433 utility-scale solar facilities with capacities 5 MW or less. (Source)
Community solar: Think smaller than utility-scale in the amount of power and the territory for community solar. One label these have is solar garden, which seems right. These are systems that make electricity for a group of buildings that are relatively close to the solar field. A community can own them, a utility or a third party.
Community solar gives home and business owners the chance to tap into solar energy without installing panels on their own buildings.
The line between utility scale and community solar can blur. One story about a New York farmer shows this. Where he used to grow hay, “Today, almost 17,500 solar panels cover those same 150 acres, enough to produce 7 megawatts of electricity and power more than 1,000 homes once the array is connected to the grid. It also will generate income for the Willis family and cover the taxes for that land under a 25-year lease with the energy company AES Corp.” (Source)
Individual building systems: Many of us have seen homes with solar panels. It takes good planning to do a home system, and it is more than the installation that requires attention. Check this link to a Department of Energy website about solar. It says there are these steps:
- Investigate your home’s energy efficiency
- Assess your solar potential and any limitations
- Assess your options for going solar
- Estimate your solar electricity needs
- Obtain bids and site assessments from contractors
- Understand available financing and incentives
- Work with your installer and utility to install the system and set up agreements
The differences in these kinds of solar projects are typically scale and where the power is used. “The primary difference between utility-scale solar and other distributed solar options (such as commercial and residential installations) is that the electricity generated from a utility project is not consumed at the host site. Depending on the installation’s geographic location, the power produced at utility solar arrays is either sold to wholesale utility buyers via a power purchase agreement (PPA) or owned directly by an electrical utility. Regardless of the exact structure of an individual utility-scale solar installation, the initial customer of the generated power is an electric utility company, which will then distribute the generated electricity to residential, commercial, and industrial ratepayers connected to the grid.” (Source)