The Kentucky Solar Energy Society

Does Solar Energy Work in Kentucky?


Yes, of course!


Solar energy technologies are used throughout the world to supply an increasing share of society's energy needs. Solar energy is now commonly used in a wide range of climates, including places that are much colder, cloudier, and farther north than Kentucky, such as Germany, Minnesota, New York, and Ontario. There are now thousands of homes and businesses in Kentucky using solar energy to produce electricity, heat water, provide space heating and daylighting, and meet other needs, as well. Meanwhile, electric utilities such as LG&E-KU and the Eastern Kentucky Power Cooperative have installed multi-megawatt solar farms large enough to supply thousands of homes with electricity.


Yes, solar works in Kentucky.


Solar Energy Technologies

There are numerous technologies available for harnessing the energy from the sun. In recent years, solar photovoltaics (PV) have become the most visible and popular solar energy system, due in part to the rapid decline in their cost. Solar PV panels are especially useful because they generate electricity, which can then be used for so many purposes. Other solar technologies take advantage of the sun's heat or light, which can be very useful for certain applications, but is not so widely useful as electricity.



SOLAR PHOTOVOLTAICS (PV)

Solar photovoltaics generate electricity from sunlight. At the residential and commercial scale, there are three basic types of solar PV systems:  


Grid-Tied PV Systems

Grid-tied PV Systems are interconnected with the utility grid and enable the user to consume the energy on-site as it's generated or feed it back to the utility grid when excess solar electricity is produced. The rules governing grid-tied systems vary by region and utility service area. In much of Kentucky, "net-metering" enables people with grid-tied systems to receive a credit for any power they supply back to the utility, at a one-for-one rate equal to the retail rate for electricity sold by the utility. (In 2019 the Kentucky legislature passed SB 100, a law that threatens to end net metering and create much uncertainty for prospective solar PV users and  solar PV installers. SB 100 directed the Public Service Commission to allow utilities to recover costs associated with net metering from their net metering customers, through rate cases that will be brought by utilities before the Commission. Visit our Net Metering page to learn more).


Kentucky statute requires all utilities regulated by the PSC to provide net metering to their customers, however large portions of the state are not regulated by the PSC. This includes much of south-central and western Kentucky, which are in TVA's service territory. TVA is a Federal agency and is not regulated by the Kentucky PSC. TVA has its own policies pertaining to grid-tied PV systems, which have frequently changed from year to year. There are also numerous municipal utilities in Kentucky which are exempt from PSC oversight and instead are managed by local boards or commissions. Some of these municipal utilities offer net metering (e.g. Frankfort Plant Board) while others do not.


Grid-tied PV systems do not require batteries since the grid is available whenever the solar PV system cannot provide all the electricity needed by the home or business. However, batteries can be used in these systems to provide resilience during power outages or for other purposes. 


Off-Grid, Battery-Based PV Systems

Off-grid solar PV systems operate without any back-up from the utility grid and therefore rely on batteries to back up the energy supplied by the PV system. Off-grid systems must be carefully designed to ensure they can supply the user's needs through the longest periods of cloudy weather expected for the location, which means properly sizing the battery bank is critical. 


Off-grid, Stand-Alone PV Systems Without Batteries

PV systems can provide power at remote locations for special applications which do not require batteries. Common applications include water pumping and greenhouse ventilation.


Grid-tied PV systems are by far the most widely used type of PV system today in U.S. residential and commercial markets.


To learn more about Solar PV:


Solar Photovoltaic Technology Basics from the National Renewable Energy Laboratory.  



 



SOLAR THERMAL

Solar thermal systems make use of the the sun's thermal (heat) energy for water heating, space heating, food dehydration, desalination, industrial heating applications, and in the case of concentrating solar power, electricity generation. At the residential and commercial scale, solar water heaters are an important application of solar thermal technology. Solar water heating is widely used in many countries, such as Germany, China, and Israel. In the United States, swimming pool heating is the largest market for solar water heaters, although they work very effectively for domestic water heating, as well.


In Kentucky, a residential solar water heater can reliably supply 50% - 80% of a home's hot water needs, using a conventional electric or gas water heater for back-up purposes. This can translate into $200 - $300 per year savings on a typical home's utility bills. 


To learn more about Solar Water Heating Systems:


Solar Water Heaters from the U.S. Department of Energy.





PASSIVE SOLAR DESIGN

Passive solar design is a fundamental strategy for conserving energy in buildings. Buildings using passive solar design can greatly reduce their heating and cooling loads, reducing operating costs and environmental impacts. Energy efficient design and construction practices are essential to passive solar design, along with attention to the building's relationship to the local environment (especially the sun, wind, and light). 


In recent years, the Passive House movement has developed, leading to the construction of buildings which use 80+% less energy than conventional buildings. Passive House is a design standard which evolved from the groundbreaking work on passive solar design during the 1960's and 1970's. Passive House is therefore related to passive solar design, yet different. The Passive House standard emphasizes super-energy efficiency, air-tight construction, very high performance windows, heat recovery ventilation, and minimal mechanical heating and cooling while maintaining higher indoor comfort. 


The German Passivhaus Institute developed the first Passive House standards in the late 1980's. More recently, the Passive House Institute US (PHIUS) developed performance standards suited to the varying climates of the United States.


To learn more:

Passive House US

An example of a certified-Passive House in Berea, Kentucky, built by Habitat for Humanity and designed by Ginger Watkins.

Passive Solar Design 

Examples of passive solar design can be seen in the work of Louisville architect Gary Watrous.





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