On-Site Energy Generation for Buildings

What Is an Onsite Energy Generation System?

Onsite generation is a broad concept, which refers to all forms of electricity production that are directly connected to the owner’s building. This includes renewable generation equipment such as solar panels and wind turbines, and also diesel generators and other traditional equipment fired by fossil fuels. 

• When electricity is delivered through the power grid, the consumer not only pays for the generation cost, but also the transmission and distribution costs associated with the grid. 
• When using onsite generation, the consumer must only deal with the ownership cost of the system, and there are no grid costs.

Depending on local regulations and utility company programs, you may be able to export surplus electricity from onsite generation systems to the grid. This is especially useful for solar owners: photovoltaic generation tends to reach its peak around noon, and it may exceed the electricity consumption of your home or business. With solar buyback or net metering programs, you can still get a credit for those kilowatt-hours by selling them to your electricity provider.

Offsite generation is also an option: Using an electricity production system located away from your property. However, this means you must use the local power grid to deliver those kilowatt-hours to the point of use. Electric utility companies will normally charge a transmission and distribution fee, but this configuration makes sense when your building lacks the space for onsite generation. For example, a high-rise office building has a small roof area relative to its floor area, and this limits the use of solar panels.

Onsite generation is also known as “behind-the-meter” generation, since the electricity production equipment and the building using it are connected directly “behind” the same power meter. Offsite generation is also known as “front-of-the-meter” generation, since electricity must go through the power meter to reach your building.

Using Renewable Energy for Onsite Generation

The following are some renewable energy technologies that are often used for onsite generation:

• Solar photovoltaic panels
• Wind turbines
• Biomass cogeneration systems (power + heating)
• Small scale hydroelectricity

Solar panels offer two major advantages for homes and businesses: Their modular design is suitable for projects of any size, and they have minimal maintenance needs compared with other types of generation equipment. For example, you can use 20 solar panels for a residential installation, or 2,000 of them for a commercial PV array. One system is much larger, but both use the same basic component. As you can read in the latest annual report from the Solar Energy Industries Association (SEIA), solar power now represents over 40% of new generation capacity being installed in the US.

Wind turbines and biomass cogeneration systems are also viable for many building owners. However, their operation and maintenance needs are more complex compared with those of photovoltaic systems. Solar panels have no moving parts like wind turbines, and they are not exposed to combustion like biomass generators.

• Wind turbines are also more demanding than solar panels when it comes to site conditions; solar panels are viable in almost any property with an available area getting decent sunshine, while wind turbines depend on the average wind speed available on your property.
• Biomass cogeneration is a great option for companies with access to large amounts of organic waste as a byproduct of their operations. However, operating costs become higher when biomass must be purchased and transported from somewhere else.

To summarize, solar power is a viable option for most homes and businesses, except when space is limited or the property is constantly shaded by taller buildings or other obstacles. Wind and solar power are also viable when the required resources are available.