Microgrids May Not Promulgate Renewable Energy

on April 19, 2017 at 8:22 AM

Microgrids are one of the hottest trends in energy recently, so much so that many have been speculated as the future for the country in which microgrids are supplying everyone with clean energy.

Microgrids, however, should not necessarily be associated with clean energy. In fact, many microgrids actually rely on fossil fuels. As per usual, microgrids running on, say natural gas, are much cheaper than those which run on solar.NREL Microgrid testing

Given how young markets tend to work, we should expect the microgrid market to be largely gas-driven – not one in which renewables dominate. This research comes from a new study by researchers at the University of California at San Diego.

Localized grids, however, can prove to be more efficient than their centralized counterparts, especially when energy is being transmitted over longer distances. The microgrids do not suffer line losses, and can combine heat and power from one generator rather than sourcing them separately from the utility. This allows for operational inefficiencies. And despite the fact that is reduces system-wide greenhouse emissions, the individual microgrids on private land still generate gas.

The UCSD researchers write that while the system has the potential to radically reduce costs for customers, it would create many decentralized gas-based carbon emission sources that will be difficult to regulate for policymakers.

The researchers also ran 3 different models in order to better understand microgrids as they appear in their most common iterations: a commercial building (for example a department store), a critical asset (like a hospital), and larger campuses (say, a university). Using data from the Department of Energy, they were able to run a cost-benefit analysis of the technologies as they appear in different forms.

The models were run assuming that solar PV would supply energy during peak hours, while natural gas would supply baseload power. For the hospital and university examples, most of the gas generation would come from combined heat and power plants, meaning that the emissions would come from thermal as well as electrical needs.

This is largely in part due to the economics of Southern California, where there is ample sunlight, cheap gas, and expensive utilities. Thus, the UCSD researchers have a potent case for self-supply microgrids. The decentralized model only stops making economic sense when they tested extremely high carbon pricing and extremely high natural-gas prices.

Making a case for microgrids is intrinsically making a case for locally-fired natural gas that simultaneously generates thermal energy, according to the researchers. Despite the fact that small microgrids rely on relatively less gas, and more on renewables, gas generators are still the favorite to provide electric and thermal energy.

Policy makers who run on cutting carbon-emissions are not fans of this.

In California, there is a legally mandated goal to reduce carbon emissions by 2030. Policy makers and elected officials need to support laws that reduce carbon to 40% below 1990 levels by the 2030 deadline. In the long-term, the goal is up to 80% below 1990 levels.

The policymakers will be responsible for the roll-out of microgrid and decentralized. Now, it is up to them to figure out how to roll the technology out without jeopardizing the state carbon mandates.