Peter Lilienthal, Ph.D.

Microgrid Categories for Quality Standards, Training, and Capacity Building

One of the great challenges facing the growing microgrid market is the wide range of applications, climates, cultures, resources, and costs associated with a highly dispersed market. The HOMER® microgrid optimization software is a useful tool for determining which particular technology combination and configuration may be economical and effective for microgrid projects of all types and sizes. We suggest there are currently four microgrid categories into which most systems can fit and which […]

Central Solar Parks versus Microgrids: Cost Versus Security and Reliability

One of the biggest debates in today’s “energy society” relates to grid-scale renewable projects versus distributed generation, in particular the role of rooftop residential solar systems. Proponents of large centralized solar parks, such as the recently announced Xcel project in Pueblo, Colorado, point out, very correctly, that economies of scale allow those projects to produce power at about half the cost (excluding incentives) of residential rooftop projects. The typical counter argument, that distributed […]

Strawman Proposal for a Taxonomy of Renewable Penetration Levels

This strawman taxonomy provides clear distinctions between different levels of renewable penetration.  By basing the criteria on the architecture and control of the power system, it avoids the ambiguity that is inherent in a taxonomy based on the percentage of renewable penetration or contribution.  Not only is the renewable penetration or contribution subject to multiple definitions, but it can vary widely depending on the load shape, characteristics of specific components, and the resource, […]

Lifestyle Change: The 3rd Rail of Clean Energy

Nobody likes being told what to do. Clean energy was probably set back a decade when Jimmy Carter told us all to wear a sweater. Now Barack Obama is telling us we don’t have to wear a jacket. Hopefully, that is better.  Without behavior changes, the transition to clean energy requires investments in new technologies. Our mission at HOMER Energy is to help people identify and design those cost-effective solutions. But behaviors do […]

The Problem with 100% Renewable Energy

The New York Times reported recently on the work of a group of Stanford researchers, who published a piece in the journal Energy Policy claiming that the main issues with 100% renewables are neither economic nor technical but rather social and political will. Jesse Berst of Smart Grid News countered with a title that included the phrase, “Get real, Stanford.” As experts in the economics of renewable energy, HOMER Energy would like to […]

How to Classify Microgrids: Setting the Stage for a Distributed Generation Energy Future

In this post by HOMER CEO Dr. Peter Lilienthal, we consider the problem of how to classify microgrids. This is a special entry in our microgrid learning series. Although microgrids are becoming more and more prevalent in both the press and in energy world, there is no common definition of exactly what constitutes a microgrid or how to differentiate among types of microgrids. The term microgrid is not well defined or distinguished from […]

Microgrids Rank High for Top Utility Issues 2012

The Intelligent Utility newsletter lists their take on the: “Top Five Issues of 2012 (so far)”.  Of the five issues listed two of them speak directly to the core of HOMER Energy’s business. Issue # 1: Keeping the lights on while integrating renewables… Issue # 4: Dealing with intrusions into their business domain such as microgrids… We are showing how microgrids are the best way to keep the lights on when integrating high […]

Microgrid Value Propositions

Microgrids are power systems that can operate autonomously using combinations of conventional generation technologies, such as diesel gensets and combined heat and power systems, renewable resources, other new generation technologies, such as micro-turbines and fuel cells, energy storage systems, and load management systems.  There are three distinct microgrid value propositions that are useful for segmenting their market: increasing reliability, reducing fuel consumption, and reducing emissions. Microgrids for reliability Because most electric service outages […]

The Island Energy Challenge

Petroleum is the problem Islands face extreme challenges from an energy security perspective. Pipelines supplying inexpensive and plentiful natural gas are not an option for them.  Only very large islands, such as Taiwan, can use coal or nuclear. These factors have left most of them completely dependent on liquid fuels derived from petroleum, mostly diesel.  With only a few weeks of on-island storage, a supply interruption that delays the oil supply barge becomes […]

Clean micro-grid technologies are going to change the utility industry

Large electric grids like we have in North America are awe-inspiring.  They are undoubtedly the most complex machines ever built.  People don’t usually think of them as a machine, but really they are a set of components connected by wires just like any electronic machine.  Only in this case it spans millions of square miles and contains billions of other machines, namely every other machine or appliance that is plugged into the grid.  […]