Page 36 - North American Clean Energy September October 2015

wind power

Figure 1
Unlikely Bedfellows

Unlocking wind microgrids with fossil fuels

by Marc Hoffman

there’s good news on However, the combination of two unlikely bedfellows—wind and fossil fuels—will serve
WITH ADVANCEMENTS IN THE RENEWABLE MICROGRID PLATFORM,
the horizon: two unlikely bedfellows—wind and fossil fuels—can make beautiful music as the breakthrough platform in power generation design, and the stepping stone toward
together after all.
bridging the divide between renewables and fossil fuels.
he rampant growth of wind is transforming the electricity market. Yet wind penetration Consider an initiative by TDX Power, which operates several regulated utilities in
is only a fraction of what it could be. Why? Wind is not available all the time, nor does it Alaska. TDX operates a wind-diesel microgrid for the Aleutian Islands town of Sand Point,

blow consistently. his rapid intermittency limits the level of wind penetration to the grid. consisting of a 1 MW wind farm and four ixed-speed diesel generators. Like several power
Current technologies, including ixed speed generators, simply cannot maintain their speed operators, TDX relies on their ixed-speed generators to provide power to ill in the short-
constant to provide a stable frequency. As a result, as wind penetration reaches higher fall from wind production. However, these ixed-speed generators can’t maintain frequency
levels, electricity cannot be guaranteed. For today's grid, that's not acceptable.
when electricity production from the medium or high penetration wind power changes

Storage is getting some traction as the antidote to this problem. Although the cost rapidly due to inconsistent wind conditions.
of storage is expected to drop in the coming years, it is a Band Aid for a root cause that TDX must always be able to ramp up to meet 700-kilowatt peak demand. To ensure grid
shouldn’t exist. he best way to solve a problem is preventing it from happening.
stability, the utility has been curtailing wind production to 20% of capacity to avoid fre-
he challenge is particularly acute in microgrids. hese localized, small-scale grids op- quency instability. Because ixed-speed generators are operating below their maximum

erate autonomously and are not connected to the traditional electricity grid. his would power output, they are less fuel eicient and produce more emissions. Moreover, ixed-
appear to be a perfect application for distributed generation, as transmission and distri- speed generators cannot run consistently below 30% load without facing increased
bution requirements are minimal. Leapfrogging the need for infrastructure is just the maintenance costs.

ticket for communities and emerging economies, which often have no grid to start with. Solving these myriad challenges requires solutions such as matching power manage-
he market opportunity for renewables is enormous; Navigant Research has projected that ment and control software, and using a variable-speed generator to decouple frequency
microgrid-enabling technologies (including diesel and natural gas-ired generators) are from engine speed, eliminating the frequency challenge in one fell swoop. he system
expected to be a $26 billion market by 2023, growing from $5.5 billion annually in 2014.
operates by burning natural gas and/or diesel to generate electricity when renewable power

Yet wind power can’t hit its full potential in most microgrids today. Grid operators must is unavailable. By dispatching power to reliably meet load demand, the microgrid platform
match supply to ever-changing demand. While shifting demand is common, the implica- operates eiciently at any load. Working down to 10% of its rated capacity, it burns far less
tions of intermittancy are far more signiicant, where sudden changes in energy supply can fuel and reduces emissions by nearly 40% relative to traditional generators. For the irst
make a disproportionate impact on microgrid stability without the resiliency of a large grid.
time, fossil fuels and wind are easily working in tandem on a single scalable, eicient, and

Moreover, the overlooked hobgoblin of frequency is a major problem in microgrids. In optimized renewable microgrid.
the US, all appliances are geared to function at 60 hertz, which the grid delivers, for the According to analysis, this solution will enable TDX to use the wind capacity for both
most part reliably. (Other standards around the world vary, but the point remains—there electricity and additional uses like heating (noted as "dump power" on Figure 1), saving
are standards at which appliances and devices operate best.) In a microgrid, as more about 450,000 liters of fuel per year.

renewables come online, they drive rapid changes to the frequency, causing devices to his is just the beginning. he new breed of microgrid platforms marks a breakthrough
malfunction and fail. As a result, too much wind power or penetration makes microgrids in power generation design that fully delivers on the promise of renewables. By eliminating
go haywire. It’s not sustainable, and it has limited wind microgrid growth signiicantly, and concerns about reliability and cost that have bedeviled renewables growth in microgrids on
prevented microgrids from being built in the irst place.
up, the unlikely bedfellows of fossil fuels and wind power are poised to reshape the electric

For over a century, the solution for reliable power in microgrids has been a diesel gener- grid toward a more sustainable future.
ator; a polluting but trusted source of energy. hese generators are ixed-speed to pro-
duce the standard 60 hertz of frequency required by appliances in the United States and Marc Hofman is the founder and CEO of Innovus Power. He has led venture-backed startups and
many other locations. However, in a renewable microgrid, these ixed-speed generators business turnarounds for private equity-funded companies since 1998. Marc founded Innovus

can’t maintain speed—and, in turn, frequency— to match luctuating demand and wind Power to drive down the cost of microgrids and drive widespread renewables growth. Previously,
production. As a result, the microgrid becomes unstable and can collapse when wind power as CEO of Glacier Bay, Marc led the company to a top market position in less than 2 years while
is too large a percentage of peak loads.
earning recognition as one of INC Magazine’s Top 100 North American growth companies.
Moreover, as ixed-speed generators strive to maintain speed and frequency, they re-

quire more fuel, especially as load diminishes. It’s ineicient, drives up costs, and emits Innovus Power | www.innovus-power.com
more carbon, running counter to the goals of renewable microgrids.

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