The Value of Fuel Flexibility Is Vital to the Zero Net Energy Carbon Transition

In 2021, a diverse fleet of distributed energy resources (DER) is expected to add more capacity globally than centralized generation sources (such as coal and nuclear plants), and the gap between the two continues to grow over time. Although the focus of this major shift is renewable resources, the transition is more complex and speaks to the need for new technologies to hold a more dynamic grid together. 

Enter the linear generator, the topic of a new Guidehouse Insights white paper sponsored by Mainspring Energy. A new category of clean, distributed power generation, the linear generator delivers onsite, fuel-flexible dispatchable power that offers cost and carbon savings as well as greater resiliency compared with the grid. 

Introducing the Linear Generator

What exactly is a linear generator? It is an electromechanical device that directly converts motion along a straight line into electricity using chemical or thermal energy. A linear generator achieves low capital and maintenance costs through the use of standard materials and without complex mechanical systems or expensive catalysts. Compared with traditional technologies, a linear generator has a substantially reduced number of moving parts, managed entirely by power electronics and controls software.

Within the overall DER market, the fuel-based distributed generation sector has been served for the past two decades by three primary technologies: engines, turbines, and fuel cells. These technologies provide the essential functions of baseload power, standby power, and combined heat and power applications, with the latter providing both electricity and thermal energy services. As the DER market moves toward solar PV and battery energy storage, new customer use cases are emerging that require greater flexibility and dispatchability.

With the prospects of tapping renewable biogas and green hydrogen in the future, linear generators can significantly reduce carbon and costs while serving as a transition from natural gas to a permanent source of zero net carbon and reliable electricity. It is this ability for incremental steps toward hydrogen that makes linear generators such a good fit for behind-the-meter applications including microgrids. Rather than a direct competitor to solar PV or batteries, as is the case with baseload natural gas technologies, linear generators can be the missing complementary technology that counters many assumptions about fuel-based generation resources. 

New Technology Challenges

The challenge with such new technologies is fitting into a public policy landscape that typically lags technology advances. Energy storage faced this problem initially, falling through the cracks in many market designs. Markets eventually caught up and recognized the value of such system buffers.

Here’s what has to happen for linear generators to reach their market potential of $10 billion per year in the US:

• Congress needs to ensure that tax policy, which currently incentivizes select clean and renewable energy technologies through the federal investment tax credit, keeps pace with innovation. Doing so enables new technologies, such as linear generators, to compete on a level playing field against legacy technologies that receive preferential tax treatment.
• State utility commissions and other regulatory agencies need to adjust tariff design and key regulations to enable new dispatchable resources such as linear generation to help solve the curtailment and resiliency challenges of increasing intermittent renewables on the grid.

So much of the existing policy was written before the recent arrival of clean, dispatchable DER options such as linear generators. They provide a perfect example of how to solve issues facing California and its reliance on diesel generators to ride through long-term power outages. Rather than invest in what could be stranded assets, linear generators rely on natural gas, biogas, or hydrogen instantaneously and without retrofits, helping accelerate the arrival of the zero net carbon grid of the future.