I take the bus to work. On any given weekday, you can find me waiting on the side of a road while vehicles of all shapes and sizes whiz by, leaving behind a trail of noise and exhaust. It would be all well and good if this was just another weekday annoyance that could be easily shrugged off, like a fresh pile of snow blocking the sidewalk or a texter blissfully skipping the line at a busy coffee shop. But that’s not the case. Vehicle exhaust is a known pollutant that significantly affects human health and the environment. Regulators put limits on emissions – but these generally focus on new car sales, and then they can still be tampered with. So as a commuter waiting at the side of a busy road, I don’t feel too reassured. But, when I see that clean technology goals for electric vehicles are on track, hear announcements from companies like Tesla, Thor and Volvo electrifying trucking fleets, and read about commitments by governments to support these efforts, I do feel hopeful.
For more than 100 years utilities have supplied electrical power to their customers and have achieved this with good reliability. The principle is simple. Loads may do as they wish, but generation — the supply — MUST be both dispatchable and monitorable. An operator must be able to start or stop a generator or to change capacity at the touch of a button to maintain a continuous balance between supply and demand. On the other hand, the loads that use the electric power can be intermittent, unmonitored and subject to starting and stopping at what the system operator would see as near random times.
Suddenly, the world is faced with a need to reduce or even eliminate emissions.
Science has told us that we must reduce carbon emissions if climate change is to be kept below acceptable limits. The transition has led us in many new directions. Most politicians outside the US believe that our energy supply must be based entirely on renewable energy. This alone creates a large issue, in that the electric grid supplies less than 20% of total energy needs. The proposal to replace all fossil fuel with renewable capacity would require a potentially large increase in grid capacity. Ironically, many politicians typically include nuclear generation among the sources to be eliminated. The one bit of good news is that the efficiency of electrical devices is often better than fossil fuel, and the existing grid operation using a generation following load approach results in a system that can deliver more energy.
The results to date have been frustrating, both in costs and performance, and there are many serious problems that may make a complete conversion very difficult. These challenges include a lack of grid and generation capacity to handle the added electrical load, as well as the operation of the existing grid with extensive distributed devices.
Distributed energy resources (DERs) give us big opportunities to build cleaner and more reliable power grids, but to be optimally effective, those resources need to orchestrated so that they are aggregated, optimized and controlled for the grid services that are needed – precisely when and where they are needed.
The platforms for achieving this orchestration encompass both Virtual Power Plants (VPPs) and Distributed Energy Resource Management Systems (DERMS). Many who talk and write about these platforms use the terms interchangeably, as if one is a synonym for the other. For those of us at Enbala who have made harnessing the power of distributed energy our life’s work, we respectfully disagree. There are foundational differences that significantly impact what can – and what can’t – be done with the DERs being harnessed.
What’s the difference – and why should you care?
There are a lot of acronyms floating around the energy world these days. It’s a veritable alphabet soup of evolving terms that are often hard to distinguish from one another. This is especially true when it comes to distributed energy – it’s a relatively new concept in and of itself, and when the terms that define this evolving move to the grid edge aren’t inherently self-defining, the ensuing confusion complicates the equation. What’s the difference between DERs and a DERMS? And what’s the definition of a DERMS versus a VPP? Just as important what difference does it make?