As the grid edge becomes more dynamic with on-premises generation and energy storage, we need to move towards a grid platform that delivers new capabilities and value.
Engerati has identified three key impact areas of distributed energy resources (DERs) on the grid edge – behind the meter renewables, behind the meter storage, and dynamic grid optimisation and balancing.
Behind the meter renewables in energy communities
Behind the meter renewables are growing rapidly, driven by the changing energy market and falling technology costs. More distributed solar has been deployed in the past three years than in the previous 50 years, and Navigant Research forecasts further growth globally of about 20 times in the next decade.
The challenge for grid operators is how to integrate high levels of DERs, expected to reach 50% of the generation mix in Europe and other jurisdictions such as California by 2030, with their intermittency and the volatility in power supply.
Luisa Matos, Innovation and Product Director at Virtual Power Solutions (VPS), offers one approach as “managing demand as an energy asset”.
She points to the role of ‘energy communities’, in which resources and demand can be aggregated in the form of a virtual power plant.
This community approach can be further supported by the transactive energy grid, which will enable the introduction of innovative business models and other mechanisms to engage with consumers.
“End-users will have an active role which will enable them to gain economic benefits and improve the return on their renewable investments,” says Matos.
VPS is currently running energy community demonstrations in two cities in Portugal involving both public buildings and private homes. The goals are the development of new business models and engagement tools, renewables optimisation and energy sharing.
“We know that energy communities are feasible in theory and we believe that by bringing members of a community together they can gain greater benefits from sharing energy.”
Behind the meter storage
Like behind the meter generation, behind the meter storage is also booming currently as prices drop and it moves to scale, with recent growth as much as 15 times year on year and a 40 times increase projected over the coming decade.
“Storage is a versatile technology with multiple benefits,” comments George Simons, Director of Consulting & Analysis at Itron. “The challenge is how best to use it, for example for backup power, demand reduction or price arbitrage or some combination of these.”
In the webinar, Simons reviews a recent evaluation by Itron of storage projects deployed in California in 2014-15.
Approximately 340 residential and non-residential storage systems with a combined capacity of 20MW were assessed for their performance and peak demand and CO2 impacts.
“Overall, we found that storage appears to have the capabilities to provide the needed operation and performance,” says Simons.
“But also we found that storage doesn’t always perform as expected,” he continues. “It depends on who is controlling the performance capabilities, whether the utility, storage provider, customer or some other party.”
In California, the smaller systems were observed to be sitting idle for long periods of time due to the lack of price signals. This resulted in the occurrence of parasitic losses and the need for ongoing trickle charging, which in turn is believed to have led to reduced round trip efficiencies.
These studies are continuing with storage deployed in 2016, more than doubling the number of systems under assessment.
Dynamic grid optimisation and balancing
With these solar PV and storage resources and others such as electric vehicles dispersed in the grid, operators have little visibility or control over them. Integrating distributed generation offers the opportunity to monitor, manage and balance these assets to adjust to the changing conditions of the grid.
The question is how can this be done easily and in a scaleable way without major upgrades to the grid?
“We believe optimisation and balancing of the grid are about making intelligent use of under-utilised grid capacity,” says Vince Martinelli, VP of Marketing and Product Management at Gridco Systems.
He proposes the approach of putting intelligence at the grid edge – or as Gridco Systems terms it, combining the power electronic systems in the ‘power plane’ with distributed controls in the ‘control plane’.
Martinelli says: “It’s a virtuous cycle where behind the meter electronics creates the opportunity of low component costs on the supply side while dynamic distributed systems create the demand for grid side power electronics.”
As an example, Martinelli reviews the use case of capacity management at the edge, which is currently in utility testing by Gridco Systems.
The premise is that by combining the capacity requirements at the global level with the capacity capabilities at the local level, interconnection constraints based for example on passive load studies can be reduced or eliminated.
“A low voltage layer based on secondary automation could be a vital building block in terms of developing an agile grid to integrate the most DER possible,” Martinelli concludes.
Grid edge webinar
For a deeper discussion of these three impact areas, watch Engerati’s In Focus webinar, Decentralised energy: What impact on the grid? available on demand now.