Self-Consumption PV Systems

Regulatory changes and technical advances are beginning to push the deployment of self-consumption PV projects in the US. Will it remain a niche application or become a common system configuration nationwide? I reached out to several industry stakeholders to get their perspectives on the past, present and future of self-consumption and zero-export PV systems.

What were some of the first global markets for self-consumption PV systems?
What factors drove the initial development and deployment of these systems?

European nations, specifically Germany, drove the self-consumption market. Utility concern over dealing with high PV penetration led to a reduction of the feed-in tariff to below the customer cost for electricity, essentially ending PV overproduction’s free ride on the utility infrastructure. PV system owners faced the dilemma of selling their highest PV production during the middle of the day for a fraction of the cost of purchasing power from the utility. From a technology standpoint, the puzzle became how to maximize the use of a building’s PV production, and in countries such as Germany the best return was to shift loads to times of PV production. This involves smart meters watchdogging the connection with the grid and intelligently managing loads such as water heaters and other appliances. The next level of maximizing self-consumption includes energy storage, typically in the form of batteries. The associated metering and controls become even more intelligent, as they need to choose between load control, battery charging or exporting to the grid. Some of these systems use predictive features and weather forecasting to change the logic around how to best use the available PV generation.

Wes Kennedy, senior field application engineer, Fronius USA

The main driver is the intersection of two market events: an increase in markets with high levels of PV saturation and a decrease in solar and storage system prices. Today, locations that lead in the deployment of self-consumption systems, such as Germany and Hawaii, have high levels of PV saturation. In these markets, utilities have adjusted the rate for energy sold back to the grid. For example, in Germany the utilities decreased the feed-in tariff. In Hawaii, they lowered the net energy metering (NEM) rate paid for PV energy fed into the grid. In such markets, system owners pay a higher price for energy purchased from the grid than they receive for energy sold to the grid. This pricing gap financially motivates owners to self-consume their own energy at an effectively lower rate.

Peter Mathews, North America general manager, SolarEdge

Germany and Australia are two of the first global markets for self-consumption PV systems. The adoption of self-consumption PV in Germany escalated due to a combination of market factors: the desire of customers to gain autonomy from the utility, favorable economics for energy storage caused by a spread between the feed-in rate versus the retail rate, and the desire to have control and transparency of energy generation and consumption. The development of energy storage technology was key to controlling the generation and consumption of PV in Germany. The deregulated energy market in Germany also provided an opportunity for customers to buy and sell excess solar energy, leading to the creation of online solar energy exchange platforms such as the sonnenCommunity.

A similar scenario occurred in Australia, which has the highest penetration of residential solar combined with incredibly high utility peak pricing between 3 pm and 8 pm daily. Storage is key to enabling Australian customers to increase their consumption of solar energy and decrease the amount of energy they require from the utility grid in the waning afternoon hours, maximizing the use of solar energy and minimizing the need to use high-cost energy from the grid.

The US market is following a similar pathway to increasing distributed energy resources (both renewables and storage) and is undergoing the same uncertainty around the future of energy costs and policies. With the influx of renewables, grid operations, power markets and financial structures will need to evolve to take these new energy sources into account. Smart energy storage provides flexibility for customers and utilities to evolve in the face of changing feed-in tariffs, energy storage and renewable energy incentives, utility-rate tariffs and use cases for distributed resources.

Greg Smith, senior technical trainer, sonnen

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