Author InfoLink
Updated June 17, 2021

The high costs of energy storage system (ESS) at the end user side still set back many households, despite having experienced rather marked cost reductions over recent two years. Take Germany and Australia, where residential ESS are more prevalent, for instance, energy storage systems with 10-15 kWh battery cost around USD 10,000, while price per kWh sit at above USD 700/kWh, nearly two to three times higher than costs of ESS at the generation side. However, traditional users mostly utilize such expensive infrastructure to store surplus solar energy, apply time-of-use rate (valley electricity price), or use as backup power. Such applications can reduce electricity bills, but not effectively enough, and thus not as beneficial as expected, for systems run independently without smart monitoring systems. As a result, such business model can hardly prevail, as end users weigh up their benefits.

Sonnen GmbH:the sonnenCommunitv

The emergence of diverse business models offers effective solutions that can benefit both the companies and the end users. One typical example of community energy storage is the sonnenCommunity introduced by Sonnen GmbH. Just like an aggregator in the grid, the sonnenCommunity connects homes with solar and energy storage systems and effectively distribute power through smart monitoring systems, optimizing the power efficiency of the community.

As in the graph below, energies generated in Place A, where there is abundant solar irradiance, are transmitted to homes in Place B, effectively overcoming renewable energy’s dependence on weather conditions and making the best use of solar and energy storage systems to realize prosumption. This idea is simple, and yet poses challenges to the power regulation ability, operating models, and price platform designs of companies, for amid the rapidly growing energy storage market, one who fails to catch up with market trends will be ultimately replaced.     

 the sonnenCommunitv
Source: sonnen

Customized tariff packages

The sonnenCommunity offers customized packages for homeowners to choose from. According to the Economy plan, as shown in the table below, members with at least 5 kWp solar PV systems and 8 kWh sonnenBatterie who pay USD 49 per month can receive 7,500 kWh of electricity free of charge per year, which is more than enough for most of the users. Calculating with electricity prices in Germany, the market price for 7,500 kWh of electricity is around EUR 2,500, indicating that the Economy plan can save EUR 2,000 of electricity bill per year, if it is thoroughly applied. However, expensive costs of ESS and solar PV systems may affect the willingness of users to install. Such issue is expected to be solved effectively through program optimization and infrastructure cost reductions.


Source: sonnen

Senior analyst Yuan Fang-wei of ESS InfoLink believes the complicated and everchanging decentralized behind-the-meter energy storage markets to be the most relatable sector for end users, which involve national conditions, electricity prices, policies, and anthropogenic factors. The expensive infrastructure and limited benefits resulted in difficulties in promoting energy storage in most regions. However, companies such as sonnen play significant roles in broadening residential energy storage markets by developing flexible business models, thereby maximizing end users’ benefits and tellingly reducing electricity bills. Costs of infrastructure and local electricity prices are the direct factors affecting residential ESS installations, whilst business models being a fine catalyst, effectively shortening payback periods for end users. Therefore, similar business models are bound to appear, in hope to universalize the development of behind-the-meter energy storage markets everywhere.