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Turnkey solutions with PV and energy storage

Cities are responsible for 70 percent of the global CO2 emissions. Therefore, there is a high potential for emissions reduction in improving the energy footprint of urban built environments. Since cities are very dynamic and dense ecosystems, they offer numerous options that can be developed to reach the climate targets. One promising option is the integration of solar PV coupled with energy storage systems (ESS).

Solar PV- Einar Mattsson building


Cities stand out as responsible for a 70 percent share of global CO2 emissions. This is coupled to the fact that urban areas consume more than two-thirds of the world’s energy. For these reasons, cities are a primary field of action for reaching the Sustainable Development Goals. In Sweden, the target has been fixed to reach zero net emissions by 2045 at the latest. As of 2018, the Swedish housing and service sector stood for 39 percent of the national energy consumption and for 58 percent of the total electricity use. Moreover, about 90 percent of the consumption within the sector corresponded to houses and other buildings. Therefore, in alignment with the global outlook, there is a high potential for emissions reduction in improving the energy footprint of urban built environments. Since cities are very dynamic and dense ecosystems, they offer numerous options that can be developed to reach the climate targets. One promising option is the integration of solar PV coupled with energy storage systems (ESS). There are, however, certain challenges to the swift deployment of this solution. Solar PV installations in Sweden have been increasing in recent years. However, as of today, PV production only accounts for less than 0.5 percent of the country’s supply mix, and it is far from the target set by 2040. The unexploited potential of PV in larger residential buildings is key towards achieving such targets.


The aim on this project is to study the implementation and optimal operation of turnkey solutions involving solar PV coupled to energy storage systems (PV-ESS). For this, a two-fold approach where the impact of policy modifications is investigated by means of techno-economic scenario analyses while also demonstrating the PV-ESS system solution at KTH Live-In Lab.

  1. Enhance access in the housing sector to solar electricity by identifying sustainable PV-ESS business models.
  2. Develop and demonstrate two key PV-ESS related innovations that increase the flexibility and resiliency of solar PV systems towards an integrated operation in buildings.

Project description

Two parallel and complementary parts :

  1. Techno-economic scenario based analyses.
    • Identify business models for solar developers, prosumers, distributors and utilities that comply to grid-regulations.
    • Evaluate the distribution of solar beyond the test-bed via machine learning, taking into account the intra-day and seasonal nature of solar energy, prices and demands.
  2. A demonstration test-bed.
    • Development and verification in a relevant environment of a new optimized PV-ESS turnkey solution for applications within the C&I market segment.
    • 150kW solar PV installation, a 300kWh target battery system and an optimized management of the integrated solution.
    • First of a kind Li-ion battery installation made of prismatic-cell packaging design manufactured and assembled in Sweden with a depth of discharge of 80% and lifetime of 5,000 cycles.
    • Measurement and evaluation of the system for at least 3,600 hours distributed among the different seasons to validate the control system.
    • Specify a generic “plug-and-play” architecture of the PV-ESS solution as turnkey for future implementation sites.
    • guidelines for design, installation and operation of the technical systems will be provided in accordance to available regulations and monetization streams,


Northvolt will lead the battery-system design, manufacturing, and installation work. Electrical equipment hardware suppliers already in collaboration with Northvolt will also support the project. KTH will lead the work in relation to the control software aspects associated to optimum charge and discharge strategies as a function of forecasted solar electricity production, consumer demand, grid prices and battery state of health (combining ML and stochastic algorithms with mixed-integer linear optimization solvers).

The complete system (hardware + control software) will be installed at KTH Live-In-Lab, where KTH researchers will manage the operation and data acquisition to ultimately perform the verifications process and suggest system modifications towards potential commercialization of the turnkey solution by Northvolt. The Live-In-Lab's installation will be part of a testbed building with a total of 150kW of solar PV capacity accounting for an average generation of 230 MWh/year (Testbed EM). EM will contribute to the project by providing surplus electricity generated by the PV facility, and supervising system integration with existing installation. EM will also contribute directly to the scenario analysis activities by providing relevant information from other existing and planned multi-family buildings in the region of Stockholm with integrated solar PV systems on rooftops. Similarly, Northvolt will contribute directly with the business modeling development tasks by means of funding a new industrial PhD at KTH, specifically aimed at identifying best business models for solar plus storage turnkey solutions, as part of an initiative to include the product to be demonstrated within their portfolio of new solutions for the large-residential, commercial and industrial segments.

Project final goals

  1. The control system shall enable an increase of self-consumption of the existing PV in the testbed facility by at least 20%, based also on annual reductions of 5% and 10% in grid use during peak-hours and distribution losses, respectively.
  2. Consider all feasible monetization strategies and technology limitations to altogether increase the profitability of the installation by at least 15%.
  3. The proposed turnkey PV-ESS solution shall meet a target of 18 öre/kWh for a product with 2 hour storage capacity and a lifetime of 20 years, including replacement of ESS after each 5,000 cycles.
  4. The CO2 footprint of the industrialized PV-ESS solution shall not exceed 50 kg CO2 eq/kWh.

Project results

The results of the project will be published in three scientific journals, and in four conference proceedings. The progress of the project, preliminary results and final deliverables will also be communicated through the KTH Live-In Lab communication channels to maximize the societal impact. The KTH Live-In Lab communication channels are primarily the website and dissemination workshops, which attract several stakeholders, including building practitioners, consultants, designers, entrepreneurs, policy makers, building users, and students. Results will also be conveyed through the Viable cities community, which includes all the relevant parties in the quadruple helix (policy makers, research, industry and civil society). Regular seminars will be held also and prepared ad-hoc to interact with stakeholders identified.


Project Manager


KTH Royal Institute of Technology

Collaborating partners

KTH – Energy Technology, KTH – Live-In Lab, Northvolt, Einar Mattsson

Research / Development area

Sustainable solar PV Energy storage Systems (ESS)


Swedish Energy Agency, Einar Matsson, NorthVolt

Time estimate

4 January 2021 to 15 December 2024 (4 years)