The overall objective of the VABISYS project was to develop new technologies and concepts that improve the value of bioenergy resources in an energy system dominated by variable renewable energy (VRE) such as wind and solar. When an energy system becomes dominated by VRE generation, completely new types of flexible resources are needed to maintain a stable and reliable supply of energy.

The objective of the Swedish work was to extend the flexibility of known bioenergy technologies and accelerate the deployment of flexible bioenergy technologies via market assessments and business plans. The specific objectives were:1. To assess the operational limitations of liquid biofuel-based energy production in low load and load changing conditions bio-oil boilers.2. To find the operation limits of an Organic Ranking Cycle (ORC). 3. To produce data to support energy system modelling and technology assessment of biofuel-based energy production in WP2 and WP6. 4. To create scenarios for the design of future energy markets. 5. To generate adequate production portfolios for bio-based flexible electricity production addressing future system needs and demands. 6. To estimate potential revenues for electricity production from bio-based production. 7. To analyse the replication potential for flexible bio-based electricity production in a European context and from a market design and policy perspective. 

The objectives were addressed in the following way:- Objective 1 and 2: A measurement campaign was performed to investigate the performance of the energy system at Falbygdens Energi with respect to emissions, ramp rates and flexibility limits for a bio-oil boiler (8,8 MW) and an ORC (2,4 MW electricity and 10 MW heat). The results will improve the possibilities of manufacturers to offer technologically and economically attractive bioenergy solutions to a market based on strengthening the robustness of VRE dominated energy system.- Objective 3: This was done by VTT and is not in the scope of this report, which only documents RISE work.- Objective 4: Scenarios for future electricity prices and fuel prices have been collected from (Svenska kraftnät, 2018) to serve as inputs to investment studies for the plants identified as interesting in the created portfolio (see objective 4 below).- Objective 5: A portfolio of current and future CHP plants was designed. The aim of this was to identify data sources that provide both economic and technical parameters for investments in new CHP plants.- Objective 6: An operational planning model has been developed to simulate operational planning of all units in district heating systems. It gives the optimal hourly schedules of all units for the coming week so as to maximize profits on the day-ahead electricity market and minimize fuel, start-up and shut-down costs.- Objective 6: continued: An investment model has been developed to study the profitability of investments in new plants in existing district heating systems. It uses scenarios covering the full lifetime of the new plants to be studied. It takes the results from the operational planning model to compute financial profitability indicators.- Objective 7: The developed models have been applied to case studies in Sweden. However, they are flexible enough to be used in other contexts. Moreover, the day-ahead electricity market has a common design in most European countries, which makes the model valid without any changes in countries included in the same coupling region as Sweden.

Some conclusions from the projects are:A biopower plant needs to have a stored resource that can produce electricity when it is needed and to be a flexible resource in the energy system. Bio-oils can be used for these purposes since they have high starting availability and are a fuel that can be stored for several years. The results showed that it is possible to obtain a fast start from 80 seconds to 13 minutes depending on operational mode and the emissions from the bio-oil boiler is not significantly affected during start-up or when changing load.

Flexibility and storage solutions will be important to meet the needs, and despite rapid development in terms of such solutions, in the longer term, a powerful expansion of Swedish electricity production and the electricity grid will also be needed. For smaller district heating plants, the ORC technology can be a good option. One of the most interesting features with the ORC is that it can operate at low load with maintained efficiency. The maximum decrease in electricity production for the studied ORC plant when running the wood chip boiler at constant load and when bypassing oil in the three-way valve was approximately 85 kW/min and when increasing the load in the ORC the ramp rate was approximately 172 kW/min. The emissions from the ORC-solid fuel boiler system was overall low and was not affected by changes in electricity production or load.

District heating can play key roles in meeting the challenges associated with the energy transition by coupling the electricity and the heat sector. District heating can provide local electricity production, decrease the share of electric heating and could be able to participate in ancillary services. To fulfil these roles, the profitability of investments in for example combined heat-and-power units needs to be evaluated, which the operational planning and investment models developed in this project can do. Future electricity price scenarios for Sweden show that higher electricity demand leads to both higher average electricity prices and larger variance in the electricity prices, the latter being due to the largest variation in available capacity from VRE from hour to hour. The results of the investment models on these scenarios indicate larger potential revenues from electricity markets in the future compared to today, which increases the profitability of investments in CHP units.