Combining renewable technologies such as wind or solar with biomass sources could boost renewable energies implementation in many areas.

According to IRENA (International Renewable Energy Agency), renewable energy shares should double current scenario by 2050 in order to meet policy goals for a low carbon economy.  Indeed, IRENA reported in a publication in 2016 that “Policies now in place would increase the renewable share in the global energy mix to only 21% by 2030”.

Global Radiation: Renewable Energy in Hybrid Mini-Grid and Isolated Grids. Economic Benefits and Business Cases. Source: FS-UNEP

Global Radiation: Renewable Energy in Hybrid Mini-Grid and Isolated Grids. Economic Benefits and Business Cases. Source: FS-UNEP

In 2014, EIA (International Energy Agency) argued that:

“Energy storage technologies can address this problem and ensure the supply of electricity as well as the achievement of climate change objectives. However, most of these technologies take time to develop for operational cost reductions”

However, the main barrier for renewables implementation is a dependence on climatic factors (e.g. wind, incident radiation  and rainfall) that challenge stability in supply. This is known as intermittency.

Intermittent renewables are challenging because they disrupt the conventional methods for planning the daily operation of the electric grid. Their power fluctuates over multiple time horizons, forcing the grid operator to adjust its day-ahead, hour-ahead, and real-time operating procedures.

In addition, these climatic factors are geographically variable.

Biomass – Solar hybrids: the example in Spain

At this point, biomass could play an important role helping renewable energy to a larger development. More over biomass residues are often available and abundant and dedicated plantations for biomass are realistic options with woody or herbaceous crops or plantations suitable in most areas.

Biomass power plant demands a huge amount of fuel feed which may not be available readily in all the places or all times during the year. A feed control in biomass fuel with variable solar radiation avoids the need of solar energy storage and saves the storage cost. In this work, solar parabolic collectors and biomass combustion have been arranged in parallel to produce steam for power generation. Solar energy is limited to a maximum share of 50% to avoid the operation of biomass combustion at low fuel feed rate in daytime.

The European Biomass Association (AEBIOM) considers that:

“Biomass has two principal advantages: On the one hand it is renewable and in the other hand biomass has no intermittency problems and can ensure a continuous energy supply as it can be easily stored and burnt.”

All this was deeply analyzed in Spain years ago for a first hybrid solar and thermal plant biomass in Borges, Lleida (Catalonia).

Termosolar Borges. Source: Power-Technology.

Termosolar Borges. Source: Power-Technology.

The operation of this plant is relatively simple: thermal-solar Borges facility is running 24 hours a day. During daylight hours the solar thermal works and, overnight, the biomass plant becomes  responsible for generating electricity.

By combining both technologies it is posible to generate electricity in a cleaner way with a variety of applications including water desalination or other realistic and profitable applications. Moreover, they benefit of solar and biomass environmental advantages.

Abantia and Comsa Emte, creators of the plant, estimated that:

“The thermal-solar power station in Borges generates the equivalent to the average consumption of more than 27,000 households. The production of this type of clean energy will save 24,500 tons of carbon dioxide.”

Besides Borges plant, other projects are nowadays running: in Italy Falck Group has developed a hybrid plant which combines thermal-solar and biomass and, again in Spain, CTAER (Advanced Technology Centre for Renewable Energy) is researching about this type of technology.

Hybrid power systems reduce carbon emissions, which is one of the top priorities of energy producing companies, thus driving their demand across the globe. Growth in the hybrid power systems market is also attributed to their high adoption in developing countries, where there is limited grid connectivity in remote and rural areas. This is prompting many end users to replace diesel generator sets with the efficient and cost-effective hybrid power systems. Hybrid power systems can actually serve as standalone mini-grids in remote and rural areas, thereby eliminating transmission expenditure. This is expected to create a high demand for these systems in the near future.

The challenges facing the global hybrid power systems market include long return on investment (ROI) period as opposed to conventional sources of energy and high installation cost. These two factors are deterring companies from setting up hybrid power systems. However, market players are making use of strategies such as innovation and advancements in technology to ensure the widespread adoption of these systems. Additionally, clearances by governments and other regulatory bodies and the provision for subsidies will encourage the market to grow and also attract new entrants to invest in the industry.

In conclusion, biomass energy offers good medium-term solution to renewable energy (which rely heavily on climatic factors) until new storage technologies will be developed.

Some recent publications on biomass and solar hybrid follow below:

1) Hybrid Solar – Biomass plants for power generation: technical and economic assessment  

2) The intermittency of wind, solar, and renewable electricity generators: Technical barrier or rhetorical excuse?

3) The costs and impacts of intermittency: An ongoing debate: “East is East, and West is West, and never the twain shall meet.”



About the author off this post:

Iván del Pozo Guillén is a Spanish energy and industrial engineer who collaborated with Bioenergy Crops during our summer internship porgram (Jun-Sept 2016).