Making regional renewable energy profitable

Generating profitable and renewable energy at a regional scale. This is what Applied Plant Research and the Animal Sciences Group (ASG) of Wageningen UR wish to achieve together with Eneco at ACRRES, the Application Centre for Renewable Resources in Lelystad.

Agricultural enterprises are extremely suitable for the small-scale production of renewable energy: they have the room and the raw materials. Problem is that such production of renewable energy is not yet cost-effective without subsidy.

Valorisation of residual products

Scientists of PPO, ASG and Eneco came up with an idea. They are trying to valorise residual products. Together with a number of innovative companies they are linking various installations that use each other’s residual flows. And they try to find a market for the remaining residual product. This not only improves the cost-effectiveness of the process but makes it more sustainable as well because nothing is lost.

Various installations at the test site in Lelystad:

  • A manure fermenter. In this installation bacteria are converting organic manure, mixed with plant material, into biogas. Grass and maize straw are used in the pilot.
  • A pre-processor. This is a sort of high-pressure cooker for pretreatment of material with a poor digestibility, such as maize straw. It makes fermentation in the fermenter more efficient resulting in the formation of more biogas.
  • An installation that produces bioethanol. This experimental installation produces a fuel with 70 per cent alcohol from maize grain.

These installations are mutually beneficial. The main product of the manure fermenter is electricity. Heat is a bypoduct; this is utilised by the bioethanol installation. A digestate remains after fermentation. This can be separated into a thick and a thin fraction. The thick fraction can be returned to the land as fertiliser; the thin fraction can be utilised in the production of algae. This also applies for the CO2 formed during fermentation.

Alcohol and protein

The bioethanol installation produces alcohol and a high-protein type of cake. The researchers wish to use the high-protein cake as animal feed. But they are also investigating other possibilities. The cake, e.g., contains the zein protein which also has other uses. It is used in adhesives and packaging materials.

Apart from these installations there is the solar field  where scientists are testing different types of experimental solar panels with a higher efficiency than existing panels.