Glasshouse CHP

Reduced utility costs and emissions versus separate CO2, heat and electrical generation systems

Energy efficiency over 95%

High quality carbon dioxide crop fertilisation

Increased revenue opportunities through the export of electricity

Cost savings can be reinvested and deployed in renewable energy technologies

Fuel flexibility - renewable, low carbon, and hydrogen ready

Recognised technology within the net-zero pathway

Glasshouse CHP – how does it work?

High-efficient gas engines provide electrical power at the alternator and is distributed to site for use in lighting or process and any surplus is exported to the local grid system for income generation.
Heat is recovered from the exhaust gas stream, engine jacket and lube oil and transferred to a site bulk hot water storage system for distribution to the glass house facility.
Carbon dioxide is released in the exhaust gases of the gas engine as a by product of the combuston of the fuel gas. The exhaust gas is purified via special catalytic converters (SCR and oxidation catalytic converters) and is cooled down by a heat exchanger to approximately 55 degrees Celsius and supplied to the glasshouse to promote crop yeild using advanced Quadgeneration technology.

As such, the electrical energy produced from the gas engine, alongside the recovery of heat or hot water, and CO₂, all provide the right conditions to promote plant growth.

Greenhouse CHP Flow Chart

CHP offers the benefit of providing an “all in one” (electricity, heat, CO₂) solution. The choice of solution needs to be considered relative to the growing requirements and the scale of the greenhouse facility. As such, CHP should be considered as an option in facilities over 10,000 m² (1 hectare).

Plants require CO₂ to grow, prosper, and propagate

Global carbon dioxide (CO₂₎ levels are approximately 350-360 part per million (ppm) and research has shown that plant growth can improve by 40-50% with increased levels of CO₂ up to 1200 ppm. Optimal CO₂ levels will be dependent on the plant being grown.

In modern glasshouse horticulture, CO₂ supplementation is a common and highly beneficial practice as the environment can be controlled to suit the plants being grown which allows plant yields to be maximised.

There are a number of ways to introduce CO₂:

The most common way of introducing CO₂ is from compressed liquid CO₂
The second method of CO₂ supplementation is from fuel combustion
The third method of CO₂ supplementation is from Combined Heat and Power (CHP) also known as cogeneration.

Rising Power Price and Managing Costs

The reopening of industry following the lifting of COVID restrictions has created worldwide demand in gas and the ongoing conflict in Ukraine has further intensified market volatility which has resulted in unprecedented gas price increases.

The soaring price for gas has also significantly impacted electricity prices more so because gas is used to produce electricity, which accounts for roughly 50% of the UK’s energy mix. Worryingly, price volatility is likely to continue beyond 2023 and the cost of inaction will place significant cost burden onto growers without a fixed long-term contract or whose contract has expired.

Whilst both gas and electricity have increased, gas is consistently cheaper than the price of grid procured electricity. By using cheaper gas to generate power, growers can benefit from a positive spark spread. This cost advantage is underlined by the rapid return on investment of CHP systems, which often provide a payback within one or two years.

The recent UK Government Energy Bill Relief Scheme (EBRS) guidance for non-domestic customers provides support on their energy costs this winter and is expected to end 31st March 2023. We advise businesses to use this period of relief to investigate the suitability of on-site generation such as Combined Heat and Power (CHP) to secure costs are managed in the long-term and businesses remain financially sustainable.

By self-generating power on-site, growers can produce most of their electricity requirements, only drawing on grid supplies where necessary. This means that they have the flexibility to avoid purchasing network power at peak times when prices are vastly inflated.