Achieving a net zero: technology & innovation

When choosing which technological solutions to adopt, consideration should be given to the embedded energy (i.e. the energy required to make it in the first place), as well as any energy required for operation. While there is no such thing as a free lunch, most energy or carbon saving technologies will have a positive impact throughout their lifetime if implemented properly.

In the following sections, we explore some examples of how considering technology could help growers achieve net zero. These are not designed as an exhaustive list but more as examples of how achievements are possible and new ways of thinking.

Renewable energy generation

Renewable technologies have been around for decades, and government schemes, such as the Renewable Heat Incentive (RHI) and Feed-in Tariff (FIT), have helped many businesses to invest in low-carbon technology, often replacing, or at least offsetting, fossil fuels.

As renewable technology develops, we can expect greater efficiency at a lower cost, but also new innovations.

Example 1 – Solar

One such option could be translucent solar panels, which let light through at the wavelengths required for photosynthesis while using the rest to produce electricity. There is, of course, a trade-off between energy production and light transmission – increasing one sacrifices the other – but the solar cells could also add a layer of insulation by reflecting infrared light, thus helping to keep glasshouse temperatures lower in summer and warmer in winter.

Using computer models, researchers have estimated how much energy could be offset with figures varying depending on geographical location: for regions experiencing particularly cold winters, the data suggest over 40% of the glasshouse’s energy demand could still be met; in more temperate regions, it may be possible to satisfy total demand. [4]

Alternatively, conventional solar PV arrays remain a viable option for on-site production of renewable energy.

Example 2 – Heat Pumps 

For glasshouse growers with a high heat requirement, heat pumps may offer a viable alternative to conventional fossil fuel sources. Depending on availability and suitability, heat can be taken from the air, water or the ground to give a relatively low temperature output which is well-suited to horticultural needs. Heat pumps can also be used for cooling, potentially allowing heat to be stored (e.g. in the ground or a water source) for use later.

Whilst the RHI, which has popularised the use of heat pumps, is set to end in 2021, it has helped drive advances in the technology such that higher flow temperatures can be achieved at greater efficiencies.

Although heat pumps require an electrical input to operate, if combined with solar panels or wind power to provide the electricity, they can be a truly carbon-neutral technology. Similarly, the ‘natural’ decarbonisation of grid electricity (50% reduction in carbon intensity in the last 10 years) could help reduce carbon emissions with very little on-site impact.

Energy storage

Example 3 – Heat Storage

Anyone with a boiler will be familiar with heat storage: the use of a medium, usually water, to store surplus heat for later use. Water is often a good option, as it is readily available and can store significant amounts of heat, but storage tanks can be large. Another option is a phase-change material, which can change between liquid and solid when the heat is stored or used. The advantage of this type of system is it often occupies a much smaller volume.

How much energy needs to be stored should be carefully considered:

• Too much and you risk heating more than necessary, some of which will be ‘lost’ even in the best-insulated systems;
• Too little and the system won’t have a big enough buffer to get through periods when the boiler isn’t running.

Other types of storage, especially long-term storage of heat, can be challenging. However, there are also developments in these areas, which could provide opportunities to harvest summer heat and re-use it during winter months, especially when used in conjunction with heat pumps to make the heat truly useful.

Example 4 – Electricity Storage Options

Battery technology has developed considerably in recent years, but the cost of hardware has prevented many from investing. Those wanting to store electrical energy produced on-site through solar, for example, have found it is not really an economically viable option.

Another option could be to store the energy in a different form, such as compressed air or pumped water. In such cases, the expansion of air or release of water under gravity can be utilised to generate electricity, giving back much of what was ‘stored’ initially. These types of solutions, however, are likely only to be practical and cost-effective when carried out on a large scale where efficiency can be maximised.

Collaboration

Although many businesses may like to operate independently and be self-reliant, another option is to identify local industries with waste heat or CO₂. Often produced as an unwanted by-product of some other process and released to the atmosphere, these ‘waste’ streams can often be an untapped resource.

Power stations and data centres produce significant amounts of heat, which is often released to the atmosphere. It may be necessary to install some infrastructure to capture or divert what you need, but sites located near these industries can potentially tap into a cheap, if not free, supply. With other industries also having to transition to net zero, having an outlet for carbon emissions and waste heat could help them reach their own targets.

Opportunities may also exist where neighbouring sites, e.g. other farmers and growers, are in a similar situation to your own. Whereas it might not be economically viable to install a piece of technology or infrastructure on your own, a collaborative approach could share the cost and the risk, while allowing all parties to benefit.

This can benefit the economy, not just farming, and is likely to be necessary if the UK is to achieve its net zero targets by 2050. Early adopters of this type of approach could profit by marketing their green credentials, while also making significant financial savings through reduced fuel usage and, where emissions are concerned, reduced Climate Change Levy (CCL) payments.

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